]> git.saurik.com Git - apple/xnu.git/blobdiff - osfmk/kern/sched_prim.h
xnu-1699.22.81.tar.gz
[apple/xnu.git] / osfmk / kern / sched_prim.h
index 758c22e2005138e771343f31d6554e9137ed3ddd..0f89239aeebb6851c08817c293aa7413481484ad 100644 (file)
@@ -1,23 +1,29 @@
 /*
- * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2010 Apple Inc. All rights reserved.
  *
- * @APPLE_LICENSE_HEADER_START@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
- * The contents of this file constitute Original Code as defined in and
- * are subject to the Apple Public Source License Version 1.1 (the
- * "License").  You may not use this file except in compliance with the
- * License.  Please obtain a copy of the License at
- * http://www.apple.com/publicsource and read it before using this file.
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
  * 
- * This Original Code and all software distributed under the License are
- * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
+ * 
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
- * License for the specific language governing rights and limitations
- * under the License.
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
  * 
- * @APPLE_LICENSE_HEADER_END@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
 /*
  * @OSF_COPYRIGHT@
 #include <kern/clock.h>
 #include <kern/kern_types.h>
 #include <kern/thread.h>
-#include <kern/lock.h>
-#include <kern/time_out.h>     /*** ??? temp - remove me soon ***/
-#include <kern/cpu_data.h>
-
-#include <sys/appleapiopts.h>
-
-#ifdef __APPLE_API_PRIVATE
+#include <sys/cdefs.h>
 
 #ifdef MACH_KERNEL_PRIVATE
 
-#include <mach_ldebug.h>
-/*
- *     Exported interface to sched_prim.c.
- *     A few of these functions are actually defined in
- *     ipc_sched.c, for historical reasons.
- */
-
-/* Initialize scheduler module */
-extern void            sched_init(void);
-
-/*
- * Set up thread timeout element(s) when thread is created.
- */
-extern void            thread_timer_setup(
-                                       thread_t                thread);
+/* Initialization */
+extern void            sched_init(void) __attribute__((section("__TEXT, initcode")));
 
-extern void            thread_timer_terminate(void);
+extern void            sched_startup(void);
 
-#define thread_bind_locked(thread, processor)  \
-               (thread)->bound_processor = (processor)
+extern void            sched_timebase_init(void);
 
-/*
- * Stop a thread and wait for it to stop running.
- */
+/* Force a preemption point for a thread and wait for it to stop running */
 extern boolean_t       thread_stop( 
                                                thread_t        thread);
 
-/*
- * Wait for a thread to stop running.
- */
-extern boolean_t       thread_wait(
+/* Release a previous stop request */
+extern void                    thread_unstop(
                                                thread_t        thread);
 
-/* Select a thread to run on a particular processor */
-extern thread_t        thread_select(
-                                               processor_t     myprocessor);
-
-extern kern_return_t thread_go_locked(
-                                               thread_t                thread,
-                                               wait_result_t   result);
+/* Wait for a thread to stop running */
+extern void                    thread_wait(
+                                               thread_t        thread);
 
-/* Stop old thread and run new thread */
-extern boolean_t thread_invoke(
-                                               thread_t                old_thread,
-                                               thread_t                new_thread,
-                                               int                             reason,
-                                               thread_continue_t continuation);
+/* Unblock thread on wake up */
+extern boolean_t       thread_unblock(
+                                               thread_t                thread,
+                                               wait_result_t   wresult);
 
-/* Called when current thread is given new stack */
-extern void            thread_continue(
-                                               thread_t                old_thread);
+/* Unblock and dispatch thread */
+extern kern_return_t   thread_go(
+                                                       thread_t                thread,
+                                                       wait_result_t   wresult);
 
-/* Switch directly to a particular thread */
-extern int             thread_run(
+/* Handle threads at context switch */
+extern void                    thread_dispatch(
                                                thread_t                old_thread,
-                                               thread_continue_t continuation,
                                                thread_t                new_thread);
 
-/* Dispatch a thread not on a run queue */
-extern void            thread_dispatch(
-                                               thread_t                thread);
+/* Switch directly to a particular thread */
+extern int                     thread_run(
+                                               thread_t                        self,
+                                               thread_continue_t       continuation,
+                                               void                            *parameter,
+                                               thread_t                        new_thread);
+
+/* Resume thread with new stack */
+extern void                    thread_continue(
+                                               thread_t                old_thread);
 
 /* Invoke continuation */
 extern void            call_continuation(
-                                               thread_continue_t continuation);                  
+                                       thread_continue_t       continuation,
+                                       void                            *parameter,
+                                       wait_result_t           wresult);
 
 /* Set the current scheduled priority */
 extern void            set_sched_pri(
@@ -162,84 +147,125 @@ extern void              compute_my_priority(
                                        thread_t                thread);
 
 /* Periodic scheduler activity */
-extern void            sched_tick_init(void);
+extern void            sched_init_thread(void (*)(void));
 
-/*
- * Update thread to the current scheduler tick.
- */
-extern void            update_priority(
+/* Perform sched_tick housekeeping activities */
+extern boolean_t               can_update_priority(
                                        thread_t                thread);
 
-/* Idle thread loop */
-extern void            idle_thread(void);
+extern void            update_priority(
+                                                                                       thread_t                thread);
 
-/*
- *     Machine-dependent code must define these functions.
- */
+extern void            lightweight_update_priority(
+                                                               thread_t                thread);
 
-/* Start thread running */
-extern void            thread_bootstrap_return(void);
+extern void            sched_traditional_quantum_expire(thread_t       thread);
+
+/* Idle processor thread */
+extern void            idle_thread(void);
 
-/* Return from exception */
-extern void            thread_exception_return(void);
+extern kern_return_t   idle_thread_create(
+                                                       processor_t             processor);
 
 /* Continuation return from syscall */
 extern void     thread_syscall_return(
                         kern_return_t   ret);
 
-extern thread_t        switch_context(
-                                               thread_t        old_thread,
-                                               thread_continue_t continuation,
-                                               thread_t        new_thread);
+/* Context switch */
+extern wait_result_t   thread_block_reason(
+                                                       thread_continue_t       continuation,
+                                                       void                            *parameter,
+                                                       ast_t                           reason);
+
+/* Reschedule thread for execution */
+extern void            thread_setrun(
+                                       thread_t        thread,
+                                       integer_t       options);
+
+#define SCHED_TAILQ            1
+#define SCHED_HEADQ            2
+#define SCHED_PREEMPT  4
+
+extern processor_set_t task_choose_pset(
+                                                       task_t                  task);
+
+/* Bind the current thread to a particular processor */
+extern processor_t             thread_bind(
+                                                       processor_t             processor);
+
+/* Choose the best processor to run a thread */
+extern processor_t     choose_processor(
+                                                                        processor_set_t                pset,
+                                                                        processor_t                    processor,
+                                                                        thread_t                       thread);
+
+/* Choose a thread from a processor's priority-based runq */
+extern thread_t choose_thread(
+                                                         processor_t           processor,
+                                                         run_queue_t           runq,
+                                                         int                           priority);
+
 
-/* Attach stack to thread */
-extern void            machine_kernel_stack_init(
-                                               thread_t        thread,
-                                               void            (*start_pos)(thread_t));
+extern void thread_quantum_init(
+                                                               thread_t thread);
 
-extern void            load_context(
+extern void            run_queue_init(
+                                       run_queue_t             runq);
+
+extern thread_t        run_queue_dequeue(
+                                                         run_queue_t           runq,
+                                                         integer_t             options);
+
+extern boolean_t       run_queue_enqueue(
+                                                         run_queue_t           runq,
+                                                         thread_t                      thread,
+                                                         integer_t             options);
+
+extern void    run_queue_remove(
+                                                                        run_queue_t            runq,
+                                                                        thread_t                       thread);
+                                                                         
+/* Remove thread from its run queue */
+extern boolean_t       thread_run_queue_remove(
                                                thread_t        thread);
 
-extern thread_act_t            switch_act(
-                                                       thread_act_t    act);
+extern void            thread_timer_expire(
+                                       void                    *thread,
+                                       void                    *p1);
 
-extern void            machine_switch_act(
-                                                       thread_t                thread,
-                                                       thread_act_t    old,
-                                                       thread_act_t    new,
-                                                       int                             cpu);
+extern boolean_t       thread_eager_preemption(
+                                               thread_t thread);
 
-/*
- *     These functions are either defined in kern/thread.c
- *     or are defined directly by machine-dependent code.
- */
+/* Fair Share routines */
+#if defined(CONFIG_SCHED_TRADITIONAL) || defined(CONFIG_SCHED_PROTO) || defined(CONFIG_SCHED_FIXEDPRIORITY)
+void           sched_traditional_fairshare_init(void);
 
-/* Allocate an activation stack */
-extern vm_offset_t     stack_alloc(thread_t thread, void (*start_pos)(thread_t));
+int                    sched_traditional_fairshare_runq_count(void);
 
-/* Free an activation stack */
-extern void            stack_free(thread_t thread);
+uint64_t       sched_traditional_fairshare_runq_stats_count_sum(void);
 
-/* Collect excess kernel stacks */
-extern void            stack_collect(void);
+void           sched_traditional_fairshare_enqueue(thread_t thread);
 
-/* Block current thread, indicating reason */
-extern wait_result_t   thread_block_reason(
-                                                       thread_continue_t       continuation,
-                                                       ast_t                           reason);
+thread_t       sched_traditional_fairshare_dequeue(void);
 
-/* Dispatch a thread for execution */
-extern void            thread_setrun(
-                                       thread_t        thread,
-                                       boolean_t       tail);
+boolean_t      sched_traditional_fairshare_queue_remove(thread_t thread);
+#endif
 
-#define HEAD_Q         0               /* FALSE */
-#define TAIL_Q         1               /* TRUE */
+#if defined(CONFIG_SCHED_GRRR) || defined(CONFIG_SCHED_FIXEDPRIORITY)
+void           sched_grrr_fairshare_init(void);
 
-/* Bind thread to a particular processor */
-extern void            thread_bind(
-                                               thread_t                thread,
-                                               processor_t             processor);
+int                    sched_grrr_fairshare_runq_count(void);
+
+uint64_t       sched_grrr_fairshare_runq_stats_count_sum(void);
+
+void           sched_grrr_fairshare_enqueue(thread_t thread);
+
+thread_t       sched_grrr_fairshare_dequeue(void);
+
+boolean_t      sched_grrr_fairshare_queue_remove(thread_t thread);
+#endif
+
+extern boolean_t sched_generic_direct_dispatch_to_idle_processors;
 
 /* Set the maximum interrupt level for the thread */
 __private_extern__ wait_interrupt_t thread_interrupt_level(
@@ -249,41 +275,146 @@ __private_extern__ wait_result_t thread_mark_wait_locked(
                                                thread_t                 thread,
                                                wait_interrupt_t interruptible);
 
-/* Sleep, unlocking and then relocking a usimple_lock in the process */
-__private_extern__ wait_result_t thread_sleep_fast_usimple_lock(
-                                               event_t                 event,
-                                               simple_lock_t   lock,
-                                               wait_interrupt_t interruptible);
-
 /* Wake up locked thread directly, passing result */
 __private_extern__ kern_return_t clear_wait_internal(
                                                thread_t                thread,
                                                wait_result_t   result);
 
+extern void sched_stats_handle_csw(
+                                                       processor_t processor, 
+                                                       int reasons, 
+                                                       int selfpri, 
+                                                       int otherpri);
+
+extern void sched_stats_handle_runq_change(
+                                                                       struct runq_stats *stats, 
+                                                                       int old_count);
+
+
+
+#define        SCHED_STATS_CSW(processor, reasons, selfpri, otherpri)          \
+do {                                                           \
+       if (__builtin_expect(sched_stats_active, 0)) {  \
+               sched_stats_handle_csw((processor),             \
+                               (reasons), (selfpri), (otherpri));      \
+       }                                                       \
+} while (0) 
+
+
+#define SCHED_STATS_RUNQ_CHANGE(stats, old_count)              \
+do {                                                           \
+       if (__builtin_expect(sched_stats_active, 0)) {  \
+               sched_stats_handle_runq_change((stats),         \
+                                                               (old_count));           \
+       }                                                       \
+} while (0) 
+
+#define THREAD_URGENCY_NONE            0       /* indicates that there is no currently runnable */
+#define THREAD_URGENCY_BACKGROUND      1       /* indicates that the thread is marked as a "background" thread */
+#define THREAD_URGENCY_NORMAL          2       /* indicates that the thread is marked as a "normal" thread */
+#define THREAD_URGENCY_REAL_TIME       3       /* indicates that the thread is marked as a "real-time" or urgent thread */
+#define        THREAD_URGENCY_MAX              4       /* Marker */
+/* Returns the "urgency" of the currently running thread (provided by scheduler) */
+extern int     thread_get_urgency(
+                                       uint64_t        *rt_period,
+                                       uint64_t        *rt_deadline);
+
+/* Tells the "urgency" of the just scheduled thread (provided by CPU PM) */
+extern void    thread_tell_urgency(
+                                       int             urgency,
+                                       uint64_t        rt_period,
+                                       uint64_t        rt_deadline);
+
+/* Tells if there are "active" RT threads in the system (provided by CPU PM) */
+extern void    active_rt_threads(
+                                       boolean_t       active);
+
 #endif /* MACH_KERNEL_PRIVATE */
 
-/*
- ****************** Only exported until BSD stops using ********************
- */
+__BEGIN_DECLS
+
+#ifdef XNU_KERNEL_PRIVATE
+
+extern boolean_t               assert_wait_possible(void);
 
 /*
- * Cancel a stop and unblock the thread if already stopped.
+ ****************** Only exported until BSD stops using ********************
  */
-extern void            thread_unstop(
-                                               thread_t                thread);
 
 /* Wake up thread directly, passing result */
 extern kern_return_t clear_wait(
                                                thread_t                thread,
                                                wait_result_t   result);
 
-#endif /* __APPLE_API_PRIVATE */
+/* Start thread running */
+extern void            thread_bootstrap_return(void);
+
+/* Return from exception (BSD-visible interface) */
+extern void            thread_exception_return(void) __dead2;
+
+#endif /* XNU_KERNEL_PRIVATE */
+
+/* Context switch */
+extern wait_result_t   thread_block(
+                                                       thread_continue_t       continuation);
+
+extern wait_result_t   thread_block_parameter(
+                                                       thread_continue_t       continuation,
+                                                       void                            *parameter);
+
+/* Declare thread will wait on a particular event */
+extern wait_result_t   assert_wait(
+                                                       event_t                         event,
+                                                       wait_interrupt_t        interruptible);
+
+/* Assert that the thread intends to wait with a timeout */
+extern wait_result_t   assert_wait_timeout(
+                                                       event_t                         event,
+                                                       wait_interrupt_t        interruptible,
+                                                       uint32_t                        interval,
+                                                       uint32_t                        scale_factor);
+
+extern wait_result_t   assert_wait_deadline(
+                                                       event_t                         event,
+                                                       wait_interrupt_t        interruptible,
+                                                       uint64_t                        deadline);
+
+/* Wake up thread (or threads) waiting on a particular event */
+extern kern_return_t   thread_wakeup_prim(
+                                                       event_t                         event,
+                                                       boolean_t                       one_thread,
+                                                       wait_result_t                   result);
+
+#ifdef MACH_KERNEL_PRIVATE
+extern kern_return_t   thread_wakeup_prim_internal(
+                                                       event_t                         event,
+                                                       boolean_t                       one_thread,
+                                                       wait_result_t                   result,
+                                                       int                             priority);
+#endif
+
+#define thread_wakeup(x)                                       \
+                       thread_wakeup_prim((x), FALSE, THREAD_AWAKENED)
+#define thread_wakeup_with_result(x, z)                \
+                       thread_wakeup_prim((x), FALSE, (z))
+#define thread_wakeup_one(x)                           \
+                       thread_wakeup_prim((x), TRUE, THREAD_AWAKENED)
+
+#ifdef MACH_KERNEL_PRIVATE
+#define thread_wakeup_one_with_pri(x, pri)                             \
+                       thread_wakeup_prim_internal((x), TRUE, THREAD_AWAKENED, pri)
+#endif
+
+extern boolean_t               preemption_enabled(void);
+
+#ifdef KERNEL_PRIVATE
+
+#ifndef        __LP64__
 
 /*
- * *********************   PUBLIC APIs ************************************
+ * Obsolete interfaces.
  */
 
-/* Set timer for current thread */
 extern void            thread_set_timer(
                                        uint32_t                interval,
                                        uint32_t                scale_factor);
@@ -293,78 +424,238 @@ extern void              thread_set_timer_deadline(
 
 extern void            thread_cancel_timer(void);
 
-/* Declare thread will wait on a particular event */
-extern wait_result_t assert_wait(
-                                               event_t                  event,
-                                               wait_interrupt_t interruptflag);
-
-/* Assert that the thread intends to wait for a timeout */
-extern wait_result_t assert_wait_timeout(
-                                               natural_t                msecs,
-                                               wait_interrupt_t interruptflags);
-
-/* Sleep, unlocking and then relocking a usimple_lock in the process */
-extern wait_result_t thread_sleep_usimple_lock(
-                                               event_t                 event,
-                                               usimple_lock_t  lock,
-                                               wait_interrupt_t interruptible);        
-
-/* Sleep, unlocking and then relocking a mutex in the process */
-extern wait_result_t thread_sleep_mutex(
-                                               event_t                 event,
-                                               mutex_t                 *mutex,
-                                               wait_interrupt_t interruptible);        
-                                                                               
-/* Sleep with a deadline, unlocking and then relocking a mutex in the process */
-extern wait_result_t thread_sleep_mutex_deadline(
-                                               event_t                 event,
-                                               mutex_t                 *mutex,
-                                               uint64_t                deadline,
-                                               wait_interrupt_t interruptible);        
-
-/* Sleep, unlocking and then relocking a write lock in the process */
-extern wait_result_t thread_sleep_lock_write(
-                                               event_t                 event,
-                                               lock_t                  *lock,
-                                               wait_interrupt_t interruptible);        
-                                                                          
-/* Sleep, hinting that a thread funnel may be involved in the process */
-extern wait_result_t thread_sleep_funnel(
-                                               event_t                 event,
-                                               wait_interrupt_t interruptible);        
+#ifndef        MACH_KERNEL_PRIVATE
 
-/* Wake up thread (or threads) waiting on a particular event */
-extern kern_return_t thread_wakeup_prim(
-                                               event_t                 event,
-                                               boolean_t               one_thread,
-                                               wait_result_t   result);
+#ifndef        ABSOLUTETIME_SCALAR_TYPE
 
-#ifdef __APPLE_API_UNSTABLE
+#define thread_set_timer_deadline(a)   \
+       thread_set_timer_deadline(__OSAbsoluteTime(a))
 
-/* Block current thread (Block reason) */
-extern wait_result_t thread_block(
-                                               thread_continue_t continuation);
+#endif /* ABSOLUTETIME_SCALAR_TYPE */
 
-#endif /* __APPLE_API_UNSTABLE */
+#endif /* MACH_KERNEL_PRIVATE */
+
+#endif /* __LP64__ */
+
+#endif /* KERNEL_PRIVATE */
+
+#ifdef MACH_KERNEL_PRIVATE
 
 /*
- *     Routines defined as macros
+ * Scheduler algorithm indirection. If only one algorithm is
+ * enabled at compile-time, a direction function call is used.
+ * If more than one is enabled, calls are dispatched through
+ * a function pointer table.
  */
 
-#define thread_wakeup(x)                                       \
-                       thread_wakeup_prim((x), FALSE, THREAD_AWAKENED)
-#define thread_wakeup_with_result(x, z)                \
-                       thread_wakeup_prim((x), FALSE, (z))
-#define thread_wakeup_one(x)                           \
-                       thread_wakeup_prim((x), TRUE, THREAD_AWAKENED)
+#if   !defined(CONFIG_SCHED_TRADITIONAL) && !defined(CONFIG_SCHED_PROTO) && !defined(CONFIG_SCHED_GRRR) && !defined(CONFIG_SCHED_FIXEDPRIORITY)
+#error Enable at least one scheduler algorithm in osfmk/conf/MASTER.XXX
+#endif
 
-#if            !defined(MACH_KERNEL_PRIVATE) && !defined(ABSOLUTETIME_SCALAR_TYPE)
+#define SCHED(f) (sched_current_dispatch->f)
+
+struct sched_dispatch_table {
+       void    (*init)(void);                          /* Init global state */
+       void    (*timebase_init)(void);         /* Timebase-dependent initialization */
+       void    (*processor_init)(processor_t processor);       /* Per-processor scheduler init */
+       void    (*pset_init)(processor_set_t pset);     /* Per-processor set scheduler init */
+       
+       void    (*maintenance_continuation)(void);      /* Function called regularly */
+       
+       /*
+        * Choose a thread of greater or equal priority from the per-processor
+        * runqueue for timeshare/fixed threads
+        */
+       thread_t        (*choose_thread)(
+                                                                 processor_t           processor,
+                                                                 int                           priority);
+       
+       /*
+        * Steal a thread from another processor in the pset so that it can run
+        * immediately
+        */
+       thread_t        (*steal_thread)(
+                                                               processor_set_t         pset);
+       
+       /*
+        * Recalculate sched_pri based on base priority, past running time,
+        * and scheduling class.
+        */
+       void            (*compute_priority)(
+                                        thread_t       thread,
+                                        boolean_t                      override_depress);
+       
+       /*
+        * Pick the best processor for a thread (any kind of thread) to run on.
+        */
+       processor_t     (*choose_processor)(
+                                                                                processor_set_t                pset,
+                                                                                processor_t                    processor,
+                                                                                thread_t                       thread);
+       /*
+        * Enqueue a timeshare or fixed priority thread onto the per-processor
+        * runqueue
+        */
+       boolean_t (*processor_enqueue)(
+                                                                processor_t                    processor,
+                                                                thread_t                       thread,
+                                                                integer_t                      options);
+       
+       /* Migrate threads away in preparation for processor shutdown */
+       void (*processor_queue_shutdown)(
+                                                                        processor_t                    processor);
+       
+       /* Remove the specific thread from the per-processor runqueue */
+       boolean_t       (*processor_queue_remove)(
+                                                                       processor_t                     processor,
+                                                                       thread_t                thread);
+       
+       /*
+        * Does the per-processor runqueue have any timeshare or fixed priority
+        * threads on it? Called without pset lock held, so should
+        * not assume immutability while executing.
+        */
+       boolean_t       (*processor_queue_empty)(processor_t            processor);
+       
+       /*
+        * Would this priority trigger an urgent preemption if it's sitting
+        * on the per-processor runqueue?
+        */
+       boolean_t       (*priority_is_urgent)(int priority);
+       
+       /*
+        * Does the per-processor runqueue contain runnable threads that
+        * should cause the currently-running thread to be preempted?
+        */
+       ast_t           (*processor_csw_check)(processor_t processor);
+       
+       /*
+        * Does the per-processor runqueue contain a runnable thread
+        * of > or >= priority, as a preflight for choose_thread() or other
+        * thread selection
+        */
+       boolean_t       (*processor_queue_has_priority)(processor_t             processor,
+                                                                                               int                             priority,
+                                                                                               boolean_t               gte);
+       
+       /* Quantum size for the specified non-realtime thread. */
+       uint32_t        (*initial_quantum_size)(thread_t thread);
+       
+       /* Scheduler mode for a new thread */
+       sched_mode_t    (*initial_thread_sched_mode)(task_t parent_task);
+       
+       /* Scheduler algorithm supports timeshare (decay) mode */
+       boolean_t       (*supports_timeshare_mode)(void);
+       
+       /*
+        * Is it safe to call update_priority, which may change a thread's
+        * runqueue or other state. This can be used to throttle changes
+        * to dynamic priority.
+        */
+       boolean_t       (*can_update_priority)(thread_t thread);
+
+       /*
+        * Update both scheduled priority and other persistent state.
+        * Side effects may including migration to another processor's runqueue.
+        */
+       void            (*update_priority)(thread_t thread);
+       
+       /* Lower overhead update to scheduled priority and state. */
+       void            (*lightweight_update_priority)(thread_t thread);
+       
+       /* Callback for non-realtime threads when the quantum timer fires */
+       void            (*quantum_expire)(thread_t thread);
+       
+       /*
+        * Even though we could continue executing on this processor, does the
+        * topology (SMT, for instance) indicate that a better processor could be
+        * chosen
+        */
+       boolean_t       (*should_current_thread_rechoose_processor)(processor_t                 processor);
+    
+       /*
+        * Runnable threads on per-processor runqueue. Should only
+        * be used for relative comparisons of load between processors.
+        */
+       int                     (*processor_runq_count)(processor_t     processor);
+       
+       /* Aggregate runcount statistics for per-processor runqueue */
+    uint64_t    (*processor_runq_stats_count_sum)(processor_t   processor);
+       
+       /* Initialize structures to track demoted fairshare threads */
+       void            (*fairshare_init)(void);
+       
+       /* Number of runnable fairshare threads */
+       int                     (*fairshare_runq_count)(void);
+       
+       /* Aggregate runcount statistics for fairshare runqueue */
+       uint64_t        (*fairshare_runq_stats_count_sum)(void);
+       
+       void            (*fairshare_enqueue)(thread_t thread);
+       
+       thread_t        (*fairshare_dequeue)(void);
+
+       boolean_t       (*fairshare_queue_remove)(thread_t thread);
+    
+       /*
+       * Use processor->next_thread to pin a thread to an idle
+       * processor. If FALSE, threads are enqueued and can
+       * be stolen by other processors.
+       */
+       boolean_t   direct_dispatch_to_idle_processors;
+};
+
+#if defined(CONFIG_SCHED_TRADITIONAL)
+#define kSchedTraditionalString "traditional"
+#define kSchedTraditionalWithPsetRunqueueString "traditional_with_pset_runqueue"
+extern const struct sched_dispatch_table sched_traditional_dispatch;
+extern const struct sched_dispatch_table sched_traditional_with_pset_runqueue_dispatch;
+#endif
 
-#include <libkern/OSBase.h>
+#if defined(CONFIG_SCHED_PROTO)
+#define kSchedProtoString "proto"
+extern const struct sched_dispatch_table sched_proto_dispatch;
+#endif
 
-#define thread_set_timer_deadline(a)   \
-       thread_set_timer_deadline(__OSAbsoluteTime(a))
+#if defined(CONFIG_SCHED_GRRR)
+#define kSchedGRRRString "grrr"
+extern const struct sched_dispatch_table sched_grrr_dispatch;
+#endif
 
+#if defined(CONFIG_SCHED_FIXEDPRIORITY)
+#define kSchedFixedPriorityString "fixedpriority"
+#define kSchedFixedPriorityWithPsetRunqueueString "fixedpriority_with_pset_runqueue"
+extern const struct sched_dispatch_table sched_fixedpriority_dispatch;
+extern const struct sched_dispatch_table sched_fixedpriority_with_pset_runqueue_dispatch;
 #endif
 
+/*
+ * It is an error to invoke any scheduler-related code
+ * before this is set up
+ */
+enum sched_enum {
+       sched_enum_unknown = 0,
+#if defined(CONFIG_SCHED_TRADITIONAL)
+       sched_enum_traditional = 1,
+       sched_enum_traditional_with_pset_runqueue = 2,
+#endif
+#if defined(CONFIG_SCHED_PROTO)
+       sched_enum_proto = 3,
+#endif
+#if defined(CONFIG_SCHED_GRRR)
+       sched_enum_grrr = 4,
+#endif
+#if defined(CONFIG_SCHED_FIXEDPRIORITY)
+       sched_enum_fixedpriority = 5,
+       sched_enum_fixedpriority_with_pset_runqueue = 6,
+#endif
+       sched_enum_max = 7
+};
+
+extern const struct sched_dispatch_table *sched_current_dispatch;
+
+#endif /* MACH_KERNEL_PRIVATE */
+
+__END_DECLS
+
 #endif /* _KERN_SCHED_PRIM_H_ */