xnu-3248.40.184.tar.gz

[apple/xnu.git] / osfmk / kern / task_policy.c

/*
 * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */

#include <mach/mach_types.h>
#include <mach/task_server.h>

#include <kern/sched.h>
#include <kern/task.h>
#include <mach/thread_policy.h>
#include <sys/errno.h>
#include <sys/resource.h>
#include <machine/limits.h>
#include <kern/ledger.h>
#include <kern/thread_call.h>
#include <kern/sfi.h>
#include <kern/coalition.h>
#if CONFIG_TELEMETRY
#include <kern/telemetry.h>
#endif

#if IMPORTANCE_INHERITANCE
#include <ipc/ipc_importance.h>
#if IMPORTANCE_DEBUG
#include <mach/machine/sdt.h>
#endif /* IMPORTANCE_DEBUG */
#endif /* IMPORTANCE_INHERITACE */

#include <sys/kdebug.h>

/*
 *  Task Policy
 *
 *  This subsystem manages task and thread IO priority and backgrounding,
 *  as well as importance inheritance, process suppression, task QoS, and apptype.
 *  These properties have a suprising number of complex interactions, so they are
 *  centralized here in one state machine to simplify the implementation of those interactions.
 *
 *  Architecture:
 *  Threads and tasks have three policy fields: requested, effective, and pending.
 *  Requested represents the wishes of each interface that influences task policy.
 *  Effective represents the distillation of that policy into a set of behaviors.
 *  Pending represents updates that haven't been applied yet.
 *
 *  Each interface that has an input into the task policy state machine controls a field in requested.
 *  If the interface has a getter, it returns what is in the field in requested, but that is
 *  not necessarily what is actually in effect.
 *
 *  All kernel subsystems that behave differently based on task policy call into
 *  the get_effective_policy function, which returns the decision of the task policy state machine
 *  for that subsystem by querying only the 'effective' field.
 *
 *  Policy change operations:
 *  Here are the steps to change a policy on a task or thread:
 *  1) Lock task
 *  2) Change requested field for the relevant policy
 *  3) Run a task policy update, which recalculates effective based on requested,
 *     then takes a diff between the old and new versions of requested and calls the relevant
 *     other subsystems to apply these changes, and updates the pending field.
 *  4) Unlock task
 *  5) Run task policy update complete, which looks at the pending field to update
 *     subsystems which cannot be touched while holding the task lock.
 *
 *  To add a new requested policy, add the field in the requested struct, the flavor in task.h,
 *  the setter and getter in proc_(set|get)_task_policy*, and dump the state in task_requested_bitfield,
 *  then set up the effects of that behavior in task_policy_update*. If the policy manifests
 *  itself as a distinct effective policy, add it to the effective struct and add it to the
 *  proc_get_effective_policy accessor.
 *
 *  Most policies are set via proc_set_task_policy, but policies that don't fit that interface
 *  roll their own lock/set/update/unlock/complete code inside this file.
 *
 *
 *  Suppression policy
 *
 *  These are a set of behaviors that can be requested for a task.  They currently have specific
 *  implied actions when they're enabled, but they may be made customizable in the future.
 *
 *  When the affected task is boosted, we temporarily disable the suppression behaviors
 *  so that the affected process has a chance to run so it can call the API to permanently
 *  disable the suppression behaviors.
 *
 *  Locking
 *
 *  Changing task policy on a task or thread takes the task lock, and not the thread lock.
 *  TODO: Should changing policy on a thread take the thread lock instead?
 *
 *  Querying the effective policy does not take the task lock, to prevent deadlocks or slowdown in sensitive code.
 *  This means that any notification of state change needs to be externally synchronized.
 *
 */

extern const qos_policy_params_t thread_qos_policy_params;

/* for task holds without dropping the lock */
extern void task_hold_locked(task_t task);
extern void task_release_locked(task_t task);
extern void task_wait_locked(task_t task, boolean_t until_not_runnable);

extern void thread_recompute_qos(thread_t thread);

/* Task policy related helper functions */
static void proc_set_task_policy_locked(task_t task, thread_t thread, int category, int flavor, int value);
static void proc_set_task_policy2_locked(task_t task, thread_t thread, int category, int flavor, int value1, int value2);

static void task_policy_update_locked(task_t task, thread_t thread, task_pend_token_t pend_token);
static void task_policy_update_internal_locked(task_t task, thread_t thread, boolean_t in_create, task_pend_token_t pend_token);
static void task_policy_update_task_locked(task_t task, boolean_t update_throttle, boolean_t update_bg_throttle, boolean_t update_sfi);
static void task_policy_update_thread_locked(thread_t thread, int update_cpu, boolean_t update_throttle, boolean_t update_sfi, boolean_t update_qos);

#if CONFIG_SCHED_SFI
static boolean_t task_policy_update_coalition_focal_tasks(task_t task, int prev_role, int next_role);
#endif

static int proc_get_effective_policy(task_t task, thread_t thread, int policy);

static void proc_iopol_to_tier(int iopolicy, int *tier, int *passive);
static int proc_tier_to_iopol(int tier, int passive);

static uintptr_t trequested_0(task_t task, thread_t thread);
static uintptr_t trequested_1(task_t task, thread_t thread);
static uintptr_t teffective_0(task_t task, thread_t thread);
static uintptr_t teffective_1(task_t task, thread_t thread);
static uint32_t tpending(task_pend_token_t pend_token);
static uint64_t task_requested_bitfield(task_t task, thread_t thread);
static uint64_t task_effective_bitfield(task_t task, thread_t thread);

void proc_get_thread_policy(thread_t thread, thread_policy_state_t info);

/* CPU Limits related helper functions */
static int task_get_cpuusage(task_t task, uint8_t *percentagep, uint64_t *intervalp, uint64_t *deadlinep, int *scope);
int task_set_cpuusage(task_t task, uint8_t percentage, uint64_t interval, uint64_t deadline, int scope, int entitled);
static int task_clear_cpuusage_locked(task_t task, int cpumon_entitled);
int task_disable_cpumon(task_t task);
static int task_apply_resource_actions(task_t task, int type);
void task_action_cpuusage(thread_call_param_t param0, thread_call_param_t param1);
void proc_init_cpumon_params(void);

#ifdef MACH_BSD
int             proc_pid(void *proc);
extern int      proc_selfpid(void);
extern char *   proc_name_address(void *p);
extern void     rethrottle_thread(void * uthread);
extern void     proc_apply_task_networkbg(void * bsd_info, thread_t thread);
#endif /* MACH_BSD */

extern zone_t thread_qos_override_zone;
static boolean_t _proc_thread_qos_remove_override_internal(task_t task, thread_t thread, uint64_t tid, user_addr_t resource, int resource_type, boolean_t reset);


/* Importance Inheritance related helper functions */

#if IMPORTANCE_INHERITANCE

static void task_add_importance_watchport(task_t task, mach_port_t port, int *boostp);
static void task_importance_update_live_donor(task_t target_task);

#endif /* IMPORTANCE_INHERITANCE */

#if IMPORTANCE_DEBUG
#define __impdebug_only
#else
#define __impdebug_only __unused
#endif

#if IMPORTANCE_INHERITANCE
#define __imp_only
#else
#define __imp_only __unused
#endif

#define TASK_LOCKED   1
#define TASK_UNLOCKED 0

#define DO_LOWPRI_CPU   1
#define UNDO_LOWPRI_CPU 2

/* Macros for making tracing simpler */

#define tpriority(task, thread)  ((uintptr_t)(thread == THREAD_NULL ? (task->priority)  : (thread->base_pri)))
#define tisthread(thread) (thread == THREAD_NULL ? TASK_POLICY_TASK  : TASK_POLICY_THREAD)
#define targetid(task, thread)   ((uintptr_t)(thread == THREAD_NULL ? (task_pid(task)) : (thread->thread_id)))

/*
 * Default parameters for certain policies
 */

int proc_standard_daemon_tier = THROTTLE_LEVEL_TIER1;
int proc_suppressed_disk_tier = THROTTLE_LEVEL_TIER1;
int proc_tal_disk_tier        = THROTTLE_LEVEL_TIER1;

int proc_graphics_timer_qos   = (LATENCY_QOS_TIER_0 & 0xFF);

const int proc_default_bg_iotier  = THROTTLE_LEVEL_TIER2;

/* Latency/throughput QoS fields remain zeroed, i.e. TIER_UNSPECIFIED at creation */
const struct task_requested_policy default_task_requested_policy = {
        .bg_iotier = proc_default_bg_iotier
};
const struct task_effective_policy default_task_effective_policy = {};
const struct task_pended_policy default_task_pended_policy = {};

/*
 * Default parameters for CPU usage monitor.
 *
 * Default setting is 50% over 3 minutes.
 */
#define         DEFAULT_CPUMON_PERCENTAGE 50
#define         DEFAULT_CPUMON_INTERVAL   (3 * 60)

uint8_t         proc_max_cpumon_percentage;
uint64_t        proc_max_cpumon_interval;

kern_return_t
qos_latency_policy_validate(task_latency_qos_t ltier) {
        if ((ltier != LATENCY_QOS_TIER_UNSPECIFIED) &&
            ((ltier > LATENCY_QOS_TIER_5) || (ltier < LATENCY_QOS_TIER_0)))
                return KERN_INVALID_ARGUMENT;

        return KERN_SUCCESS;
}

kern_return_t
qos_throughput_policy_validate(task_throughput_qos_t ttier) {
        if ((ttier != THROUGHPUT_QOS_TIER_UNSPECIFIED) &&
            ((ttier > THROUGHPUT_QOS_TIER_5) || (ttier < THROUGHPUT_QOS_TIER_0)))
                return KERN_INVALID_ARGUMENT;

        return KERN_SUCCESS;
}

static kern_return_t
task_qos_policy_validate(task_qos_policy_t qosinfo, mach_msg_type_number_t count) {
        if (count < TASK_QOS_POLICY_COUNT)
                return KERN_INVALID_ARGUMENT;

        task_latency_qos_t ltier = qosinfo->task_latency_qos_tier;
        task_throughput_qos_t ttier = qosinfo->task_throughput_qos_tier;

        kern_return_t kr = qos_latency_policy_validate(ltier);

        if (kr != KERN_SUCCESS)
                return kr;

        kr = qos_throughput_policy_validate(ttier);

        return kr;
}

uint32_t
qos_extract(uint32_t qv) {
        return (qv & 0xFF);
}

uint32_t
qos_latency_policy_package(uint32_t qv) {
        return (qv == LATENCY_QOS_TIER_UNSPECIFIED) ? LATENCY_QOS_TIER_UNSPECIFIED : ((0xFF << 16) | qv);
}

uint32_t
qos_throughput_policy_package(uint32_t qv) {
        return (qv == THROUGHPUT_QOS_TIER_UNSPECIFIED) ? THROUGHPUT_QOS_TIER_UNSPECIFIED : ((0xFE << 16) | qv);
}

/* TEMPORARY boot-arg controlling task_policy suppression (App Nap) */
static boolean_t task_policy_suppression_disable = FALSE;

kern_return_t
task_policy_set(
        task_t                                  task,
        task_policy_flavor_t    flavor,
        task_policy_t                   policy_info,
        mach_msg_type_number_t  count)
{
        kern_return_t           result = KERN_SUCCESS;

        if (task == TASK_NULL || task == kernel_task)
                return (KERN_INVALID_ARGUMENT);

        switch (flavor) {

        case TASK_CATEGORY_POLICY: {
                task_category_policy_t info = (task_category_policy_t)policy_info;

                if (count < TASK_CATEGORY_POLICY_COUNT)
                        return (KERN_INVALID_ARGUMENT);


                switch(info->role) {
                        case TASK_FOREGROUND_APPLICATION:
                        case TASK_BACKGROUND_APPLICATION:
                        case TASK_DEFAULT_APPLICATION:
                                proc_set_task_policy(task, THREAD_NULL,
                                                     TASK_POLICY_ATTRIBUTE, TASK_POLICY_ROLE,
                                                     info->role);
                                break;

                        case TASK_CONTROL_APPLICATION:
                                if (task != current_task() || task->sec_token.val[0] != 0)
                                        result = KERN_INVALID_ARGUMENT;
                                else
                                        proc_set_task_policy(task, THREAD_NULL,
                                                             TASK_POLICY_ATTRIBUTE, TASK_POLICY_ROLE,
                                                             info->role);
                                break;

                        case TASK_GRAPHICS_SERVER:
                                /* TODO: Restrict this role to FCFS <rdar://problem/12552788> */
                                if (task != current_task() || task->sec_token.val[0] != 0)
                                        result = KERN_INVALID_ARGUMENT;
                                else
                                        proc_set_task_policy(task, THREAD_NULL,
                                                             TASK_POLICY_ATTRIBUTE, TASK_POLICY_ROLE,
                                                             info->role);
                                break;
                        default:
                                result = KERN_INVALID_ARGUMENT;
                                break;
                } /* switch (info->role) */

                break;
        }

/* Desired energy-efficiency/performance "quality-of-service" */
        case TASK_BASE_QOS_POLICY:
        case TASK_OVERRIDE_QOS_POLICY:
        {
                task_qos_policy_t qosinfo = (task_qos_policy_t)policy_info;
                kern_return_t kr = task_qos_policy_validate(qosinfo, count);

                if (kr != KERN_SUCCESS)
                        return kr;


                uint32_t lqos = qos_extract(qosinfo->task_latency_qos_tier);
                uint32_t tqos = qos_extract(qosinfo->task_throughput_qos_tier);

                proc_set_task_policy2(task, THREAD_NULL, TASK_POLICY_ATTRIBUTE,
                                                          flavor == TASK_BASE_QOS_POLICY ? TASK_POLICY_BASE_LATENCY_AND_THROUGHPUT_QOS : TASK_POLICY_OVERRIDE_LATENCY_AND_THROUGHPUT_QOS,
                                                          lqos, tqos);
        }
        break;

        case TASK_BASE_LATENCY_QOS_POLICY:
        {
                task_qos_policy_t qosinfo = (task_qos_policy_t)policy_info;
                kern_return_t kr = task_qos_policy_validate(qosinfo, count);

                if (kr != KERN_SUCCESS)
                        return kr;

                uint32_t lqos = qos_extract(qosinfo->task_latency_qos_tier);

                proc_set_task_policy(task, NULL, TASK_POLICY_ATTRIBUTE, TASK_BASE_LATENCY_QOS_POLICY, lqos);
        }
        break;

        case TASK_BASE_THROUGHPUT_QOS_POLICY:
        {
                task_qos_policy_t qosinfo = (task_qos_policy_t)policy_info;
                kern_return_t kr = task_qos_policy_validate(qosinfo, count);

                if (kr != KERN_SUCCESS)
                        return kr;

                uint32_t tqos = qos_extract(qosinfo->task_throughput_qos_tier);

                proc_set_task_policy(task, NULL, TASK_POLICY_ATTRIBUTE, TASK_BASE_THROUGHPUT_QOS_POLICY, tqos);
        }
        break;

        case TASK_SUPPRESSION_POLICY:
        {

                task_suppression_policy_t info = (task_suppression_policy_t)policy_info;

                if (count < TASK_SUPPRESSION_POLICY_COUNT)
                        return (KERN_INVALID_ARGUMENT);

                struct task_qos_policy qosinfo;

                qosinfo.task_latency_qos_tier = info->timer_throttle;
                qosinfo.task_throughput_qos_tier = info->throughput_qos;

                kern_return_t kr = task_qos_policy_validate(&qosinfo, TASK_QOS_POLICY_COUNT);

                if (kr != KERN_SUCCESS)
                        return kr;

                /* TEMPORARY disablement of task suppression */
                if (task_policy_suppression_disable && info->active)
                        return KERN_SUCCESS;

                struct task_pend_token pend_token = {};

                task_lock(task);

                KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE,
                                          (IMPORTANCE_CODE(IMP_TASK_SUPPRESSION, info->active)) | DBG_FUNC_START,
                                          proc_selfpid(), task_pid(task), trequested_0(task, THREAD_NULL),
                                          trequested_1(task, THREAD_NULL), 0);

                task->requested_policy.t_sup_active      = (info->active)         ? 1 : 0;
                task->requested_policy.t_sup_lowpri_cpu  = (info->lowpri_cpu)     ? 1 : 0;
                task->requested_policy.t_sup_timer       = qos_extract(info->timer_throttle);
                task->requested_policy.t_sup_disk        = (info->disk_throttle)  ? 1 : 0;
                task->requested_policy.t_sup_cpu_limit   = (info->cpu_limit)      ? 1 : 0;
                task->requested_policy.t_sup_suspend     = (info->suspend)        ? 1 : 0;
                task->requested_policy.t_sup_throughput  = qos_extract(info->throughput_qos);
                task->requested_policy.t_sup_cpu         = (info->suppressed_cpu) ? 1 : 0;
                task->requested_policy.t_sup_bg_sockets  = (info->background_sockets) ? 1 : 0;

                task_policy_update_locked(task, THREAD_NULL, &pend_token);

                task_unlock(task);

                task_policy_update_complete_unlocked(task, THREAD_NULL, &pend_token);

                KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE,
                                          (IMPORTANCE_CODE(IMP_TASK_SUPPRESSION, info->active)) | DBG_FUNC_END,
                                          proc_selfpid(), task_pid(task), trequested_0(task, THREAD_NULL),
                                          trequested_1(task, THREAD_NULL), 0);

                break;

        }

        default:
                result = KERN_INVALID_ARGUMENT;
                break;
        }

        return (result);
}

/* Sets BSD 'nice' value on the task */
kern_return_t
task_importance(
        task_t                          task,
        integer_t                       importance)
{
        if (task == TASK_NULL || task == kernel_task)
                return (KERN_INVALID_ARGUMENT);

        task_lock(task);

        if (!task->active) {
                task_unlock(task);

                return (KERN_TERMINATED);
        }

        if (proc_get_effective_task_policy(task, TASK_POLICY_ROLE) >= TASK_CONTROL_APPLICATION) {
                task_unlock(task);

                return (KERN_INVALID_ARGUMENT);
        }

        task->importance = importance;

        /* TODO: tracepoint? */

        /* Redrive only the task priority calculation */
        task_policy_update_task_locked(task, FALSE, FALSE, FALSE);

        task_unlock(task);

        return (KERN_SUCCESS);
}

kern_return_t
task_policy_get(
        task_t                                  task,
        task_policy_flavor_t    flavor,
        task_policy_t                   policy_info,
        mach_msg_type_number_t  *count,
        boolean_t                               *get_default)
{
        if (task == TASK_NULL || task == kernel_task)
                return (KERN_INVALID_ARGUMENT);

        switch (flavor) {

        case TASK_CATEGORY_POLICY:
        {
                task_category_policy_t          info = (task_category_policy_t)policy_info;

                if (*count < TASK_CATEGORY_POLICY_COUNT)
                        return (KERN_INVALID_ARGUMENT);

                if (*get_default)
                        info->role = TASK_UNSPECIFIED;
                else
                        info->role = proc_get_task_policy(task, THREAD_NULL, TASK_POLICY_ATTRIBUTE, TASK_POLICY_ROLE);
                break;
        }

        case TASK_BASE_QOS_POLICY: /* FALLTHRU */
        case TASK_OVERRIDE_QOS_POLICY:
        {
                task_qos_policy_t info = (task_qos_policy_t)policy_info;

                if (*count < TASK_QOS_POLICY_COUNT)
                        return (KERN_INVALID_ARGUMENT);

                if (*get_default) {
                        info->task_latency_qos_tier = LATENCY_QOS_TIER_UNSPECIFIED;
                        info->task_throughput_qos_tier = THROUGHPUT_QOS_TIER_UNSPECIFIED;
                } else if (flavor == TASK_BASE_QOS_POLICY) {
                        int value1, value2;

                        proc_get_task_policy2(task, THREAD_NULL, TASK_POLICY_ATTRIBUTE, TASK_POLICY_BASE_LATENCY_AND_THROUGHPUT_QOS, &value1, &value2);

                        info->task_latency_qos_tier = qos_latency_policy_package(value1);
                        info->task_throughput_qos_tier = qos_throughput_policy_package(value2);

                } else if (flavor == TASK_OVERRIDE_QOS_POLICY) {
                        int value1, value2;

                        proc_get_task_policy2(task, THREAD_NULL, TASK_POLICY_ATTRIBUTE, TASK_POLICY_OVERRIDE_LATENCY_AND_THROUGHPUT_QOS, &value1, &value2);

                        info->task_latency_qos_tier = qos_latency_policy_package(value1);
                        info->task_throughput_qos_tier = qos_throughput_policy_package(value2);
                }

                break;
        }

        case TASK_POLICY_STATE:
        {
                task_policy_state_t info = (task_policy_state_t)policy_info;

                if (*count < TASK_POLICY_STATE_COUNT)
                        return (KERN_INVALID_ARGUMENT);

                /* Only root can get this info */
                if (current_task()->sec_token.val[0] != 0)
                        return KERN_PROTECTION_FAILURE;

                if (*get_default) {
                        info->requested = 0;
                        info->effective = 0;
                        info->pending = 0;
                        info->imp_assertcnt = 0;
                        info->imp_externcnt = 0;
                        info->flags = 0;
                        info->imp_transitions = 0;
                } else {
                        task_lock(task);

                        info->requested = task_requested_bitfield(task, THREAD_NULL);
                        info->effective = task_effective_bitfield(task, THREAD_NULL);
                        info->pending   = 0;
                        
                        info->flags = 0;
                        if (task->task_imp_base != NULL) {
                                info->imp_assertcnt = task->task_imp_base->iit_assertcnt;
                                info->imp_externcnt = IIT_EXTERN(task->task_imp_base);
                                info->flags |= (task_is_marked_importance_receiver(task) ? TASK_IMP_RECEIVER : 0);
                                info->flags |= (task_is_marked_importance_denap_receiver(task) ? TASK_DENAP_RECEIVER : 0);
                                info->flags |= (task_is_marked_importance_donor(task) ? TASK_IMP_DONOR : 0);
                                info->flags |= (task_is_marked_live_importance_donor(task) ? TASK_IMP_LIVE_DONOR : 0);
                                info->imp_transitions = task->task_imp_base->iit_transitions;
                        } else {
                                info->imp_assertcnt = 0;
                                info->imp_externcnt = 0;
                                info->imp_transitions = 0;
                        }
                        task_unlock(task);
                }

                info->reserved[0] = 0;
                info->reserved[1] = 0;

                break;
        }

        case TASK_SUPPRESSION_POLICY:
        {
                task_suppression_policy_t info = (task_suppression_policy_t)policy_info;

                if (*count < TASK_SUPPRESSION_POLICY_COUNT)
                        return (KERN_INVALID_ARGUMENT);

                task_lock(task);

                if (*get_default) {
                        info->active            = 0;
                        info->lowpri_cpu        = 0;
                        info->timer_throttle    = LATENCY_QOS_TIER_UNSPECIFIED;
                        info->disk_throttle     = 0;
                        info->cpu_limit         = 0;
                        info->suspend           = 0;
                        info->throughput_qos    = 0;
                        info->suppressed_cpu    = 0;
                } else {
                        info->active            = task->requested_policy.t_sup_active;
                        info->lowpri_cpu        = task->requested_policy.t_sup_lowpri_cpu;
                        info->timer_throttle    = qos_latency_policy_package(task->requested_policy.t_sup_timer);
                        info->disk_throttle     = task->requested_policy.t_sup_disk;
                        info->cpu_limit         = task->requested_policy.t_sup_cpu_limit;
                        info->suspend           = task->requested_policy.t_sup_suspend;
                        info->throughput_qos    = qos_throughput_policy_package(task->requested_policy.t_sup_throughput);
                        info->suppressed_cpu    = task->requested_policy.t_sup_cpu;
                        info->background_sockets = task->requested_policy.t_sup_bg_sockets;
                }

                task_unlock(task);
                break;
        }

        default:
                return (KERN_INVALID_ARGUMENT);
        }

        return (KERN_SUCCESS);
}

/*
 * Called at task creation
 * We calculate the correct effective but don't apply it to anything yet.
 * The threads, etc will inherit from the task as they get created.
 */
void
task_policy_create(task_t task, int parent_boosted)
{
        if (task->requested_policy.t_apptype == TASK_APPTYPE_DAEMON_ADAPTIVE) {
                if (parent_boosted) {
                        task->requested_policy.t_apptype = TASK_APPTYPE_DAEMON_INTERACTIVE;
                        task_importance_mark_donor(task, TRUE);
                } else {
                        task->requested_policy.t_apptype = TASK_APPTYPE_DAEMON_BACKGROUND;
                        task_importance_mark_receiver(task, FALSE);
                }
        }

        KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE,
                                  (IMPORTANCE_CODE(IMP_UPDATE, (IMP_UPDATE_TASK_CREATE | TASK_POLICY_TASK))) | DBG_FUNC_START,
                                  task_pid(task), teffective_0(task, THREAD_NULL),
                                  teffective_1(task, THREAD_NULL), tpriority(task, THREAD_NULL), 0);

        task_policy_update_internal_locked(task, THREAD_NULL, TRUE, NULL);

        KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE,
                                  (IMPORTANCE_CODE(IMP_UPDATE, (IMP_UPDATE_TASK_CREATE | TASK_POLICY_TASK))) | DBG_FUNC_END,
                                  task_pid(task), teffective_0(task, THREAD_NULL),
                                  teffective_1(task, THREAD_NULL), tpriority(task, THREAD_NULL), 0);

        task_importance_update_live_donor(task);
        task_policy_update_task_locked(task, FALSE, FALSE, FALSE);
}

void
thread_policy_create(thread_t thread)
{
        task_t task = thread->task;

        KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE,
                                  (IMPORTANCE_CODE(IMP_UPDATE, (IMP_UPDATE_TASK_CREATE | TASK_POLICY_THREAD))) | DBG_FUNC_START,
                                  targetid(task, thread), teffective_0(task, thread),
                                  teffective_1(task, thread), tpriority(task, thread), 0);

        task_policy_update_internal_locked(task, thread, TRUE, NULL);

        KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE,
                                  (IMPORTANCE_CODE(IMP_UPDATE, (IMP_UPDATE_TASK_CREATE | TASK_POLICY_THREAD))) | DBG_FUNC_END,
                                  targetid(task, thread), teffective_0(task, thread),
                                  teffective_1(task, thread), tpriority(task, thread), 0);
}

static void
task_policy_update_locked(task_t task, thread_t thread, task_pend_token_t pend_token)
{
        KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE,
                                  (IMPORTANCE_CODE(IMP_UPDATE, tisthread(thread)) | DBG_FUNC_START),
                                  targetid(task, thread), teffective_0(task, thread),
                                  teffective_1(task, thread), tpriority(task, thread), 0);

        task_policy_update_internal_locked(task, thread, FALSE, pend_token);

        KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE,
                                  (IMPORTANCE_CODE(IMP_UPDATE, tisthread(thread))) | DBG_FUNC_END,
                                  targetid(task, thread), teffective_0(task, thread),
                                  teffective_1(task, thread), tpriority(task, thread), 0);
}

/*
 * One state update function TO RULE THEM ALL
 *
 * This function updates the task or thread effective policy fields
 * and pushes the results to the relevant subsystems.
 *
 * Must call update_complete after unlocking the task,
 * as some subsystems cannot be updated while holding the task lock.
 *
 * Called with task locked, not thread
 */

static void
task_policy_update_internal_locked(task_t task, thread_t thread, boolean_t in_create, task_pend_token_t pend_token)
{
        boolean_t on_task = (thread == THREAD_NULL) ? TRUE : FALSE;

        /*
         * Step 1:
         *  Gather requested policy
         */

        struct task_requested_policy requested =
                (on_task) ? task->requested_policy : thread->requested_policy;


        /*
         * Step 2:
         *  Calculate new effective policies from requested policy and task state
         *  Rules:
         *      If in an 'on_task' block, must only look at and set fields starting with t_
         *      If operating on a task, don't touch anything starting with th_
         *      If operating on a thread, don't touch anything starting with t_
         *      Don't change requested, it won't take effect
         */

        struct task_effective_policy next = {};
        struct task_effective_policy task_effective;

        /* Calculate QoS policies */

        if (on_task) {
                /* Update task role */
                next.t_role = requested.t_role;

                /* Set task qos clamp and ceiling */
                next.t_qos_clamp = requested.t_qos_clamp;

                if (requested.t_apptype == TASK_APPTYPE_APP_DEFAULT ||
                    requested.t_apptype == TASK_APPTYPE_APP_TAL) {

                        switch (next.t_role) {
                                case TASK_FOREGROUND_APPLICATION:
                                        /* Foreground apps get urgent scheduler priority */
                                        next.qos_ui_is_urgent = 1;
                                        next.t_qos_ceiling = THREAD_QOS_UNSPECIFIED;
                                        break;

                                case TASK_BACKGROUND_APPLICATION:
                                        /* This is really 'non-focal but on-screen' */
                                        next.t_qos_ceiling = THREAD_QOS_UNSPECIFIED;
                                        break;

                                case TASK_DEFAULT_APPLICATION:
                                        /* This is 'may render UI but we don't know if it's focal/nonfocal' */
                                        next.t_qos_ceiling = THREAD_QOS_UNSPECIFIED;
                                        break;

                                case TASK_NONUI_APPLICATION:
                                        /* i.e. 'off-screen' */
                                        next.t_qos_ceiling = THREAD_QOS_LEGACY;
                                        break;

                                case TASK_CONTROL_APPLICATION:
                                case TASK_GRAPHICS_SERVER:
                                        next.qos_ui_is_urgent = 1;
                                        next.t_qos_ceiling = THREAD_QOS_UNSPECIFIED;
                                        break;

                                case TASK_THROTTLE_APPLICATION:
                                        /* i.e. 'TAL launch' */
                                        next.t_qos_ceiling = THREAD_QOS_UTILITY;
                                        break;

                                case TASK_UNSPECIFIED:
                                default:
                                        /* Apps that don't have an application role get
                                         * USER_INTERACTIVE and USER_INITIATED squashed to LEGACY */
                                        next.t_qos_ceiling = THREAD_QOS_LEGACY;
                                        break;
                        }
                } else {
                        /* Daemons get USER_INTERACTIVE squashed to USER_INITIATED */
                        next.t_qos_ceiling = THREAD_QOS_USER_INITIATED;
                }
        } else {
                /*
                 * Set thread qos tier
                 * Note that an override only overrides the QoS field, not other policy settings.
                 * A thread must already be participating in QoS for override to take effect
                 */

                /* Snapshot the task's effective policy */
                task_effective = task->effective_policy;

                next.qos_ui_is_urgent = task_effective.qos_ui_is_urgent;

                if ((requested.thrp_qos_override != THREAD_QOS_UNSPECIFIED) && (requested.thrp_qos != THREAD_QOS_UNSPECIFIED))
                        next.thep_qos = MAX(requested.thrp_qos_override, requested.thrp_qos);
                else
                        next.thep_qos = requested.thrp_qos;

                /* A task clamp will result in an effective QoS even when requested is UNSPECIFIED */
                if (task_effective.t_qos_clamp != THREAD_QOS_UNSPECIFIED) {
                        if (next.thep_qos != THREAD_QOS_UNSPECIFIED)
                                next.thep_qos = MIN(task_effective.t_qos_clamp, next.thep_qos);
                        else
                                next.thep_qos = task_effective.t_qos_clamp;
                }

                /* The ceiling only applies to threads that are in the QoS world */
                if (task_effective.t_qos_ceiling != THREAD_QOS_UNSPECIFIED &&
                    next.thep_qos                != THREAD_QOS_UNSPECIFIED) {
                        next.thep_qos = MIN(task_effective.t_qos_ceiling, next.thep_qos);
                }

                /*
                 * The QoS relative priority is only applicable when the original programmer's
                 * intended (requested) QoS is in effect. When the QoS is clamped (e.g.
                 * USER_INITIATED-13REL clamped to UTILITY), the relative priority is not honored,
                 * since otherwise it would be lower than unclamped threads. Similarly, in the
                 * presence of boosting, the programmer doesn't know what other actors
                 * are boosting the thread.
                 */
                if ((requested.thrp_qos != THREAD_QOS_UNSPECIFIED) &&
                    (requested.thrp_qos == next.thep_qos) &&
                    (requested.thrp_qos_override == THREAD_QOS_UNSPECIFIED)) {
                        next.thep_qos_relprio = requested.thrp_qos_relprio;
                } else {
                        next.thep_qos_relprio = 0;
                }
        }

        /* Calculate DARWIN_BG */
        boolean_t wants_darwinbg        = FALSE;
        boolean_t wants_all_sockets_bg  = FALSE; /* Do I want my existing sockets to be bg */
        boolean_t wants_watchersbg      = FALSE; /* Do I want my pidbound threads to be bg */

        /*
         * If DARWIN_BG has been requested at either level, it's engaged.
         * Only true DARWIN_BG changes cause watchers to transition.
         *
         * Backgrounding due to apptype does.
         */
        if (requested.int_darwinbg || requested.ext_darwinbg)
                wants_watchersbg = wants_all_sockets_bg = wants_darwinbg = TRUE;

        if (on_task) {
                /* Background TAL apps are throttled when TAL is enabled */
                if (requested.t_apptype      == TASK_APPTYPE_APP_TAL &&
                    requested.t_role         == TASK_BACKGROUND_APPLICATION &&
                    requested.t_tal_enabled  == 1) {
                        next.t_tal_engaged = 1;
                }

                if ((requested.t_apptype     == TASK_APPTYPE_APP_DEFAULT ||
                     requested.t_apptype     == TASK_APPTYPE_APP_TAL) &&
                    requested.t_role         == TASK_THROTTLE_APPLICATION) {
                        next.t_tal_engaged = 1;
                }

                /* Adaptive daemons are DARWIN_BG unless boosted, and don't get network throttled. */
                if (requested.t_apptype == TASK_APPTYPE_DAEMON_ADAPTIVE &&
                    requested.t_boosted == 0)
                        wants_darwinbg = TRUE;

                /* Background daemons are always DARWIN_BG, no exceptions, and don't get network throttled. */
                if (requested.t_apptype == TASK_APPTYPE_DAEMON_BACKGROUND)
                        wants_darwinbg = TRUE;

                if (next.t_qos_clamp == THREAD_QOS_BACKGROUND || next.t_qos_clamp == THREAD_QOS_MAINTENANCE)
                        wants_darwinbg = TRUE;
        } else {
                if (requested.th_pidbind_bg)
                        wants_all_sockets_bg = wants_darwinbg = TRUE;

                if (requested.th_workq_bg)
                        wants_darwinbg = TRUE;

                if (next.thep_qos == THREAD_QOS_BACKGROUND || next.thep_qos == THREAD_QOS_MAINTENANCE)
                        wants_darwinbg = TRUE;
        }

        /* Calculate side effects of DARWIN_BG */

        if (wants_darwinbg) {
                next.darwinbg = 1;
                /* darwinbg threads/tasks always create bg sockets, but we don't always loop over all sockets */
                next.new_sockets_bg = 1;
                next.lowpri_cpu = 1;
        }

        if (wants_all_sockets_bg)
                next.all_sockets_bg = 1;

        if (on_task && wants_watchersbg)
                next.t_watchers_bg = 1;

        /* darwinbg on either task or thread implies background QOS (or lower) */
        if (!on_task &&
                (wants_darwinbg || task_effective.darwinbg) &&
                (next.thep_qos > THREAD_QOS_BACKGROUND || next.thep_qos == THREAD_QOS_UNSPECIFIED)){
                next.thep_qos = THREAD_QOS_BACKGROUND;
                next.thep_qos_relprio = 0;
        }

        /* Calculate low CPU priority */

        boolean_t wants_lowpri_cpu = FALSE;

        if (wants_darwinbg)
                wants_lowpri_cpu = TRUE;

        if (next.t_tal_engaged)
                wants_lowpri_cpu = TRUE;

        if (on_task && requested.t_sup_lowpri_cpu && requested.t_boosted == 0)
                wants_lowpri_cpu = TRUE;

        if (wants_lowpri_cpu)
                next.lowpri_cpu = 1;

        /* Calculate IO policy */

        /* Update BG IO policy (so we can see if it has changed) */
        next.bg_iotier = requested.bg_iotier;

        int iopol = THROTTLE_LEVEL_TIER0;

        if (wants_darwinbg)
                iopol = MAX(iopol, requested.bg_iotier);

        if (on_task) {
                if (requested.t_apptype == TASK_APPTYPE_DAEMON_STANDARD)
                        iopol = MAX(iopol, proc_standard_daemon_tier);

                if (requested.t_sup_disk && requested.t_boosted == 0)
                        iopol = MAX(iopol, proc_suppressed_disk_tier);

                if (next.t_tal_engaged)
                        iopol = MAX(iopol, proc_tal_disk_tier);

                if (next.t_qos_clamp != THREAD_QOS_UNSPECIFIED)
                        iopol = MAX(iopol, thread_qos_policy_params.qos_iotier[next.t_qos_clamp]);

        } else {
                /* Look up the associated IO tier value for the QoS class */
                iopol = MAX(iopol, thread_qos_policy_params.qos_iotier[next.thep_qos]);
        }

        iopol = MAX(iopol, requested.int_iotier);
        iopol = MAX(iopol, requested.ext_iotier);

        next.io_tier = iopol;

        /* Calculate Passive IO policy */

        if (requested.ext_iopassive || requested.int_iopassive)
                next.io_passive = 1;

        /* Calculate miscellaneous policy */

        if (on_task) {
                /* Calculate suppression-active flag */
                if (requested.t_sup_active && requested.t_boosted == 0)
                        next.t_sup_active = 1;

                /* Calculate suspend policy */
                if (requested.t_sup_suspend && requested.t_boosted == 0)
                        next.t_suspended = 1;

                /* Calculate timer QOS */
                int latency_qos = requested.t_base_latency_qos;

                if (requested.t_sup_timer && requested.t_boosted == 0)
                        latency_qos = requested.t_sup_timer;

                if (next.t_qos_clamp != THREAD_QOS_UNSPECIFIED)
                        latency_qos = MAX(latency_qos, (int)thread_qos_policy_params.qos_latency_qos[next.t_qos_clamp]);

                if (requested.t_over_latency_qos != 0)
                        latency_qos = requested.t_over_latency_qos;

                /* Treat the windowserver special */
                if (requested.t_role == TASK_GRAPHICS_SERVER)
                        latency_qos = proc_graphics_timer_qos;

                next.t_latency_qos = latency_qos;

                /* Calculate throughput QOS */
                int through_qos = requested.t_base_through_qos;

                if (requested.t_sup_throughput && requested.t_boosted == 0)
                        through_qos = requested.t_sup_throughput;

                if (next.t_qos_clamp != THREAD_QOS_UNSPECIFIED)
                        through_qos = MAX(through_qos, (int)thread_qos_policy_params.qos_through_qos[next.t_qos_clamp]);

                if (requested.t_over_through_qos != 0)
                        through_qos = requested.t_over_through_qos;

                next.t_through_qos = through_qos;

                /* Calculate suppressed CPU priority */
                if (requested.t_sup_cpu && requested.t_boosted == 0)
                        next.t_suppressed_cpu = 1;

                /*
                 * Calculate background sockets
                 * Don't take into account boosting to limit transition frequency.
                 */
                if (requested.t_sup_bg_sockets){
                        next.all_sockets_bg = 1;
                        next.new_sockets_bg = 1;
                }

                /* Apply SFI Managed class bit */
                next.t_sfi_managed = requested.t_sfi_managed;

                /* Calculate 'live donor' status for live importance */
                switch (requested.t_apptype) {
                        case TASK_APPTYPE_APP_TAL:
                        case TASK_APPTYPE_APP_DEFAULT:
                                if (requested.ext_darwinbg == 0)
                                        next.t_live_donor = 1;
                                else
                                        next.t_live_donor = 0;
                                break;

                        case TASK_APPTYPE_DAEMON_INTERACTIVE:
                        case TASK_APPTYPE_DAEMON_STANDARD:
                        case TASK_APPTYPE_DAEMON_ADAPTIVE:
                        case TASK_APPTYPE_DAEMON_BACKGROUND:
                        default:
                                next.t_live_donor = 0;
                                break;
                }
        }

        if (requested.terminated) {
                /*
                 * Shoot down the throttles that slow down exit or response to SIGTERM
                 * We don't need to shoot down:
                 * passive        (don't want to cause others to throttle)
                 * all_sockets_bg (don't need to iterate FDs on every exit)
                 * new_sockets_bg (doesn't matter for exiting process)
                 * pidsuspend     (jetsam-ed BG process shouldn't run again)
                 * watchers_bg    (watcher threads don't need to be unthrottled)
                 * t_latency_qos  (affects userspace timers only)
                 */

                next.terminated         = 1;
                next.darwinbg           = 0;
                next.lowpri_cpu         = 0;
                next.io_tier            = THROTTLE_LEVEL_TIER0;
                if (on_task) {
                        next.t_tal_engaged = 0;
                        next.t_role = TASK_UNSPECIFIED;
                        next.t_suppressed_cpu = 0;

                        /* TODO: This should only be shot down on SIGTERM, not exit */
                        next.t_suspended   = 0;
                } else {
                        next.thep_qos = THREAD_QOS_UNSPECIFIED;
                }
        }

        /*
         * Step 3:
         *  Swap out old policy for new policy
         */

        if (!on_task) {
                /* Acquire thread mutex to synchronize against
                 * thread_policy_set(). Consider reworking to separate qos
                 * fields, or locking the task in thread_policy_set.
                 * A more efficient model would be to make the thread bits
                 * authoritative.
                 */
                thread_mtx_lock(thread);
        }

        struct task_effective_policy prev =
                (on_task) ? task->effective_policy : thread->effective_policy;

        /*
         * Check for invalid transitions here for easier debugging
         * TODO: dump the structs as hex in the panic string
         */
        if (task == kernel_task && prev.all_sockets_bg != next.all_sockets_bg)
                panic("unexpected network change for kernel task");

        /* This is the point where the new values become visible to other threads */
        if (on_task)
                task->effective_policy = next;
        else {
                /* Preserve thread specific latency/throughput QoS modified via
                 * thread_policy_set(). Inelegant in the extreme, to be reworked.
                 *
                 * If thread QoS class is set, we don't need to preserve the previously set values.
                 * We should ensure to not accidentally preserve previous thread QoS values if you set a thread
                 * back to default QoS.
                 */
                uint32_t lqos = thread->effective_policy.t_latency_qos, tqos = thread->effective_policy.t_through_qos;

                if (prev.thep_qos == THREAD_QOS_UNSPECIFIED && next.thep_qos == THREAD_QOS_UNSPECIFIED) {
                        next.t_latency_qos = lqos;
                        next.t_through_qos = tqos;
                } else if (prev.thep_qos != THREAD_QOS_UNSPECIFIED && next.thep_qos == THREAD_QOS_UNSPECIFIED) {
                        next.t_latency_qos = 0;
                        next.t_through_qos = 0;
                } else {
                        next.t_latency_qos = thread_qos_policy_params.qos_latency_qos[next.thep_qos];
                        next.t_through_qos = thread_qos_policy_params.qos_through_qos[next.thep_qos];
                }

                thread_update_qos_cpu_time(thread, TRUE);
                thread->effective_policy = next;
                thread_mtx_unlock(thread);
        }

        /* Don't do anything further to a half-formed task or thread */
        if (in_create)
                return;

        /*
         * Step 4:
         *  Pend updates that can't be done while holding the task lock
         */

        if (prev.all_sockets_bg != next.all_sockets_bg)
                pend_token->tpt_update_sockets = 1;

        if (on_task) {
                /* Only re-scan the timer list if the qos level is getting less strong */
                if (prev.t_latency_qos > next.t_latency_qos)
                        pend_token->tpt_update_timers = 1;


                if (prev.t_live_donor != next.t_live_donor)
                        pend_token->tpt_update_live_donor = 1;
        }

        /*
         * Step 5:
         *  Update other subsystems as necessary if something has changed
         */

        boolean_t update_throttle = (prev.io_tier != next.io_tier) ? TRUE : FALSE;

        if (on_task) {
                if (prev.t_suspended == 0 && next.t_suspended == 1 && task->active) {
                        task_hold_locked(task);
                        task_wait_locked(task, FALSE);
                }
                if (prev.t_suspended == 1 && next.t_suspended == 0 && task->active) {
                        task_release_locked(task);
                }

                boolean_t update_threads = FALSE;
                boolean_t update_sfi = FALSE;

                if (prev.bg_iotier          != next.bg_iotier        ||
                    prev.terminated         != next.terminated       ||
                    prev.t_qos_clamp        != next.t_qos_clamp      ||
                    prev.t_qos_ceiling      != next.t_qos_ceiling    ||
                    prev.qos_ui_is_urgent   != next.qos_ui_is_urgent ||
                    prev.darwinbg           != next.darwinbg)
                        update_threads = TRUE;

                /*
                 * A bit of a layering violation. We know what task policy attributes
                 * sfi_thread_classify() consults, so if they change, trigger SFI
                 * re-evaluation.
                 */
                if ((prev.t_latency_qos != next.t_latency_qos) ||
                        (prev.t_role != next.t_role) ||
                        (prev.darwinbg != next.darwinbg) ||
                        (prev.t_sfi_managed != next.t_sfi_managed))
                        update_sfi = TRUE;

#if CONFIG_SCHED_SFI
                if (prev.t_role != next.t_role && task_policy_update_coalition_focal_tasks(task, prev.t_role, next.t_role)) {
                        update_sfi = TRUE;
                        pend_token->tpt_update_coal_sfi = 1;
                }
#endif /* !CONFIG_SCHED_SFI */

                task_policy_update_task_locked(task, update_throttle, update_threads, update_sfi);
        } else {
                int update_cpu = 0;
                boolean_t update_sfi = FALSE;
                boolean_t update_qos = FALSE;

                if (prev.lowpri_cpu != next.lowpri_cpu)
                        update_cpu = (next.lowpri_cpu ? DO_LOWPRI_CPU : UNDO_LOWPRI_CPU);

                if (prev.darwinbg != next.darwinbg ||
                    prev.thep_qos != next.thep_qos)
                        update_sfi = TRUE;

                if (prev.thep_qos           != next.thep_qos          ||
                    prev.thep_qos_relprio   != next.thep_qos_relprio  ||
                    prev.qos_ui_is_urgent   != next.qos_ui_is_urgent  ||
                    prev.terminated         != next.terminated) {
                        update_qos = TRUE;
                }

                task_policy_update_thread_locked(thread, update_cpu, update_throttle, update_sfi, update_qos);
        }
}


#if CONFIG_SCHED_SFI
/*
 * Yet another layering violation. We reach out and bang on the coalition directly.
 */
static boolean_t
task_policy_update_coalition_focal_tasks(task_t     task,
                                         int        prev_role,
                                         int        next_role)
{
        boolean_t sfi_transition = FALSE;

        /* task moving into/out-of the foreground */
        if (prev_role != TASK_FOREGROUND_APPLICATION && next_role == TASK_FOREGROUND_APPLICATION) {
                if (task_coalition_adjust_focal_count(task, 1) == 1)
                        sfi_transition = TRUE;
        } else if (prev_role == TASK_FOREGROUND_APPLICATION && next_role != TASK_FOREGROUND_APPLICATION) {
                if (task_coalition_adjust_focal_count(task, -1) == 0)
                        sfi_transition = TRUE;
        }

        /* task moving into/out-of background */
        if (prev_role != TASK_BACKGROUND_APPLICATION && next_role == TASK_BACKGROUND_APPLICATION) {
                if (task_coalition_adjust_nonfocal_count(task, 1) == 1)
                        sfi_transition = TRUE;
        } else if (prev_role == TASK_BACKGROUND_APPLICATION && next_role != TASK_BACKGROUND_APPLICATION) {
                if (task_coalition_adjust_nonfocal_count(task, -1) == 0)
                        sfi_transition = TRUE;
        }

        return sfi_transition;
}
#endif /* CONFIG_SCHED_SFI */

/* Despite the name, the thread's task is locked, the thread is not */
void
task_policy_update_thread_locked(thread_t thread,
                                 int update_cpu,
                                 boolean_t update_throttle,
                                 boolean_t update_sfi,
                                 boolean_t update_qos)
{
        thread_precedence_policy_data_t policy;

        if (update_throttle) {
                rethrottle_thread(thread->uthread);
        }

        if (update_sfi) {
                sfi_reevaluate(thread);
        }

        /*
         * TODO: pidbind needs to stuff remembered importance into saved_importance
         * properly deal with bg'ed threads being pidbound and unbging while pidbound
         *
         * TODO: A BG thread's priority is 0 on desktop and 4 on embedded.  Need to reconcile this.
         * */
        if (update_cpu == DO_LOWPRI_CPU) {
                thread->saved_importance = thread->importance;
                policy.importance = INT_MIN;
        } else if (update_cpu == UNDO_LOWPRI_CPU) {
                policy.importance = thread->saved_importance;
                thread->saved_importance = 0;
        }

        /* Takes thread lock and thread mtx lock */
        if (update_cpu)
                thread_policy_set_internal(thread, THREAD_PRECEDENCE_POLICY,
                                           (thread_policy_t)&policy,
                                           THREAD_PRECEDENCE_POLICY_COUNT);

        if (update_qos)
                thread_recompute_qos(thread);
}

/*
 * Calculate priority on a task, loop through its threads, and tell them about
 * priority changes and throttle changes.
 */
void
task_policy_update_task_locked(task_t    task,
                               boolean_t update_throttle,
                               boolean_t update_threads,
                               boolean_t update_sfi)
{
        boolean_t update_priority = FALSE;

        if (task == kernel_task)
                panic("Attempting to set task policy on kernel_task");

        int priority     = BASEPRI_DEFAULT;
        int max_priority = MAXPRI_USER;

        if (proc_get_effective_task_policy(task, TASK_POLICY_LOWPRI_CPU)) {
                priority = MAXPRI_THROTTLE;
                max_priority = MAXPRI_THROTTLE;
        } else if (proc_get_effective_task_policy(task, TASK_POLICY_SUPPRESSED_CPU)) {
                priority = MAXPRI_SUPPRESSED;
                max_priority = MAXPRI_SUPPRESSED;
        } else {
                switch (proc_get_effective_task_policy(task, TASK_POLICY_ROLE)) {
                        case TASK_CONTROL_APPLICATION:
                                priority = BASEPRI_CONTROL;
                                break;
                        case TASK_GRAPHICS_SERVER:
                                priority = BASEPRI_GRAPHICS;
                                max_priority = MAXPRI_RESERVED;
                                break;
                        default:
                                break;
                }

                /* factor in 'nice' value */
                priority += task->importance;

                if (task->effective_policy.t_qos_clamp != THREAD_QOS_UNSPECIFIED) {
                        int qos_clamp_priority = thread_qos_policy_params.qos_pri[task->effective_policy.t_qos_clamp];

                        priority        = MIN(priority, qos_clamp_priority);
                        max_priority    = MIN(max_priority, qos_clamp_priority);
                }
        }

        /* avoid extra work if priority isn't changing */
        if (task->priority != priority || task->max_priority != max_priority) {
                update_priority = TRUE;

                /* update the scheduling priority for the task */
                task->max_priority = max_priority;

                if (priority > task->max_priority)
                        priority = task->max_priority;
                else if (priority < MINPRI)
                        priority = MINPRI;

                task->priority = priority;
        }

        /* Loop over the threads in the task only once, and only if necessary */
        if (update_threads || update_throttle || update_priority || update_sfi ) {
                thread_t thread;

                queue_iterate(&task->threads, thread, thread_t, task_threads) {
                        if (update_priority) {
                                thread_mtx_lock(thread);

                                thread_task_priority(thread, priority, max_priority);

                                thread_mtx_unlock(thread);
                        }

                        if (update_throttle) {
                                rethrottle_thread(thread->uthread);
                        }

                        if (update_sfi) {
                                sfi_reevaluate(thread);
                        }

                        if (update_threads) {
                                thread->requested_policy.bg_iotier  = task->effective_policy.bg_iotier;
                                thread->requested_policy.terminated = task->effective_policy.terminated;

                                task_policy_update_internal_locked(task, thread, FALSE, NULL);
                                /*  The thread policy must not emit any completion actions due to this change. */
                        }
                }
        }
}

#if CONFIG_SCHED_SFI
/* coalition object is locked */
static void
task_sfi_reevaluate_cb(coalition_t coal, void *ctx, task_t task)
{
        thread_t thread;

        /* unused for now */
        (void)coal;

        /* skip the task we're re-evaluating on behalf of: it's already updated */
        if (task == (task_t)ctx)
                return;

        task_lock(task);

        queue_iterate(&task->threads, thread, thread_t, task_threads) {
                sfi_reevaluate(thread);
        }

        task_unlock(task);
}
#endif /* CONFIG_SCHED_SFI */

/*
 * Called with task unlocked to do things that can't be done while holding the task lock
 */
void
task_policy_update_complete_unlocked(task_t task, thread_t thread, task_pend_token_t pend_token)
{
        boolean_t on_task = (thread == THREAD_NULL) ? TRUE : FALSE;

#ifdef MACH_BSD
        if (pend_token->tpt_update_sockets)
                proc_apply_task_networkbg(task->bsd_info, thread);
#endif /* MACH_BSD */

        if (on_task) {
                /* The timer throttle has been removed or reduced, we need to look for expired timers and fire them */
                if (pend_token->tpt_update_timers)
                        ml_timer_evaluate();


                if (pend_token->tpt_update_live_donor)
                        task_importance_update_live_donor(task);

#if CONFIG_SCHED_SFI
                /* use the resource coalition for SFI re-evaluation */
                if (pend_token->tpt_update_coal_sfi)
                        coalition_for_each_task(task->coalition[COALITION_TYPE_RESOURCE],
                                                (void *)task, task_sfi_reevaluate_cb);
#endif /* CONFIG_SCHED_SFI */
        }
}

/*
 * Initiate a task policy state transition
 *
 * Everything that modifies requested except functions that need to hold the task lock
 * should use this function
 *
 * Argument validation should be performed before reaching this point.
 *
 * TODO: Do we need to check task->active or thread->active?
 */
void
proc_set_task_policy(task_t     task,
                     thread_t   thread,
                     int        category,
                     int        flavor,
                     int        value)
{
        struct task_pend_token pend_token = {};
        
        task_lock(task);

        KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE,
                                  (IMPORTANCE_CODE(flavor, (category | tisthread(thread)))) | DBG_FUNC_START,
                                  targetid(task, thread), trequested_0(task, thread), trequested_1(task, thread), value, 0);

        proc_set_task_policy_locked(task, thread, category, flavor, value);

        task_policy_update_locked(task, thread, &pend_token);

        task_unlock(task);

        KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE,
                                  (IMPORTANCE_CODE(flavor, (category | tisthread(thread)))) | DBG_FUNC_END,
                                  targetid(task, thread), trequested_0(task, thread), trequested_1(task, thread), tpending(&pend_token), 0);

        task_policy_update_complete_unlocked(task, thread, &pend_token);
}

/*
 * Initiate a task policy state transition on a thread with its TID
 * Useful if you cannot guarantee the thread won't get terminated
 */
void
proc_set_task_policy_thread(task_t     task,
                            uint64_t   tid,
                            int        category,
                            int        flavor,
                            int        value)
{
        thread_t thread;
        thread_t self = current_thread();
        struct task_pend_token pend_token = {};

        task_lock(task);

        if (tid == TID_NULL || tid == self->thread_id)
                thread = self;
        else
                thread = task_findtid(task, tid);

        if (thread == THREAD_NULL) {
                task_unlock(task);
                return;
        }

        KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE,
                                  (IMPORTANCE_CODE(flavor, (category | TASK_POLICY_THREAD))) | DBG_FUNC_START,
                                  targetid(task, thread), trequested_0(task, thread), trequested_1(task, thread), value, 0);

        proc_set_task_policy_locked(task, thread, category, flavor, value);

        task_policy_update_locked(task, thread, &pend_token);

        task_unlock(task);

        KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE,
                                  (IMPORTANCE_CODE(flavor, (category | TASK_POLICY_THREAD))) | DBG_FUNC_END,
                                  targetid(task, thread), trequested_0(task, thread), trequested_1(task, thread), tpending(&pend_token), 0);

        task_policy_update_complete_unlocked(task, thread, &pend_token);
}

/*
 * Variant of proc_set_task_policy() that sets two scalars in the requested policy structure.
 * Same locking rules apply.
 */
void
proc_set_task_policy2(task_t task, thread_t thread, int category, int flavor, int value1, int value2)
{
        struct task_pend_token pend_token = {};
        
        task_lock(task);

        KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE,
                                  (IMPORTANCE_CODE(flavor, (category | tisthread(thread)))) | DBG_FUNC_START,
                                  targetid(task, thread), trequested_0(task, thread), trequested_1(task, thread), value1, 0);

        proc_set_task_policy2_locked(task, thread, category, flavor, value1, value2);

        task_policy_update_locked(task, thread, &pend_token);

        task_unlock(task);

        KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE,
                                  (IMPORTANCE_CODE(flavor, (category | tisthread(thread)))) | DBG_FUNC_END,
                                  targetid(task, thread), trequested_0(task, thread), trequested_0(task, thread), tpending(&pend_token), 0);

        task_policy_update_complete_unlocked(task, thread, &pend_token);
}

/*
 * Set the requested state for a specific flavor to a specific value.
 *
 *  TODO:
 *  Verify that arguments to non iopol things are 1 or 0
 */
static void
proc_set_task_policy_locked(task_t      task,
                            thread_t    thread,
                            int         category,
                            int         flavor,
                            int         value)
{
        boolean_t on_task = (thread == THREAD_NULL) ? TRUE : FALSE;

        int tier, passive;

        struct task_requested_policy requested =
                (on_task) ? task->requested_policy : thread->requested_policy;

        switch (flavor) {

        /* Category: EXTERNAL and INTERNAL, thread and task */

                case TASK_POLICY_DARWIN_BG:
                        if (category == TASK_POLICY_EXTERNAL)
                                requested.ext_darwinbg = value;
                        else
                                requested.int_darwinbg = value;
                        break;

                case TASK_POLICY_IOPOL:
                        proc_iopol_to_tier(value, &tier, &passive);
                        if (category == TASK_POLICY_EXTERNAL) {
                                requested.ext_iotier  = tier;
                                requested.ext_iopassive = passive;
                        } else {
                                requested.int_iotier  = tier;
                                requested.int_iopassive = passive;
                        }
                        break;

                case TASK_POLICY_IO:
                        if (category == TASK_POLICY_EXTERNAL)
                                requested.ext_iotier = value;
                        else
                                requested.int_iotier = value;
                        break;

                case TASK_POLICY_PASSIVE_IO:
                        if (category == TASK_POLICY_EXTERNAL)
                                requested.ext_iopassive = value;
                        else
                                requested.int_iopassive = value;
                        break;

        /* Category: INTERNAL, task only */

                case TASK_POLICY_DARWIN_BG_IOPOL:
                        assert(on_task && category == TASK_POLICY_INTERNAL);
                        proc_iopol_to_tier(value, &tier, &passive);
                        requested.bg_iotier = tier;
                        break;

        /* Category: ATTRIBUTE, task only */

                case TASK_POLICY_TAL:
                        assert(on_task && category == TASK_POLICY_ATTRIBUTE);
                        requested.t_tal_enabled = value;
                        break;

                case TASK_POLICY_BOOST:
                        assert(on_task && category == TASK_POLICY_ATTRIBUTE);
                        requested.t_boosted = value;
                        break;

                case TASK_POLICY_ROLE:
                        assert(on_task && category == TASK_POLICY_ATTRIBUTE);
                        requested.t_role = value;
                        break;

                case TASK_POLICY_TERMINATED:
                        assert(on_task && category == TASK_POLICY_ATTRIBUTE);
                        requested.terminated = value;
                        break;
                case TASK_BASE_LATENCY_QOS_POLICY:
                        assert(on_task && category == TASK_POLICY_ATTRIBUTE);
                        requested.t_base_latency_qos = value;
                        break;
                case TASK_BASE_THROUGHPUT_QOS_POLICY:
                        assert(on_task && category == TASK_POLICY_ATTRIBUTE);
                        requested.t_base_through_qos = value;
                        break;
                case TASK_POLICY_SFI_MANAGED:
                        assert(on_task && category == TASK_POLICY_ATTRIBUTE);
                        requested.t_sfi_managed = value;
                        break;

        /* Category: ATTRIBUTE, thread only */

                case TASK_POLICY_PIDBIND_BG:
                        assert(!on_task && category == TASK_POLICY_ATTRIBUTE);
                        requested.th_pidbind_bg = value;
                        break;

                case TASK_POLICY_WORKQ_BG:
                        assert(!on_task && category == TASK_POLICY_ATTRIBUTE);
                        requested.th_workq_bg = value;
                        break;

                case TASK_POLICY_QOS:
                        assert(!on_task && category == TASK_POLICY_ATTRIBUTE);
                        requested.thrp_qos = value;
                        break;

                case TASK_POLICY_QOS_OVERRIDE:
                        assert(!on_task && category == TASK_POLICY_ATTRIBUTE);
                        requested.thrp_qos_override = value;
                        break;

                default:
                        panic("unknown task policy: %d %d %d", category, flavor, value);
                        break;
        }

        if (on_task)
                task->requested_policy = requested;
        else
                thread->requested_policy = requested;
}

/*
 * Variant of proc_set_task_policy_locked() that sets two scalars in the requested policy structure.
 */
static void
proc_set_task_policy2_locked(task_t      task,
                             thread_t    thread,
                             int         category,
                             int         flavor,
                             int         value1,
                             int         value2)
{
        boolean_t on_task = (thread == THREAD_NULL) ? TRUE : FALSE;

        struct task_requested_policy requested =
                (on_task) ? task->requested_policy : thread->requested_policy;

        switch (flavor) {

        /* Category: ATTRIBUTE, task only */

                case TASK_POLICY_BASE_LATENCY_AND_THROUGHPUT_QOS:
                        assert(on_task && category == TASK_POLICY_ATTRIBUTE);
                        requested.t_base_latency_qos = value1;
                        requested.t_base_through_qos = value2;
                        break;

                case TASK_POLICY_OVERRIDE_LATENCY_AND_THROUGHPUT_QOS:
                        assert(on_task && category == TASK_POLICY_ATTRIBUTE);
                        requested.t_over_latency_qos = value1;
                        requested.t_over_through_qos = value2;
                        break;

        /* Category: ATTRIBUTE, thread only */

                case TASK_POLICY_QOS_AND_RELPRIO:

                        assert(!on_task && category == TASK_POLICY_ATTRIBUTE);
                        requested.thrp_qos = value1;
                        requested.thrp_qos_relprio = value2;
                        DTRACE_BOOST3(qos_set, uint64_t, thread->thread_id, int, requested.thrp_qos, int, requested.thrp_qos_relprio);
                        break;

                default:
                        panic("unknown task policy: %d %d %d %d", category, flavor, value1, value2);
                        break;
        }

        if (on_task)
                task->requested_policy = requested;
        else
                thread->requested_policy = requested;
}


/*
 * Gets what you set. Effective values may be different.
 */
int
proc_get_task_policy(task_t     task,
                     thread_t   thread,
                     int        category,
                     int        flavor)
{
        boolean_t on_task = (thread == THREAD_NULL) ? TRUE : FALSE;

        int value = 0;

        task_lock(task);

        struct task_requested_policy requested =
                (on_task) ? task->requested_policy : thread->requested_policy;

        switch (flavor) {
                case TASK_POLICY_DARWIN_BG:
                        if (category == TASK_POLICY_EXTERNAL)
                                value = requested.ext_darwinbg;
                        else
                                value = requested.int_darwinbg;
                        break;
                case TASK_POLICY_IOPOL:
                        if (category == TASK_POLICY_EXTERNAL)
                                value = proc_tier_to_iopol(requested.ext_iotier,
                                                            requested.ext_iopassive);
                        else
                                value = proc_tier_to_iopol(requested.int_iotier,
                                                            requested.int_iopassive);
                        break;
                case TASK_POLICY_IO:
                        if (category == TASK_POLICY_EXTERNAL)
                                value = requested.ext_iotier;
                        else
                                value = requested.int_iotier;
                        break;
                case TASK_POLICY_PASSIVE_IO:
                        if (category == TASK_POLICY_EXTERNAL)
                                value = requested.ext_iopassive;
                        else
                                value = requested.int_iopassive;
                        break;
                case TASK_POLICY_DARWIN_BG_IOPOL:
                        assert(on_task && category == TASK_POLICY_ATTRIBUTE);
                        value = proc_tier_to_iopol(requested.bg_iotier, 0);
                        break;
                case TASK_POLICY_ROLE:
                        assert(on_task && category == TASK_POLICY_ATTRIBUTE);
                        value = requested.t_role;
                        break;
                case TASK_POLICY_SFI_MANAGED:
                        assert(on_task && category == TASK_POLICY_ATTRIBUTE);
                        value = requested.t_sfi_managed;
                        break;
                case TASK_POLICY_QOS:
                        assert(!on_task && category == TASK_POLICY_ATTRIBUTE);
                        value = requested.thrp_qos;
                        break;
                case TASK_POLICY_QOS_OVERRIDE:
                        assert(!on_task && category == TASK_POLICY_ATTRIBUTE);
                        value = requested.thrp_qos_override;
                        break;
                default:
                        panic("unknown policy_flavor %d", flavor);
                        break;
        }

        task_unlock(task);

        return value;
}

/*
 * Variant of proc_get_task_policy() that returns two scalar outputs.
 */
void
proc_get_task_policy2(task_t task, thread_t thread, int category __unused, int flavor, int *value1, int *value2)
{
        boolean_t on_task = (thread == THREAD_NULL) ? TRUE : FALSE;

        task_lock(task);

        struct task_requested_policy requested =
                (on_task) ? task->requested_policy : thread->requested_policy;

        switch (flavor) {
                /* TASK attributes */
                case TASK_POLICY_BASE_LATENCY_AND_THROUGHPUT_QOS:
                        assert(on_task && category == TASK_POLICY_ATTRIBUTE);
                        *value1 = requested.t_base_latency_qos;
                        *value2 = requested.t_base_through_qos;
                        break;

                case TASK_POLICY_OVERRIDE_LATENCY_AND_THROUGHPUT_QOS:
                        assert(on_task && category == TASK_POLICY_ATTRIBUTE);
                        *value1 = requested.t_over_latency_qos;
                        *value2 = requested.t_over_through_qos;
                        break;

                /* THREAD attributes */
                case TASK_POLICY_QOS_AND_RELPRIO:
                        assert(!on_task && category == TASK_POLICY_ATTRIBUTE);
                        *value1 = requested.thrp_qos;
                        *value2 = requested.thrp_qos_relprio;
                        break;

                default:
                        panic("unknown policy_flavor %d", flavor);
                        break;
        }

        task_unlock(task);
}


/*
 * Functions for querying effective state for relevant subsystems
 * ONLY the relevant subsystem should query these.
 * NEVER take a value from one of the 'effective' functions and stuff it into a setter.
 */

int
proc_get_effective_task_policy(task_t task, int flavor)
{
        return proc_get_effective_policy(task, THREAD_NULL, flavor);
}

int
proc_get_effective_thread_policy(thread_t thread, int flavor)
{
        return proc_get_effective_policy(thread->task, thread, flavor);
}

/*
 * Gets what is actually in effect, for subsystems which pull policy instead of receive updates.
 *
 * NOTE: This accessor does not take the task lock.
 * Notifications of state updates need to be externally synchronized with state queries.
 * This routine *MUST* remain interrupt safe, as it is potentially invoked
 * within the context of a timer interrupt.  It is also called in KDP context for stackshot.
 */
static int
proc_get_effective_policy(task_t   task,
                          thread_t thread,
                          int      flavor)
{
        boolean_t on_task = (thread == THREAD_NULL) ? TRUE : FALSE;
        int value = 0;

        switch (flavor) {
                case TASK_POLICY_DARWIN_BG:
                        /*
                         * This backs the KPI call proc_pidbackgrounded to find
                         * out if a pid is backgrounded,
                         * as well as proc_get_effective_thread_policy. 
                         * Its main use is within the timer layer, as well as
                         * prioritizing requests to the graphics system.
                         * Returns 1 for background mode, 0 for normal mode
                         */
                        if (on_task)
                                value = task->effective_policy.darwinbg;
                        else
                                value = (task->effective_policy.darwinbg ||
                                          thread->effective_policy.darwinbg) ? 1 : 0;
                        break;
                case TASK_POLICY_IO:
                        /*
                         * The I/O system calls here to find out what throttling tier to apply to an operation.
                         * Returns THROTTLE_LEVEL_* values. Some userspace spinlock operations can apply
                         * a temporary iotier override to make the I/O more aggressive to get the lock
                         * owner to release the spinlock.
                         */
                        if (on_task)
                                value = task->effective_policy.io_tier;
                        else {
                                value = MAX(task->effective_policy.io_tier,
                                             thread->effective_policy.io_tier);
                                if (thread->iotier_override != THROTTLE_LEVEL_NONE)
                                        value = MIN(value, thread->iotier_override);
                        }
                        break;
                case TASK_POLICY_PASSIVE_IO:
                        /*
                         * The I/O system calls here to find out whether an operation should be passive.
                         * (i.e. not cause operations with lower throttle tiers to be throttled)
                         * Returns 1 for passive mode, 0 for normal mode.
                         * If a userspace spinlock has applied an override, that I/O should always
                         * be passive to avoid self-throttling when the override is removed and lower
                         * iotier I/Os are issued.
                         */
                        if (on_task)
                                value = task->effective_policy.io_passive;
                        else {
                                int io_tier = MAX(task->effective_policy.io_tier, thread->effective_policy.io_tier);
                                boolean_t override_in_effect = (thread->iotier_override != THROTTLE_LEVEL_NONE) && (thread->iotier_override < io_tier);

                                value = (task->effective_policy.io_passive ||
                                          thread->effective_policy.io_passive || override_in_effect) ? 1 : 0;
                        }
                        break;
                case TASK_POLICY_ALL_SOCKETS_BG:
                        /*
                         * do_background_socket() calls this to determine what it should do to the proc's sockets
                         * Returns 1 for background mode, 0 for normal mode
                         *
                         * This consults both thread and task so un-DBGing a thread while the task is BG
                         * doesn't get you out of the network throttle.
                         */
                        if (on_task)
                                value = task->effective_policy.all_sockets_bg;
                        else
                                value = (task->effective_policy.all_sockets_bg ||
                                         thread->effective_policy.all_sockets_bg) ? 1 : 0;
                        break;
                case TASK_POLICY_NEW_SOCKETS_BG:
                        /*
                         * socreate() calls this to determine if it should mark a new socket as background
                         * Returns 1 for background mode, 0 for normal mode
                         */
                        if (on_task)
                                value = task->effective_policy.new_sockets_bg;
                        else
                                value = (task->effective_policy.new_sockets_bg ||
                                          thread->effective_policy.new_sockets_bg) ? 1 : 0;
                        break;
                case TASK_POLICY_LOWPRI_CPU:
                        /*
                         * Returns 1 for low priority cpu mode, 0 for normal mode
                         */
                        if (on_task)
                                value = task->effective_policy.lowpri_cpu;
                        else
                                value = (task->effective_policy.lowpri_cpu ||
                                          thread->effective_policy.lowpri_cpu) ? 1 : 0;
                        break;
                case TASK_POLICY_SUPPRESSED_CPU:
                        /*
                         * Returns 1 for suppressed cpu mode, 0 for normal mode
                         */
                        assert(on_task);
                        value = task->effective_policy.t_suppressed_cpu;
                        break;
                case TASK_POLICY_LATENCY_QOS:
                        /*
                         * timer arming calls into here to find out the timer coalescing level
                         * Returns a QoS tier (0-6)
                         */
                        if (on_task) {
                                value = task->effective_policy.t_latency_qos;
                        } else {
                                value = MAX(task->effective_policy.t_latency_qos, thread->effective_policy.t_latency_qos);
                        }
                        break;
                case TASK_POLICY_THROUGH_QOS:
                        /*
                         * Returns a QoS tier (0-6)
                         */
                        assert(on_task);
                        value = task->effective_policy.t_through_qos;
                        break;
                case TASK_POLICY_ROLE:
                        assert(on_task);
                        value = task->effective_policy.t_role;
                        break;
                case TASK_POLICY_WATCHERS_BG:
                        assert(on_task);
                        value = task->effective_policy.t_watchers_bg;
                        break;
                case TASK_POLICY_SFI_MANAGED:
                        assert(on_task);
                        value = task->effective_policy.t_sfi_managed;
                        break;
                case TASK_POLICY_QOS:
                        assert(!on_task);
                        value = thread->effective_policy.thep_qos;
                        break;
                default:
                        panic("unknown policy_flavor %d", flavor);
                        break;
        }

        return value;
}

/*
 * Convert from IOPOL_* values to throttle tiers.
 *
 * TODO: Can this be made more compact, like an array lookup
 * Note that it is possible to support e.g. IOPOL_PASSIVE_STANDARD in the future
 */

static void
proc_iopol_to_tier(int iopolicy, int *tier, int *passive)
{
        *passive = 0;
        *tier = 0;
        switch (iopolicy) {
                case IOPOL_IMPORTANT:
                        *tier = THROTTLE_LEVEL_TIER0;
                        break;
                case IOPOL_PASSIVE:
                        *tier = THROTTLE_LEVEL_TIER0;
                        *passive = 1;
                        break;
                case IOPOL_STANDARD:
                        *tier = THROTTLE_LEVEL_TIER1;
                        break;
                case IOPOL_UTILITY:
                        *tier = THROTTLE_LEVEL_TIER2;
                        break;
                case IOPOL_THROTTLE:
                        *tier = THROTTLE_LEVEL_TIER3;
                        break;
                default:
                        panic("unknown I/O policy %d", iopolicy);
                        break;
        }
}

static int
proc_tier_to_iopol(int tier, int passive)
{
        if (passive == 1) {
                switch (tier) {
                        case THROTTLE_LEVEL_TIER0:
                                return IOPOL_PASSIVE;
                                break;
                        default:
                                panic("unknown passive tier %d", tier);
                                return IOPOL_DEFAULT;
                                break;
                }
        } else {
                switch (tier) {
                        case THROTTLE_LEVEL_NONE:
                        case THROTTLE_LEVEL_TIER0:
                                return IOPOL_DEFAULT;
                                break;
                        case THROTTLE_LEVEL_TIER1:
                                return IOPOL_STANDARD;
                                break;
                        case THROTTLE_LEVEL_TIER2:
                                return IOPOL_UTILITY;
                                break;
                        case THROTTLE_LEVEL_TIER3:
                                return IOPOL_THROTTLE;
                                break;
                        default:
                                panic("unknown tier %d", tier);
                                return IOPOL_DEFAULT;
                                break;
                }
        }
}

int
proc_darwin_role_to_task_role(int darwin_role, int* task_role)
{
        integer_t role = TASK_UNSPECIFIED;

        switch (darwin_role) {
                case PRIO_DARWIN_ROLE_DEFAULT:
                        role = TASK_UNSPECIFIED;
                        break;
                case PRIO_DARWIN_ROLE_UI_FOCAL:
                        role = TASK_FOREGROUND_APPLICATION;
                        break;
                case PRIO_DARWIN_ROLE_UI:
                        role = TASK_DEFAULT_APPLICATION;
                        break;
                case PRIO_DARWIN_ROLE_NON_UI:
                        role = TASK_NONUI_APPLICATION;
                        break;
                case PRIO_DARWIN_ROLE_UI_NON_FOCAL:
                        role = TASK_BACKGROUND_APPLICATION;
                        break;
                case PRIO_DARWIN_ROLE_TAL_LAUNCH:
                        role = TASK_THROTTLE_APPLICATION;
                        break;
                default:
                        return EINVAL;
        }

        *task_role = role;

        return 0;
}

int
proc_task_role_to_darwin_role(int task_role)
{
        switch (task_role) {
                case TASK_FOREGROUND_APPLICATION:
                        return PRIO_DARWIN_ROLE_UI_FOCAL;
                case TASK_BACKGROUND_APPLICATION:
                        return PRIO_DARWIN_ROLE_UI;
                case TASK_NONUI_APPLICATION:
                        return PRIO_DARWIN_ROLE_NON_UI;
                case TASK_DEFAULT_APPLICATION:
                        return PRIO_DARWIN_ROLE_UI_NON_FOCAL;
                case TASK_THROTTLE_APPLICATION:
                        return PRIO_DARWIN_ROLE_TAL_LAUNCH;
                case TASK_UNSPECIFIED:
                default:
                        return PRIO_DARWIN_ROLE_DEFAULT;
        }
}


/* apply internal backgrounding for workqueue threads */
int
proc_apply_workq_bgthreadpolicy(thread_t thread)
{
        if (thread == THREAD_NULL)
                return ESRCH;

        proc_set_task_policy(thread->task, thread, TASK_POLICY_ATTRIBUTE,
                             TASK_POLICY_WORKQ_BG, TASK_POLICY_ENABLE);

        return(0);
}

/*
 * remove internal backgrounding for workqueue threads
 * does NOT go find sockets created while BG and unbackground them
 */
int
proc_restore_workq_bgthreadpolicy(thread_t thread)
{
        if (thread == THREAD_NULL)
                return ESRCH;

        proc_set_task_policy(thread->task, thread, TASK_POLICY_ATTRIBUTE,
                             TASK_POLICY_WORKQ_BG, TASK_POLICY_DISABLE);

        return(0);
}

/* here for temporary compatibility */
int
proc_setthread_saved_importance(__unused thread_t thread, __unused int importance)
{
        return(0);
}

/*
 * Set an override on the thread which is consulted with a
 * higher priority than the task/thread policy. This should
 * only be set for temporary grants until the thread
 * returns to the userspace boundary
 *
 * We use atomic operations to swap in the override, with
 * the assumption that the thread itself can
 * read the override and clear it on return to userspace.
 *
 * No locking is performed, since it is acceptable to see
 * a stale override for one loop through throttle_lowpri_io().
 * However a thread reference must be held on the thread.
 */

void set_thread_iotier_override(thread_t thread, int policy)
{
        int current_override;

        /* Let most aggressive I/O policy win until user boundary */
        do {
                current_override = thread->iotier_override;

                if (current_override != THROTTLE_LEVEL_NONE)
                        policy = MIN(current_override, policy);

                if (current_override == policy) {
                        /* no effective change */
                        return;
                }
        } while (!OSCompareAndSwap(current_override, policy, &thread->iotier_override));

        /*
         * Since the thread may be currently throttled,
         * re-evaluate tiers and potentially break out
         * of an msleep
         */
        rethrottle_thread(thread->uthread);
}

/*
 * Userspace synchronization routines (like pthread mutexes, pthread reader-writer locks,
 * semaphores, dispatch_sync) may result in priority inversions where a higher priority
 * (i.e. scheduler priority, I/O tier, QoS tier) is waiting on a resource owned by a lower
 * priority thread. In these cases, we attempt to propagate the priority token, as long
 * as the subsystem informs us of the relationships between the threads. The userspace
 * synchronization subsystem should maintain the information of owner->resource and
 * resource->waiters itself.
 */

/*
 * This helper canonicalizes the resource/resource_type given the current qos_override_mode
 * in effect. Note that wildcards (THREAD_QOS_OVERRIDE_RESOURCE_WILDCARD) may need
 * to be handled specially in the future, but for now it's fine to slam
 * *resource to USER_ADDR_NULL even if it was previously a wildcard.
 */
static void _canonicalize_resource_and_type(user_addr_t *resource, int *resource_type) {
        if (qos_override_mode == QOS_OVERRIDE_MODE_OVERHANG_PEAK || qos_override_mode == QOS_OVERRIDE_MODE_IGNORE_OVERRIDE) {
                /* Map all input resource/type to a single one */
                *resource = USER_ADDR_NULL;
                *resource_type = THREAD_QOS_OVERRIDE_TYPE_UNKNOWN;
        } else if (qos_override_mode == QOS_OVERRIDE_MODE_FINE_GRAINED_OVERRIDE) {
                /* no transform */
        } else if (qos_override_mode == QOS_OVERRIDE_MODE_FINE_GRAINED_OVERRIDE_BUT_IGNORE_DISPATCH) {
                /* Map all dispatch overrides to a single one, to avoid memory overhead */
                if (*resource_type == THREAD_QOS_OVERRIDE_TYPE_DISPATCH_ASYNCHRONOUS_OVERRIDE) {
                        *resource = USER_ADDR_NULL;
                }
        } else if (qos_override_mode == QOS_OVERRIDE_MODE_FINE_GRAINED_OVERRIDE_BUT_SINGLE_MUTEX_OVERRIDE) {
                /* Map all mutex overrides to a single one, to avoid memory overhead */
                if (*resource_type == THREAD_QOS_OVERRIDE_TYPE_PTHREAD_MUTEX) {
                        *resource = USER_ADDR_NULL;
                }
        }
}

/* This helper routine finds an existing override if known. Locking should be done by caller */
static struct thread_qos_override *_find_qos_override(thread_t thread, user_addr_t resource, int resource_type) {
        struct thread_qos_override *override;

        override = thread->overrides;
        while (override) {
                if (override->override_resource == resource &&
                        override->override_resource_type == resource_type) {
                        return override;
                }
                
                override = override->override_next;
        }

        return NULL;
}

static void _find_and_decrement_qos_override(thread_t thread, user_addr_t resource, int resource_type, boolean_t reset, struct thread_qos_override **free_override_list) {
        struct thread_qos_override *override, *override_prev;

        override_prev = NULL;
        override = thread->overrides;
        while (override) {
                struct thread_qos_override *override_next = override->override_next;

                if ((THREAD_QOS_OVERRIDE_RESOURCE_WILDCARD == resource || override->override_resource == resource) &&
                        override->override_resource_type == resource_type) {
                        if (reset) {
                                override->override_contended_resource_count = 0;
                        } else {
                                override->override_contended_resource_count--;
                        }

                        if (override->override_contended_resource_count == 0) {
                                if (override_prev == NULL) {
                                        thread->overrides = override_next;
                                } else {
                                        override_prev->override_next = override_next;
                                }
                                
                                /* Add to out-param for later zfree */
                                override->override_next = *free_override_list;
                                *free_override_list = override;
                        } else {
                                override_prev = override;
                        }

                        if (THREAD_QOS_OVERRIDE_RESOURCE_WILDCARD != resource) {
                                return;
                        }
                } else {
                        override_prev = override;
                }
                
                override = override_next;
        }
}

/* This helper recalculates the current requested override using the policy selected at boot */
static int _calculate_requested_qos_override(thread_t thread)
{
        if (qos_override_mode == QOS_OVERRIDE_MODE_IGNORE_OVERRIDE) {
                return THREAD_QOS_UNSPECIFIED;
        }

        /* iterate over all overrides and calculate MAX */
        struct thread_qos_override *override;
        int qos_override = THREAD_QOS_UNSPECIFIED;

        override = thread->overrides;
        while (override) {
                if (qos_override_mode != QOS_OVERRIDE_MODE_FINE_GRAINED_OVERRIDE_BUT_IGNORE_DISPATCH ||
                        override->override_resource_type != THREAD_QOS_OVERRIDE_TYPE_DISPATCH_ASYNCHRONOUS_OVERRIDE) {
                        qos_override = MAX(qos_override, override->override_qos);
                }
                
                override = override->override_next;
        }

        return qos_override;
}

boolean_t proc_thread_qos_add_override(task_t task, thread_t thread, uint64_t tid, int override_qos, boolean_t first_override_for_resource, user_addr_t resource, int resource_type)
{
        thread_t        self = current_thread();
        struct task_pend_token pend_token = {};

        /* XXX move to thread mutex when thread policy does */
        task_lock(task);

        /*
         * If thread is passed, it is assumed to be most accurate, since the caller must have an explicit (or implicit) reference
         * to the thread
         */
        
        if (thread != THREAD_NULL) {
                assert(task == thread->task);
        } else {
                if (tid == self->thread_id) {
                        thread = self;
                } else {
                        thread = task_findtid(task, tid);

                        if (thread == THREAD_NULL) {
                                KERNEL_DEBUG_CONSTANT((IMPORTANCE_CODE(IMP_USYNCH_QOS_OVERRIDE, IMP_USYNCH_ADD_OVERRIDE)) | DBG_FUNC_NONE,
                                                                          tid, 0, 0xdead, 0, 0);
                                task_unlock(task);
                                return FALSE;
                        }
                }
        }

        KERNEL_DEBUG_CONSTANT((IMPORTANCE_CODE(IMP_USYNCH_QOS_OVERRIDE, IMP_USYNCH_ADD_OVERRIDE)) | DBG_FUNC_START,
                                                  thread_tid(thread), override_qos, first_override_for_resource ? 1 : 0, 0, 0);

        DTRACE_BOOST5(qos_add_override_pre, uint64_t, tid, uint64_t, thread->requested_policy.thrp_qos,
                uint64_t, thread->effective_policy.thep_qos, int, override_qos, boolean_t, first_override_for_resource);

        struct task_requested_policy requested = thread->requested_policy;
        struct thread_qos_override *override;
        struct thread_qos_override *deferred_free_override = NULL;
        int new_qos_override, prev_qos_override;
        int new_effective_qos;
        boolean_t has_thread_reference = FALSE;

        _canonicalize_resource_and_type(&resource, &resource_type);

        if (first_override_for_resource) {
                override = _find_qos_override(thread, resource, resource_type);
                if (override) {
                        override->override_contended_resource_count++;
                } else {
                        struct thread_qos_override *override_new;

                        /* We need to allocate a new object. Drop the task lock and recheck afterwards in case someone else added the override */
                        thread_reference(thread);
                        has_thread_reference = TRUE;
                        task_unlock(task);
                        override_new = zalloc(thread_qos_override_zone);
                        task_lock(task);

                        override = _find_qos_override(thread, resource, resource_type);
                        if (override) {
                                /* Someone else already allocated while the task lock was dropped */
                                deferred_free_override = override_new;
                                override->override_contended_resource_count++;
                        } else {
                                override = override_new;
                                override->override_next = thread->overrides;
                                override->override_contended_resource_count = 1 /* since first_override_for_resource was TRUE */;
                                override->override_resource = resource;
                                override->override_resource_type = resource_type;
                                override->override_qos = THREAD_QOS_UNSPECIFIED;
                                thread->overrides = override;
                        }
                }
        } else {
                override = _find_qos_override(thread, resource, resource_type);
        }

        if (override) {
                if (override->override_qos == THREAD_QOS_UNSPECIFIED)
                        override->override_qos = override_qos;
                else
                        override->override_qos = MAX(override->override_qos, override_qos);
        }

        /* Determine how to combine the various overrides into a single current requested override */
        prev_qos_override = requested.thrp_qos_override;
        new_qos_override = _calculate_requested_qos_override(thread);

        if (new_qos_override != prev_qos_override) {
                requested.thrp_qos_override = new_qos_override;

                thread->requested_policy = requested;

                task_policy_update_locked(task, thread, &pend_token);
                
                if (!has_thread_reference) {
                        thread_reference(thread);
                }
                
                task_unlock(task);
                
                task_policy_update_complete_unlocked(task, thread, &pend_token);

                new_effective_qos = thread->effective_policy.thep_qos;
                
                thread_deallocate(thread);
        } else {
                new_effective_qos = thread->effective_policy.thep_qos;

                task_unlock(task);

                if (has_thread_reference) {
                        thread_deallocate(thread);
                }
        }

        if (deferred_free_override) {
                zfree(thread_qos_override_zone, deferred_free_override);
        }

        DTRACE_BOOST3(qos_add_override_post, int, prev_qos_override, int, new_qos_override,
                                  int, new_effective_qos);

        KERNEL_DEBUG_CONSTANT((IMPORTANCE_CODE(IMP_USYNCH_QOS_OVERRIDE, IMP_USYNCH_ADD_OVERRIDE)) | DBG_FUNC_END,
                                                  new_qos_override, resource, resource_type, 0, 0);

        return TRUE;
}


static boolean_t _proc_thread_qos_remove_override_internal(task_t task, thread_t thread, uint64_t tid, user_addr_t resource, int resource_type, boolean_t reset)
{
        thread_t        self = current_thread();
        struct task_pend_token pend_token = {};

        /* XXX move to thread mutex when thread policy does */
        task_lock(task);

        /*
         * If thread is passed, it is assumed to be most accurate, since the caller must have an explicit (or implicit) reference
         * to the thread
         */
        if (thread != THREAD_NULL) {
                assert(task == thread->task);
        } else {
                if (tid == self->thread_id) {
                        thread = self;
                } else {
                        thread = task_findtid(task, tid);

                        if (thread == THREAD_NULL) {
                                KERNEL_DEBUG_CONSTANT((IMPORTANCE_CODE(IMP_USYNCH_QOS_OVERRIDE, IMP_USYNCH_REMOVE_OVERRIDE)) | DBG_FUNC_NONE,
                                                                          tid, 0, 0xdead, 0, 0);
                                task_unlock(task);
                                return FALSE;
                        }
                }
        }

        struct task_requested_policy requested = thread->requested_policy;
        struct thread_qos_override *deferred_free_override_list = NULL;
        int new_qos_override, prev_qos_override;

        _canonicalize_resource_and_type(&resource, &resource_type);

        _find_and_decrement_qos_override(thread, resource, resource_type, reset, &deferred_free_override_list);

        KERNEL_DEBUG_CONSTANT((IMPORTANCE_CODE(IMP_USYNCH_QOS_OVERRIDE, IMP_USYNCH_REMOVE_OVERRIDE)) | DBG_FUNC_START,
                                                  thread_tid(thread), resource, reset, 0, 0);

        /* Determine how to combine the various overrides into a single current requested override */
        prev_qos_override = requested.thrp_qos_override;
        new_qos_override = _calculate_requested_qos_override(thread);

        if (new_qos_override != prev_qos_override) {
                requested.thrp_qos_override = new_qos_override;

                thread->requested_policy = requested;

                task_policy_update_locked(task, thread, &pend_token);
                
                thread_reference(thread);
                        
                task_unlock(task);
                
                task_policy_update_complete_unlocked(task, thread, &pend_token);
                
                thread_deallocate(thread);
        } else {
                task_unlock(task);
        }

        while (deferred_free_override_list) {
                struct thread_qos_override *override_next = deferred_free_override_list->override_next;
                
                zfree(thread_qos_override_zone, deferred_free_override_list);
                deferred_free_override_list = override_next;
        }

        KERNEL_DEBUG_CONSTANT((IMPORTANCE_CODE(IMP_USYNCH_QOS_OVERRIDE, IMP_USYNCH_REMOVE_OVERRIDE)) | DBG_FUNC_END,
                                                  0, 0, 0, 0, 0);

        return TRUE;
}

boolean_t proc_thread_qos_remove_override(task_t task, thread_t thread, uint64_t tid, user_addr_t resource, int resource_type)
{
        return _proc_thread_qos_remove_override_internal(task, thread, tid, resource, resource_type, FALSE);

}

boolean_t proc_thread_qos_reset_override(task_t task, thread_t thread, uint64_t tid, user_addr_t resource, int resource_type)
{
        return _proc_thread_qos_remove_override_internal(task, thread, tid, resource, resource_type, TRUE);
}

/* Deallocate before thread termination */
void proc_thread_qos_deallocate(thread_t thread)
{
        task_t task = thread->task;
        struct thread_qos_override *override;

        /* XXX move to thread mutex when thread policy does */
        task_lock(task);
        override = thread->overrides;
        thread->overrides = NULL;               /* task policy re-evaluation needed? */
        thread->requested_policy.thrp_qos_override = THREAD_QOS_UNSPECIFIED;
        task_unlock(task);

        while (override) {
                struct thread_qos_override *override_next = override->override_next;
                
                zfree(thread_qos_override_zone, override);
                override = override_next;
        }
}

/* TODO: remove this variable when interactive daemon audit period is over */
extern boolean_t ipc_importance_interactive_receiver;

/*
 * Called at process exec to initialize the apptype, qos clamp, and qos seed of a process
 *
 * TODO: Make this function more table-driven instead of ad-hoc
 */
void
proc_set_task_spawnpolicy(task_t task, int apptype, int qos_clamp, int role,
                          ipc_port_t * portwatch_ports, int portwatch_count)
{
        struct task_pend_token pend_token = {};

        KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE,
                                  (IMPORTANCE_CODE(IMP_TASK_APPTYPE, apptype)) | DBG_FUNC_START,
                                  task_pid(task), trequested_0(task, THREAD_NULL), trequested_1(task, THREAD_NULL),
                                  apptype, 0);

        switch (apptype) {
                case TASK_APPTYPE_APP_TAL:
                case TASK_APPTYPE_APP_DEFAULT:
                        /* Apps become donors via the 'live-donor' flag instead of the static donor flag */
                        task_importance_mark_donor(task, FALSE);
                        task_importance_mark_live_donor(task, TRUE);
                        task_importance_mark_receiver(task, FALSE);
                        /* Apps are de-nap recievers on desktop for suppression behaviors */
                        task_importance_mark_denap_receiver(task, TRUE);
                        break;

                case TASK_APPTYPE_DAEMON_INTERACTIVE:
                        task_importance_mark_donor(task, TRUE);
                        task_importance_mark_live_donor(task, FALSE);

                        /* 
                         * A boot arg controls whether interactive daemons are importance receivers.
                         * Normally, they are not.  But for testing their behavior as an adaptive
                         * daemon, the boot-arg can be set.
                         *
                         * TODO: remove this when the interactive daemon audit period is over.
                         */
                        task_importance_mark_receiver(task, /* FALSE */ ipc_importance_interactive_receiver);
                        task_importance_mark_denap_receiver(task, FALSE);
                        break;

                case TASK_APPTYPE_DAEMON_STANDARD:
                        task_importance_mark_donor(task, TRUE);
                        task_importance_mark_live_donor(task, FALSE);
                        task_importance_mark_receiver(task, FALSE);
                        task_importance_mark_denap_receiver(task, FALSE);
                        break;

                case TASK_APPTYPE_DAEMON_ADAPTIVE:
                        task_importance_mark_donor(task, FALSE);
                        task_importance_mark_live_donor(task, FALSE);
                        task_importance_mark_receiver(task, TRUE);
                        task_importance_mark_denap_receiver(task, FALSE);
                        break;

                case TASK_APPTYPE_DAEMON_BACKGROUND:
                        task_importance_mark_donor(task, FALSE);
                        task_importance_mark_live_donor(task, FALSE);
                        task_importance_mark_receiver(task, FALSE);
                        task_importance_mark_denap_receiver(task, FALSE);
                        break;

                case TASK_APPTYPE_NONE:
                        break;
        }

        if (portwatch_ports != NULL && apptype == TASK_APPTYPE_DAEMON_ADAPTIVE) {
                int portwatch_boosts = 0;

                for (int i = 0; i < portwatch_count; i++) {
                        ipc_port_t port = NULL;

                        if ((port = portwatch_ports[i]) != NULL) {
                                int boost = 0;
                                task_add_importance_watchport(task, port, &boost);
                                portwatch_boosts += boost;
                        }
                }

                if (portwatch_boosts > 0) {
                        task_importance_hold_internal_assertion(task, portwatch_boosts);
                }
        }

        task_lock(task);

        if (apptype == TASK_APPTYPE_APP_TAL) {
                /* TAL starts off enabled by default */
                task->requested_policy.t_tal_enabled = 1;
        }

        if (apptype != TASK_APPTYPE_NONE) {
                task->requested_policy.t_apptype = apptype;
        }

        if (role != TASK_UNSPECIFIED) {
                task->requested_policy.t_role = role;
        }

        if (qos_clamp != THREAD_QOS_UNSPECIFIED) {
                task->requested_policy.t_qos_clamp = qos_clamp;
        }

        task_policy_update_locked(task, THREAD_NULL, &pend_token);

        task_unlock(task);

        /* Ensure the donor bit is updated to be in sync with the new live donor status */
        pend_token.tpt_update_live_donor = 1;

        task_policy_update_complete_unlocked(task, THREAD_NULL, &pend_token);

        KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE,
                                  (IMPORTANCE_CODE(IMP_TASK_APPTYPE, apptype)) | DBG_FUNC_END,
                                  task_pid(task), trequested_0(task, THREAD_NULL), trequested_1(task, THREAD_NULL),
                                  task_is_importance_receiver(task), 0);
}

extern task_t bsd_init_task;

/* Set up the primordial thread's QoS */
void
task_set_main_thread_qos(task_t task, thread_t main_thread) {
        struct task_pend_token pend_token = {};

        assert(main_thread->task == task);

        task_lock(task);

        KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE,
                                  (IMPORTANCE_CODE(IMP_MAIN_THREAD_QOS, 0)) | DBG_FUNC_START,
                                  task_pid(task), trequested_0(task, THREAD_NULL), trequested_1(task, THREAD_NULL),
                                  main_thread->requested_policy.thrp_qos, 0);

        int primordial_qos = THREAD_QOS_UNSPECIFIED;

        int qos_clamp = task->requested_policy.t_qos_clamp;

        if (task == bsd_init_task) {
                /* PID 1 gets a special case */
                primordial_qos = THREAD_QOS_USER_INITIATED;
        }

        switch (task->requested_policy.t_apptype) {
                case TASK_APPTYPE_APP_TAL:
                case TASK_APPTYPE_APP_DEFAULT:
                        primordial_qos = THREAD_QOS_USER_INTERACTIVE;
                        break;

                case TASK_APPTYPE_DAEMON_INTERACTIVE:
                case TASK_APPTYPE_DAEMON_STANDARD:
                case TASK_APPTYPE_DAEMON_ADAPTIVE:
                        primordial_qos = THREAD_QOS_LEGACY;
                        break;

                case TASK_APPTYPE_DAEMON_BACKGROUND:
                        primordial_qos = THREAD_QOS_BACKGROUND;
                        break;
        }

        if (qos_clamp != THREAD_QOS_UNSPECIFIED) {
                if (primordial_qos != THREAD_QOS_UNSPECIFIED) {
                        primordial_qos = MIN(qos_clamp, primordial_qos);
                } else {
                        primordial_qos = qos_clamp;
                }
        }

        main_thread->requested_policy.thrp_qos = primordial_qos;

        task_policy_update_locked(task, main_thread, &pend_token);

        task_unlock(task);

        task_policy_update_complete_unlocked(task, main_thread, &pend_token);

        KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE,
                                  (IMPORTANCE_CODE(IMP_MAIN_THREAD_QOS, 0)) | DBG_FUNC_END,
                                  task_pid(task), trequested_0(task, THREAD_NULL), trequested_1(task, THREAD_NULL),
                                  primordial_qos, 0);
}

/* for process_policy to check before attempting to set */
boolean_t
proc_task_is_tal(task_t task)
{
        return (task->requested_policy.t_apptype == TASK_APPTYPE_APP_TAL) ? TRUE : FALSE;
}

int
task_get_apptype(task_t task)
{
        return task->requested_policy.t_apptype;
}

/* for telemetry */
integer_t
task_grab_latency_qos(task_t task)
{
        return qos_latency_policy_package(proc_get_effective_task_policy(task, TASK_POLICY_LATENCY_QOS));
}

/* update the darwin background action state in the flags field for libproc */
int
proc_get_darwinbgstate(task_t task, uint32_t * flagsp)
{
        if (task->requested_policy.ext_darwinbg)
                *flagsp |= PROC_FLAG_EXT_DARWINBG;

        if (task->requested_policy.int_darwinbg)
                *flagsp |= PROC_FLAG_DARWINBG;


        if (task->requested_policy.t_apptype == TASK_APPTYPE_APP_DEFAULT ||
            task->requested_policy.t_apptype == TASK_APPTYPE_APP_TAL)
                *flagsp |= PROC_FLAG_APPLICATION;

        if (task->requested_policy.t_apptype == TASK_APPTYPE_DAEMON_ADAPTIVE)
                *flagsp |= PROC_FLAG_ADAPTIVE;

        if (task->requested_policy.t_apptype == TASK_APPTYPE_DAEMON_ADAPTIVE && task->requested_policy.t_boosted == 1)
                *flagsp |= PROC_FLAG_ADAPTIVE_IMPORTANT;

        if (task_is_importance_donor(task))
                *flagsp |= PROC_FLAG_IMPORTANCE_DONOR;

        if (task->effective_policy.t_sup_active)
                *flagsp |= PROC_FLAG_SUPPRESSED;

        return(0);
}

/* All per-thread state is in the first 32-bits of the bitfield */
void
proc_get_thread_policy(thread_t thread, thread_policy_state_t info)
{
        task_t task = thread->task;
        task_lock(task);
        info->requested = (integer_t)task_requested_bitfield(task, thread);
        info->effective = (integer_t)task_effective_bitfield(task, thread);
        info->pending   = 0;
        task_unlock(task);
}

/*
 * Tracepoint data... Reading the tracepoint data can be somewhat complicated.
 * The current scheme packs as much data into a single tracepoint as it can.
 *
 * Each task/thread requested/effective structure is 64 bits in size. Any
 * given tracepoint will emit either requested or effective data, but not both.
 *
 * A tracepoint may emit any of task, thread, or task & thread data.
 * 
 * The type of data emitted varies with pointer size. Where possible, both
 * task and thread data are emitted. In LP32 systems, the first and second
 * halves of either the task or thread data is emitted.
 *
 * The code uses uintptr_t array indexes instead of high/low to avoid
 * confusion WRT big vs little endian.
 *
 * The truth table for the tracepoint data functions is below, and has the
 * following invariants:
 *
 * 1) task and thread are uintptr_t*
 * 2) task may never be NULL
 *
 *
 *                                     LP32            LP64
 * trequested_0(task, NULL)            task[0]         task[0]
 * trequested_1(task, NULL)            task[1]         NULL
 * trequested_0(task, thread)          thread[0]       task[0]
 * trequested_1(task, thread)          thread[1]       thread[0]
 *
 * Basically, you get a full task or thread on LP32, and both on LP64.
 *
 * The uintptr_t munging here is squicky enough to deserve a comment.
 *
 * The variables we are accessing are laid out in memory like this:
 *
 * [            LP64 uintptr_t  0          ]
 * [ LP32 uintptr_t 0 ] [ LP32 uintptr_t 1 ]
 *
 *      1   2   3   4     5   6   7   8
 *
 */

static uintptr_t
trequested_0(task_t task, thread_t thread)
{
        assert(task);
        _Static_assert(sizeof(struct task_requested_policy) == sizeof(uint64_t), "size invariant violated");
        _Static_assert(sizeof(task->requested_policy) == sizeof(thread->requested_policy), "size invariant violated");

        uintptr_t* raw = (uintptr_t*)((thread == THREAD_NULL) ? &task->requested_policy : &thread->requested_policy);
        return raw[0];
}

static uintptr_t
trequested_1(task_t task, thread_t thread)
{
        assert(task);
        _Static_assert(sizeof(struct task_requested_policy) == sizeof(uint64_t), "size invariant violated");
        _Static_assert(sizeof(task->requested_policy) == sizeof(thread->requested_policy), "size invariant violated");

#if defined __LP64__
        return (thread == NULL) ? 0 : *(uintptr_t*)&thread->requested_policy;
#else
        uintptr_t* raw = (uintptr_t*)((thread == THREAD_NULL) ? &task->requested_policy : &thread->requested_policy);
        return raw[1];
#endif
}

static uintptr_t
teffective_0(task_t task, thread_t thread)
{
        assert(task);
        _Static_assert(sizeof(struct task_effective_policy) == sizeof(uint64_t), "size invariant violated");
        _Static_assert(sizeof(task->effective_policy) == sizeof(thread->effective_policy), "size invariant violated");

        uintptr_t* raw = (uintptr_t*)((thread == THREAD_NULL) ? &task->effective_policy : &thread->effective_policy);
        return raw[0];
}

static uintptr_t
teffective_1(task_t task, thread_t thread)
{
        assert(task);
        _Static_assert(sizeof(struct task_effective_policy) == sizeof(uint64_t), "size invariant violated");
        _Static_assert(sizeof(task->effective_policy) == sizeof(thread->effective_policy), "size invariant violated");

#if defined __LP64__
        return (thread == NULL) ? 0 : *(uintptr_t*)&thread->effective_policy;
#else
        uintptr_t* raw = (uintptr_t*)((thread == THREAD_NULL) ? &task->effective_policy : &thread->effective_policy);
        return raw[1];
#endif
}

/* dump pending for tracepoint */
static uint32_t tpending(task_pend_token_t pend_token) { return *(uint32_t*)(void*)(pend_token); }

uint64_t
task_requested_bitfield(task_t task, thread_t thread)
{
        uint64_t bits = 0;
        struct task_requested_policy requested =
                (thread == THREAD_NULL) ? task->requested_policy : thread->requested_policy;

        bits |= (requested.int_darwinbg         ? POLICY_REQ_INT_DARWIN_BG  : 0);
        bits |= (requested.ext_darwinbg         ? POLICY_REQ_EXT_DARWIN_BG  : 0);
        bits |= (requested.int_iotier           ? (((uint64_t)requested.int_iotier) << POLICY_REQ_INT_IO_TIER_SHIFT) : 0);
        bits |= (requested.ext_iotier           ? (((uint64_t)requested.ext_iotier) << POLICY_REQ_EXT_IO_TIER_SHIFT) : 0);
        bits |= (requested.int_iopassive        ? POLICY_REQ_INT_PASSIVE_IO : 0);
        bits |= (requested.ext_iopassive        ? POLICY_REQ_EXT_PASSIVE_IO : 0);
        bits |= (requested.bg_iotier            ? (((uint64_t)requested.bg_iotier)  << POLICY_REQ_BG_IOTIER_SHIFT)   : 0);
        bits |= (requested.terminated           ? POLICY_REQ_TERMINATED     : 0);

        bits |= (requested.th_pidbind_bg        ? POLICY_REQ_PIDBIND_BG     : 0);
        bits |= (requested.th_workq_bg          ? POLICY_REQ_WORKQ_BG       : 0);

        if (thread != THREAD_NULL) {
                bits |= (requested.thrp_qos     ? (((uint64_t)requested.thrp_qos)   << POLICY_REQ_TH_QOS_SHIFT)  : 0);
                bits |= (requested.thrp_qos_override     ? (((uint64_t)requested.thrp_qos_override)   << POLICY_REQ_TH_QOS_OVER_SHIFT)  : 0);
        }

        bits |= (requested.t_boosted            ? POLICY_REQ_BOOSTED        : 0);
        bits |= (requested.t_tal_enabled        ? POLICY_REQ_TAL_ENABLED    : 0);
        bits |= (requested.t_apptype            ? (((uint64_t)requested.t_apptype)    << POLICY_REQ_APPTYPE_SHIFT)  : 0);
        bits |= (requested.t_role               ? (((uint64_t)requested.t_role)       << POLICY_REQ_ROLE_SHIFT)     : 0);

        bits |= (requested.t_sup_active         ? POLICY_REQ_SUP_ACTIVE         : 0);
        bits |= (requested.t_sup_lowpri_cpu     ? POLICY_REQ_SUP_LOWPRI_CPU     : 0);
        bits |= (requested.t_sup_cpu            ? POLICY_REQ_SUP_CPU            : 0);
        bits |= (requested.t_sup_timer          ? (((uint64_t)requested.t_sup_timer)  << POLICY_REQ_SUP_TIMER_THROTTLE_SHIFT) : 0);
        bits |= (requested.t_sup_throughput     ? (((uint64_t)requested.t_sup_throughput)   << POLICY_REQ_SUP_THROUGHPUT_SHIFT)   : 0);
        bits |= (requested.t_sup_disk           ? POLICY_REQ_SUP_DISK_THROTTLE  : 0);
        bits |= (requested.t_sup_cpu_limit      ? POLICY_REQ_SUP_CPU_LIMIT      : 0);
        bits |= (requested.t_sup_suspend        ? POLICY_REQ_SUP_SUSPEND        : 0);
        bits |= (requested.t_sup_bg_sockets     ? POLICY_REQ_SUP_BG_SOCKETS     : 0);
        bits |= (requested.t_base_latency_qos   ? (((uint64_t)requested.t_base_latency_qos) << POLICY_REQ_BASE_LATENCY_QOS_SHIFT) : 0);
        bits |= (requested.t_over_latency_qos   ? (((uint64_t)requested.t_over_latency_qos) << POLICY_REQ_OVER_LATENCY_QOS_SHIFT) : 0);
        bits |= (requested.t_base_through_qos   ? (((uint64_t)requested.t_base_through_qos) << POLICY_REQ_BASE_THROUGH_QOS_SHIFT) : 0);
        bits |= (requested.t_over_through_qos   ? (((uint64_t)requested.t_over_through_qos) << POLICY_REQ_OVER_THROUGH_QOS_SHIFT) : 0);
        bits |= (requested.t_sfi_managed        ? POLICY_REQ_SFI_MANAGED        : 0);
        bits |= (requested.t_qos_clamp          ? (((uint64_t)requested.t_qos_clamp)        << POLICY_REQ_QOS_CLAMP_SHIFT)        : 0);

        return bits;
}

uint64_t
task_effective_bitfield(task_t task, thread_t thread)
{
        uint64_t bits = 0;
        struct task_effective_policy effective =
                (thread == THREAD_NULL) ? task->effective_policy : thread->effective_policy;

        bits |= (effective.io_tier              ? (((uint64_t)effective.io_tier) << POLICY_EFF_IO_TIER_SHIFT) : 0);
        bits |= (effective.io_passive           ? POLICY_EFF_IO_PASSIVE     : 0);
        bits |= (effective.darwinbg             ? POLICY_EFF_DARWIN_BG      : 0);
        bits |= (effective.lowpri_cpu           ? POLICY_EFF_LOWPRI_CPU     : 0);
        bits |= (effective.terminated           ? POLICY_EFF_TERMINATED     : 0);
        bits |= (effective.all_sockets_bg       ? POLICY_EFF_ALL_SOCKETS_BG : 0);
        bits |= (effective.new_sockets_bg       ? POLICY_EFF_NEW_SOCKETS_BG : 0);
        bits |= (effective.bg_iotier            ? (((uint64_t)effective.bg_iotier) << POLICY_EFF_BG_IOTIER_SHIFT) : 0);
        bits |= (effective.qos_ui_is_urgent     ? POLICY_EFF_QOS_UI_IS_URGENT : 0);

        if (thread != THREAD_NULL)
                bits |= (effective.thep_qos     ? (((uint64_t)effective.thep_qos)   << POLICY_EFF_TH_QOS_SHIFT)  : 0);

        bits |= (effective.t_tal_engaged        ? POLICY_EFF_TAL_ENGAGED    : 0);
        bits |= (effective.t_suspended          ? POLICY_EFF_SUSPENDED      : 0);
        bits |= (effective.t_watchers_bg        ? POLICY_EFF_WATCHERS_BG    : 0);
        bits |= (effective.t_sup_active         ? POLICY_EFF_SUP_ACTIVE     : 0);
        bits |= (effective.t_suppressed_cpu     ? POLICY_EFF_SUP_CPU        : 0);
        bits |= (effective.t_role               ? (((uint64_t)effective.t_role)        << POLICY_EFF_ROLE_SHIFT)        : 0);
        bits |= (effective.t_latency_qos        ? (((uint64_t)effective.t_latency_qos) << POLICY_EFF_LATENCY_QOS_SHIFT) : 0);
        bits |= (effective.t_through_qos        ? (((uint64_t)effective.t_through_qos) << POLICY_EFF_THROUGH_QOS_SHIFT) : 0);
        bits |= (effective.t_sfi_managed        ? POLICY_EFF_SFI_MANAGED    : 0);
        bits |= (effective.t_qos_ceiling        ? (((uint64_t)effective.t_qos_ceiling) << POLICY_EFF_QOS_CEILING_SHIFT) : 0);

        return bits;
}


/*
 * Resource usage and CPU related routines
 */

int 
proc_get_task_ruse_cpu(task_t task, uint32_t *policyp, uint8_t *percentagep, uint64_t *intervalp, uint64_t *deadlinep)
{
        
        int error = 0;
        int scope;

        task_lock(task);

        
        error = task_get_cpuusage(task, percentagep, intervalp, deadlinep, &scope);
        task_unlock(task);

        /*
         * Reverse-map from CPU resource limit scopes back to policies (see comment below).
         */
        if (scope == TASK_RUSECPU_FLAGS_PERTHR_LIMIT) {
                *policyp = TASK_POLICY_RESOURCE_ATTRIBUTE_NOTIFY_EXC;
        } else if (scope == TASK_RUSECPU_FLAGS_PROC_LIMIT) {
                *policyp = TASK_POLICY_RESOURCE_ATTRIBUTE_THROTTLE;
        } else if (scope == TASK_RUSECPU_FLAGS_DEADLINE) {
                *policyp = TASK_POLICY_RESOURCE_ATTRIBUTE_NONE;
        }

        return(error);
}

/*
 * Configure the default CPU usage monitor parameters.
 *
 * For tasks which have this mechanism activated: if any thread in the
 * process consumes more CPU than this, an EXC_RESOURCE exception will be generated.
 */
void
proc_init_cpumon_params(void)
{
        /*
         * The max CPU percentage can be configured via the boot-args and
         * a key in the device tree. The boot-args are honored first, then the
         * device tree.
         */
        if (!PE_parse_boot_argn("max_cpumon_percentage", &proc_max_cpumon_percentage,
                sizeof (proc_max_cpumon_percentage)))
        {
                uint64_t max_percentage = 0ULL;

                if (!PE_get_default("kern.max_cpumon_percentage", &max_percentage,
                        sizeof(max_percentage)))
                {
                        max_percentage = DEFAULT_CPUMON_PERCENTAGE;
                }

                assert(max_percentage <= UINT8_MAX);
                proc_max_cpumon_percentage = (uint8_t) max_percentage;
        }

        if (proc_max_cpumon_percentage > 100) {
                proc_max_cpumon_percentage = 100;
        }

        /*
         * The interval should be specified in seconds.
         *
         * Like the max CPU percentage, the max CPU interval can be configured
         * via boot-args and the device tree.
         */
        if (!PE_parse_boot_argn("max_cpumon_interval", &proc_max_cpumon_interval,
                sizeof (proc_max_cpumon_interval)))
        {
                if (!PE_get_default("kern.max_cpumon_interval", &proc_max_cpumon_interval,
                        sizeof(proc_max_cpumon_interval)))
                {
                        proc_max_cpumon_interval = DEFAULT_CPUMON_INTERVAL;
                }
        }

        proc_max_cpumon_interval *= NSEC_PER_SEC;

        /* TEMPORARY boot arg to control App suppression */
        PE_parse_boot_argn("task_policy_suppression_disable",
                           &task_policy_suppression_disable,
                           sizeof(task_policy_suppression_disable));
}

/*
 * Currently supported configurations for CPU limits.
 *
 * Policy                               | Deadline-based CPU limit | Percentage-based CPU limit
 * -------------------------------------+--------------------------+------------------------------
 * PROC_POLICY_RSRCACT_THROTTLE         | ENOTSUP                  | Task-wide scope only
 * PROC_POLICY_RSRCACT_SUSPEND          | Task-wide scope only     | ENOTSUP
 * PROC_POLICY_RSRCACT_TERMINATE        | Task-wide scope only     | ENOTSUP
 * PROC_POLICY_RSRCACT_NOTIFY_KQ        | Task-wide scope only     | ENOTSUP
 * PROC_POLICY_RSRCACT_NOTIFY_EXC       | ENOTSUP                  | Per-thread scope only
 *
 * A deadline-based CPU limit is actually a simple wallclock timer - the requested action is performed
 * after the specified amount of wallclock time has elapsed.
 *
 * A percentage-based CPU limit performs the requested action after the specified amount of actual CPU time
 * has been consumed -- regardless of how much wallclock time has elapsed -- by either the task as an
 * aggregate entity (so-called "Task-wide" or "Proc-wide" scope, whereby the CPU time consumed by all threads
 * in the task are added together), or by any one thread in the task (so-called "per-thread" scope).
 *
 * We support either deadline != 0 OR percentage != 0, but not both. The original intention in having them
 * share an API was to use actual CPU time as the basis of the deadline-based limit (as in: perform an action
 * after I have used some amount of CPU time; this is different than the recurring percentage/interval model)
 * but the potential consumer of the API at the time was insisting on wallclock time instead.
 *
 * Currently, requesting notification via an exception is the only way to get per-thread scope for a
 * CPU limit. All other types of notifications force task-wide scope for the limit.
 */
int 
proc_set_task_ruse_cpu(task_t task, uint32_t policy, uint8_t percentage, uint64_t interval, uint64_t deadline,
        int cpumon_entitled)
{
        int error = 0;
        int scope;

        /*
         * Enforce the matrix of supported configurations for policy, percentage, and deadline.
         */
        switch (policy) {
        // If no policy is explicitly given, the default is to throttle.
        case TASK_POLICY_RESOURCE_ATTRIBUTE_NONE:
        case TASK_POLICY_RESOURCE_ATTRIBUTE_THROTTLE:
                if (deadline != 0)
                        return (ENOTSUP);
                scope = TASK_RUSECPU_FLAGS_PROC_LIMIT;
                break;
        case TASK_POLICY_RESOURCE_ATTRIBUTE_SUSPEND:
        case TASK_POLICY_RESOURCE_ATTRIBUTE_TERMINATE:
        case TASK_POLICY_RESOURCE_ATTRIBUTE_NOTIFY_KQ:
                if (percentage != 0)
                        return (ENOTSUP);
                scope = TASK_RUSECPU_FLAGS_DEADLINE;
                break;
        case TASK_POLICY_RESOURCE_ATTRIBUTE_NOTIFY_EXC:
                if (deadline != 0)
                        return (ENOTSUP);
                scope = TASK_RUSECPU_FLAGS_PERTHR_LIMIT;
#ifdef CONFIG_NOMONITORS
                return (error);
#endif /* CONFIG_NOMONITORS */
                break;
        default:
                return (EINVAL);
        }

        task_lock(task);
        if (task != current_task()) {
                task->policy_ru_cpu_ext = policy;
        } else {
                task->policy_ru_cpu = policy;
        }
        error = task_set_cpuusage(task, percentage, interval, deadline, scope, cpumon_entitled);
        task_unlock(task);
        return(error);
}

int 
proc_clear_task_ruse_cpu(task_t task, int cpumon_entitled)
{
        int error = 0;
        int action;
        void * bsdinfo = NULL;

        task_lock(task);
        if (task != current_task()) {
                task->policy_ru_cpu_ext = TASK_POLICY_RESOURCE_ATTRIBUTE_DEFAULT;
        } else {
                task->policy_ru_cpu = TASK_POLICY_RESOURCE_ATTRIBUTE_DEFAULT;
        }

        error = task_clear_cpuusage_locked(task, cpumon_entitled);
        if (error != 0)
                goto out;       

        action = task->applied_ru_cpu;
        if (task->applied_ru_cpu_ext != TASK_POLICY_RESOURCE_ATTRIBUTE_NONE) {
                /* reset action */
                task->applied_ru_cpu_ext = TASK_POLICY_RESOURCE_ATTRIBUTE_NONE;
        }
        if (action != TASK_POLICY_RESOURCE_ATTRIBUTE_NONE) {
                bsdinfo = task->bsd_info;
                task_unlock(task);
                proc_restore_resource_actions(bsdinfo, TASK_POLICY_CPU_RESOURCE_USAGE, action);
                goto out1;
        }

out:
        task_unlock(task);
out1:
        return(error);

}

/* used to apply resource limit related actions */
static int
task_apply_resource_actions(task_t task, int type)
{
        int action = TASK_POLICY_RESOURCE_ATTRIBUTE_NONE;
        void * bsdinfo = NULL;
        
        switch (type) {
                case TASK_POLICY_CPU_RESOURCE_USAGE:
                        break;
                case TASK_POLICY_WIREDMEM_RESOURCE_USAGE:
                case TASK_POLICY_VIRTUALMEM_RESOURCE_USAGE:
                case TASK_POLICY_DISK_RESOURCE_USAGE:
                case TASK_POLICY_NETWORK_RESOURCE_USAGE:
                case TASK_POLICY_POWER_RESOURCE_USAGE:
                        return(0);

                default:
                        return(1);
        };

        /* only cpu actions for now */
        task_lock(task);
        
        if (task->applied_ru_cpu_ext == TASK_POLICY_RESOURCE_ATTRIBUTE_NONE) {
                /* apply action */
                task->applied_ru_cpu_ext = task->policy_ru_cpu_ext;
                action = task->applied_ru_cpu_ext;
        } else {
                action = task->applied_ru_cpu_ext;
        }

        if (action != TASK_POLICY_RESOURCE_ATTRIBUTE_NONE) {
                bsdinfo = task->bsd_info;
                task_unlock(task);
                proc_apply_resource_actions(bsdinfo, TASK_POLICY_CPU_RESOURCE_USAGE, action);
        } else
                task_unlock(task);

        return(0);
}

/*
 * XXX This API is somewhat broken; we support multiple simultaneous CPU limits, but the get/set API
 * only allows for one at a time. This means that if there is a per-thread limit active, the other
 * "scopes" will not be accessible via this API. We could change it to pass in the scope of interest
 * to the caller, and prefer that, but there's no need for that at the moment.
 */
int
task_get_cpuusage(task_t task, uint8_t *percentagep, uint64_t *intervalp, uint64_t *deadlinep, int *scope)
{
        *percentagep = 0;
        *intervalp = 0;
        *deadlinep = 0;

        if ((task->rusage_cpu_flags & TASK_RUSECPU_FLAGS_PERTHR_LIMIT) != 0) {
                *scope = TASK_RUSECPU_FLAGS_PERTHR_LIMIT;
                *percentagep = task->rusage_cpu_perthr_percentage;
                *intervalp = task->rusage_cpu_perthr_interval;
        } else if ((task->rusage_cpu_flags & TASK_RUSECPU_FLAGS_PROC_LIMIT) != 0) {
                *scope = TASK_RUSECPU_FLAGS_PROC_LIMIT;
                *percentagep = task->rusage_cpu_percentage;
                *intervalp = task->rusage_cpu_interval;
        } else if ((task->rusage_cpu_flags & TASK_RUSECPU_FLAGS_DEADLINE) != 0) {
                *scope = TASK_RUSECPU_FLAGS_DEADLINE;
                *deadlinep = task->rusage_cpu_deadline;
        } else {
                *scope = 0;
        }

        return(0);
}

/*
 * Disable the CPU usage monitor for the task. Return value indicates
 * if the mechanism was actually enabled.
 */
int
task_disable_cpumon(task_t task) {
        thread_t thread;
        
        task_lock_assert_owned(task);

        if ((task->rusage_cpu_flags & TASK_RUSECPU_FLAGS_PERTHR_LIMIT) == 0) {
                return (KERN_INVALID_ARGUMENT);
        }

#if CONFIG_TELEMETRY
        /*
         * Disable task-wide telemetry if it was ever enabled by the CPU usage
         * monitor's warning zone.
         */
        telemetry_task_ctl_locked(task, TF_CPUMON_WARNING, 0);
#endif

        /*
         * Disable the monitor for the task, and propagate that change to each thread.
         */
        task->rusage_cpu_flags &= ~(TASK_RUSECPU_FLAGS_PERTHR_LIMIT | TASK_RUSECPU_FLAGS_FATAL_CPUMON);         
        queue_iterate(&task->threads, thread, thread_t, task_threads) {
                set_astledger(thread);
        }
        task->rusage_cpu_perthr_percentage = 0;
        task->rusage_cpu_perthr_interval = 0;

        return (KERN_SUCCESS);
}

int
task_set_cpuusage(task_t task, uint8_t percentage, uint64_t interval, uint64_t deadline, int scope, int cpumon_entitled)
{
        thread_t thread;        
        uint64_t abstime = 0;
        uint64_t limittime = 0;

        lck_mtx_assert(&task->lock, LCK_MTX_ASSERT_OWNED);

        /* By default, refill once per second */
        if (interval == 0)
                interval = NSEC_PER_SEC;

        if (percentage != 0) {
                if (scope == TASK_RUSECPU_FLAGS_PERTHR_LIMIT) {
                        boolean_t warn = FALSE;

                        /*
                         * A per-thread CPU limit on a task generates an exception
                         * (LEDGER_ACTION_EXCEPTION) if any one thread in the task
                         * exceeds the limit.
                         */

                        if (percentage == TASK_POLICY_CPUMON_DISABLE) {
                                if (cpumon_entitled) {
                                        task_disable_cpumon(task);
                                        return (0);
                                }

                                /*
                                 * This task wishes to disable the CPU usage monitor, but it's
                                 * missing the required entitlement:
                                 *     com.apple.private.kernel.override-cpumon
                                 *
                                 * Instead, treat this as a request to reset its params 
                                 * back to the defaults.
                                 */
                                warn = TRUE;
                                percentage = TASK_POLICY_CPUMON_DEFAULTS;
                        }

                        if (percentage == TASK_POLICY_CPUMON_DEFAULTS) {
                                percentage = proc_max_cpumon_percentage;
                                interval   = proc_max_cpumon_interval;
                        }

                        if (percentage > 100) {
                                percentage = 100;
                        }

                        /*
                         * Passing in an interval of -1 means either:
                         * - Leave the interval as-is, if there's already a per-thread
                         *   limit configured
                         * - Use the system default.
                         */
                        if (interval == -1ULL) {
                                if (task->rusage_cpu_flags & TASK_RUSECPU_FLAGS_PERTHR_LIMIT) {
                                        interval = task->rusage_cpu_perthr_interval;
                                } else {
                                        interval = proc_max_cpumon_interval;
                                }
                        }

                        /*
                         * Enforce global caps on CPU usage monitor here if the process is not
                         * entitled to escape the global caps.
                         */
                         if ((percentage > proc_max_cpumon_percentage) && (cpumon_entitled == 0)) {
                                warn = TRUE;
                                percentage = proc_max_cpumon_percentage;
                         }

                         if ((interval > proc_max_cpumon_interval) && (cpumon_entitled == 0)) {
                                warn = TRUE;
                                interval = proc_max_cpumon_interval;
                         }

                        if (warn) {
                                int       pid = 0;
                                const char *procname = "unknown";

#ifdef MACH_BSD
                                pid = proc_selfpid();
                                if (current_task()->bsd_info != NULL) {
                                        procname = proc_name_address(current_task()->bsd_info);
                                }
#endif

                                printf("process %s[%d] denied attempt to escape CPU monitor"
                                        " (missing required entitlement).\n", procname, pid);
                        }

                        task->rusage_cpu_flags |= TASK_RUSECPU_FLAGS_PERTHR_LIMIT;
                        task->rusage_cpu_perthr_percentage = percentage;
                        task->rusage_cpu_perthr_interval = interval;
                        queue_iterate(&task->threads, thread, thread_t, task_threads) {
                                set_astledger(thread);
                        }
                } else if (scope == TASK_RUSECPU_FLAGS_PROC_LIMIT) {
                        /*
                         * Currently, a proc-wide CPU limit always blocks if the limit is
                         * exceeded (LEDGER_ACTION_BLOCK).
                         */
                        task->rusage_cpu_flags |= TASK_RUSECPU_FLAGS_PROC_LIMIT;
                        task->rusage_cpu_percentage = percentage;
                        task->rusage_cpu_interval = interval;

                        limittime = (interval * percentage) / 100;
                        nanoseconds_to_absolutetime(limittime, &abstime);

                        ledger_set_limit(task->ledger, task_ledgers.cpu_time, abstime, 0);
                        ledger_set_period(task->ledger, task_ledgers.cpu_time, interval);
                        ledger_set_action(task->ledger, task_ledgers.cpu_time, LEDGER_ACTION_BLOCK);
                }
        }

        if (deadline != 0) {
                assert(scope == TASK_RUSECPU_FLAGS_DEADLINE);

                /* if already in use, cancel and wait for it to cleanout */
                if (task->rusage_cpu_callt != NULL) {
                        task_unlock(task);
                        thread_call_cancel_wait(task->rusage_cpu_callt);
                        task_lock(task);
                }
                if (task->rusage_cpu_callt == NULL) {
                        task->rusage_cpu_callt = thread_call_allocate_with_priority(task_action_cpuusage, (thread_call_param_t)task, THREAD_CALL_PRIORITY_KERNEL);
                }
                /* setup callout */
                if (task->rusage_cpu_callt != 0) {
                        uint64_t save_abstime = 0;

                        task->rusage_cpu_flags |= TASK_RUSECPU_FLAGS_DEADLINE;
                        task->rusage_cpu_deadline = deadline;

                        nanoseconds_to_absolutetime(deadline, &abstime);
                        save_abstime = abstime;
                        clock_absolutetime_interval_to_deadline(save_abstime, &abstime);
                        thread_call_enter_delayed(task->rusage_cpu_callt, abstime);
                }
        }

        return(0);
}

int
task_clear_cpuusage(task_t task, int cpumon_entitled)
{
        int retval = 0;

        task_lock(task);
        retval = task_clear_cpuusage_locked(task, cpumon_entitled);
        task_unlock(task);

        return(retval);
}

int
task_clear_cpuusage_locked(task_t task, int cpumon_entitled)
{
        thread_call_t savecallt;

        /* cancel percentage handling if set */
        if (task->rusage_cpu_flags & TASK_RUSECPU_FLAGS_PROC_LIMIT) {
                task->rusage_cpu_flags &= ~TASK_RUSECPU_FLAGS_PROC_LIMIT;               
                ledger_set_limit(task->ledger, task_ledgers.cpu_time, LEDGER_LIMIT_INFINITY, 0);
                task->rusage_cpu_percentage = 0;
                task->rusage_cpu_interval = 0;
        }

        /*
         * Disable the CPU usage monitor.
         */
        if (cpumon_entitled) {
                task_disable_cpumon(task);
        }

        /* cancel deadline handling if set */
        if (task->rusage_cpu_flags & TASK_RUSECPU_FLAGS_DEADLINE) {
                task->rusage_cpu_flags &= ~TASK_RUSECPU_FLAGS_DEADLINE;
                if (task->rusage_cpu_callt != 0) {
                        savecallt = task->rusage_cpu_callt;
                        task->rusage_cpu_callt = NULL;
                        task->rusage_cpu_deadline = 0;
                        task_unlock(task);
                        thread_call_cancel_wait(savecallt);
                        thread_call_free(savecallt);
                        task_lock(task);
                }
        }
        return(0);
}

/* called by ledger unit to enforce action due to  resource usage criteria being met */
void
task_action_cpuusage(thread_call_param_t param0, __unused thread_call_param_t param1)
{
        task_t task = (task_t)param0;
        (void)task_apply_resource_actions(task, TASK_POLICY_CPU_RESOURCE_USAGE);
        return;
}


/*
 * Routines for taskwatch and pidbind
 */


/*
 * Routines for importance donation/inheritance/boosting
 */

static void
task_importance_update_live_donor(task_t target_task)
{
#if IMPORTANCE_INHERITANCE

        ipc_importance_task_t task_imp;

        task_imp = ipc_importance_for_task(target_task, FALSE);
        if (IIT_NULL != task_imp) {
                ipc_importance_task_update_live_donor(task_imp);
                ipc_importance_task_release(task_imp);
        }
#endif /* IMPORTANCE_INHERITANCE */
}

void
task_importance_mark_donor(task_t task, boolean_t donating)
{
#if IMPORTANCE_INHERITANCE
        ipc_importance_task_t task_imp;

        task_imp = ipc_importance_for_task(task, FALSE);
        if (IIT_NULL != task_imp) {
                ipc_importance_task_mark_donor(task_imp, donating);
                ipc_importance_task_release(task_imp);
        }
#endif /* IMPORTANCE_INHERITANCE */
}

void
task_importance_mark_live_donor(task_t task, boolean_t live_donating)
{
#if IMPORTANCE_INHERITANCE
        ipc_importance_task_t task_imp;

        task_imp = ipc_importance_for_task(task, FALSE);
        if (IIT_NULL != task_imp) {
                ipc_importance_task_mark_live_donor(task_imp, live_donating);
                ipc_importance_task_release(task_imp);
        }
#endif /* IMPORTANCE_INHERITANCE */
}

void
task_importance_mark_receiver(task_t task, boolean_t receiving)
{
#if IMPORTANCE_INHERITANCE
        ipc_importance_task_t task_imp;

        task_imp = ipc_importance_for_task(task, FALSE);
        if (IIT_NULL != task_imp) {
                ipc_importance_task_mark_receiver(task_imp, receiving);
                ipc_importance_task_release(task_imp);
        }
#endif /* IMPORTANCE_INHERITANCE */
}

void
task_importance_mark_denap_receiver(task_t task, boolean_t denap)
{
#if IMPORTANCE_INHERITANCE
        ipc_importance_task_t task_imp;

        task_imp = ipc_importance_for_task(task, FALSE);
        if (IIT_NULL != task_imp) {
                ipc_importance_task_mark_denap_receiver(task_imp, denap);
                ipc_importance_task_release(task_imp);
        }
#endif /* IMPORTANCE_INHERITANCE */
}

void
task_importance_reset(__imp_only task_t task)
{
#if IMPORTANCE_INHERITANCE
        ipc_importance_task_t task_imp;

        /* TODO: Lower importance downstream before disconnect */
        task_imp = task->task_imp_base;
        ipc_importance_reset(task_imp, FALSE);
        task_importance_update_live_donor(task);
#endif /* IMPORTANCE_INHERITANCE */
}

#if IMPORTANCE_INHERITANCE

/*
 * Sets the task boost bit to the provided value.  Does NOT run the update function.
 *
 * Task lock must be held.
 */
void
task_set_boost_locked(task_t task, boolean_t boost_active)
{
#if IMPORTANCE_DEBUG
        KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE, (IMPORTANCE_CODE(IMP_BOOST, (boost_active ? IMP_BOOSTED : IMP_UNBOOSTED)) | DBG_FUNC_START),
                                  proc_selfpid(), task_pid(task), trequested_0(task, THREAD_NULL), trequested_1(task, THREAD_NULL), 0);
#endif

        task->requested_policy.t_boosted = boost_active;

#if IMPORTANCE_DEBUG
        if (boost_active == TRUE){
                DTRACE_BOOST2(boost, task_t, task, int, task_pid(task));
        } else {
                DTRACE_BOOST2(unboost, task_t, task, int, task_pid(task));
        }
        KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE, (IMPORTANCE_CODE(IMP_BOOST, (boost_active ? IMP_BOOSTED : IMP_UNBOOSTED)) | DBG_FUNC_END),
                                  proc_selfpid(), task_pid(task),
                                  trequested_0(task, THREAD_NULL), trequested_1(task, THREAD_NULL), 0);
#endif
}

/*
 * Sets the task boost bit to the provided value and applies the update.
 *
 * Task lock must be held.  Must call update complete after unlocking the task.
 */
void
task_update_boost_locked(task_t task, boolean_t boost_active, task_pend_token_t pend_token)
{
        task_set_boost_locked(task, boost_active);

        task_policy_update_locked(task, THREAD_NULL, pend_token);
}

/*
 * Check if this task should donate importance.
 *
 * May be called without taking the task lock. In that case, donor status can change
 * so you must check only once for each donation event.
 */
boolean_t
task_is_importance_donor(task_t task)
{
        if (task->task_imp_base == IIT_NULL)
                return FALSE;
        return ipc_importance_task_is_donor(task->task_imp_base);
}

/*
 * Query the status of the task's donor mark.
 */
boolean_t
task_is_marked_importance_donor(task_t task)
{
        if (task->task_imp_base == IIT_NULL)
                return FALSE;
        return ipc_importance_task_is_marked_donor(task->task_imp_base);
}

/*
 * Query the status of the task's live donor and donor mark.
 */
boolean_t
task_is_marked_live_importance_donor(task_t task)
{
        if (task->task_imp_base == IIT_NULL)
                return FALSE;
        return ipc_importance_task_is_marked_live_donor(task->task_imp_base);
}


/*
 * This routine may be called without holding task lock
 * since the value of imp_receiver can never be unset.
 */
boolean_t
task_is_importance_receiver(task_t task)
{
        if (task->task_imp_base == IIT_NULL)
                return FALSE;
        return ipc_importance_task_is_marked_receiver(task->task_imp_base);
}

/*
 * Query the task's receiver mark.
 */
boolean_t
task_is_marked_importance_receiver(task_t task)
{
        if (task->task_imp_base == IIT_NULL)
                return FALSE;
        return ipc_importance_task_is_marked_receiver(task->task_imp_base);
}

/*
 * This routine may be called without holding task lock
 * since the value of de-nap receiver can never be unset.
 */
boolean_t
task_is_importance_denap_receiver(task_t task)
{
        if (task->task_imp_base == IIT_NULL)
                return FALSE;
        return ipc_importance_task_is_denap_receiver(task->task_imp_base);
}

/*
 * Query the task's de-nap receiver mark.
 */
boolean_t
task_is_marked_importance_denap_receiver(task_t task)
{
        if (task->task_imp_base == IIT_NULL)
                return FALSE;
        return ipc_importance_task_is_marked_denap_receiver(task->task_imp_base);
}

/*
 * This routine may be called without holding task lock
 * since the value of imp_receiver can never be unset.
 */
boolean_t
task_is_importance_receiver_type(task_t task)
{
        if (task->task_imp_base == IIT_NULL)
                return FALSE;
        return (task_is_importance_receiver(task) ||
                task_is_importance_denap_receiver(task));
}

/*
 * External importance assertions are managed by the process in userspace
 * Internal importance assertions are the responsibility of the kernel
 * Assertions are changed from internal to external via task_importance_externalize_assertion
 */

int
task_importance_hold_watchport_assertion(task_t target_task, uint32_t count)
{
        ipc_importance_task_t task_imp;
        kern_return_t ret;

        /* must already have set up an importance */
        task_imp = target_task->task_imp_base;
        assert(IIT_NULL != task_imp);

        ret = ipc_importance_task_hold_internal_assertion(task_imp, count);
        return (KERN_SUCCESS != ret) ? ENOTSUP : 0;
}

int
task_importance_hold_internal_assertion(task_t target_task, uint32_t count)
{
        ipc_importance_task_t task_imp;
        kern_return_t ret;

        /* may be first time, so allow for possible importance setup */
        task_imp = ipc_importance_for_task(target_task, FALSE);
        if (IIT_NULL == task_imp) {
                return EOVERFLOW;
        }
        ret = ipc_importance_task_hold_internal_assertion(task_imp, count);
        ipc_importance_task_release(task_imp);

        return (KERN_SUCCESS != ret) ? ENOTSUP : 0;
}

int
task_importance_hold_file_lock_assertion(task_t target_task, uint32_t count)
{
        ipc_importance_task_t task_imp;
        kern_return_t ret;

        /* may be first time, so allow for possible importance setup */
        task_imp = ipc_importance_for_task(target_task, FALSE);
        if (IIT_NULL == task_imp) {
                return EOVERFLOW;
        }
        ret = ipc_importance_task_hold_file_lock_assertion(task_imp, count);
        ipc_importance_task_release(task_imp);

        return (KERN_SUCCESS != ret) ? ENOTSUP : 0;
}

int
task_importance_hold_legacy_external_assertion(task_t target_task, uint32_t count)
{
        ipc_importance_task_t task_imp;
        kern_return_t ret;
 
        /* must already have set up an importance */
        task_imp = target_task->task_imp_base;
        if (IIT_NULL == task_imp) {
                return EOVERFLOW;
        }         
        ret = ipc_importance_task_hold_legacy_external_assertion(task_imp, count);
        return (KERN_SUCCESS != ret) ? ENOTSUP : 0;
}

int
task_importance_drop_internal_assertion(task_t target_task, uint32_t count)
{
        ipc_importance_task_t task_imp;
        kern_return_t ret;
 
        /* must already have set up an importance */
        task_imp = target_task->task_imp_base;
        if (IIT_NULL == task_imp) {
                return EOVERFLOW;
        }
        ret = ipc_importance_task_drop_internal_assertion(target_task->task_imp_base, count);
        return (KERN_SUCCESS != ret) ? ENOTSUP : 0;
}

int
task_importance_drop_file_lock_assertion(task_t target_task, uint32_t count)
{
        ipc_importance_task_t task_imp;
        kern_return_t ret;
 
        /* must already have set up an importance */
        task_imp = target_task->task_imp_base;
        if (IIT_NULL == task_imp) {
                return EOVERFLOW;
        }
        ret = ipc_importance_task_drop_file_lock_assertion(target_task->task_imp_base, count);
        return (KERN_SUCCESS != ret) ? EOVERFLOW : 0;
}

int
task_importance_drop_legacy_external_assertion(task_t target_task, uint32_t count)
{
        ipc_importance_task_t task_imp;
        kern_return_t ret;
 
        /* must already have set up an importance */
        task_imp = target_task->task_imp_base;
        if (IIT_NULL == task_imp) {
                return EOVERFLOW;
        }
        ret = ipc_importance_task_drop_legacy_external_assertion(task_imp, count);
        return (KERN_SUCCESS != ret) ? EOVERFLOW : 0;
}

static void
task_add_importance_watchport(task_t task, mach_port_t port, int *boostp)
{
        int boost = 0;

        __impdebug_only int released_pid = 0;
        __impdebug_only int pid = task_pid(task);

        ipc_importance_task_t release_imp_task = IIT_NULL;

        if (IP_VALID(port) != 0) {
                ipc_importance_task_t new_imp_task = ipc_importance_for_task(task, FALSE);

                ip_lock(port);

                /*
                 * The port must have been marked tempowner already.
                 * This also filters out ports whose receive rights
                 * are already enqueued in a message, as you can't
                 * change the right's destination once it's already
                 * on its way.
                 */
                if (port->ip_tempowner != 0) {
                        assert(port->ip_impdonation != 0);

                        boost = port->ip_impcount;
                        if (IIT_NULL != port->ip_imp_task) {
                                /*
                                 * if this port is already bound to a task,
                                 * release the task reference and drop any
                                 * watchport-forwarded boosts
                                 */
                                release_imp_task = port->ip_imp_task;
                                port->ip_imp_task = IIT_NULL;
                        }

                        /* mark the port is watching another task (reference held in port->ip_imp_task) */
                        if (ipc_importance_task_is_marked_receiver(new_imp_task)) {
                                port->ip_imp_task = new_imp_task;
                                new_imp_task = IIT_NULL;
                        }
                }
                ip_unlock(port);

                if (IIT_NULL != new_imp_task) {
                        ipc_importance_task_release(new_imp_task);
                }

                if (IIT_NULL != release_imp_task) {
                        if (boost > 0)
                                ipc_importance_task_drop_internal_assertion(release_imp_task, boost);

                        // released_pid = task_pid(release_imp_task); /* TODO: Need ref-safe way to get pid */
                        ipc_importance_task_release(release_imp_task);
                }
#if IMPORTANCE_DEBUG
                KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE, (IMPORTANCE_CODE(IMP_WATCHPORT, 0)) | DBG_FUNC_NONE,
                        proc_selfpid(), pid, boost, released_pid, 0);
#endif /* IMPORTANCE_DEBUG */
        }

        *boostp = boost;
        return;
}

#endif /* IMPORTANCE_INHERITANCE */

/*
 * Routines for VM to query task importance
 */


/*
 * Order to be considered while estimating importance
 * for low memory notification and purging purgeable memory.
 */
#define TASK_IMPORTANCE_FOREGROUND     4
#define TASK_IMPORTANCE_NOTDARWINBG    1


/*
 * (Un)Mark the task as a privileged listener for memory notifications.
 * if marked, this task will be among the first to be notified amongst
 * the bulk of all other tasks when the system enters a pressure level
 * of interest to this task.
 */
int
task_low_mem_privileged_listener(task_t task, boolean_t new_value, boolean_t *old_value)
{
        if (old_value != NULL) {
                *old_value = (boolean_t)task->low_mem_privileged_listener;
        } else {
                task_lock(task);
                task->low_mem_privileged_listener = (uint32_t)new_value;
                task_unlock(task);
        }

        return 0;
}

/*
 * Checks if the task is already notified.
 *
 * Condition: task lock should be held while calling this function.
 */
boolean_t
task_has_been_notified(task_t task, int pressurelevel)
{
        if (task == NULL) {
                return FALSE;
        }
        
        if (pressurelevel == kVMPressureWarning) 
                return (task->low_mem_notified_warn ? TRUE : FALSE);
        else if (pressurelevel == kVMPressureCritical) 
                return (task->low_mem_notified_critical ? TRUE : FALSE);
        else 
                return TRUE;
}


/*
 * Checks if the task is used for purging.
 *
 * Condition: task lock should be held while calling this function.
 */
boolean_t
task_used_for_purging(task_t task, int pressurelevel)
{
        if (task == NULL) {
                return FALSE;
        }
        
        if (pressurelevel == kVMPressureWarning)
                return (task->purged_memory_warn ? TRUE : FALSE);
        else if (pressurelevel == kVMPressureCritical)
                return (task->purged_memory_critical ? TRUE : FALSE);
        else
                return TRUE;
}


/*
 * Mark the task as notified with memory notification.
 * 
 * Condition: task lock should be held while calling this function.
 */
void
task_mark_has_been_notified(task_t task, int pressurelevel)
{
        if (task == NULL) {
                return;
        }
        
        if (pressurelevel == kVMPressureWarning)
                task->low_mem_notified_warn = 1;
        else if (pressurelevel == kVMPressureCritical)
                task->low_mem_notified_critical = 1;
}


/*
 * Mark the task as purged.
 *
 * Condition: task lock should be held while calling this function.
 */
void
task_mark_used_for_purging(task_t task, int pressurelevel)
{
        if (task == NULL) {
                return;
        }
        
        if (pressurelevel == kVMPressureWarning)
                task->purged_memory_warn = 1;
        else if (pressurelevel == kVMPressureCritical)
                task->purged_memory_critical = 1;
}


/*
 * Mark the task eligible for low memory notification.
 * 
 * Condition: task lock should be held while calling this function.
 */
void
task_clear_has_been_notified(task_t task, int pressurelevel)
{
        if (task == NULL) {
                return;
        }
        
        if (pressurelevel == kVMPressureWarning)
                task->low_mem_notified_warn = 0;
        else if (pressurelevel == kVMPressureCritical)
                task->low_mem_notified_critical = 0;
}


/*
 * Mark the task eligible for purging its purgeable memory.
 *
 * Condition: task lock should be held while calling this function.
 */
void
task_clear_used_for_purging(task_t task)
{
        if (task == NULL) {
                return;
        }
        
        task->purged_memory_warn = 0;
        task->purged_memory_critical = 0;
}


/*
 * Estimate task importance for purging its purgeable memory 
 * and low memory notification.
 * 
 * Importance is calculated in the following order of criteria:
 * -Task role : Background vs Foreground
 * -Boost status: Not boosted vs Boosted
 * -Darwin BG status.
 *
 * Returns: Estimated task importance. Less important task will have lower 
 *          estimated importance.
 */
int
task_importance_estimate(task_t task)
{
        int task_importance = 0;

        if (task == NULL) {
                return 0;
        }

        if (proc_get_effective_task_policy(task, TASK_POLICY_ROLE) == TASK_FOREGROUND_APPLICATION)
                        task_importance += TASK_IMPORTANCE_FOREGROUND;

        if (proc_get_effective_task_policy(task, TASK_POLICY_DARWIN_BG) == 0)
                        task_importance += TASK_IMPORTANCE_NOTDARWINBG;
        
        return task_importance;
}