xnu-2422.90.20.tar.gz
[apple/xnu.git] / bsd / kern / kern_memorystatus.c
index f5e141455921d02845e6ec2b974a49d3dc47977f..852037af4d7699baa55f80dab3e3a419b84581c3 100644 (file)
  *
  */
 
-#include <sys/kern_event.h>
-#include <sys/kern_memorystatus.h>
-
 #include <kern/sched_prim.h>
+#include <kern/kalloc.h>
+#include <kern/assert.h>
+#include <kern/debug.h>
 #include <kern/lock.h>
 #include <kern/task.h>
 #include <kern/thread.h>
+#include <kern/host.h>
 #include <libkern/libkern.h>
+#include <mach/mach_time.h>
 #include <mach/task.h>
-#include <mach/task_info.h>
+#include <mach/host_priv.h>
+#include <mach/mach_host.h>
+#include <pexpert/pexpert.h>
+#include <sys/kern_event.h>
 #include <sys/proc.h>
+#include <sys/proc_info.h>
 #include <sys/signal.h>
 #include <sys/signalvar.h>
 #include <sys/sysctl.h>
+#include <sys/sysproto.h>
 #include <sys/wait.h>
+#include <sys/tree.h>
+#include <sys/priv.h>
+#include <vm/vm_pageout.h>
+#include <vm/vm_protos.h>
+
+#if CONFIG_FREEZE
+#include <vm/vm_map.h>
+#endif /* CONFIG_FREEZE */
+
+#include <sys/kern_memorystatus.h> 
+
+/* These are very verbose printfs(), enable with
+ * MEMORYSTATUS_DEBUG_LOG
+ */
+#if MEMORYSTATUS_DEBUG_LOG
+#define MEMORYSTATUS_DEBUG(cond, format, ...)      \
+do {                                              \
+       if (cond) { printf(format, ##__VA_ARGS__); } \
+} while(0)
+#else
+#define MEMORYSTATUS_DEBUG(cond, format, ...)
+#endif
+
+/* General tunables */
+
+unsigned long delta_percentage = 5;
+unsigned long critical_threshold_percentage = 5;
+unsigned long idle_offset_percentage = 5;
+unsigned long pressure_threshold_percentage = 15;
+unsigned long freeze_threshold_percentage = 50;
+
+/* General memorystatus stuff */
+
+struct klist memorystatus_klist;
+static lck_mtx_t memorystatus_klist_mutex;
+
+static void memorystatus_klist_lock(void);
+static void memorystatus_klist_unlock(void);
+
+static uint64_t memorystatus_idle_delay_time = 0;
+
+/*
+ * Memorystatus kevents
+ */
+
+static int filt_memorystatusattach(struct knote *kn);
+static void filt_memorystatusdetach(struct knote *kn);
+static int filt_memorystatus(struct knote *kn, long hint);
+
+struct filterops memorystatus_filtops = {
+       .f_attach = filt_memorystatusattach,
+       .f_detach = filt_memorystatusdetach,
+       .f_event = filt_memorystatus,
+};
+
+enum {
+       kMemorystatusNoPressure = 1,
+       kMemorystatusPressure = 2
+};
+
+/* Idle guard handling */
+
+static int32_t memorystatus_scheduled_idle_demotions = 0;
+
+static thread_call_t memorystatus_idle_demotion_call;
+
+static void memorystatus_perform_idle_demotion(__unused void *spare1, __unused void *spare2);
+static void memorystatus_schedule_idle_demotion_locked(proc_t p, boolean_t set_state);
+static void memorystatus_invalidate_idle_demotion_locked(proc_t p, boolean_t clean_state);
+static void memorystatus_reschedule_idle_demotion_locked(void);
+
+static void memorystatus_update_priority_locked(proc_t p, int priority);
+
+int memorystatus_wakeup = 0;
+
+unsigned int memorystatus_level = 0;
+
+static int memorystatus_list_count = 0;
+
+#define MEMSTAT_BUCKET_COUNT (JETSAM_PRIORITY_MAX + 1)
+
+typedef struct memstat_bucket {
+    TAILQ_HEAD(, proc) list;
+    int count;
+} memstat_bucket_t;
+
+memstat_bucket_t memstat_bucket[MEMSTAT_BUCKET_COUNT];
+
+uint64_t memstat_idle_demotion_deadline = 0;
+
+static unsigned int memorystatus_dirty_count = 0;
+
+#if !CONFIG_JETSAM
+static boolean_t kill_idle_exit = FALSE;
+#endif
+
+
+int
+memorystatus_get_level(__unused struct proc *p, struct memorystatus_get_level_args *args, __unused int *ret)
+{
+       user_addr_t     level = 0;
+       
+       level = args->level;
+       
+       if (copyout(&memorystatus_level, level, sizeof(memorystatus_level)) != 0) {
+               return EFAULT;
+       }
+       
+       return 0;
+}
+
+static proc_t memorystatus_get_first_proc_locked(unsigned int *bucket_index, boolean_t search);
+static proc_t memorystatus_get_next_proc_locked(unsigned int *bucket_index, proc_t p, boolean_t search);
+
+static void memorystatus_thread(void *param __unused, wait_result_t wr __unused);
+
+/* Jetsam */
+
+#if CONFIG_JETSAM
+
+/* Kill processes exceeding their limit either under memory pressure (1), or as soon as possible (0) */
+#define LEGACY_HIWATER 1
+
+static int memorystatus_highwater_enabled = 1;
 
 extern unsigned int    vm_page_free_count;
 extern unsigned int    vm_page_active_count;
 extern unsigned int    vm_page_inactive_count;
+extern unsigned int    vm_page_throttled_count;
 extern unsigned int    vm_page_purgeable_count;
 extern unsigned int    vm_page_wire_count;
 
-static void kern_memorystatus_thread(void);
+unsigned int memorystatus_delta = 0;
+
+static unsigned int memorystatus_available_pages = (unsigned int)-1;
+static unsigned int memorystatus_available_pages_pressure = 0;
+static unsigned int memorystatus_available_pages_critical = 0;
+static unsigned int memorystatus_available_pages_critical_base = 0;
+static unsigned int memorystatus_last_foreground_pressure_pages = (unsigned int)-1;
+#if !LATENCY_JETSAM
+static unsigned int memorystatus_available_pages_critical_idle_offset = 0;
+#endif
 
-int kern_memorystatus_wakeup = 0;
-int kern_memorystatus_level = 0;
-int kern_memorystatus_last_level = 0;
-unsigned int kern_memorystatus_kev_failure_count = 0;
-int kern_memorystatus_level_critical = 5;
+#if DEVELOPMENT || DEBUG
+static unsigned int memorystatus_jetsam_panic_debug = 0;
 
-static struct {
-       jetsam_kernel_stats_t stats;
-       size_t entry_count;
-       jetsam_snapshot_entry_t entries[kMaxSnapshotEntries];
-} jetsam_snapshot;
+static unsigned int memorystatus_jetsam_policy = kPolicyDefault;
+static unsigned int memorystatus_jetsam_policy_offset_pages_diagnostic = 0;
+#endif
 
-static jetsam_priority_entry_t jetsam_priority_list[kMaxPriorityEntries];
-#define jetsam_snapshot_list jetsam_snapshot.entries
+static boolean_t kill_under_pressure = FALSE;
 
-static int jetsam_priority_list_index = 0;
-static int jetsam_priority_list_count = 0;
-static int jetsam_snapshot_list_count = 0;
+static memorystatus_jetsam_snapshot_t *memorystatus_jetsam_snapshot;
+#define memorystatus_jetsam_snapshot_list memorystatus_jetsam_snapshot->entries
 
-static lck_mtx_t * jetsam_list_mlock;
-static lck_attr_t * jetsam_lck_attr;
-static lck_grp_t * jetsam_lck_grp;
-static lck_grp_attr_t * jetsam_lck_grp_attr;
+static unsigned int memorystatus_jetsam_snapshot_count = 0;
+static unsigned int memorystatus_jetsam_snapshot_max = 0;
 
-SYSCTL_INT(_kern, OID_AUTO, memorystatus_level, CTLFLAG_RD, &kern_memorystatus_level, 0, "");
-SYSCTL_UINT(_kern, OID_AUTO, memorystatus_kev_failure_count, CTLFLAG_RD, &kern_memorystatus_kev_failure_count, 0, "");
+static void memorystatus_clear_errors(void);
+static void memorystatus_get_task_page_counts(task_t task, uint32_t *footprint, uint32_t *max_footprint);
+static int memorystatus_send_note(int event_code, void *data, size_t data_length);
+static uint32_t memorystatus_build_state(proc_t p);
+static void memorystatus_update_levels_locked(boolean_t critical_only);
+static boolean_t memorystatus_issue_pressure_kevent(boolean_t pressured);
 
-__private_extern__ void
-kern_memorystatus_init(void)
-{
-    jetsam_lck_attr = lck_attr_alloc_init();
-    jetsam_lck_grp_attr= lck_grp_attr_alloc_init();
-    jetsam_lck_grp = lck_grp_alloc_init("jetsam",  jetsam_lck_grp_attr);
-    jetsam_list_mlock = lck_mtx_alloc_init(jetsam_lck_grp, jetsam_lck_attr);
+static boolean_t memorystatus_kill_specific_process(pid_t victim_pid, uint32_t cause);
+static boolean_t memorystatus_kill_top_process(boolean_t any, uint32_t cause, int32_t *priority, uint32_t *errors);
+#if LEGACY_HIWATER
+static boolean_t memorystatus_kill_hiwat_proc(uint32_t *errors);
+#endif
 
-       (void)kernel_thread(kernel_task, kern_memorystatus_thread);
-}
+static boolean_t memorystatus_kill_process_async(pid_t victim_pid, uint32_t cause);
+static boolean_t memorystatus_kill_process_sync(pid_t victim_pid, uint32_t cause);
 
-static uint32_t
-jetsam_task_page_count(task_t task)
+#endif /* CONFIG_JETSAM */
+
+/* VM pressure */
+
+#if VM_PRESSURE_EVENTS
+
+#include "vm_pressure.h"
+
+extern boolean_t memorystatus_warn_process(pid_t pid);
+
+vm_pressure_level_t memorystatus_vm_pressure_level = kVMPressureNormal;
+
+#endif /* VM_PRESSURE_EVENTS */
+
+/* Freeze */
+
+#if CONFIG_FREEZE
+
+boolean_t memorystatus_freeze_enabled = FALSE;
+int memorystatus_freeze_wakeup = 0;
+
+static inline boolean_t memorystatus_can_freeze_processes(void);
+static boolean_t memorystatus_can_freeze(boolean_t *memorystatus_freeze_swap_low);
+
+static void memorystatus_freeze_thread(void *param __unused, wait_result_t wr __unused);
+
+/* Thresholds */
+static unsigned int memorystatus_freeze_threshold = 0;
+
+static unsigned int memorystatus_freeze_pages_min = FREEZE_PAGES_MIN;
+static unsigned int memorystatus_freeze_pages_max = FREEZE_PAGES_MAX;
+
+static unsigned int memorystatus_frozen_count = 0;
+
+static unsigned int memorystatus_freeze_suspended_threshold = FREEZE_SUSPENDED_THRESHOLD_DEFAULT;
+
+/* Stats */
+static uint64_t memorystatus_freeze_count = 0;
+static uint64_t memorystatus_freeze_pageouts = 0;
+
+/* Throttling */
+static throttle_interval_t throttle_intervals[] = {
+       {      60,  8, 0, 0, { 0, 0 }, FALSE }, /* 1 hour intermediate interval, 8x burst */
+       { 24 * 60,  1, 0, 0, { 0, 0 }, FALSE }, /* 24 hour long interval, no burst */
+};
+
+static uint64_t memorystatus_freeze_throttle_count = 0;
+
+static unsigned int memorystatus_suspended_count = 0;
+static unsigned int memorystatus_suspended_footprint_total = 0;
+
+#endif /* CONFIG_FREEZE */
+
+/* Debug */
+
+#if DEVELOPMENT || DEBUG
+
+#if CONFIG_JETSAM
+
+/* Debug aid to aid determination of limit */
+
+static int
+sysctl_memorystatus_highwater_enable SYSCTL_HANDLER_ARGS
 {
-       kern_return_t ret;
-       static task_info_data_t data;
-       static struct task_basic_info *info = (struct task_basic_info *)&data;
-       static mach_msg_type_number_t count = TASK_BASIC_INFO_COUNT;
+#pragma unused(oidp, arg2)
+       proc_t p;
+       unsigned int b = 0;
+       int error, enable = 0;
+       int32_t memlimit;
 
-       ret = task_info(task, TASK_BASIC_INFO, (task_info_t)&data, &count);
-       if (ret == KERN_SUCCESS) {
-               return info->resident_size / PAGE_SIZE;
+       error = SYSCTL_OUT(req, arg1, sizeof(int));
+       if (error || !req->newptr) {
+               return (error);
        }
-       return 0;
-}
 
-static uint32_t
-jetsam_flags_for_pid(pid_t pid)
-{
-       int i;
+       error = SYSCTL_IN(req, &enable, sizeof(int));
+       if (error || !req->newptr) {
+               return (error);
+       }
 
-       for (i = 0; i < jetsam_priority_list_count; i++) {
-               if (pid == jetsam_priority_list[i].pid) {
-                       return jetsam_priority_list[i].flags;
+       if (!(enable == 0 || enable == 1)) {
+               return EINVAL;
+       }
+
+       proc_list_lock();
+
+       p = memorystatus_get_first_proc_locked(&b, TRUE);
+       while (p) {
+               if (enable) {
+                       if ((p->p_memstat_state & P_MEMSTAT_MEMLIMIT_BACKGROUND) && (p->p_memstat_effectivepriority >= JETSAM_PRIORITY_FOREGROUND)) {          
+                               memlimit = -1;
+                       } else {
+                               memlimit = p->p_memstat_memlimit;                               
+                       }
+               } else {
+                       memlimit = -1;
                }
+               task_set_phys_footprint_limit_internal(p->task, (memlimit  > 0) ? memlimit : -1, NULL, TRUE);
+               
+               p = memorystatus_get_next_proc_locked(&b, p, TRUE);
        }
+       
+       memorystatus_highwater_enabled = enable;
+
+       proc_list_unlock();
+
        return 0;
 }
 
-static void
-jetsam_snapshot_procs(void)
+SYSCTL_PROC(_kern, OID_AUTO, memorystatus_highwater_enabled, CTLTYPE_INT|CTLFLAG_RW|CTLFLAG_LOCKED, &memorystatus_highwater_enabled, 0, sysctl_memorystatus_highwater_enable, "I", "");
+
+SYSCTL_UINT(_kern, OID_AUTO, memorystatus_available_pages, CTLFLAG_RD|CTLFLAG_LOCKED, &memorystatus_available_pages, 0, "");
+SYSCTL_UINT(_kern, OID_AUTO, memorystatus_available_pages_critical, CTLFLAG_RD|CTLFLAG_LOCKED, &memorystatus_available_pages_critical, 0, "");
+SYSCTL_UINT(_kern, OID_AUTO, memorystatus_available_pages_critical_base, CTLFLAG_RW|CTLFLAG_LOCKED, &memorystatus_available_pages_critical_base, 0, "");
+#if !LATENCY_JETSAM
+SYSCTL_UINT(_kern, OID_AUTO, memorystatus_available_pages_critical_idle_offset, CTLFLAG_RW|CTLFLAG_LOCKED, &memorystatus_available_pages_critical_idle_offset, 0, "");
+#endif
+
+/* Diagnostic code */
+
+enum {
+       kJetsamDiagnosticModeNone =              0, 
+       kJetsamDiagnosticModeAll  =              1,
+       kJetsamDiagnosticModeStopAtFirstActive = 2,
+       kJetsamDiagnosticModeCount
+} jetsam_diagnostic_mode = kJetsamDiagnosticModeNone;
+
+static int jetsam_diagnostic_suspended_one_active_proc = 0;
+
+static int
+sysctl_jetsam_diagnostic_mode SYSCTL_HANDLER_ARGS
 {
-       proc_t p;
-       int i = 0;
+#pragma unused(arg1, arg2)
+
+       const char *diagnosticStrings[] = {
+               "jetsam: diagnostic mode: resetting critical level.",
+               "jetsam: diagnostic mode: will examine all processes",
+               "jetsam: diagnostic mode: will stop at first active process"                
+       };
+        
+       int error, val = jetsam_diagnostic_mode;
+       boolean_t changed = FALSE;
 
-       jetsam_snapshot.stats.free_pages = vm_page_free_count;
-       jetsam_snapshot.stats.active_pages = vm_page_active_count;
-       jetsam_snapshot.stats.inactive_pages = vm_page_inactive_count;
-       jetsam_snapshot.stats.purgeable_pages = vm_page_purgeable_count;
-       jetsam_snapshot.stats.wired_pages = vm_page_wire_count;
+       error = sysctl_handle_int(oidp, &val, 0, req);
+       if (error || !req->newptr)
+               return (error);
+       if ((val < 0) || (val >= kJetsamDiagnosticModeCount)) {
+               printf("jetsam: diagnostic mode: invalid value - %d\n", val);
+               return EINVAL;
+       }
+       
        proc_list_lock();
-       LIST_FOREACH(p, &allproc, p_list) {
-               task_t task = p->task;
-               jetsam_snapshot_list[i].pid = p->p_pid;
-               jetsam_snapshot_list[i].pages = jetsam_task_page_count(task);
-               jetsam_snapshot_list[i].flags = jetsam_flags_for_pid(p->p_pid);
-               strlcpy(&jetsam_snapshot_list[i].name[0], p->p_comm, MAXCOMLEN+1);
-#ifdef DEBUG
-               printf("jetsam snapshot pid = %d, uuid = %02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x\n",
-                       p->p_pid, 
-                       p->p_uuid[0], p->p_uuid[1], p->p_uuid[2], p->p_uuid[3], p->p_uuid[4], p->p_uuid[5], p->p_uuid[6], p->p_uuid[7],
-                       p->p_uuid[8], p->p_uuid[9], p->p_uuid[10], p->p_uuid[11], p->p_uuid[12], p->p_uuid[13], p->p_uuid[14], p->p_uuid[15]);
-#endif
-               memcpy(&jetsam_snapshot_list[i].uuid[0], &p->p_uuid[0], sizeof(p->p_uuid));
-               i++;
-               if (i == kMaxSnapshotEntries) {
+       
+       if ((unsigned int) val != jetsam_diagnostic_mode) {
+               jetsam_diagnostic_mode = val;
+
+               memorystatus_jetsam_policy &= ~kPolicyDiagnoseActive;
+                
+               switch (jetsam_diagnostic_mode) {
+               case kJetsamDiagnosticModeNone:
+                       /* Already cleared */
                        break;
-               }       
+               case kJetsamDiagnosticModeAll:
+                       memorystatus_jetsam_policy |= kPolicyDiagnoseAll;
+                       break;
+               case kJetsamDiagnosticModeStopAtFirstActive:
+                       memorystatus_jetsam_policy |= kPolicyDiagnoseFirst;
+                       break;
+               default:
+                       /* Already validated */
+                       break;
+               }
+               
+               memorystatus_update_levels_locked(FALSE);
+               changed = TRUE;
        }
-       proc_list_unlock();     
-       jetsam_snapshot.entry_count = jetsam_snapshot_list_count = i - 1;
+        
+       proc_list_unlock();
+       
+       if (changed) {
+               printf("%s\n", diagnosticStrings[val]);
+       }
+       
+       return (0);
 }
 
-static void
-jetsam_mark_pid_in_snapshot(pid_t pid)
+SYSCTL_PROC(_debug, OID_AUTO, jetsam_diagnostic_mode, CTLTYPE_INT|CTLFLAG_RW|CTLFLAG_LOCKED|CTLFLAG_ANYBODY,
+               &jetsam_diagnostic_mode, 0, sysctl_jetsam_diagnostic_mode, "I", "Jetsam Diagnostic Mode");
+
+SYSCTL_UINT(_kern, OID_AUTO, memorystatus_jetsam_policy_offset_pages_diagnostic, CTLFLAG_RW|CTLFLAG_LOCKED, &memorystatus_jetsam_policy_offset_pages_diagnostic, 0, "");
+
+#if VM_PRESSURE_EVENTS
+
+SYSCTL_UINT(_kern, OID_AUTO, memorystatus_available_pages_pressure, CTLFLAG_RW|CTLFLAG_LOCKED, &memorystatus_available_pages_pressure, 0, "");
+
+static int
+sysctl_memorystatus_vm_pressure_level SYSCTL_HANDLER_ARGS
 {
+#pragma unused(arg1, arg2, oidp)
+       int error = 0;
 
-       int i = 0;
+       error = priv_check_cred(kauth_cred_get(), PRIV_VM_PRESSURE, 0);
+       if (error)
+               return (error);
 
-       for (i = 0; i < jetsam_snapshot_list_count; i++) {
-               if (jetsam_snapshot_list[i].pid == pid) {
-                       jetsam_snapshot_list[i].flags |= kJetsamFlagsKilled;
-                       return;
-               }
-       }
+       return SYSCTL_OUT(req, &memorystatus_vm_pressure_level, sizeof(memorystatus_vm_pressure_level));
 }
 
+SYSCTL_PROC(_kern, OID_AUTO, memorystatus_vm_pressure_level, CTLTYPE_INT|CTLFLAG_RD|CTLFLAG_LOCKED|CTLFLAG_MASKED,
+    0, 0, &sysctl_memorystatus_vm_pressure_level, "I", "");
+
+static int
+sysctl_memorystatus_vm_pressure_send SYSCTL_HANDLER_ARGS
+{
+#pragma unused(arg1, arg2)
+
+       int error, pid = 0;
+
+       error = sysctl_handle_int(oidp, &pid, 0, req);
+       if (error || !req->newptr)
+               return (error);
+
+       return vm_dispatch_pressure_note_to_pid(pid, FALSE);
+}
+
+SYSCTL_PROC(_kern, OID_AUTO, memorystatus_vm_pressure_send, CTLTYPE_INT|CTLFLAG_WR|CTLFLAG_LOCKED|CTLFLAG_MASKED,
+    0, 0, &sysctl_memorystatus_vm_pressure_send, "I", "");
+
+#endif /* VM_PRESSURE_EVENTS */
+
+#endif /* CONFIG_JETSAM */
+
+#endif /* DEVELOPMENT || DEBUG */
+
+#if CONFIG_FREEZE
+
+SYSCTL_UINT(_kern, OID_AUTO, memorystatus_freeze_threshold, CTLFLAG_RW|CTLFLAG_LOCKED, &memorystatus_freeze_threshold, 0, "");
+
+SYSCTL_UINT(_kern, OID_AUTO, memorystatus_freeze_pages_min, CTLFLAG_RW|CTLFLAG_LOCKED, &memorystatus_freeze_pages_min, 0, "");
+SYSCTL_UINT(_kern, OID_AUTO, memorystatus_freeze_pages_max, CTLFLAG_RW|CTLFLAG_LOCKED, &memorystatus_freeze_pages_max, 0, "");
+
+SYSCTL_QUAD(_kern, OID_AUTO, memorystatus_freeze_count, CTLFLAG_RD|CTLFLAG_LOCKED, &memorystatus_freeze_count, "");
+SYSCTL_QUAD(_kern, OID_AUTO, memorystatus_freeze_pageouts, CTLFLAG_RD|CTLFLAG_LOCKED, &memorystatus_freeze_pageouts, "");
+SYSCTL_QUAD(_kern, OID_AUTO, memorystatus_freeze_throttle_count, CTLFLAG_RD|CTLFLAG_LOCKED, &memorystatus_freeze_throttle_count, "");
+SYSCTL_UINT(_kern, OID_AUTO, memorystatus_freeze_min_processes, CTLFLAG_RW|CTLFLAG_LOCKED, &memorystatus_freeze_suspended_threshold, 0, "");
+
+boolean_t memorystatus_freeze_throttle_enabled = TRUE;
+SYSCTL_UINT(_kern, OID_AUTO, memorystatus_freeze_throttle_enabled, CTLFLAG_RW|CTLFLAG_LOCKED, &memorystatus_freeze_throttle_enabled, 0, "");
+
+/* 
+ * Enabled via: <rdar://problem/13248767> Enable the sysctl_memorystatus_freeze/thaw sysctls on Release KC
+ * 
+ * TODO: Manual trigger of freeze and thaw for dev / debug kernels only.
+ * <rdar://problem/13248795> Disable/restrict the sysctl_memorystatus_freeze/thaw sysctls on Release KC
+ */
 static int
-jetsam_kill_top_proc(void)
+sysctl_memorystatus_freeze SYSCTL_HANDLER_ARGS
 {
+#pragma unused(arg1, arg2)
+
+       int error, pid = 0;
        proc_t p;
 
-       if (jetsam_snapshot_list_count == 0) {
-               jetsam_snapshot_procs();
-       }
-       lck_mtx_lock(jetsam_list_mlock);
-       while (jetsam_priority_list_index < jetsam_priority_list_count) {
-               pid_t aPid;
-               aPid = jetsam_priority_list[jetsam_priority_list_index].pid;
-               jetsam_priority_list_index++;
-               /* skip empty slots in the list */
-               if (aPid == 0) {
-                       continue; // with lock held
-               }
-               lck_mtx_unlock(jetsam_list_mlock);
-               jetsam_mark_pid_in_snapshot(aPid);
-               p = proc_find(aPid);
-               if (p != NULL) {
-#if DEBUG
-                       printf("jetsam: killing pid %d [%s] - memory_status_level: %d - ", aPid, p->p_comm, kern_memorystatus_level);
-#endif /* DEBUG */
-                       exit1(p, W_EXITCODE(0, SIGKILL), (int *)NULL);
-                       proc_rele(p);
-#if DEBUG
-                       printf("jetsam: pid %d killed - memory_status_level: %d\n", aPid, kern_memorystatus_level);
-#endif /* DEBUG */
-                       return 0;
+       error = sysctl_handle_int(oidp, &pid, 0, req);
+       if (error || !req->newptr)
+               return (error);
+
+       p = proc_find(pid);
+       if (p != NULL) {
+               uint32_t purgeable, wired, clean, dirty;
+               boolean_t shared;
+               uint32_t max_pages = 0;
+
+               if (DEFAULT_FREEZER_IS_ACTIVE || DEFAULT_FREEZER_COMPRESSED_PAGER_IS_ACTIVE) {
+                       max_pages = MIN(default_pager_swap_pages_free(), memorystatus_freeze_pages_max);
+               } else {
+                       max_pages = UINT32_MAX - 1;
                }
-           lck_mtx_lock(jetsam_list_mlock);
+               error = task_freeze(p->task, &purgeable, &wired, &clean, &dirty, max_pages, &shared, FALSE);
+               proc_rele(p);
+
+               if (error)
+                       error = EIO;
+               return error;
        }
-       lck_mtx_unlock(jetsam_list_mlock);
-       return -1;
+       return EINVAL;
 }
 
-static void
-kern_memorystatus_thread(void)
+SYSCTL_PROC(_kern, OID_AUTO, memorystatus_freeze, CTLTYPE_INT|CTLFLAG_WR|CTLFLAG_LOCKED|CTLFLAG_MASKED,
+    0, 0, &sysctl_memorystatus_freeze, "I", "");
+
+static int
+sysctl_memorystatus_available_pages_thaw SYSCTL_HANDLER_ARGS
 {
-       struct kev_msg ev_msg;
-       jetsam_kernel_stats_t data;
-       int ret;
+#pragma unused(arg1, arg2)
 
-       while(1) {
+       int error, pid = 0;
+       proc_t p;
 
-               while (kern_memorystatus_level <= kern_memorystatus_level_critical) {
-                       if (jetsam_kill_top_proc() < 0) {
-                               break;
-                       }
-               }
+       error = sysctl_handle_int(oidp, &pid, 0, req);
+       if (error || !req->newptr)
+               return (error);
 
-               kern_memorystatus_last_level = kern_memorystatus_level;
+       p = proc_find(pid);
+       if (p != NULL) {
+               error = task_thaw(p->task);
+               proc_rele(p);
+               
+               if (error)
+                       error = EIO;
+               return error;
+       }
 
-               ev_msg.vendor_code    = KEV_VENDOR_APPLE;
-               ev_msg.kev_class      = KEV_SYSTEM_CLASS;
-               ev_msg.kev_subclass   = KEV_MEMORYSTATUS_SUBCLASS;
+       return EINVAL;
+}
 
-               /* pass the memory status level (percent free) */
-               ev_msg.event_code     = kMemoryStatusLevelNote;
+SYSCTL_PROC(_kern, OID_AUTO, memorystatus_thaw, CTLTYPE_INT|CTLFLAG_WR|CTLFLAG_LOCKED|CTLFLAG_MASKED,
+    0, 0, &sysctl_memorystatus_available_pages_thaw, "I", "");
 
-               ev_msg.dv[0].data_length = sizeof kern_memorystatus_last_level;
-               ev_msg.dv[0].data_ptr = &kern_memorystatus_last_level;
-               ev_msg.dv[1].data_length = sizeof data;
-               ev_msg.dv[1].data_ptr = &data;
-               ev_msg.dv[2].data_length = 0;
+#endif /* CONFIG_FREEZE */
 
-               data.free_pages = vm_page_free_count;
-               data.active_pages = vm_page_active_count;
-               data.inactive_pages = vm_page_inactive_count;
-               data.purgeable_pages = vm_page_purgeable_count;
-               data.wired_pages = vm_page_wire_count;
+extern kern_return_t kernel_thread_start_priority(thread_continue_t continuation,
+                                                  void *parameter,
+                                                  integer_t priority,
+                                                  thread_t *new_thread);
 
-               ret = kev_post_msg(&ev_msg);
-               if (ret) {
-                       kern_memorystatus_kev_failure_count++;
-                       printf("%s: kev_post_msg() failed, err %d\n", __func__, ret);
-               }
+static proc_t memorystatus_get_first_proc_locked(unsigned int *bucket_index, boolean_t search) {
+       memstat_bucket_t *current_bucket;
+       proc_t next_p;
 
-               if (jetsam_snapshot_list_count) {
-                       size_t snapshot_size =  sizeof(jetsam_kernel_stats_t) + sizeof(size_t) + sizeof(jetsam_snapshot_entry_t) * jetsam_snapshot_list_count;
-                       ev_msg.event_code = kMemoryStatusSnapshotNote;
-                       ev_msg.dv[0].data_length = sizeof snapshot_size;
-                       ev_msg.dv[0].data_ptr = &snapshot_size;
-                       ev_msg.dv[1].data_length = 0;
+       if ((*bucket_index) >= MEMSTAT_BUCKET_COUNT) {
+               return NULL;
+       }
 
-                       ret = kev_post_msg(&ev_msg);
-                       if (ret) {
-                               kern_memorystatus_kev_failure_count++;
-                               printf("%s: kev_post_msg() failed, err %d\n", __func__, ret);
-                       }
+       current_bucket = &memstat_bucket[*bucket_index];
+       next_p = TAILQ_FIRST(&current_bucket->list);
+       if (!next_p && search) {
+               while (!next_p && (++(*bucket_index) < MEMSTAT_BUCKET_COUNT)) {
+                       current_bucket = &memstat_bucket[*bucket_index];
+                       next_p = TAILQ_FIRST(&current_bucket->list);
                }
+       }
+       
+       return next_p;
+}
 
-               if (kern_memorystatus_level >= kern_memorystatus_last_level + 5 ||
-                   kern_memorystatus_level <= kern_memorystatus_last_level - 5)
-                       continue;
+static proc_t memorystatus_get_next_proc_locked(unsigned int *bucket_index, proc_t p, boolean_t search) {
+       memstat_bucket_t *current_bucket;
+       proc_t next_p;
+        
+       if (!p || ((*bucket_index) >= MEMSTAT_BUCKET_COUNT)) {
+               return NULL;
+       }
 
-               assert_wait(&kern_memorystatus_wakeup, THREAD_UNINT);
-               (void)thread_block((thread_continue_t)kern_memorystatus_thread);
+       next_p = TAILQ_NEXT(p, p_memstat_list);
+       while (!next_p && search && (++(*bucket_index) < MEMSTAT_BUCKET_COUNT)) {
+               current_bucket = &memstat_bucket[*bucket_index];
+               next_p = TAILQ_FIRST(&current_bucket->list);
        }
+
+       return next_p;
 }
 
-static int
-sysctl_io_variable(struct sysctl_req *req, void *pValue, size_t currentsize, size_t maxsize, size_t *newsize)
+__private_extern__ void
+memorystatus_init(void)
 {
-    int error;
+       thread_t thread = THREAD_NULL;
+       kern_return_t result;
+       int i;
 
-    /* Copy blob out */
-    error = SYSCTL_OUT(req, pValue, currentsize);
+       nanoseconds_to_absolutetime((uint64_t)DEFERRED_IDLE_EXIT_TIME_SECS * NSEC_PER_SEC, &memorystatus_idle_delay_time);
+       
+       /* Init buckets */
+       for (i = 0; i < MEMSTAT_BUCKET_COUNT; i++) {
+               TAILQ_INIT(&memstat_bucket[i].list);
+               memstat_bucket[i].count = 0;
+       }
+       
+       memorystatus_idle_demotion_call = thread_call_allocate((thread_call_func_t)memorystatus_perform_idle_demotion, NULL);
 
-    /* error or nothing to set */
-    if (error || !req->newptr)
-        return(error);
+       /* Apply overrides */
+       PE_get_default("kern.jetsam_delta", &delta_percentage, sizeof(delta_percentage));
+       assert(delta_percentage < 100);
+       PE_get_default("kern.jetsam_critical_threshold", &critical_threshold_percentage, sizeof(critical_threshold_percentage));
+       assert(critical_threshold_percentage < 100);
+       PE_get_default("kern.jetsam_idle_offset", &idle_offset_percentage, sizeof(idle_offset_percentage));
+       assert(idle_offset_percentage < 100);
+       PE_get_default("kern.jetsam_pressure_threshold", &pressure_threshold_percentage, sizeof(pressure_threshold_percentage));
+       assert(pressure_threshold_percentage < 100);
+       PE_get_default("kern.jetsam_freeze_threshold", &freeze_threshold_percentage, sizeof(freeze_threshold_percentage));
+       assert(freeze_threshold_percentage < 100);
+       
+#if CONFIG_JETSAM
+       memorystatus_delta = delta_percentage * atop_64(max_mem) / 100;
+#if !LATENCY_JETSAM
+       memorystatus_available_pages_critical_idle_offset = idle_offset_percentage * atop_64(max_mem) / 100;
+#endif
 
-    if (req->newlen > maxsize) {
-               return EINVAL;
+       memorystatus_available_pages_critical_base = (critical_threshold_percentage / delta_percentage) * memorystatus_delta;
+       
+       memorystatus_jetsam_snapshot_max = maxproc;
+       memorystatus_jetsam_snapshot = 
+               (memorystatus_jetsam_snapshot_t*)kalloc(sizeof(memorystatus_jetsam_snapshot_t) +
+               sizeof(memorystatus_jetsam_snapshot_entry_t) * memorystatus_jetsam_snapshot_max);
+       if (!memorystatus_jetsam_snapshot) {
+               panic("Could not allocate memorystatus_jetsam_snapshot");
+       }
+
+       /* No contention at this point */
+       memorystatus_update_levels_locked(FALSE);
+#endif
+       
+#if CONFIG_FREEZE
+       memorystatus_freeze_threshold = (freeze_threshold_percentage / delta_percentage) * memorystatus_delta;
+#endif
+       
+       result = kernel_thread_start_priority(memorystatus_thread, NULL, 95 /* MAXPRI_KERNEL */, &thread);
+       if (result == KERN_SUCCESS) {
+               thread_deallocate(thread);
+       } else {
+               panic("Could not create memorystatus_thread");
        }
-       error = SYSCTL_IN(req, pValue, req->newlen);
+}
+
+/* Centralised for the purposes of allowing panic-on-jetsam */
+extern void
+vm_wake_compactor_swapper(void);
+
+static boolean_t
+memorystatus_do_kill(proc_t p, uint32_t cause) {
 
-       if (!error) {
-               *newsize = req->newlen;
+       int retval = 0;
+
+#if CONFIG_JETSAM && (DEVELOPMENT || DEBUG)
+       if (memorystatus_jetsam_panic_debug & (1 << cause)) {
+               panic("memorystatus_do_kill(): jetsam debug panic (cause: %d)", cause);
+       }
+#else
+#pragma unused(cause)
+#endif
+       int jetsam_flags = P_LTERM_JETSAM;
+       switch (cause) {
+               case kMemorystatusKilledHiwat:                  jetsam_flags |= P_JETSAM_HIWAT; break;
+               case kMemorystatusKilledVnodes:                 jetsam_flags |= P_JETSAM_VNODE; break;
+               case kMemorystatusKilledVMPageShortage:         jetsam_flags |= P_JETSAM_VMPAGESHORTAGE; break;
+               case kMemorystatusKilledVMThrashing:            jetsam_flags |= P_JETSAM_VMTHRASHING; break;
+               case kMemorystatusKilledPerProcessLimit:        jetsam_flags |= P_JETSAM_PID; break;
+               case kMemorystatusKilledIdleExit:               jetsam_flags |= P_JETSAM_IDLEEXIT; break;
        }
+       retval = exit1_internal(p, W_EXITCODE(0, SIGKILL), (int *)NULL, FALSE, FALSE, jetsam_flags);
 
-    return(error);
+       if (COMPRESSED_PAGER_IS_ACTIVE || DEFAULT_FREEZER_COMPRESSED_PAGER_IS_ACTIVE) {
+               vm_wake_compactor_swapper();
+       }
+       
+       return (retval == 0);
 }
 
-static int
-sysctl_handle_kern_memorystatus_priority_list(__unused struct sysctl_oid *oid, __unused void *arg1, __unused int arg2, struct sysctl_req *req)
+/*
+ * Node manipulation
+ */
+
+static void
+memorystatus_check_levels_locked(void) {
+#if CONFIG_JETSAM
+       /* Update levels */
+       memorystatus_update_levels_locked(TRUE);
+#endif
+}
+
+static void
+memorystatus_perform_idle_demotion(__unused void *spare1, __unused void *spare2) 
 {
-       int i, ret;
-       jetsam_priority_entry_t temp_list[kMaxPriorityEntries];
-       size_t newsize, currentsize;
+       proc_t p;
+       uint64_t current_time;
+       memstat_bucket_t *demotion_bucket;
+   
+       MEMORYSTATUS_DEBUG(1, "memorystatus_perform_idle_demotion()\n");
+   
+       KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_MEMSTAT, BSD_MEMSTAT_IDLE_DEMOTE) | DBG_FUNC_START, 0, 0, 0, 0, 0);
+       current_time = mach_absolute_time();
+       proc_list_lock();
 
-       if (req->oldptr) {
-               lck_mtx_lock(jetsam_list_mlock);
-               for (i = 0; i < jetsam_priority_list_count; i++) {
-                       temp_list[i] = jetsam_priority_list[i];
+       demotion_bucket = &memstat_bucket[JETSAM_PRIORITY_IDLE_DEFERRED];
+       p = TAILQ_FIRST(&demotion_bucket->list);
+           
+       while (p) {
+               MEMORYSTATUS_DEBUG(1, "memorystatus_perform_idle_demotion() found %d\n", p->p_pid);
+               
+               assert(p->p_memstat_idledeadline);
+               assert(p->p_memstat_dirty & P_DIRTY_DEFER_IN_PROGRESS);
+               assert((p->p_memstat_dirty & (P_DIRTY_IDLE_EXIT_ENABLED|P_DIRTY_IS_DIRTY)) == P_DIRTY_IDLE_EXIT_ENABLED);
+        
+               if (current_time >= p->p_memstat_idledeadline) {
+#if DEBUG || DEVELOPMENT
+                       if (!(p->p_memstat_dirty & P_DIRTY_MARKED)) {
+                               printf("memorystatus_perform_idle_demotion: moving process %d to idle band, but never dirtied (0x%x)!\n", p->p_pid, p->p_memstat_dirty);
+                       }
+#endif
+                       memorystatus_invalidate_idle_demotion_locked(p, TRUE);
+                       memorystatus_update_priority_locked(p, JETSAM_PRIORITY_IDLE);
+                       
+                       // The prior process has moved out of the demotion bucket, so grab the new head and continue
+                       p = TAILQ_FIRST(&demotion_bucket->list);
+                       continue;
                }
-               lck_mtx_unlock(jetsam_list_mlock);
+               
+               // No further candidates
+               break;
        }
+       
+       memorystatus_reschedule_idle_demotion_locked();
+       
+       proc_list_unlock();
 
-       currentsize = sizeof(jetsam_priority_list[0]) * jetsam_priority_list_count;
+       KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_MEMSTAT, BSD_MEMSTAT_IDLE_DEMOTE) | DBG_FUNC_END, 0, 0, 0, 0, 0);
+}
 
-       ret = sysctl_io_variable(req, &temp_list[0], currentsize, sizeof(temp_list), &newsize);
+static void
+memorystatus_schedule_idle_demotion_locked(proc_t p, boolean_t set_state) 
+{      
+       MEMORYSTATUS_DEBUG(1, "memorystatus_schedule_idle_demotion_locked: scheduling demotion to idle band for process %d (dirty:0x%x, set_state %d, demotions %d).\n", 
+           p->p_pid, p->p_memstat_dirty, set_state, memorystatus_scheduled_idle_demotions);
 
-       if (!ret && req->newptr) {
-               jetsam_priority_list_count = newsize / sizeof(jetsam_priority_list[0]);
-#if DEBUG 
-               printf("set jetsam priority pids = { ");
-               for (i = 0; i < jetsam_priority_list_count; i++) {
-                       printf("%d ", temp_list[i].pid);
-               }
-               printf("}\n");
-#endif /* DEBUG */
-               lck_mtx_lock(jetsam_list_mlock);
-               for (i = 0; i < jetsam_priority_list_count; i++) {
-                       jetsam_priority_list[i] = temp_list[i];
-               }
-               for (i = jetsam_priority_list_count; i < kMaxPriorityEntries; i++) {
-                       jetsam_priority_list[i].pid = 0;
-                       jetsam_priority_list[i].flags = 0;
+       assert((p->p_memstat_dirty & (P_DIRTY_IDLE_EXIT_ENABLED|P_DIRTY_DEFER_IN_PROGRESS)) == (P_DIRTY_IDLE_EXIT_ENABLED|P_DIRTY_DEFER_IN_PROGRESS));
+
+       if (set_state) {
+               assert(p->p_memstat_idledeadline == 0);
+               p->p_memstat_idledeadline = mach_absolute_time() + memorystatus_idle_delay_time;
+       }
+       
+       assert(p->p_memstat_idledeadline);
+       
+       memorystatus_scheduled_idle_demotions++;
+}
+
+static void
+memorystatus_invalidate_idle_demotion_locked(proc_t p, boolean_t clear_state) 
+{
+       MEMORYSTATUS_DEBUG(1, "memorystatus_invalidate_idle_demotion(): invalidating demotion to idle band for process %d (clear_state %d, demotions %d).\n", 
+           p->p_pid, clear_state, memorystatus_scheduled_idle_demotions);
+    
+       assert(p->p_memstat_idledeadline);
+       if (clear_state) {
+               p->p_memstat_idledeadline = 0;
+               p->p_memstat_dirty &= ~P_DIRTY_DEFER_IN_PROGRESS;
+       }
+       
+       memorystatus_scheduled_idle_demotions--;
+       assert(memorystatus_scheduled_idle_demotions >= 0);
+}
+
+static void
+memorystatus_reschedule_idle_demotion_locked(void) {
+       if (0 == memorystatus_scheduled_idle_demotions) {
+               if (memstat_idle_demotion_deadline) {
+                       /* Transitioned 1->0, so cancel next call */
+                       thread_call_cancel(memorystatus_idle_demotion_call);
+                       memstat_idle_demotion_deadline = 0;
+               }
+       } else {
+               memstat_bucket_t *demotion_bucket;
+               proc_t p;
+               demotion_bucket = &memstat_bucket[JETSAM_PRIORITY_IDLE_DEFERRED];
+               p = TAILQ_FIRST(&demotion_bucket->list);
+               assert(p && p->p_memstat_idledeadline);
+               
+               if (memstat_idle_demotion_deadline != p->p_memstat_idledeadline){
+                       thread_call_enter_delayed(memorystatus_idle_demotion_call, p->p_memstat_idledeadline);
+                       memstat_idle_demotion_deadline = p->p_memstat_idledeadline;
                }
-               jetsam_priority_list_index = 0;
-               lck_mtx_unlock(jetsam_list_mlock);
-       }       
-       return ret;
+       }
 }
 
-static int
-sysctl_handle_kern_memorystatus_snapshot(__unused struct sysctl_oid *oid, __unused void *arg1, __unused int arg2, struct sysctl_req *req)
+/* 
+ * List manipulation
+ */
+int 
+memorystatus_add(proc_t p, boolean_t locked)
 {
-       int ret;
-       size_t currentsize = 0;
+       memstat_bucket_t *bucket;
+       
+       MEMORYSTATUS_DEBUG(1, "memorystatus_list_add(): adding process %d with priority %d.\n", p->pid, priority);
+   
+       if (!locked) {
+               proc_list_lock();
+       }
+       
+       /* Processes marked internal do not have priority tracked */
+       if (p->p_memstat_state & P_MEMSTAT_INTERNAL) {
+                goto exit;
+       }
+       
+       bucket = &memstat_bucket[p->p_memstat_effectivepriority];
+       
+       TAILQ_INSERT_TAIL(&bucket->list, p, p_memstat_list);
+       bucket->count++;
+
+       memorystatus_list_count++;
+
+       memorystatus_check_levels_locked();
+       
+exit:
+       if (!locked) {
+               proc_list_unlock();
+       }
+       
+       return 0;
+}
 
-       if (jetsam_snapshot_list_count > 0) {
-               currentsize = sizeof(jetsam_kernel_stats_t) + sizeof(size_t) + sizeof(jetsam_snapshot_entry_t) * jetsam_snapshot_list_count;
+static void
+memorystatus_update_priority_locked(proc_t p, int priority)
+{
+       memstat_bucket_t *old_bucket, *new_bucket;
+       
+       assert(priority < MEMSTAT_BUCKET_COUNT);
+       
+       /* Ensure that exit isn't underway, leaving the proc retained but removed from its bucket */
+       if ((p->p_listflag & P_LIST_EXITED) != 0) {
+               return;
        }
-       if (!currentsize) {
-               if (req->oldptr) {
-#ifdef DEBUG
-                       printf("kern.memorystatus_snapshot returning EINVAL\n");
-#endif
-                       return EINVAL;
+       
+       MEMORYSTATUS_DEBUG(1, "memorystatus_update_priority_locked(): setting process %d to priority %d\n", p->p_pid, priority);        
+
+       old_bucket = &memstat_bucket[p->p_memstat_effectivepriority];
+       TAILQ_REMOVE(&old_bucket->list, p, p_memstat_list);
+       old_bucket->count--;
+       
+       new_bucket = &memstat_bucket[priority]; 
+       TAILQ_INSERT_TAIL(&new_bucket->list, p, p_memstat_list);
+       new_bucket->count++;
+       
+#if CONFIG_JETSAM
+       if (memorystatus_highwater_enabled && (p->p_memstat_state & P_MEMSTAT_MEMLIMIT_BACKGROUND)) {        
+               if (((priority >= JETSAM_PRIORITY_FOREGROUND) && (p->p_memstat_effectivepriority < JETSAM_PRIORITY_FOREGROUND)) ||
+                       ((priority < JETSAM_PRIORITY_FOREGROUND) && (p->p_memstat_effectivepriority >= JETSAM_PRIORITY_FOREGROUND))) {            
+                       int32_t memlimit = (priority >= JETSAM_PRIORITY_FOREGROUND) ? -1 : p->p_memstat_memlimit;
+                       task_set_phys_footprint_limit_internal(p->task, (memlimit  > 0) ? memlimit : -1, NULL, TRUE);
                }
-               else {
-#ifdef DEBUG
-                       printf("kern.memorystatus_snapshot returning 0 for size\n");
+       }
 #endif
-               }
-       } else {
-#ifdef DEBUG
-                       printf("kern.memorystatus_snapshot returning %ld for size\n", (long)currentsize);
+       
+       p->p_memstat_effectivepriority = priority;
+       
+       memorystatus_check_levels_locked();
+}
+
+int
+memorystatus_update(proc_t p, int priority, uint64_t user_data, boolean_t effective, boolean_t update_memlimit, int32_t memlimit, boolean_t memlimit_background)
+{
+       int ret;
+       
+#if !CONFIG_JETSAM
+#pragma unused(update_memlimit, memlimit, memlimit_background)
 #endif
-       }       
-       ret = sysctl_io_variable(req, &jetsam_snapshot, currentsize, 0, NULL);
-       if (!ret && req->oldptr) {
-               jetsam_snapshot.entry_count = jetsam_snapshot_list_count = 0;
+
+       MEMORYSTATUS_DEBUG(1, "memorystatus_update: changing process %d: priority %d, user_data 0x%llx\n", p->p_pid, priority, user_data);
+    
+       KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_MEMSTAT, BSD_MEMSTAT_UPDATE) | DBG_FUNC_START, p->p_pid, priority, user_data, effective, 0);
+       
+       if (priority == -1) {
+               /* Use as shorthand for default priority */
+               priority = JETSAM_PRIORITY_DEFAULT;
+       } else if (priority == JETSAM_PRIORITY_IDLE_DEFERRED) {
+               /* JETSAM_PRIORITY_IDLE_DEFERRED is reserved for internal use; if requested, adjust to JETSAM_PRIORITY_IDLE. */
+               priority = JETSAM_PRIORITY_IDLE;                
+       } else if ((priority < 0) || (priority >= MEMSTAT_BUCKET_COUNT)) {
+               /* Sanity check */
+               ret = EINVAL;
+               goto out;
+       }
+       
+       proc_list_lock();
+       
+       assert(!(p->p_memstat_state & P_MEMSTAT_INTERNAL));
+
+       if (effective && (p->p_memstat_state & P_MEMSTAT_PRIORITYUPDATED)) {
+               ret = EALREADY;
+               proc_list_unlock();
+               MEMORYSTATUS_DEBUG(1, "memorystatus_update: effective change specified for pid %d, but change already occurred.\n", pid);
+               goto out;             
+       }
+
+       p->p_memstat_state |= P_MEMSTAT_PRIORITYUPDATED;
+       p->p_memstat_userdata = user_data;
+       p->p_memstat_requestedpriority = priority;
+       
+#if CONFIG_JETSAM
+       if (update_memlimit) {
+               p->p_memstat_memlimit = memlimit;
+               if (memlimit_background) {
+                       /* Will be set as priority is updated */
+                       p->p_memstat_state |= P_MEMSTAT_MEMLIMIT_BACKGROUND;
+               } else {
+                       /* Otherwise, apply now */
+                       if (memorystatus_highwater_enabled) {
+                               task_set_phys_footprint_limit_internal(p->task, (memlimit  > 0) ? memlimit : -1, NULL, TRUE);
+                       }
+               }
        }
+#endif
+
+       memorystatus_update_priority_locked(p, priority);
+       
+       proc_list_unlock();
+       ret = 0;
+
+out:
+       KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_MEMSTAT, BSD_MEMSTAT_UPDATE) | DBG_FUNC_END, ret, 0, 0, 0, 0);
+
        return ret;
 }
 
-SYSCTL_PROC(_kern, OID_AUTO, memorystatus_priority_list, CTLTYPE_OPAQUE|CTLFLAG_RW, 0, 0, sysctl_handle_kern_memorystatus_priority_list, "S,jetsam_priorities", "");
-SYSCTL_PROC(_kern, OID_AUTO, memorystatus_snapshot, CTLTYPE_OPAQUE|CTLFLAG_RD, 0, 0, sysctl_handle_kern_memorystatus_snapshot, "S,jetsam_snapshot", "");
+int
+memorystatus_remove(proc_t p, boolean_t locked)
+{
+       int ret;
+       memstat_bucket_t *bucket;
+
+       MEMORYSTATUS_DEBUG(1, "memorystatus_list_remove: removing process %d\n", pid);
+
+       if (!locked) {
+               proc_list_lock();
+       }
+
+       assert(!(p->p_memstat_state & P_MEMSTAT_INTERNAL));
+
+       bucket = &memstat_bucket[p->p_memstat_effectivepriority];
+       TAILQ_REMOVE(&bucket->list, p, p_memstat_list);
+       bucket->count--;
+
+       memorystatus_list_count--;
+
+       /* If awaiting demotion to the idle band, clean up */
+       if (p->p_memstat_effectivepriority == JETSAM_PRIORITY_IDLE_DEFERRED) {
+               memorystatus_invalidate_idle_demotion_locked(p, TRUE);
+               memorystatus_reschedule_idle_demotion_locked();
+       }
+
+       memorystatus_check_levels_locked();
+
+#if CONFIG_FREEZE    
+       if (p->p_memstat_state & (P_MEMSTAT_FROZEN)) {
+               memorystatus_frozen_count--;
+       }
+
+       if (p->p_memstat_state & P_MEMSTAT_SUSPENDED) {
+               memorystatus_suspended_footprint_total -= p->p_memstat_suspendedfootprint;
+               memorystatus_suspended_count--;
+       }
+#endif
+
+       if (!locked) {
+               proc_list_unlock();
+       }
+
+       if (p) {
+               ret = 0; 
+       } else {
+               ret = ESRCH;
+       }
+
+       return ret;
+}
+
+static boolean_t
+memorystatus_validate_track_flags(struct proc *target_p, uint32_t pcontrol) {
+       /* See that the process isn't marked for termination */
+       if (target_p->p_memstat_dirty & P_DIRTY_TERMINATED) {
+               return FALSE;
+       }
+       
+       /* Idle exit requires that process be tracked */
+       if ((pcontrol & PROC_DIRTY_ALLOW_IDLE_EXIT) &&
+          !(pcontrol & PROC_DIRTY_TRACK)) {
+               return FALSE;           
+       }
+
+       /* Deferral is only relevant if idle exit is specified */
+       if ((pcontrol & PROC_DIRTY_DEFER) && 
+          !(pcontrol & PROC_DIRTY_ALLOWS_IDLE_EXIT)) {
+               return FALSE;           
+       }
+       
+       return TRUE;
+}
+
+static void
+memorystatus_update_idle_priority_locked(proc_t p) {
+       int32_t priority;
+       
+       MEMORYSTATUS_DEBUG(1, "memorystatus_update_idle_priority_locked(): pid %d dirty 0x%X\n", p->p_pid, p->p_memstat_dirty);
+       
+       if ((p->p_memstat_dirty & (P_DIRTY_IDLE_EXIT_ENABLED|P_DIRTY_IS_DIRTY)) == P_DIRTY_IDLE_EXIT_ENABLED) {
+               priority = (p->p_memstat_dirty & P_DIRTY_DEFER_IN_PROGRESS) ? JETSAM_PRIORITY_IDLE_DEFERRED : JETSAM_PRIORITY_IDLE;
+       } else {
+               priority = p->p_memstat_requestedpriority;
+       }
+       
+       memorystatus_update_priority_locked(p, priority);
+} 
+
+/*
+ * Processes can opt to have their state tracked by the kernel, indicating  when they are busy (dirty) or idle
+ * (clean). They may also indicate that they support termination when idle, with the result that they are promoted
+ * to their desired, higher, jetsam priority when dirty (and are therefore killed later), and demoted to the low
+ * priority idle band when clean (and killed earlier, protecting higher priority procesess).
+ *
+ * If the deferral flag is set, then newly tracked processes will be protected for an initial period (as determined by
+ * memorystatus_idle_delay_time); if they go clean during this time, then they will be moved to a deferred-idle band
+ * with a slightly higher priority, guarding against immediate termination under memory pressure and being unable to
+ * make forward progress. Finally, when the guard expires, they will be moved to the standard, lowest-priority, idle
+ * band. The deferral can be cleared early by clearing the appropriate flag.
+ *
+ * The deferral timer is active only for the duration that the process is marked as guarded and clean; if the process
+ * is marked dirty, the timer will be cancelled. Upon being subsequently marked clean, the deferment will either be
+ * re-enabled or the guard state cleared, depending on whether the guard deadline has passed.
+ */
+
+int
+memorystatus_dirty_track(proc_t p, uint32_t pcontrol) {
+       unsigned int old_dirty;
+       boolean_t reschedule = FALSE;
+       int ret;
+    
+       proc_list_lock();
+       
+       if (p->p_memstat_state & P_MEMSTAT_INTERNAL) {
+               ret = EPERM;
+               goto exit;
+       }
+       
+       if (!memorystatus_validate_track_flags(p, pcontrol)) {
+               ret = EINVAL;
+               goto exit;
+        }
+
+        old_dirty = p->p_memstat_dirty;
+
+       /* These bits are cumulative, as per <rdar://problem/11159924> */
+       if (pcontrol & PROC_DIRTY_TRACK) {
+               p->p_memstat_dirty |= P_DIRTY_TRACK;
+       }
+
+       if (pcontrol & PROC_DIRTY_ALLOW_IDLE_EXIT) {
+               p->p_memstat_dirty |= P_DIRTY_ALLOW_IDLE_EXIT;                                  
+       }
+
+       /* This can be set and cleared exactly once. */
+       if ((pcontrol & PROC_DIRTY_DEFER) && !(old_dirty & P_DIRTY_DEFER)) {
+               p->p_memstat_dirty |= (P_DIRTY_DEFER|P_DIRTY_DEFER_IN_PROGRESS);                                
+       } else {
+               p->p_memstat_dirty &= ~P_DIRTY_DEFER_IN_PROGRESS;                                       
+       }
+
+       MEMORYSTATUS_DEBUG(1, "memorystatus_on_track_dirty(): set idle-exit %s / deferred %s / dirty %s for process %d\n",
+               ((p->p_memstat_dirty & P_DIRTY_IDLE_EXIT_ENABLED) == P_DIRTY_IDLE_EXIT_ENABLED) ? "Y" : "N",
+               p->p_memstat_dirty & P_DIRTY_DEFER_IN_PROGRESS ? "Y" : "N",
+               p->p_memstat_dirty & P_DIRTY ? "Y" : "N",
+               p->p_pid);
+
+       /* Kick off or invalidate the idle exit deferment if there's a state transition. */
+       if (!(p->p_memstat_dirty & P_DIRTY_IS_DIRTY)) {
+               if (((p->p_memstat_dirty & P_DIRTY_IDLE_EXIT_ENABLED) == P_DIRTY_IDLE_EXIT_ENABLED) && 
+                       (p->p_memstat_dirty & P_DIRTY_DEFER_IN_PROGRESS) && !(old_dirty & P_DIRTY_DEFER_IN_PROGRESS)) {
+                       memorystatus_schedule_idle_demotion_locked(p, TRUE);
+                       reschedule = TRUE;
+               } else if (!(p->p_memstat_dirty & P_DIRTY_DEFER_IN_PROGRESS) && (old_dirty & P_DIRTY_DEFER_IN_PROGRESS)) {
+                       memorystatus_invalidate_idle_demotion_locked(p, TRUE);
+                       reschedule = TRUE;
+               }
+       }
+
+       memorystatus_update_idle_priority_locked(p);
+       
+       if (reschedule) {
+               memorystatus_reschedule_idle_demotion_locked();
+       }
+               
+       ret = 0;
+       
+exit:          
+       proc_list_unlock();
+       
+       return ret;
+}
+
+int
+memorystatus_dirty_set(proc_t p, boolean_t self, uint32_t pcontrol) {
+       int ret;
+       boolean_t kill = false;
+       boolean_t reschedule = FALSE;
+       boolean_t was_dirty = FALSE;
+       boolean_t now_dirty = FALSE;
+
+       MEMORYSTATUS_DEBUG(1, "memorystatus_dirty_set(): %d %d 0x%x 0x%x\n", self, p->p_pid, pcontrol, p->p_memstat_dirty);
+
+       proc_list_lock();
+
+       if (p->p_memstat_state & P_MEMSTAT_INTERNAL) {
+               ret = EPERM;
+               goto exit;
+       }
+
+       if (p->p_memstat_dirty & P_DIRTY_IS_DIRTY)
+               was_dirty = TRUE;
+
+       if (!(p->p_memstat_dirty & P_DIRTY_TRACK)) {
+               /* Dirty tracking not enabled */
+               ret = EINVAL;                   
+       } else if (pcontrol && (p->p_memstat_dirty & P_DIRTY_TERMINATED)) {
+               /* 
+                * Process is set to be terminated and we're attempting to mark it dirty.
+                * Set for termination and marking as clean is OK - see <rdar://problem/10594349>.
+                */
+               ret = EBUSY;            
+       } else {
+               int flag = (self == TRUE) ? P_DIRTY : P_DIRTY_SHUTDOWN;
+               if (pcontrol && !(p->p_memstat_dirty & flag)) {
+                       /* Mark the process as having been dirtied at some point */
+                       p->p_memstat_dirty |= (flag | P_DIRTY_MARKED);
+                       memorystatus_dirty_count++;
+                       ret = 0;
+               } else if ((pcontrol == 0) && (p->p_memstat_dirty & flag)) {
+                       if ((flag == P_DIRTY_SHUTDOWN) && (!p->p_memstat_dirty & P_DIRTY)) {
+                               /* Clearing the dirty shutdown flag, and the process is otherwise clean - kill */
+                               p->p_memstat_dirty |= P_DIRTY_TERMINATED;
+                               kill = true;
+                       } else if ((flag == P_DIRTY) && (p->p_memstat_dirty & P_DIRTY_TERMINATED)) {
+                               /* Kill previously terminated processes if set clean */
+                               kill = true;                                            
+                       }
+                       p->p_memstat_dirty &= ~flag;
+                       memorystatus_dirty_count--;
+                       ret = 0;
+               } else {
+                       /* Already set */
+                       ret = EALREADY;
+               }
+       }
+
+       if (ret != 0) {
+               goto exit;
+       }
+           
+       if (p->p_memstat_dirty & P_DIRTY_IS_DIRTY)
+               now_dirty = TRUE;
+
+       if ((was_dirty == TRUE && now_dirty == FALSE) ||
+           (was_dirty == FALSE && now_dirty == TRUE)) {
+
+               /* Manage idle exit deferral, if applied */
+               if ((p->p_memstat_dirty & (P_DIRTY_IDLE_EXIT_ENABLED|P_DIRTY_DEFER_IN_PROGRESS)) ==
+                   (P_DIRTY_IDLE_EXIT_ENABLED|P_DIRTY_DEFER_IN_PROGRESS)) {
+                       if (p->p_memstat_dirty & P_DIRTY_IS_DIRTY) {
+                               memorystatus_invalidate_idle_demotion_locked(p, FALSE);
+                               reschedule = TRUE;
+                       } else {
+                               /* We evaluate lazily, so reset the idle-deadline if it's expired by the time the process becomes clean. */
+                               if (mach_absolute_time() >= p->p_memstat_idledeadline) {
+                                       p->p_memstat_idledeadline = 0;
+                                       p->p_memstat_dirty &= ~P_DIRTY_DEFER_IN_PROGRESS;
+                               } else {
+                                       memorystatus_schedule_idle_demotion_locked(p, FALSE);
+                                       reschedule = TRUE;
+                               }
+                       }
+               }
+    
+               memorystatus_update_idle_priority_locked(p);
+       
+               /* If the deferral state changed, reschedule the demotion timer */
+               if (reschedule) {
+                       memorystatus_reschedule_idle_demotion_locked();
+               }
+       }
+               
+       if (kill) {
+               psignal(p, SIGKILL);
+       }
+       
+exit:
+       proc_list_unlock();
+
+       return ret;
+}
+
+int
+memorystatus_dirty_get(proc_t p) {
+       int ret = 0;
+    
+       proc_list_lock();
+       
+       if (p->p_memstat_dirty & P_DIRTY_TRACK) {
+               ret |= PROC_DIRTY_TRACKED;
+               if (p->p_memstat_dirty & P_DIRTY_ALLOW_IDLE_EXIT) {
+                       ret |= PROC_DIRTY_ALLOWS_IDLE_EXIT;
+               }
+               if (p->p_memstat_dirty & P_DIRTY) {
+                       ret |= PROC_DIRTY_IS_DIRTY;
+               }
+       }
+       
+       proc_list_unlock();
+    
+       return ret;
+}
+
+int
+memorystatus_on_terminate(proc_t p) {
+       int sig;
+    
+       proc_list_lock();
+       
+       p->p_memstat_dirty |= P_DIRTY_TERMINATED;
+       
+       if ((p->p_memstat_dirty & (P_DIRTY_TRACK|P_DIRTY_IS_DIRTY)) == P_DIRTY_TRACK) {
+               /* Clean; mark as terminated and issue SIGKILL */
+               sig = SIGKILL;
+       } else {
+               /* Dirty, terminated, or state tracking is unsupported; issue SIGTERM to allow cleanup */
+               sig = SIGTERM;
+       }
+
+       proc_list_unlock();
+       
+       return sig;
+}
+
+void
+memorystatus_on_suspend(proc_t p)
+{
+#if CONFIG_FREEZE
+       uint32_t pages;
+       memorystatus_get_task_page_counts(p->task, &pages, NULL);
+#endif
+       proc_list_lock();
+#if CONFIG_FREEZE
+       p->p_memstat_suspendedfootprint = pages;
+       memorystatus_suspended_footprint_total += pages;
+       memorystatus_suspended_count++;
+#endif
+       p->p_memstat_state |= P_MEMSTAT_SUSPENDED;
+       proc_list_unlock();
+}
+
+void
+memorystatus_on_resume(proc_t p)
+{
+#if CONFIG_FREEZE
+       boolean_t frozen;
+       pid_t pid;
+#endif
+
+       proc_list_lock();
+
+#if CONFIG_FREEZE
+       frozen = (p->p_memstat_state & P_MEMSTAT_FROZEN);
+       if (frozen) {
+               memorystatus_frozen_count--;
+               p->p_memstat_state |= P_MEMSTAT_PRIOR_THAW;
+       }
+
+       memorystatus_suspended_footprint_total -= p->p_memstat_suspendedfootprint;
+       memorystatus_suspended_count--;
+       
+       pid = p->p_pid;
+#endif
+
+       p->p_memstat_state &= ~(P_MEMSTAT_SUSPENDED | P_MEMSTAT_FROZEN);
+
+       proc_list_unlock();
+    
+#if CONFIG_FREEZE
+       if (frozen) {
+               memorystatus_freeze_entry_t data = { pid, FALSE, 0 };
+               memorystatus_send_note(kMemorystatusFreezeNote, &data, sizeof(data));
+       }
+#endif
+}
+
+void
+memorystatus_on_inactivity(proc_t p)
+{
+#pragma unused(p)
+#if CONFIG_FREEZE
+       /* Wake the freeze thread */
+       thread_wakeup((event_t)&memorystatus_freeze_wakeup);
+#endif 
+}
+
+static uint32_t
+memorystatus_build_state(proc_t p) {
+       uint32_t snapshot_state = 0;
+    
+       /* General */
+       if (p->p_memstat_state & P_MEMSTAT_SUSPENDED) {
+               snapshot_state |= kMemorystatusSuspended;
+       }
+       if (p->p_memstat_state & P_MEMSTAT_FROZEN) {
+               snapshot_state |= kMemorystatusFrozen;
+       }
+       if (p->p_memstat_state & P_MEMSTAT_PRIOR_THAW) {
+               snapshot_state |= kMemorystatusWasThawed;
+       }
+       
+       /* Tracking */
+       if (p->p_memstat_dirty & P_DIRTY_TRACK) {
+               snapshot_state |= kMemorystatusTracked;
+       }
+       if ((p->p_memstat_dirty & P_DIRTY_IDLE_EXIT_ENABLED) == P_DIRTY_IDLE_EXIT_ENABLED) {
+               snapshot_state |= kMemorystatusSupportsIdleExit;
+       }
+       if (p->p_memstat_dirty & P_DIRTY_IS_DIRTY) {
+               snapshot_state |= kMemorystatusDirty;
+       }
+
+       return snapshot_state;
+}
+
+#if !CONFIG_JETSAM
+
+static boolean_t
+kill_idle_exit_proc(void)
+{
+       proc_t p, victim_p = PROC_NULL;
+       uint64_t current_time;
+       boolean_t killed = FALSE;
+       unsigned int i = 0;
+
+       /* Pick next idle exit victim. */
+       current_time = mach_absolute_time();
+       
+       proc_list_lock();
+       
+       p = memorystatus_get_first_proc_locked(&i, FALSE);
+       while (p) {
+               /* No need to look beyond the idle band */
+               if (p->p_memstat_effectivepriority != JETSAM_PRIORITY_IDLE) {
+                       break;
+               }
+               
+               if ((p->p_memstat_dirty & (P_DIRTY_ALLOW_IDLE_EXIT|P_DIRTY_IS_DIRTY|P_DIRTY_TERMINATED)) == (P_DIRTY_ALLOW_IDLE_EXIT)) {                                
+                       if (current_time >= p->p_memstat_idledeadline) {
+                               p->p_memstat_dirty |= P_DIRTY_TERMINATED;
+                               victim_p = proc_ref_locked(p);
+                               break;
+                       }
+               }
+               
+               p = memorystatus_get_next_proc_locked(&i, p, FALSE);
+       }
+       
+       proc_list_unlock();
+       
+       if (victim_p) {
+               printf("memorystatus_thread: idle exiting pid %d [%s]\n", victim_p->p_pid, (victim_p->p_comm ? victim_p->p_comm : "(unknown)"));
+               killed = memorystatus_do_kill(victim_p, kMemorystatusKilledIdleExit);
+               proc_rele(victim_p);
+       }
+
+       return killed;
+}
+#endif
+
+static void
+memorystatus_thread_wake(void) {
+       thread_wakeup((event_t)&memorystatus_wakeup);
+}
+
+static int
+memorystatus_thread_block(uint32_t interval_ms, thread_continue_t continuation)
+{
+       if (interval_ms) {
+               assert_wait_timeout(&memorystatus_wakeup, THREAD_UNINT, interval_ms, 1000 * NSEC_PER_USEC);
+       } else {
+               assert_wait(&memorystatus_wakeup, THREAD_UNINT);
+       }
+       
+       return thread_block(continuation);   
+}
+
+extern boolean_t vm_compressor_thrashing_detected;
+extern uint64_t vm_compressor_total_compressions(void);
+
+static void
+memorystatus_thread(void *param __unused, wait_result_t wr __unused)
+{
+       static boolean_t is_vm_privileged = FALSE;
+#if CONFIG_JETSAM
+       boolean_t post_snapshot = FALSE;
+       uint32_t errors = 0;
+#endif
+
+       if (is_vm_privileged == FALSE) {
+               /* 
+                * It's the first time the thread has run, so just mark the thread as privileged and block.
+                * This avoids a spurious pass with unset variables, as set out in <rdar://problem/9609402>.
+                */
+               thread_wire(host_priv_self(), current_thread(), TRUE);
+               is_vm_privileged = TRUE;
+               
+               memorystatus_thread_block(0, memorystatus_thread);
+       }
+       
+#if CONFIG_JETSAM
+       
+       KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_MEMSTAT, BSD_MEMSTAT_SCAN) | DBG_FUNC_START,
+               memorystatus_available_pages, 0, 0, 0, 0);
+
+       uint32_t cause = vm_compressor_thrashing_detected ? kMemorystatusKilledVMThrashing : kMemorystatusKilledVMPageShortage;
+
+       /* Jetsam aware version.
+        *
+        * If woken under pressure, go down the path of killing:
+        *
+        * - processes exceeding their highwater mark if no clean victims available
+        * - the least recently used process if no highwater mark victims available
+        */
+#if !LATENCY_JETSAM       
+       while (vm_compressor_thrashing_detected || memorystatus_available_pages <= memorystatus_available_pages_critical) {
+#else
+       while (kill_under_pressure) {
+               const uint32_t SNAPSHOT_WAIT_TIMEOUT_MS = 100;
+               wait_result_t wait_result;
+#endif
+               boolean_t killed;
+               int32_t priority;
+
+#if LEGACY_HIWATER
+               /* Highwater */
+               killed = memorystatus_kill_hiwat_proc(&errors);
+               if (killed) {
+                       post_snapshot = TRUE;
+                       goto done;
+               }
+#endif
+               
+               /* LRU */
+               killed = memorystatus_kill_top_process(TRUE, cause, &priority, &errors);
+               if (killed) {
+                       if (!kill_under_pressure && (priority != JETSAM_PRIORITY_IDLE)) {
+                               /* Don't generate logs for steady-state idle-exit kills */
+                               post_snapshot = TRUE;
+                       }
+                       goto done;
+               }
+                       
+               /* Under pressure and unable to kill a process - panic */
+               panic("memorystatus_jetsam_thread: no victim! available pages:%d\n", memorystatus_available_pages);
+                       
+done:          
+               kill_under_pressure = FALSE;
+               vm_compressor_thrashing_detected = FALSE;
+                               
+#if LATENCY_JETSAM
+               KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_MEMSTAT, BSD_MEMSTAT_LATENCY_COALESCE) | DBG_FUNC_START,
+                       memorystatus_available_pages, 0, 0, 0, 0);
+               thread_wakeup((event_t)&latency_jetsam_wakeup);
+               /* 
+                * Coalesce snapshot reports in the face of repeated jetsams by blocking here with a timeout. 
+                * If the wait expires, issue the note.
+                */
+               wait_result = memorystatus_thread_block(SNAPSHOT_WAIT_TIMEOUT_MS, THREAD_CONTINUE_NULL);        
+               KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_MEMSTAT, BSD_MEMSTAT_LATENCY_COALESCE) | DBG_FUNC_END,
+                       memorystatus_available_pages, 0, 0, 0, 0);
+               if (wait_result != THREAD_AWAKENED) {
+                       /* Catch-all */
+                       break;
+               }
+#endif
+       }
+               
+       if (errors) {
+               memorystatus_clear_errors();
+       }
+
+#if VM_PRESSURE_EVENTS
+       memorystatus_update_vm_pressure(TRUE);
+#endif
+
+       if (post_snapshot) {
+               size_t snapshot_size = sizeof(memorystatus_jetsam_snapshot_t) +
+                       sizeof(memorystatus_jetsam_snapshot_entry_t) * (memorystatus_jetsam_snapshot_count);
+               memorystatus_jetsam_snapshot->notification_time = mach_absolute_time();
+               memorystatus_send_note(kMemorystatusSnapshotNote, &snapshot_size, sizeof(snapshot_size));
+       }
+       
+       KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_MEMSTAT, BSD_MEMSTAT_SCAN) | DBG_FUNC_END,
+               memorystatus_available_pages, 0, 0, 0, 0);
+
+#else /* CONFIG_JETSAM */
+
+       /* Simple version.
+        *
+        * Jetsam not enabled, so just kill the first suitable clean process
+        * and sleep.
+        */
+
+       if (kill_idle_exit) {
+               kill_idle_exit_proc();
+               kill_idle_exit = FALSE;
+       }
+       
+#endif /* CONFIG_JETSAM */
+
+       memorystatus_thread_block(0, memorystatus_thread);
+}
+
+#if !CONFIG_JETSAM
+boolean_t memorystatus_idle_exit_from_VM(void) {
+       kill_idle_exit = TRUE;  
+       memorystatus_thread_wake();
+       return TRUE;
+}
+#endif
+
+#if CONFIG_JETSAM
+
+/*
+ * Callback invoked when allowable physical memory footprint exceeded
+ * (dirty pages + IOKit mappings)
+ *
+ * This is invoked for both advisory, non-fatal per-task high watermarks,
+ * as well as the fatal system-wide task memory limit.
+ */
+void
+memorystatus_on_ledger_footprint_exceeded(boolean_t warning, const int max_footprint_mb)
+{
+       proc_t p = current_proc();
+    
+       printf("process %d (%s) %s physical memory footprint limit of %d MB\n",
+               p->p_pid, p->p_comm,
+               warning ? "approaching" : "exceeded",
+               max_footprint_mb);
+
+#if VM_PRESSURE_EVENTS
+       if (warning == TRUE) {
+               if (memorystatus_warn_process(p->p_pid) != TRUE) {
+                       /* Print warning, since it's possible that task has not registered for pressure notifications */
+                       printf("task_exceeded_footprint: failed to warn the current task (exiting?).\n");                       
+               }
+               return;
+       }
+#endif /* VM_PRESSURE_EVENTS */
+
+       if (p->p_memstat_memlimit <= 0) {
+               /*
+                * If this process has no high watermark, then we have been invoked because the task
+                * has violated the system-wide per-task memory limit.
+                */
+               if (memorystatus_kill_process_sync(p->p_pid, kMemorystatusKilledPerProcessLimit) != TRUE) {
+                       printf("task_exceeded_footprint: failed to kill the current task (exiting?).\n");
+               }
+       }
+}
+
+static void
+memorystatus_get_task_page_counts(task_t task, uint32_t *footprint, uint32_t *max_footprint)
+{
+       assert(task);
+       assert(footprint);
+    
+       *footprint = (uint32_t)(get_task_phys_footprint(task) / PAGE_SIZE_64);
+       if (max_footprint) {
+               *max_footprint = (uint32_t)(get_task_phys_footprint_max(task) / PAGE_SIZE_64);
+       }
+}
+
+static int
+memorystatus_send_note(int event_code, void *data, size_t data_length) {
+       int ret;
+       struct kev_msg ev_msg;
+       
+       ev_msg.vendor_code    = KEV_VENDOR_APPLE;
+       ev_msg.kev_class      = KEV_SYSTEM_CLASS;
+       ev_msg.kev_subclass   = KEV_MEMORYSTATUS_SUBCLASS;
+
+       ev_msg.event_code     = event_code;
+
+       ev_msg.dv[0].data_length = data_length;
+       ev_msg.dv[0].data_ptr = data;
+       ev_msg.dv[1].data_length = 0;
+
+       ret = kev_post_msg(&ev_msg);
+       if (ret) {
+               printf("%s: kev_post_msg() failed, err %d\n", __func__, ret);
+       }
+       
+       return ret;
+}
+
+static void
+memorystatus_update_snapshot_locked(proc_t p, uint32_t kill_cause)
+{
+       unsigned int i;
+
+       for (i = 0; i < memorystatus_jetsam_snapshot_count; i++) {
+               if (memorystatus_jetsam_snapshot_list[i].pid == p->p_pid) {
+                       /* Update if the priority has changed since the snapshot was taken */
+                       if (memorystatus_jetsam_snapshot_list[i].priority != p->p_memstat_effectivepriority) {
+                               memorystatus_jetsam_snapshot_list[i].priority = p->p_memstat_effectivepriority;
+                               strlcpy(memorystatus_jetsam_snapshot_list[i].name, p->p_comm, MAXCOMLEN+1);
+                               memorystatus_jetsam_snapshot_list[i].state = memorystatus_build_state(p);
+                               memorystatus_jetsam_snapshot_list[i].user_data = p->p_memstat_userdata;
+                               memorystatus_jetsam_snapshot_list[i].fds = p->p_fd->fd_nfiles;
+                       }
+                       memorystatus_jetsam_snapshot_list[i].killed = kill_cause;
+                       return;
+               }
+       }
+}
+
+void memorystatus_pages_update(unsigned int pages_avail)
+{
+       boolean_t critical, delta;
+        
+       if (!memorystatus_delta) {
+           return;
+       }
+       
+       critical = (pages_avail < memorystatus_available_pages_critical) ? TRUE : FALSE;
+       delta = ((pages_avail >= (memorystatus_available_pages + memorystatus_delta)) 
+                || (memorystatus_available_pages >= (pages_avail + memorystatus_delta))) ? TRUE : FALSE;
+        
+       if (critical || delta) {
+               memorystatus_available_pages = pages_avail;
+               memorystatus_level = memorystatus_available_pages * 100 / atop_64(max_mem);
+
+#if LATENCY_JETSAM
+               /* Bail early to avoid excessive wake-ups */
+               if (critical) {
+                       return;
+               }
+#endif
+
+               memorystatus_thread_wake();
+       }
+}
+
+static boolean_t
+memorystatus_get_snapshot_properties_for_proc_locked(proc_t p, memorystatus_jetsam_snapshot_entry_t *entry)
+{      
+       memset(entry, 0, sizeof(memorystatus_jetsam_snapshot_entry_t));
+       
+       entry->pid = p->p_pid;
+       strlcpy(&entry->name[0], p->p_comm, MAXCOMLEN+1);
+       entry->priority = p->p_memstat_effectivepriority;
+       memorystatus_get_task_page_counts(p->task, &entry->pages, &entry->max_pages);
+       entry->state = memorystatus_build_state(p);
+       entry->user_data = p->p_memstat_userdata;
+       memcpy(&entry->uuid[0], &p->p_uuid[0], sizeof(p->p_uuid));
+
+       return TRUE;    
+}
+
+static void
+memorystatus_jetsam_snapshot_procs_locked(void)
+{
+       proc_t p, next_p;
+       unsigned int b = 0, i = 0;
+       kern_return_t kr = KERN_SUCCESS;
+
+       mach_msg_type_number_t  count = HOST_VM_INFO64_COUNT;
+       vm_statistics64_data_t  vm_stat;
+
+       if ((kr = host_statistics64(host_self(), HOST_VM_INFO64, (host_info64_t)&vm_stat, &count) != KERN_SUCCESS)) {
+               printf("memorystatus_jetsam_snapshot_procs_locked: host_statistics64 failed with %d\n", kr);
+               memset(&memorystatus_jetsam_snapshot->stats, 0, sizeof(memorystatus_jetsam_snapshot->stats));
+       } else {
+               memorystatus_jetsam_snapshot->stats.free_pages = vm_stat.free_count;
+               memorystatus_jetsam_snapshot->stats.active_pages = vm_stat.active_count;
+               memorystatus_jetsam_snapshot->stats.inactive_pages = vm_stat.inactive_count;
+               memorystatus_jetsam_snapshot->stats.throttled_pages = vm_stat.throttled_count;
+               memorystatus_jetsam_snapshot->stats.purgeable_pages = vm_stat.purgeable_count;
+               memorystatus_jetsam_snapshot->stats.wired_pages = vm_stat.wire_count;
+               
+               memorystatus_jetsam_snapshot->stats.speculative_pages = vm_stat.speculative_count;
+               memorystatus_jetsam_snapshot->stats.filebacked_pages = vm_stat.external_page_count;
+               memorystatus_jetsam_snapshot->stats.anonymous_pages = vm_stat.internal_page_count;
+               memorystatus_jetsam_snapshot->stats.compressions = vm_stat.compressions;
+               memorystatus_jetsam_snapshot->stats.decompressions = vm_stat.decompressions;
+               memorystatus_jetsam_snapshot->stats.compressor_pages = vm_stat.compressor_page_count;
+               memorystatus_jetsam_snapshot->stats.total_uncompressed_pages_in_compressor = vm_stat.total_uncompressed_pages_in_compressor;
+       }
+
+       next_p = memorystatus_get_first_proc_locked(&b, TRUE);
+       while (next_p) {
+               p = next_p;
+               next_p = memorystatus_get_next_proc_locked(&b, p, TRUE);
+               
+               if (FALSE == memorystatus_get_snapshot_properties_for_proc_locked(p, &memorystatus_jetsam_snapshot_list[i])) {
+                       continue;
+               }
+               
+               MEMORYSTATUS_DEBUG(0, "jetsam snapshot pid = %d, uuid = %02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x\n",
+                       p->p_pid, 
+                       p->p_uuid[0], p->p_uuid[1], p->p_uuid[2], p->p_uuid[3], p->p_uuid[4], p->p_uuid[5], p->p_uuid[6], p->p_uuid[7],
+                       p->p_uuid[8], p->p_uuid[9], p->p_uuid[10], p->p_uuid[11], p->p_uuid[12], p->p_uuid[13], p->p_uuid[14], p->p_uuid[15]);
+
+               if (++i == memorystatus_jetsam_snapshot_max) {
+                       break;
+               }       
+       }
+
+       memorystatus_jetsam_snapshot->snapshot_time = mach_absolute_time();
+       memorystatus_jetsam_snapshot->entry_count = memorystatus_jetsam_snapshot_count = i;
+}
+
+#if DEVELOPMENT || DEBUG
+
+static int
+memorystatus_cmd_set_panic_bits(user_addr_t buffer, uint32_t buffer_size) {
+       int ret;
+       memorystatus_jetsam_panic_options_t debug;
+       
+       if (buffer_size != sizeof(memorystatus_jetsam_panic_options_t)) {
+               return EINVAL;
+       }
+
+       ret = copyin(buffer, &debug, buffer_size);
+       if (ret) {
+               return ret;
+       }
+       
+       /* Panic bits match kMemorystatusKilled* enum */
+       memorystatus_jetsam_panic_debug = (memorystatus_jetsam_panic_debug & ~debug.mask) | (debug.data & debug.mask);
+       
+       /* Copyout new value */
+       debug.data = memorystatus_jetsam_panic_debug;
+       ret = copyout(&debug, buffer, sizeof(memorystatus_jetsam_panic_options_t));
+       
+       return ret;
+}
+
+#endif
+
+/*
+ * Jetsam a specific process.
+ */
+static boolean_t 
+memorystatus_kill_specific_process(pid_t victim_pid, uint32_t cause) {
+       boolean_t killed;
+       proc_t p;
+
+       /* TODO - add a victim queue and push this into the main jetsam thread */
+
+       p = proc_find(victim_pid);
+       if (!p) {
+               return FALSE;
+       }
+
+       printf("memorystatus: specifically killing pid %d [%s] - memorystatus_available_pages: %d\n", 
+               victim_pid, (p->p_comm ? p->p_comm : "(unknown)"), memorystatus_available_pages);
+
+       proc_list_lock();
+
+       if (memorystatus_jetsam_snapshot_count == 0) {
+               memorystatus_jetsam_snapshot_procs_locked();
+       }
+
+       memorystatus_update_snapshot_locked(p, cause);
+       proc_list_unlock();
+       
+       killed = memorystatus_do_kill(p, cause);
+       proc_rele(p);
+       
+       return killed;
+}
+
+/*
+ * Jetsam the first process in the queue.
+ */
+static boolean_t
+memorystatus_kill_top_process(boolean_t any, uint32_t cause, int32_t *priority, uint32_t *errors)
+{
+       pid_t aPid;
+       proc_t p = PROC_NULL, next_p = PROC_NULL;
+       boolean_t new_snapshot = FALSE, killed = FALSE;
+       unsigned int i = 0;
+
+#ifndef CONFIG_FREEZE
+#pragma unused(any)
+#endif
+       
+       KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_MEMSTAT, BSD_MEMSTAT_JETSAM) | DBG_FUNC_START,
+               memorystatus_available_pages, 0, 0, 0, 0);
+
+       proc_list_lock();
+
+       next_p = memorystatus_get_first_proc_locked(&i, TRUE);
+       while (next_p) {
+#if DEVELOPMENT || DEBUG
+               int activeProcess;
+               int procSuspendedForDiagnosis;
+#endif /* DEVELOPMENT || DEBUG */
+        
+               p = next_p;
+               next_p = memorystatus_get_next_proc_locked(&i, p, TRUE);
+               
+#if DEVELOPMENT || DEBUG
+               activeProcess = p->p_memstat_state & P_MEMSTAT_FOREGROUND;
+               procSuspendedForDiagnosis = p->p_memstat_state & P_MEMSTAT_DIAG_SUSPENDED;
+#endif /* DEVELOPMENT || DEBUG */
+               
+               aPid = p->p_pid;
+
+               if (p->p_memstat_state & (P_MEMSTAT_ERROR | P_MEMSTAT_TERMINATED)) {
+                       continue;
+               }
+                   
+#if DEVELOPMENT || DEBUG
+               if ((memorystatus_jetsam_policy & kPolicyDiagnoseActive) && procSuspendedForDiagnosis) {
+                       printf("jetsam: continuing after ignoring proc suspended already for diagnosis - %d\n", aPid);
+                       continue;
+               }
+#endif /* DEVELOPMENT || DEBUG */
+
+#if CONFIG_FREEZE
+               boolean_t skip;
+               boolean_t reclaim_proc = !(p->p_memstat_state & (P_MEMSTAT_LOCKED | P_MEMSTAT_NORECLAIM));
+               if (any || reclaim_proc) {
+                       skip = FALSE;
+               } else {
+                       skip = TRUE;
+               }
+                       
+               if (skip) {
+                       continue;
+               } else
+#endif
+               {
+                       if (priority) {
+                               *priority = p->p_memstat_effectivepriority;
+                       }
+                       
+                       /*
+                        * Capture a snapshot if none exists and:
+                        * - priority was not requested (this is something other than an ambient kill)
+                        * - the priority was requested *and* the targeted process is not at idle priority
+                        */
+                       if ((memorystatus_jetsam_snapshot_count == 0) && 
+                           ((!priority) || (priority && (*priority != JETSAM_PRIORITY_IDLE)))) {
+                               memorystatus_jetsam_snapshot_procs_locked();
+                               new_snapshot = TRUE;
+                       }
+                       
+                       /* 
+                        * Mark as terminated so that if exit1() indicates success, but the process (for example)
+                        * is blocked in task_exception_notify(), it'll be skipped if encountered again - see 
+                        * <rdar://problem/13553476>. This is cheaper than examining P_LEXIT, which requires the 
+                        * acquisition of the proc lock.
+                        */
+                       p->p_memstat_state |= P_MEMSTAT_TERMINATED;
+                       
+#if DEVELOPMENT || DEBUG
+                       if ((memorystatus_jetsam_policy & kPolicyDiagnoseActive) && activeProcess) {
+                               MEMORYSTATUS_DEBUG(1, "jetsam: suspending pid %d [%s] (active) for diagnosis - memory_status_level: %d\n",
+                                       aPid, (p->p_comm ? p->p_comm: "(unknown)"), memorystatus_level);
+                               memorystatus_update_snapshot_locked(p, kMemorystatusKilledDiagnostic);
+                               p->p_memstat_state |= P_MEMSTAT_DIAG_SUSPENDED;
+                               if (memorystatus_jetsam_policy & kPolicyDiagnoseFirst) {
+                                       jetsam_diagnostic_suspended_one_active_proc = 1;
+                                       printf("jetsam: returning after suspending first active proc - %d\n", aPid);
+                               }
+                               
+                               p = proc_ref_locked(p);
+                               proc_list_unlock();
+                               if (p) {
+                                       task_suspend(p->task);
+                                       proc_rele(p);
+                                       killed = TRUE;
+                               }
+                               
+                               goto exit;
+                       } else
+#endif /* DEVELOPMENT || DEBUG */
+                       {
+                               /* Shift queue, update stats */
+                               memorystatus_update_snapshot_locked(p, cause);
+                               
+                               p = proc_ref_locked(p);
+                               proc_list_unlock();
+                               if (p) {
+                                       printf("memorystatus: jetsam killing pid %d [%s] - memorystatus_available_pages: %d\n", 
+                                               aPid, (p->p_comm ? p->p_comm : "(unknown)"), memorystatus_available_pages);
+                                       killed = memorystatus_do_kill(p, cause);
+                               }
+                               
+                               /* Success? */
+                               if (killed) {
+                                       proc_rele(p);
+                                       goto exit;
+                               }
+                               
+                               /* Failure - unwind and restart. */
+                               proc_list_lock();
+                               proc_rele_locked(p);
+                               p->p_memstat_state &= ~P_MEMSTAT_TERMINATED;
+                               p->p_memstat_state |= P_MEMSTAT_ERROR;
+                               *errors += 1;
+                               i = 0;
+                               next_p = memorystatus_get_first_proc_locked(&i, TRUE);
+                       }
+               }
+       }
+       
+       proc_list_unlock();
+       
+exit:
+       /* Clear snapshot if freshly captured and no target was found */
+       if (new_snapshot && !killed) {
+           memorystatus_jetsam_snapshot->entry_count = memorystatus_jetsam_snapshot_count = 0;
+       }
+       
+       KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_MEMSTAT, BSD_MEMSTAT_JETSAM) | DBG_FUNC_END,
+           memorystatus_available_pages, killed ? aPid : 0, 0, 0, 0);
+
+       return killed;
+}
+
+#if LEGACY_HIWATER
+
+static boolean_t
+memorystatus_kill_hiwat_proc(uint32_t *errors)
+{
+       pid_t aPid = 0;
+       proc_t p = PROC_NULL, next_p = PROC_NULL;
+       boolean_t new_snapshot = FALSE, killed = FALSE;
+       unsigned int i = 0;
+       
+       KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_MEMSTAT, BSD_MEMSTAT_JETSAM_HIWAT) | DBG_FUNC_START,
+               memorystatus_available_pages, 0, 0, 0, 0);
+       
+       proc_list_lock();
+       
+       next_p = memorystatus_get_first_proc_locked(&i, TRUE);
+       while (next_p) {
+               uint32_t footprint;
+               boolean_t skip;
+
+               p = next_p;
+               next_p = memorystatus_get_next_proc_locked(&i, p, TRUE);
+               
+               aPid = p->p_pid;
+               
+               if (p->p_memstat_state  & (P_MEMSTAT_ERROR | P_MEMSTAT_TERMINATED)) {
+                       continue;
+               }
+               
+               /* skip if no limit set */
+               if (p->p_memstat_memlimit <= 0) {
+                       continue;
+               }
+               
+               /* skip if a currently inapplicable limit is encountered */
+               if ((p->p_memstat_state & P_MEMSTAT_MEMLIMIT_BACKGROUND) && (p->p_memstat_effectivepriority >= JETSAM_PRIORITY_FOREGROUND)) {          
+                       continue;
+               }
+
+               footprint = (uint32_t)(get_task_phys_footprint(p->task) / (1024 * 1024));
+               skip = (((int32_t)footprint) <= p->p_memstat_memlimit);
+#if DEVELOPMENT || DEBUG
+               if (!skip && (memorystatus_jetsam_policy & kPolicyDiagnoseActive)) {
+                       if (p->p_memstat_state & P_MEMSTAT_DIAG_SUSPENDED) {
+                               continue;
+                       }
+               }
+#endif /* DEVELOPMENT || DEBUG */
+
+#if CONFIG_FREEZE
+               if (!skip) {
+                       if (p->p_memstat_state & P_MEMSTAT_LOCKED) {
+                               skip = TRUE;
+                       } else {
+                               skip = FALSE;
+                       }                               
+               }
+#endif
+
+               if (skip) {
+                       continue;
+               } else {
+                       MEMORYSTATUS_DEBUG(1, "jetsam: %s pid %d [%s] - %d pages > 1 (%d)\n",
+                               (memorystatus_jetsam_policy & kPolicyDiagnoseActive) ? "suspending": "killing", aPid, p->p_comm, pages, hiwat);
+                               
+                       if (memorystatus_jetsam_snapshot_count == 0) {
+                               memorystatus_jetsam_snapshot_procs_locked();
+                               new_snapshot = TRUE;
+                       }
+                       
+                       p->p_memstat_state |= P_MEMSTAT_TERMINATED;
+                               
+#if DEVELOPMENT || DEBUG
+                       if (memorystatus_jetsam_policy & kPolicyDiagnoseActive) {
+                               MEMORYSTATUS_DEBUG(1, "jetsam: pid %d suspended for diagnosis - memorystatus_available_pages: %d\n", aPid, memorystatus_available_pages);
+                               memorystatus_update_snapshot_locked(p, kMemorystatusKilledDiagnostic);
+                               p->p_memstat_state |= P_MEMSTAT_DIAG_SUSPENDED;
+                               
+                               p = proc_ref_locked(p);
+                               proc_list_unlock();
+                               if (p) {
+                                       task_suspend(p->task);
+                                       proc_rele(p);
+                                       killed = TRUE;
+                               }
+                               
+                               goto exit;
+                       } else
+#endif /* DEVELOPMENT || DEBUG */
+                       {
+                               memorystatus_update_snapshot_locked(p, kMemorystatusKilledHiwat);
+                               
+                               p = proc_ref_locked(p);
+                               proc_list_unlock();
+                               if (p) {
+                                   printf("memorystatus: jetsam killing pid %d [%s] (highwater) - memorystatus_available_pages: %d\n", 
+                                               aPid, (p->p_comm ? p->p_comm : "(unknown)"), memorystatus_available_pages);
+                                   killed = memorystatus_do_kill(p, kMemorystatusKilledHiwat);
+                               }
+                               
+                               /* Success? */
+                               if (killed) {
+                                       proc_rele(p);
+                                       goto exit;
+                               }
+
+                               /* Failure - unwind and restart. */
+                               proc_list_lock();
+                               proc_rele_locked(p);
+                               p->p_memstat_state &= ~P_MEMSTAT_TERMINATED;
+                               p->p_memstat_state |= P_MEMSTAT_ERROR;
+                               *errors += 1;
+                               i = 0;
+                               next_p = memorystatus_get_first_proc_locked(&i, TRUE);
+                       }
+               }
+       }
+       
+       proc_list_unlock();
+       
+exit:
+       /* Clear snapshot if freshly captured and no target was found */
+       if (new_snapshot && !killed) {
+               memorystatus_jetsam_snapshot->entry_count = memorystatus_jetsam_snapshot_count = 0;
+       }
+       
+       KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_MEMSTAT, BSD_MEMSTAT_JETSAM_HIWAT) | DBG_FUNC_END, 
+           memorystatus_available_pages, killed ? aPid : 0, 0, 0, 0);
+
+       return killed;
+}
+
+#endif /* LEGACY_HIWATER */
+
+static boolean_t 
+memorystatus_kill_process_async(pid_t victim_pid, uint32_t cause) {
+       /* TODO: allow a general async path */
+       if ((victim_pid != -1) || (cause != kMemorystatusKilledVMPageShortage || cause != kMemorystatusKilledVMThrashing)) {
+               return FALSE;
+       }
+    
+       kill_under_pressure = TRUE;
+       memorystatus_thread_wake();
+       return TRUE;
+}
+
+static boolean_t 
+memorystatus_kill_process_sync(pid_t victim_pid, uint32_t cause) {
+       boolean_t res;
+       uint32_t errors = 0;
+    
+       if (victim_pid == -1) {
+               /* No pid, so kill first process */
+               res = memorystatus_kill_top_process(TRUE, cause, NULL, &errors);
+       } else {
+               res = memorystatus_kill_specific_process(victim_pid, cause);
+       }
+       
+       if (errors) {
+               memorystatus_clear_errors();
+       }
+    
+       if (res == TRUE) {
+               /* Fire off snapshot notification */
+               size_t snapshot_size = sizeof(memorystatus_jetsam_snapshot_t) + 
+                       sizeof(memorystatus_jetsam_snapshot_entry_t) * memorystatus_jetsam_snapshot_count;
+               memorystatus_jetsam_snapshot->notification_time = mach_absolute_time();
+               memorystatus_send_note(kMemorystatusSnapshotNote, &snapshot_size, sizeof(snapshot_size));
+       }
+    
+       return res;
+}
+
+boolean_t 
+memorystatus_kill_on_VM_page_shortage(boolean_t async) {
+       if (async) {
+               return memorystatus_kill_process_async(-1, kMemorystatusKilledVMPageShortage);
+       } else {
+               return memorystatus_kill_process_sync(-1, kMemorystatusKilledVMPageShortage);
+       }
+}
+
+boolean_t
+memorystatus_kill_on_VM_thrashing(boolean_t async) {
+       if (async) {
+               return memorystatus_kill_process_async(-1, kMemorystatusKilledVMThrashing);
+       } else {
+               return memorystatus_kill_process_sync(-1, kMemorystatusKilledVMThrashing);
+       }
+}
+
+boolean_t 
+memorystatus_kill_on_vnode_limit(void) {
+       return memorystatus_kill_process_sync(-1, kMemorystatusKilledVnodes);
+}
+
+#endif /* CONFIG_JETSAM */
+
+#if CONFIG_FREEZE
+
+__private_extern__ void
+memorystatus_freeze_init(void)
+{
+       kern_return_t result;
+       thread_t thread;
+               
+       result = kernel_thread_start(memorystatus_freeze_thread, NULL, &thread);
+       if (result == KERN_SUCCESS) {
+               thread_deallocate(thread);
+       } else {
+               panic("Could not create memorystatus_freeze_thread");
+       }
+}
+
+static int
+memorystatus_freeze_top_process(boolean_t *memorystatus_freeze_swap_low)
+{
+       pid_t aPid = 0;
+       int ret = -1;
+       proc_t p = PROC_NULL, next_p = PROC_NULL;
+       unsigned int i = 0;
+
+       KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_MEMSTAT, BSD_MEMSTAT_FREEZE) | DBG_FUNC_START,
+               memorystatus_available_pages, 0, 0, 0, 0);
+
+       proc_list_lock();
+       
+       next_p = memorystatus_get_first_proc_locked(&i, TRUE);
+       while (next_p) {
+               kern_return_t kr;
+               uint32_t purgeable, wired, clean, dirty;
+               boolean_t shared;
+               uint32_t pages;
+               uint32_t max_pages = 0;
+               uint32_t state;
+               
+               p = next_p;
+               next_p = memorystatus_get_next_proc_locked(&i, p, TRUE);
+
+               aPid = p->p_pid;
+               state = p->p_memstat_state;
+
+               /* Ensure the process is eligible for freezing */
+               if ((state & (P_MEMSTAT_TERMINATED | P_MEMSTAT_LOCKED | P_MEMSTAT_FROZEN)) || !(state & P_MEMSTAT_SUSPENDED)) {
+                       continue; // with lock held
+               }
+                                       
+               /* Only freeze processes meeting our minimum resident page criteria */
+               memorystatus_get_task_page_counts(p->task, &pages, NULL);
+               if (pages < memorystatus_freeze_pages_min) {
+                       continue; // with lock held
+               } 
+
+               if (DEFAULT_FREEZER_IS_ACTIVE || DEFAULT_FREEZER_COMPRESSED_PAGER_IS_ACTIVE) {
+                       /* Ensure there's enough free space to freeze this process. */                  
+                       max_pages = MIN(default_pager_swap_pages_free(), memorystatus_freeze_pages_max);
+                       if (max_pages < memorystatus_freeze_pages_min) {
+                               *memorystatus_freeze_swap_low = TRUE;
+                               proc_list_unlock();
+                               goto exit;
+                       }
+               } else {
+                       max_pages = UINT32_MAX - 1;
+               }
+               
+               /* Mark as locked temporarily to avoid kill */
+               p->p_memstat_state |= P_MEMSTAT_LOCKED;
+
+               p = proc_ref_locked(p);
+               proc_list_unlock();        
+               if (!p) {
+                       goto exit;
+               }
+        
+               kr = task_freeze(p->task, &purgeable, &wired, &clean, &dirty, max_pages, &shared, FALSE);
+               
+               MEMORYSTATUS_DEBUG(1, "memorystatus_freeze_top_process: task_freeze %s for pid %d [%s] - "
+                       "memorystatus_pages: %d, purgeable: %d, wired: %d, clean: %d, dirty: %d, shared %d, free swap: %d\n", 
+                       (kr == KERN_SUCCESS) ? "SUCCEEDED" : "FAILED", aPid, (p->p_comm ? p->p_comm : "(unknown)"), 
+                       memorystatus_available_pages, purgeable, wired, clean, dirty, shared, default_pager_swap_pages_free());
+     
+               proc_list_lock();
+               p->p_memstat_state &= ~P_MEMSTAT_LOCKED;
+               
+               /* Success? */
+               if (KERN_SUCCESS == kr) {
+                       memorystatus_freeze_entry_t data = { aPid, TRUE, dirty };
+                       
+                       memorystatus_frozen_count++;
+                       
+                       p->p_memstat_state |= (P_MEMSTAT_FROZEN | (shared ? 0: P_MEMSTAT_NORECLAIM));
+               
+                       /* Update stats */
+                       for (i = 0; i < sizeof(throttle_intervals) / sizeof(struct throttle_interval_t); i++) {
+                                       throttle_intervals[i].pageouts += dirty;
+                       }
+               
+                       memorystatus_freeze_pageouts += dirty;
+                       memorystatus_freeze_count++;
+
+                       proc_list_unlock();
+
+                       memorystatus_send_note(kMemorystatusFreezeNote, &data, sizeof(data));
+
+                       /* Return the number of reclaimed pages */
+                       ret = dirty;
+
+               } else {
+                       proc_list_unlock();
+               }
+        
+               proc_rele(p);
+               goto exit;
+       }
+       
+       proc_list_unlock();
+       
+exit:
+       KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_MEMSTAT, BSD_MEMSTAT_FREEZE) | DBG_FUNC_END,
+               memorystatus_available_pages, aPid, 0, 0, 0);
+       
+       return ret;
+}
+
+static inline boolean_t 
+memorystatus_can_freeze_processes(void) 
+{
+       boolean_t ret;
+       
+       proc_list_lock();
+       
+       if (memorystatus_suspended_count) {
+               uint32_t average_resident_pages, estimated_processes;
+        
+               /* Estimate the number of suspended processes we can fit */
+               average_resident_pages = memorystatus_suspended_footprint_total / memorystatus_suspended_count;
+               estimated_processes = memorystatus_suspended_count +
+                       ((memorystatus_available_pages - memorystatus_available_pages_critical) / average_resident_pages);
+
+               /* If it's predicted that no freeze will occur, lower the threshold temporarily */
+               if (estimated_processes <= FREEZE_SUSPENDED_THRESHOLD_DEFAULT) {
+                       memorystatus_freeze_suspended_threshold = FREEZE_SUSPENDED_THRESHOLD_LOW;
+               } else {
+                       memorystatus_freeze_suspended_threshold = FREEZE_SUSPENDED_THRESHOLD_DEFAULT;
+               }
+
+               MEMORYSTATUS_DEBUG(1, "memorystatus_can_freeze_processes: %d suspended processes, %d average resident pages / process, %d suspended processes estimated\n", 
+                       memorystatus_suspended_count, average_resident_pages, estimated_processes);
+       
+               if ((memorystatus_suspended_count - memorystatus_frozen_count) > memorystatus_freeze_suspended_threshold) {
+                       ret = TRUE;
+               } else {
+                       ret = FALSE;
+               }
+       } else {
+               ret = FALSE;
+       }
+                               
+       proc_list_unlock();
+       
+       return ret;
+}
+
+static boolean_t 
+memorystatus_can_freeze(boolean_t *memorystatus_freeze_swap_low)
+{
+       /* Only freeze if we're sufficiently low on memory; this holds off freeze right
+          after boot,  and is generally is a no-op once we've reached steady state. */
+       if (memorystatus_available_pages > memorystatus_freeze_threshold) {
+               return FALSE;
+       }
+       
+       /* Check minimum suspended process threshold. */
+       if (!memorystatus_can_freeze_processes()) {
+               return FALSE;
+       }
+
+       /* Is swap running low? */
+       if (*memorystatus_freeze_swap_low) {
+               /* If there's been no movement in free swap pages since we last attempted freeze, return. */
+               if (default_pager_swap_pages_free() < memorystatus_freeze_pages_min) {
+                       return FALSE;
+               }
+               
+               /* Pages have been freed - we can retry. */
+               *memorystatus_freeze_swap_low = FALSE;  
+       }
+       
+       /* OK */
+       return TRUE;
+}
+
+static void
+memorystatus_freeze_update_throttle_interval(mach_timespec_t *ts, struct throttle_interval_t *interval)
+{
+       if (CMP_MACH_TIMESPEC(ts, &interval->ts) >= 0) {
+               if (!interval->max_pageouts) {
+                       interval->max_pageouts = (interval->burst_multiple * (((uint64_t)interval->mins * FREEZE_DAILY_PAGEOUTS_MAX) / (24 * 60)));
+               } else {
+                       printf("memorystatus_freeze_update_throttle_interval: %d minute throttle timeout, resetting\n", interval->mins);
+               }
+               interval->ts.tv_sec = interval->mins * 60;
+               interval->ts.tv_nsec = 0;
+               ADD_MACH_TIMESPEC(&interval->ts, ts);
+               /* Since we update the throttle stats pre-freeze, adjust for overshoot here */
+               if (interval->pageouts > interval->max_pageouts) {
+                       interval->pageouts -= interval->max_pageouts;
+               } else {
+                       interval->pageouts = 0;
+               }
+               interval->throttle = FALSE;
+       } else if (!interval->throttle && interval->pageouts >= interval->max_pageouts) {
+               printf("memorystatus_freeze_update_throttle_interval: %d minute pageout limit exceeded; enabling throttle\n", interval->mins);
+               interval->throttle = TRUE;
+       }       
+
+       MEMORYSTATUS_DEBUG(1, "memorystatus_freeze_update_throttle_interval: throttle updated - %d frozen (%d max) within %dm; %dm remaining; throttle %s\n", 
+               interval->pageouts, interval->max_pageouts, interval->mins, (interval->ts.tv_sec - ts->tv_sec) / 60, 
+               interval->throttle ? "on" : "off");
+}
+
+static boolean_t
+memorystatus_freeze_update_throttle(void) 
+{
+       clock_sec_t sec;
+       clock_nsec_t nsec;
+       mach_timespec_t ts;
+       uint32_t i;
+       boolean_t throttled = FALSE;
+
+#if DEVELOPMENT || DEBUG
+       if (!memorystatus_freeze_throttle_enabled)
+               return FALSE;
+#endif
+
+       clock_get_system_nanotime(&sec, &nsec);
+       ts.tv_sec = sec;
+       ts.tv_nsec = nsec;
+       
+       /* Check freeze pageouts over multiple intervals and throttle if we've exceeded our budget.
+        *
+        * This ensures that periods of inactivity can't be used as 'credit' towards freeze if the device has
+        * remained dormant for a long period. We do, however, allow increased thresholds for shorter intervals in
+        * order to allow for bursts of activity.
+        */
+       for (i = 0; i < sizeof(throttle_intervals) / sizeof(struct throttle_interval_t); i++) {
+               memorystatus_freeze_update_throttle_interval(&ts, &throttle_intervals[i]);
+               if (throttle_intervals[i].throttle == TRUE)
+                       throttled = TRUE;
+       }                                                               
+
+       return throttled;
+}
+
+static void
+memorystatus_freeze_thread(void *param __unused, wait_result_t wr __unused)
+{
+       static boolean_t memorystatus_freeze_swap_low = FALSE;
+       
+       if (memorystatus_freeze_enabled) {
+               if (memorystatus_can_freeze(&memorystatus_freeze_swap_low)) {
+                       /* Only freeze if we've not exceeded our pageout budgets */
+                       if (!memorystatus_freeze_update_throttle()) {
+                               memorystatus_freeze_top_process(&memorystatus_freeze_swap_low);
+                       } else {
+                               printf("memorystatus_freeze_thread: in throttle, ignoring freeze\n");
+                               memorystatus_freeze_throttle_count++; /* Throttled, update stats */
+                       }
+               }
+       }
+
+       assert_wait((event_t) &memorystatus_freeze_wakeup, THREAD_UNINT);
+       thread_block((thread_continue_t) memorystatus_freeze_thread);   
+}
+
+#endif /* CONFIG_FREEZE */
+
+#if CONFIG_JETSAM && VM_PRESSURE_EVENTS
+
+boolean_t
+memorystatus_warn_process(pid_t pid) {
+       return (vm_dispatch_pressure_note_to_pid(pid, FALSE) == 0);
+}
+
+static inline boolean_t
+memorystatus_update_pressure_locked(boolean_t *pressured) {
+       vm_pressure_level_t old_level, new_level;
+       
+       old_level = memorystatus_vm_pressure_level;
+       
+       if (memorystatus_available_pages > memorystatus_available_pages_pressure) {
+               /* Too many free pages */
+               new_level = kVMPressureNormal;
+       }       
+#if CONFIG_FREEZE
+       else if (memorystatus_frozen_count > 0) {
+               /* Frozen processes exist */
+               new_level = kVMPressureNormal;          
+       }
+#endif
+       else if (memorystatus_suspended_count > MEMORYSTATUS_SUSPENDED_THRESHOLD) {
+               /* Too many supended processes */
+               new_level = kVMPressureNormal;
+       }
+       else if (memorystatus_suspended_count > 0) {
+               /* Some suspended processes - warn */
+               new_level = kVMPressureWarning;
+       }
+    else {
+               /* Otherwise, pressure level is urgent */
+               new_level = kVMPressureUrgent;
+       }
+       
+       *pressured = (new_level != kVMPressureNormal);
+       
+       /* Did the pressure level change? */
+       if (old_level != new_level) {
+               MEMORYSTATUS_DEBUG(1, "memorystatus_update_pressure_locked(): memory pressure changed %d -> %d; memorystatus_available_pages: %d\n ", 
+                   old_level, new_level, memorystatus_available_pages);
+               memorystatus_vm_pressure_level = new_level;
+               return TRUE;
+       }
+       
+       return FALSE;
+}
+
+kern_return_t
+memorystatus_update_vm_pressure(boolean_t target_foreground) {
+       boolean_t pressure_changed, pressured;
+       boolean_t warn = FALSE;
+
+       /* 
+        * Centralised pressure handling routine. Called from:
+        * - The main jetsam thread. In this case, we update the pressure level and dispatch warnings to the foreground 
+        *   process *only*, each time the available page % drops.
+        * - The pageout scan path. In this scenario, every other registered process is targeted in footprint order.
+        *
+        * This scheme guarantees delivery to the foreground app, while providing for warnings to the remaining processes
+        * driven by the pageout scan.
+        */
+
+       MEMORYSTATUS_DEBUG(1, "memorystatus_update_vm_pressure(): foreground %d; available %d, critical %d, pressure %d\n", 
+               target_foreground, memorystatus_available_pages, memorystatus_available_pages_critical, memorystatus_available_pages_pressure);
+
+       proc_list_lock();
+
+       pressure_changed = memorystatus_update_pressure_locked(&pressured);
+       
+       if (pressured) {
+               if (target_foreground) {
+                       if (memorystatus_available_pages != memorystatus_last_foreground_pressure_pages) {
+                               if (memorystatus_available_pages < memorystatus_last_foreground_pressure_pages) {
+                                       warn = TRUE;
+                               }
+                               memorystatus_last_foreground_pressure_pages = memorystatus_available_pages;
+                       }
+               } else {
+                       warn = TRUE;
+               }
+       } else if (pressure_changed) {
+               memorystatus_last_foreground_pressure_pages =  (unsigned int)-1;
+       }
+       
+       proc_list_unlock();
+
+       /* Target foreground processes if specified */
+       if (warn) {
+               if (target_foreground) {
+                       MEMORYSTATUS_DEBUG(1, "memorystatus_update_vm_pressure(): invoking vm_find_pressure_foreground_candidates()\n");
+                       vm_find_pressure_foreground_candidates();
+               } else {
+                       MEMORYSTATUS_DEBUG(1, "memorystatus_update_vm_pressure(): invoking vm_find_pressure_candidate()\n");
+                       /* Defer to VM code. This can race with the foreground priority, but
+                        * it's preferable to holding onto locks for an extended period. */
+                       vm_find_pressure_candidate();
+               }
+       }
+    
+       /* Dispatch the global kevent to privileged listeners */
+       if (pressure_changed) {
+               memorystatus_issue_pressure_kevent(pressured);
+       }
+
+       return KERN_SUCCESS;
+}
+
+int
+memorystatus_send_pressure_note(pid_t pid) {
+       MEMORYSTATUS_DEBUG(1, "memorystatus_send_pressure_note(): pid %d\n", pid);      
+       return memorystatus_send_note(kMemorystatusPressureNote, &pid, sizeof(pid));
+}
+
+boolean_t
+memorystatus_bg_pressure_eligible(proc_t p) {
+       boolean_t eligible = FALSE;
+        
+       proc_list_lock();
+       
+       MEMORYSTATUS_DEBUG(1, "memorystatus_bg_pressure_eligible: pid %d, state 0x%x\n", p->p_pid, p->p_memstat_state);
+        
+       /* Foreground processes have already been dealt with at this point, so just test for eligibility */
+       if (!(p->p_memstat_state & (P_MEMSTAT_TERMINATED | P_MEMSTAT_LOCKED | P_MEMSTAT_SUSPENDED | P_MEMSTAT_FROZEN))) {
+                eligible = TRUE;
+       }
+        
+       proc_list_unlock();
+       
+       return eligible;
+}
+
+boolean_t
+memorystatus_is_foreground_locked(proc_t p) {
+        return ((p->p_memstat_effectivepriority == JETSAM_PRIORITY_FOREGROUND) || 
+                (p->p_memstat_effectivepriority == JETSAM_PRIORITY_FOREGROUND_SUPPORT));
+}
+
+#else /* CONFIG_JETSAM && VM_PRESSURE_EVENTS */
+
+/*
+ * Trigger levels to test the mechanism.
+ * Can be used via a sysctl.
+ */
+#define TEST_LOW_MEMORY_TRIGGER_ONE            1
+#define TEST_LOW_MEMORY_TRIGGER_ALL            2
+#define TEST_PURGEABLE_TRIGGER_ONE             3
+#define TEST_PURGEABLE_TRIGGER_ALL             4
+#define TEST_LOW_MEMORY_PURGEABLE_TRIGGER_ONE  5
+#define TEST_LOW_MEMORY_PURGEABLE_TRIGGER_ALL  6
+
+boolean_t              memorystatus_manual_testing_on = FALSE;
+vm_pressure_level_t    memorystatus_manual_testing_level = kVMPressureNormal;
+
+extern struct knote *
+vm_pressure_select_optimal_candidate_to_notify(struct klist *, int);
+
+extern
+kern_return_t vm_pressure_notification_without_levels(void);
+
+extern void vm_pressure_klist_lock(void);
+extern void vm_pressure_klist_unlock(void);
+
+extern void vm_reset_active_list(void);
+
+extern void delay(int);
+
+#define INTER_NOTIFICATION_DELAY       (250000)        /* .25 second */
+
+void memorystatus_on_pageout_scan_end(void) {
+       /* No-op */
+}
+
+/*
+ * kn_max - knote
+ *
+ * knote_pressure_level - to check if the knote is registered for this notification level.
+ *
+ * task        - task whose bits we'll be modifying
+ *
+ * pressure_level_to_clear - if the task has been notified of this past level, clear that notification bit so that if/when we revert to that level, the task will be notified again.
+ *
+ * pressure_level_to_set - the task is about to be notified of this new level. Update the task's bit notification information appropriately.
+ *
+ */
+boolean_t
+is_knote_registered_modify_task_pressure_bits(struct knote*, int, task_t, vm_pressure_level_t, vm_pressure_level_t);
+
+boolean_t
+is_knote_registered_modify_task_pressure_bits(struct knote *kn_max, int knote_pressure_level, task_t task, vm_pressure_level_t pressure_level_to_clear, vm_pressure_level_t pressure_level_to_set)
+{
+       if (kn_max->kn_sfflags & knote_pressure_level) {
+
+               if (task_has_been_notified(task, pressure_level_to_clear) == TRUE) {
+
+                       task_clear_has_been_notified(task, pressure_level_to_clear);
+               }
+
+               task_mark_has_been_notified(task, pressure_level_to_set);
+               return TRUE;
+       }
+
+       return FALSE;
+}
+
+extern kern_return_t vm_pressure_notify_dispatch_vm_clients(void);
+
+kern_return_t
+memorystatus_update_vm_pressure(boolean_t target_best_process) 
+{
+       struct knote                    *kn_max = NULL;
+        pid_t                          target_pid = -1;
+        struct klist                   dispatch_klist = { NULL };
+       proc_t                          target_proc = PROC_NULL;
+       static vm_pressure_level_t      level_snapshot = kVMPressureNormal;
+       struct task                     *task = NULL;
+       boolean_t                       found_candidate = FALSE;
+
+       while (1) {
+       
+               /*
+                * There is a race window here. But it's not clear
+                * how much we benefit from having extra synchronization.
+                */
+               level_snapshot = memorystatus_vm_pressure_level;
+
+               memorystatus_klist_lock();
+               kn_max = vm_pressure_select_optimal_candidate_to_notify(&memorystatus_klist, level_snapshot);
+
+               if (kn_max == NULL) {
+                       memorystatus_klist_unlock();
+
+                       /*
+                        * No more level-based clients to notify.
+                        * Try the non-level based notification clients.
+                        *      
+                        * However, these non-level clients don't understand
+                        * the "return-to-normal" notification.
+                        *
+                        * So don't consider them for those notifications. Just
+                        * return instead.
+                        *
+                        */
+
+                       if (level_snapshot != kVMPressureNormal) {
+                               goto try_dispatch_vm_clients;
+                       } else {
+                               return KERN_FAILURE;
+                       }       
+               }
+               
+               target_proc = kn_max->kn_kq->kq_p;
+               
+               proc_list_lock();
+               if (target_proc != proc_ref_locked(target_proc)) {
+                       target_proc = PROC_NULL;
+                       proc_list_unlock();
+                       memorystatus_klist_unlock();
+                       continue;
+               }
+               proc_list_unlock();
+               memorystatus_klist_unlock();
+               
+               target_pid = target_proc->p_pid;
+
+               task = (struct task *)(target_proc->task);
+       
+               if (level_snapshot != kVMPressureNormal) {
+
+                       if (level_snapshot == kVMPressureWarning || level_snapshot == kVMPressureUrgent) {
+
+                               if (is_knote_registered_modify_task_pressure_bits(kn_max, NOTE_MEMORYSTATUS_PRESSURE_WARN, task, kVMPressureCritical, kVMPressureWarning) == TRUE) {
+                                       found_candidate = TRUE;
+                               }
+                       } else {
+                               if (level_snapshot == kVMPressureCritical) {
+                               
+                                       if (is_knote_registered_modify_task_pressure_bits(kn_max, NOTE_MEMORYSTATUS_PRESSURE_CRITICAL, task, kVMPressureWarning, kVMPressureCritical) == TRUE) {
+                                               found_candidate = TRUE;
+                                       }
+                               }
+                       }
+               } else {
+                       if (kn_max->kn_sfflags & NOTE_MEMORYSTATUS_PRESSURE_NORMAL) {
+
+                               task_clear_has_been_notified(task, kVMPressureWarning);
+                               task_clear_has_been_notified(task, kVMPressureCritical);
+
+                               found_candidate = TRUE;
+                       }
+               }
+
+               if (found_candidate == FALSE) {
+                       continue;
+               }
+
+               memorystatus_klist_lock();
+               KNOTE_DETACH(&memorystatus_klist, kn_max);
+               KNOTE_ATTACH(&dispatch_klist, kn_max);
+               memorystatus_klist_unlock();
+
+               KNOTE(&dispatch_klist, (level_snapshot != kVMPressureNormal) ? kMemorystatusPressure : kMemorystatusNoPressure);
+
+               memorystatus_klist_lock();
+               KNOTE_DETACH(&dispatch_klist, kn_max);
+               KNOTE_ATTACH(&memorystatus_klist, kn_max);
+               memorystatus_klist_unlock();
+
+               microuptime(&target_proc->vm_pressure_last_notify_tstamp);
+               proc_rele(target_proc);
+
+               if (target_best_process == TRUE) {
+                       break;
+               }
+
+try_dispatch_vm_clients:
+               if (level_snapshot != kVMPressureNormal) {
+                       /* 
+                        * Wake up idle-exit thread.
+                        * Targets one process per invocation.
+                        *
+                        * TODO: memorystatus_idle_exit_from_VM should return FALSE once it's
+                        * done with all idle-exitable processes. Currently, we will exit this
+                        * loop when we are done with notification clients (level and non-level based)
+                        * but we may still have some idle-exitable processes around.
+                        *
+                        */
+                       memorystatus_idle_exit_from_VM();
+
+                       if ((vm_pressure_notify_dispatch_vm_clients() == KERN_FAILURE) && (kn_max == NULL)) {
+                               /*
+                                * kn_max == NULL i.e. we didn't find any eligible clients for the level-based notifications
+                                * AND
+                                * we have failed to find any eligible clients for the non-level based notifications too.
+                                * So, we are done.
+                                */
+
+                               return KERN_FAILURE;
+                       }
+               }
+
+               if (memorystatus_manual_testing_on == FALSE) {
+                       delay(INTER_NOTIFICATION_DELAY);
+               }
+       }
+
+       return KERN_SUCCESS;
+}
+
+vm_pressure_level_t
+convert_internal_pressure_level_to_dispatch_level(vm_pressure_level_t);
+
+vm_pressure_level_t
+convert_internal_pressure_level_to_dispatch_level(vm_pressure_level_t internal_pressure_level)
+{
+       vm_pressure_level_t     dispatch_level = NOTE_MEMORYSTATUS_PRESSURE_NORMAL;
+       
+       switch (internal_pressure_level) {
+
+               case kVMPressureNormal:
+               {
+                       dispatch_level = NOTE_MEMORYSTATUS_PRESSURE_NORMAL;
+                       break;
+               }
+
+               case kVMPressureWarning:
+               case kVMPressureUrgent:
+               {
+                       dispatch_level = NOTE_MEMORYSTATUS_PRESSURE_WARN;
+                       break;
+               }
+
+               case kVMPressureCritical:
+               {
+                       dispatch_level = NOTE_MEMORYSTATUS_PRESSURE_CRITICAL;
+                       break;
+               }
+
+               default:
+                       break;
+       }
+
+       return dispatch_level;
+}
+
+static int
+sysctl_memorystatus_vm_pressure_level SYSCTL_HANDLER_ARGS
+{
+#pragma unused(arg1, arg2, oidp)
+       
+       vm_pressure_level_t dispatch_level = convert_internal_pressure_level_to_dispatch_level(memorystatus_vm_pressure_level);
+
+       return SYSCTL_OUT(req, &dispatch_level, sizeof(dispatch_level));
+}
+
+SYSCTL_PROC(_kern, OID_AUTO, memorystatus_vm_pressure_level, CTLTYPE_INT|CTLFLAG_RD|CTLFLAG_LOCKED,
+    0, 0, &sysctl_memorystatus_vm_pressure_level, "I", "");
+
+
+extern int memorystatus_purge_on_warning;
+extern int memorystatus_purge_on_critical;
+
+static int
+sysctl_memorypressure_manual_trigger SYSCTL_HANDLER_ARGS
+{
+#pragma unused(arg1, arg2)
+
+       int level = 0;
+       int error = 0;
+       int pressure_level = 0;
+       int trigger_request = 0;
+       int force_purge;
+
+       error = sysctl_handle_int(oidp, &level, 0, req);
+       if (error || !req->newptr) {
+               return (error);
+       }
+
+       memorystatus_manual_testing_on = TRUE;
+
+       trigger_request = (level >> 16) & 0xFFFF;
+       pressure_level = (level & 0xFFFF); 
+
+       if (trigger_request < TEST_LOW_MEMORY_TRIGGER_ONE ||
+           trigger_request > TEST_LOW_MEMORY_PURGEABLE_TRIGGER_ALL) {
+               return EINVAL;
+       }
+       switch (pressure_level) {
+       case NOTE_MEMORYSTATUS_PRESSURE_NORMAL:
+       case NOTE_MEMORYSTATUS_PRESSURE_WARN:
+       case NOTE_MEMORYSTATUS_PRESSURE_CRITICAL:
+               break;
+       default:
+               return EINVAL;
+       }
+
+       /*
+        * The pressure level is being set from user-space.
+        * And user-space uses the constants in sys/event.h
+        * So we translate those events to our internal levels here.
+        */
+       if (pressure_level == NOTE_MEMORYSTATUS_PRESSURE_NORMAL) {
+
+               memorystatus_manual_testing_level = kVMPressureNormal;
+               force_purge = 0;
+
+       } else if (pressure_level == NOTE_MEMORYSTATUS_PRESSURE_WARN) {
+
+               memorystatus_manual_testing_level = kVMPressureWarning;
+               force_purge = memorystatus_purge_on_warning;
+
+       } else if (pressure_level == NOTE_MEMORYSTATUS_PRESSURE_CRITICAL) {
+
+               memorystatus_manual_testing_level = kVMPressureCritical;
+               force_purge = memorystatus_purge_on_critical;
+       }
+
+       memorystatus_vm_pressure_level = memorystatus_manual_testing_level;
+
+       /* purge according to the new pressure level */
+       switch (trigger_request) {
+       case TEST_PURGEABLE_TRIGGER_ONE:
+       case TEST_LOW_MEMORY_PURGEABLE_TRIGGER_ONE:
+               if (force_purge == 0) {
+                       /* no purging requested */
+                       break;
+               }
+               vm_purgeable_object_purge_one_unlocked(force_purge);
+               break;
+       case TEST_PURGEABLE_TRIGGER_ALL:
+       case TEST_LOW_MEMORY_PURGEABLE_TRIGGER_ALL:
+               if (force_purge == 0) {
+                       /* no purging requested */
+                       break;
+               }
+               while (vm_purgeable_object_purge_one_unlocked(force_purge));
+               break;
+       }
+
+       if ((trigger_request == TEST_LOW_MEMORY_TRIGGER_ONE) ||
+           (trigger_request == TEST_LOW_MEMORY_PURGEABLE_TRIGGER_ONE)) {
+
+               memorystatus_update_vm_pressure(TRUE);
+       }
+
+       if ((trigger_request == TEST_LOW_MEMORY_TRIGGER_ALL) ||
+           (trigger_request == TEST_LOW_MEMORY_PURGEABLE_TRIGGER_ALL)) {
+
+               while (memorystatus_update_vm_pressure(FALSE) == KERN_SUCCESS) {
+                       continue;
+               }
+       }
+               
+       if (pressure_level == NOTE_MEMORYSTATUS_PRESSURE_NORMAL) {
+               memorystatus_manual_testing_on = FALSE;
+                               
+               vm_pressure_klist_lock();
+               vm_reset_active_list();
+               vm_pressure_klist_unlock();
+       } else {
+
+               vm_pressure_klist_lock();
+               vm_pressure_notification_without_levels();
+               vm_pressure_klist_unlock();
+       }
+
+       return 0;
+}
+
+SYSCTL_PROC(_kern, OID_AUTO, memorypressure_manual_trigger, CTLTYPE_INT|CTLFLAG_WR|CTLFLAG_LOCKED|CTLFLAG_MASKED,
+    0, 0, &sysctl_memorypressure_manual_trigger, "I", "");
+
+
+extern int memorystatus_purge_on_warning;
+extern int memorystatus_purge_on_urgent;
+extern int memorystatus_purge_on_critical;
+
+SYSCTL_INT(_kern, OID_AUTO, memorystatus_purge_on_warning, CTLFLAG_RW|CTLFLAG_LOCKED, &memorystatus_purge_on_warning, 0, "");
+SYSCTL_INT(_kern, OID_AUTO, memorystatus_purge_on_urgent, CTLTYPE_INT|CTLFLAG_RW|CTLFLAG_LOCKED, &memorystatus_purge_on_urgent, 0, "");
+SYSCTL_INT(_kern, OID_AUTO, memorystatus_purge_on_critical, CTLTYPE_INT|CTLFLAG_RW|CTLFLAG_LOCKED, &memorystatus_purge_on_critical, 0, "");
+
+
+#endif /* CONFIG_JETSAM && VM_PRESSURE_EVENTS */
+
+/* Return both allocated and actual size, since there's a race between allocation and list compilation */
+static int
+memorystatus_get_priority_list(memorystatus_priority_entry_t **list_ptr, size_t *buffer_size, size_t *list_size, boolean_t size_only) 
+{
+       uint32_t list_count, i = 0;
+       memorystatus_priority_entry_t *list_entry;
+       proc_t p;
+
+       list_count = memorystatus_list_count;
+       *list_size = sizeof(memorystatus_priority_entry_t) * list_count;
+
+       /* Just a size check? */
+       if (size_only) {
+               return 0;
+       }
+       
+       /* Otherwise, validate the size of the buffer */
+       if (*buffer_size < *list_size) {
+               return EINVAL;
+       }
+
+       *list_ptr = (memorystatus_priority_entry_t*)kalloc(*list_size);
+       if (!list_ptr) {
+               return ENOMEM;
+       }
+
+       memset(*list_ptr, 0, *list_size);
+
+       *buffer_size = *list_size;
+       *list_size = 0;
+
+       list_entry = *list_ptr;
+
+       proc_list_lock();
+
+       p = memorystatus_get_first_proc_locked(&i, TRUE);
+       while (p && (*list_size < *buffer_size)) {
+               list_entry->pid = p->p_pid;
+               list_entry->priority = p->p_memstat_effectivepriority;
+               list_entry->user_data = p->p_memstat_userdata;
+#if LEGACY_HIWATER
+               if (((p->p_memstat_state & P_MEMSTAT_MEMLIMIT_BACKGROUND) && (p->p_memstat_effectivepriority >= JETSAM_PRIORITY_FOREGROUND)) ||
+                    (p->p_memstat_memlimit <= 0)) {
+                       task_get_phys_footprint_limit(p->task, &list_entry->limit);  
+               } else {
+                       list_entry->limit = p->p_memstat_memlimit;
+               }
+#else
+               task_get_phys_footprint_limit(p->task, &list_entry->limit);
+#endif
+               list_entry->state = memorystatus_build_state(p);
+               list_entry++;
+
+               *list_size += sizeof(memorystatus_priority_entry_t);
+               
+               p = memorystatus_get_next_proc_locked(&i, p, TRUE);
+       }
+       
+       proc_list_unlock();
+       
+       MEMORYSTATUS_DEBUG(1, "memorystatus_get_priority_list: returning %lu for size\n", (unsigned long)*list_size);
+       
+       return 0;
+}
+
+static int
+memorystatus_cmd_get_priority_list(user_addr_t buffer, size_t buffer_size, int32_t *retval) {
+       int error = EINVAL;
+       boolean_t size_only;
+       memorystatus_priority_entry_t *list = NULL;
+       size_t list_size;
+       
+       size_only = ((buffer == USER_ADDR_NULL) ? TRUE: FALSE);
+               
+       error = memorystatus_get_priority_list(&list, &buffer_size, &list_size, size_only);
+       if (error) {
+               goto out;
+       }
+
+       if (!size_only) {
+               error = copyout(list, buffer, list_size);
+       }
+       
+       if (error == 0) {
+               *retval = list_size;
+       }
+out:
+
+       if (list) {
+               kfree(list, buffer_size);
+       }
+
+       return error;
+}
+
+#if CONFIG_JETSAM
+
+static void 
+memorystatus_clear_errors(void)
+{
+       proc_t p;
+       unsigned int i = 0;
+
+       KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_MEMSTAT, BSD_MEMSTAT_CLEAR_ERRORS) | DBG_FUNC_START, 0, 0, 0, 0, 0);
+    
+       proc_list_lock();
+    
+       p = memorystatus_get_first_proc_locked(&i, TRUE);
+       while (p) {
+               if (p->p_memstat_state & P_MEMSTAT_ERROR) {
+                       p->p_memstat_state &= ~P_MEMSTAT_ERROR;
+               }
+               p = memorystatus_get_next_proc_locked(&i, p, TRUE);
+       }
+       
+       proc_list_unlock();
+
+       KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_MEMSTAT, BSD_MEMSTAT_CLEAR_ERRORS) | DBG_FUNC_END, 0, 0, 0, 0, 0);
+}
+
+static void
+memorystatus_update_levels_locked(boolean_t critical_only) {
+       memorystatus_available_pages_critical = memorystatus_available_pages_critical_base;
+#if !LATENCY_JETSAM
+       {
+               // If there's an entry in the first bucket, we have idle processes
+               memstat_bucket_t *first_bucket = &memstat_bucket[JETSAM_PRIORITY_IDLE];
+               if (first_bucket->count) {
+                       memorystatus_available_pages_critical += memorystatus_available_pages_critical_idle_offset;
+               }
+       }
+#endif
+#if DEBUG || DEVELOPMENT
+       if (memorystatus_jetsam_policy & kPolicyDiagnoseActive) {
+               memorystatus_available_pages_critical += memorystatus_jetsam_policy_offset_pages_diagnostic;
+       }
+#endif
+        
+       if (critical_only) {
+               return;
+       }
+       
+#if VM_PRESSURE_EVENTS
+       memorystatus_available_pages_pressure = (pressure_threshold_percentage / delta_percentage) * memorystatus_delta;
+#if DEBUG || DEVELOPMENT
+       if (memorystatus_jetsam_policy & kPolicyDiagnoseActive) {
+               memorystatus_available_pages_pressure += memorystatus_jetsam_policy_offset_pages_diagnostic;
+       }
+#endif
+#endif
+}
+
+static int
+memorystatus_get_snapshot(memorystatus_jetsam_snapshot_t **snapshot, size_t *snapshot_size, boolean_t size_only) {
+       size_t input_size = *snapshot_size;
+       
+       if (memorystatus_jetsam_snapshot_count > 0) {
+               *snapshot_size = sizeof(memorystatus_jetsam_snapshot_t) + (sizeof(memorystatus_jetsam_snapshot_entry_t) * (memorystatus_jetsam_snapshot_count));
+       } else {
+               *snapshot_size = 0;
+       }
+
+       if (size_only) {
+               return 0;
+       }
+
+       if (input_size < *snapshot_size) {
+               return EINVAL;
+       }
+
+       *snapshot = memorystatus_jetsam_snapshot;
+       
+       MEMORYSTATUS_DEBUG(1, "memorystatus_snapshot: returning %ld for size\n", (long)*snapshot_size);
+       
+       return 0;
+}
+
+static int
+memorystatus_cmd_get_jetsam_snapshot(user_addr_t buffer, size_t buffer_size, int32_t *retval) {
+       int error = EINVAL;
+       boolean_t size_only;
+       memorystatus_jetsam_snapshot_t *snapshot;
+       
+       size_only = ((buffer == USER_ADDR_NULL) ? TRUE : FALSE);
+       
+       error = memorystatus_get_snapshot(&snapshot, &buffer_size, size_only);
+       if (error) {
+               goto out;
+       }
+
+       /* Copy out and reset */
+       if (!size_only) {
+               if ((error = copyout(snapshot, buffer, buffer_size)) == 0) {
+                       snapshot->entry_count = memorystatus_jetsam_snapshot_count = 0;
+               }
+       }
+
+       if (error == 0) {
+               *retval = buffer_size;
+       }
+out:
+       return error;
+}
+
+static int
+memorystatus_cmd_set_priority_properties(pid_t pid, user_addr_t buffer, size_t buffer_size, __unused int32_t *retval) {
+       const uint32_t MAX_ENTRY_COUNT = 2; /* Cap the entry count */
+       
+       int error;
+       uint32_t i;
+       uint32_t entry_count;
+       memorystatus_priority_properties_t *entries;
+       
+       /* Validate inputs */
+       if ((pid == 0) || (buffer == USER_ADDR_NULL) || (buffer_size == 0)) {
+               return EINVAL;
+       }
+       
+       /* Make sure the buffer is a multiple of the entry size, and that an excessive size isn't specified */
+       entry_count = (buffer_size / sizeof(memorystatus_priority_properties_t));
+       if (((buffer_size % sizeof(memorystatus_priority_properties_t)) != 0) || (entry_count > MAX_ENTRY_COUNT)) {
+               return EINVAL;
+       }
+               
+       entries = (memorystatus_priority_properties_t *)kalloc(buffer_size);
+               
+       error = copyin(buffer, entries, buffer_size);
+       
+       for (i = 0; i < entry_count; i++) {
+               proc_t p;
+                
+               if (error) {
+                       break;
+               }
+               
+               p = proc_find(pid);
+               if (!p) {
+                       error = ESRCH;
+                       break;         
+               }
+               
+               if (p->p_memstat_state & P_MEMSTAT_INTERNAL) {
+                       error = EPERM;
+                       proc_rele(p);
+                       break;          
+               }
+               
+               error = memorystatus_update(p, entries[i].priority, entries[i].user_data, FALSE, FALSE, 0, 0);
+               proc_rele(p);
+       }
+       
+       kfree(entries, buffer_size);
+       
+       return error;
+}
+
+static int
+memorystatus_cmd_get_pressure_status(int32_t *retval) {        
+       int error;
+       
+       /* Need privilege for check */
+       error = priv_check_cred(kauth_cred_get(), PRIV_VM_PRESSURE, 0);
+       if (error) {
+               return (error);
+       }
+       
+       /* Inherently racy, so it's not worth taking a lock here */
+       *retval = (kVMPressureNormal != memorystatus_vm_pressure_level) ? 1 : 0;
+       
+       return error;
+}
+
+static int
+memorystatus_cmd_set_jetsam_high_water_mark(pid_t pid, int32_t high_water_mark, __unused int32_t *retval) {
+       int error = 0;
+        
+       proc_t p = proc_find(pid);
+       if (!p) {
+               return ESRCH;
+       }
+        
+       if (high_water_mark <= 0) {
+               high_water_mark = -1; /* Disable */
+       }
+    
+       proc_list_lock();
+    
+       if (p->p_memstat_state & P_MEMSTAT_INTERNAL) {
+               error = EPERM;
+               goto exit;              
+       }
+    
+       p->p_memstat_memlimit = high_water_mark;
+       if (memorystatus_highwater_enabled) {
+               if (p->p_memstat_state & P_MEMSTAT_MEMLIMIT_BACKGROUND) {
+                       memorystatus_update_priority_locked(p, p->p_memstat_effectivepriority);
+               } else {
+                       error = (task_set_phys_footprint_limit_internal(p->task, high_water_mark, NULL, TRUE) == 0) ? 0 : EINVAL;
+               }
+       }
+
+exit:
+       proc_list_unlock();
+       proc_rele(p);
+       
+       return error;
+}
+
+#endif /* CONFIG_JETSAM */
+
+int
+memorystatus_control(struct proc *p __unused, struct memorystatus_control_args *args, int *ret) {
+       int error = EINVAL;
+
+#if !CONFIG_JETSAM
+       #pragma unused(ret)
+#endif
+
+       /* Root only for now */
+       if (!kauth_cred_issuser(kauth_cred_get())) {
+               error = EPERM;
+               goto out;
+       }
+       
+       /* Sanity check */
+       if (args->buffersize > MEMORYSTATUS_BUFFERSIZE_MAX) {
+               error = EINVAL;
+               goto out;
+       }
+
+       switch (args->command) {
+       case MEMORYSTATUS_CMD_GET_PRIORITY_LIST:
+               error = memorystatus_cmd_get_priority_list(args->buffer, args->buffersize, ret);
+               break;
+#if CONFIG_JETSAM
+       case MEMORYSTATUS_CMD_SET_PRIORITY_PROPERTIES:
+               error = memorystatus_cmd_set_priority_properties(args->pid, args->buffer, args->buffersize, ret);
+               break;
+       case MEMORYSTATUS_CMD_GET_JETSAM_SNAPSHOT:
+               error = memorystatus_cmd_get_jetsam_snapshot(args->buffer, args->buffersize, ret);
+               break;
+       case MEMORYSTATUS_CMD_GET_PRESSURE_STATUS:
+               error = memorystatus_cmd_get_pressure_status(ret);
+               break;
+       case MEMORYSTATUS_CMD_SET_JETSAM_HIGH_WATER_MARK:
+               /* TODO: deprecate. Keeping it in as there's no pid based way to set the ledger limit right now. */
+               error = memorystatus_cmd_set_jetsam_high_water_mark(args->pid, (int32_t)args->flags, ret);
+               break;
+       /* Test commands */
+#if DEVELOPMENT || DEBUG
+       case MEMORYSTATUS_CMD_TEST_JETSAM:
+               error = memorystatus_kill_process_sync(args->pid, kMemorystatusKilled) ? 0 : EINVAL;
+               break;
+       case MEMORYSTATUS_CMD_SET_JETSAM_PANIC_BITS:
+               error = memorystatus_cmd_set_panic_bits(args->buffer, args->buffersize);
+               break;
+#endif /* DEVELOPMENT || DEBUG */
+#endif /* CONFIG_JETSAM */
+       default:
+               break;
+       }
+
+out:
+       return error;
+}
+
+
+static int
+filt_memorystatusattach(struct knote *kn)
+{      
+       kn->kn_flags |= EV_CLEAR;
+       return memorystatus_knote_register(kn);
+}
+
+static void
+filt_memorystatusdetach(struct knote *kn)
+{
+       memorystatus_knote_unregister(kn);
+}
+
+static int
+filt_memorystatus(struct knote *kn __unused, long hint)
+{
+       if (hint) {
+               switch (hint) {
+               case kMemorystatusNoPressure:
+                       if (kn->kn_sfflags & NOTE_MEMORYSTATUS_PRESSURE_NORMAL) {
+                               kn->kn_fflags |= NOTE_MEMORYSTATUS_PRESSURE_NORMAL;
+                       }
+                       break;
+               case kMemorystatusPressure:
+                       if (memorystatus_vm_pressure_level == kVMPressureWarning || memorystatus_vm_pressure_level == kVMPressureUrgent) {
+                               if (kn->kn_sfflags & NOTE_MEMORYSTATUS_PRESSURE_WARN) {
+                                       kn->kn_fflags |= NOTE_MEMORYSTATUS_PRESSURE_WARN;
+                               }
+                       } else if (memorystatus_vm_pressure_level == kVMPressureCritical) {
+
+                               if (kn->kn_sfflags & NOTE_MEMORYSTATUS_PRESSURE_CRITICAL) {
+                                       kn->kn_fflags |= NOTE_MEMORYSTATUS_PRESSURE_CRITICAL;
+                               }
+                       }
+                       break;
+               default:
+                       break;
+               }
+       }
+       
+       return (kn->kn_fflags != 0);
+}
+
+static void
+memorystatus_klist_lock(void) {
+       lck_mtx_lock(&memorystatus_klist_mutex);
+}
+
+static void
+memorystatus_klist_unlock(void) {
+       lck_mtx_unlock(&memorystatus_klist_mutex);
+}
+
+void 
+memorystatus_kevent_init(lck_grp_t *grp, lck_attr_t *attr) {
+       lck_mtx_init(&memorystatus_klist_mutex, grp, attr);
+       klist_init(&memorystatus_klist);
+}
+
+int
+memorystatus_knote_register(struct knote *kn) {
+       int error = 0;
+       
+       memorystatus_klist_lock();
+       
+       if (kn->kn_sfflags & (NOTE_MEMORYSTATUS_PRESSURE_NORMAL | NOTE_MEMORYSTATUS_PRESSURE_WARN | NOTE_MEMORYSTATUS_PRESSURE_CRITICAL)) {
+
+#if CONFIG_JETSAM && VM_PRESSURE_EVENTS
+               /* Need a privilege to register */
+               error = priv_check_cred(kauth_cred_get(), PRIV_VM_PRESSURE, 0);
+#endif /* CONFIG_JETSAM && VM_PRESSURE_EVENTS */
+
+               if (!error) {
+                       KNOTE_ATTACH(&memorystatus_klist, kn);
+               }
+       } else {          
+               error = ENOTSUP;
+       }
+       
+       memorystatus_klist_unlock();
+       
+       return error;
+}
+
+void
+memorystatus_knote_unregister(struct knote *kn __unused) {     
+       memorystatus_klist_lock();
+       KNOTE_DETACH(&memorystatus_klist, kn);
+       memorystatus_klist_unlock();
+}
+
+#if CONFIG_JETSAM && VM_PRESSURE_EVENTS
+static boolean_t
+memorystatus_issue_pressure_kevent(boolean_t pressured) {
+       memorystatus_klist_lock();
+       KNOTE(&memorystatus_klist, pressured ? kMemorystatusPressure : kMemorystatusNoPressure);
+       memorystatus_klist_unlock();
+       return TRUE;
+}
+
+#endif /* CONFIG_JETSAM && VM_PRESSURE_EVENTS */