xref: /macosx-10.10.1/xnu-2782.1.97/bsd/kern/kern_memorystatus.c

/*
 * Copyright (c) 2006 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 *
 */

#include <kern/sched_prim.h>
#include <kern/kalloc.h>
#include <kern/assert.h>
#include <kern/debug.h>
#include <kern/locks.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/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>

#if CONFIG_JETSAM
/* For logging clarity */
static const char *jetsam_kill_cause_name[] = {
	""                      ,
	"jettisoned"		,       /* kMemorystatusKilled			*/
	"highwater"             ,       /* kMemorystatusKilledHiwat		*/
	"vnode-limit"           ,       /* kMemorystatusKilledVnodes		*/
	"vm-pageshortage"       ,       /* kMemorystatusKilledVMPageShortage	*/
	"vm-thrashing"          ,       /* kMemorystatusKilledVMThrashing	*/
	"fc-thrashing"          ,       /* kMemorystatusKilledFCThrashing	*/
	"per-process-limit"     ,       /* kMemorystatusKilledPerProcessLimit	*/
	"diagnostic"            ,       /* kMemorystatusKilledDiagnostic	*/
	"idle-exit"             ,       /* kMemorystatusKilledIdleExit		*/
};

/* Does cause indicate vm or fc thrashing? */
static boolean_t
is_thrashing(unsigned cause)
{
	switch (cause) {
	case kMemorystatusKilledVMThrashing:
	case kMemorystatusKilledFCThrashing:
		return TRUE;
	default:
		return FALSE;
	}
}

/* Callback into vm_compressor.c to signal that thrashing has been mitigated. */
extern void vm_thrashing_jetsam_done(void);
#endif

/* 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 = 0x1,
	kMemorystatusPressure = 0x2,
	kMemorystatusLowSwap = 0x4
};

/* 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, boolean_t head_insert);

boolean_t is_knote_registered_modify_task_pressure_bits(struct knote*, int, task_t, vm_pressure_level_t, vm_pressure_level_t);
void memorystatus_send_low_swap_note(void);

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;


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

int proc_get_memstat_priority(proc_t, boolean_t);

/* Kill processes exceeding their limit either under memory pressure (1), or as soon as possible (0) */
#define LEGACY_HIWATER 1

static boolean_t memorystatus_idle_snapshot = 0;

static int memorystatus_highwater_enabled = 1;

unsigned int memorystatus_delta = 0;

static unsigned int memorystatus_available_pages_critical_base = 0;
//static unsigned int memorystatus_last_foreground_pressure_pages = (unsigned int)-1;
static unsigned int memorystatus_available_pages_critical_idle_offset = 0;

#if DEVELOPMENT || DEBUG
static unsigned int memorystatus_jetsam_panic_debug = 0;

static unsigned int memorystatus_jetsam_policy = kPolicyDefault;
static unsigned int memorystatus_jetsam_policy_offset_pages_diagnostic = 0;
#endif

static unsigned int memorystatus_thread_wasted_wakeup = 0;

static uint32_t kill_under_pressure_cause = 0;

static memorystatus_jetsam_snapshot_t *memorystatus_jetsam_snapshot;
#define memorystatus_jetsam_snapshot_list memorystatus_jetsam_snapshot->entries

static unsigned int memorystatus_jetsam_snapshot_count = 0;
static unsigned int memorystatus_jetsam_snapshot_max = 0;

static void memorystatus_clear_errors(void);
static void memorystatus_get_task_page_counts(task_t task, uint32_t *footprint, uint32_t *max_footprint, uint32_t *max_footprint_lifetime, uint32_t *purgeable_pages);
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);

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

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);

#endif /* CONFIG_JETSAM */

/* VM pressure */

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;

#if VM_PRESSURE_EVENTS

#include "vm_pressure.h"

extern boolean_t memorystatus_warn_process(pid_t pid, boolean_t critical);

vm_pressure_level_t memorystatus_vm_pressure_level = kVMPressureNormal;

#if CONFIG_MEMORYSTATUS
unsigned int memorystatus_available_pages = (unsigned int)-1;
unsigned int memorystatus_available_pages_pressure = 0;
unsigned int memorystatus_available_pages_critical = 0;
unsigned int memorystatus_frozen_count = 0;
unsigned int memorystatus_suspended_count = 0;

/*
 * We use this flag to signal if we have any HWM offenders
 * on the system. This way we can reduce the number of wakeups
 * of the memorystatus_thread when the system is between the
 * "pressure" and "critical" threshold.
 *
 * The (re-)setting of this variable is done without any locks
 * or synchronization simply because it is not possible (currently)
 * to keep track of HWM offenders that drop down below their memory
 * limit and/or exit. So, we choose to burn a couple of wasted wakeups
 * by allowing the unguarded modification of this variable.
 */
boolean_t memorystatus_hwm_candidates = 0;

static int memorystatus_send_note(int event_code, void *data, size_t data_length);
#endif /* CONFIG_MEMORYSTATUS */

#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 = 0;
static unsigned int memorystatus_freeze_pages_max = 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_footprint_total = 0;

#endif /* CONFIG_FREEZE */

/* Debug */

extern struct knote *vm_find_knote_from_pid(pid_t, struct klist *);

#if DEVELOPMENT || DEBUG

#if CONFIG_JETSAM

/* Debug aid to aid determination of limit */

static int
sysctl_memorystatus_highwater_enable SYSCTL_HANDLER_ARGS
{
#pragma unused(oidp, arg2)
	proc_t p;
	unsigned int b = 0;
	int error, enable = 0;
	int32_t memlimit;

	error = SYSCTL_OUT(req, arg1, sizeof(int));
	if (error || !req->newptr) {
		return (error);
	}

	error = SYSCTL_IN(req, &enable, sizeof(int));
	if (error || !req->newptr) {
		return (error);
	}

	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);

		if (memlimit == -1) {
        		p->p_memstat_state |= P_MEMSTAT_FATAL_MEMLIMIT;
		} else {
        		if (p->p_memstat_state & P_MEMSTAT_MEMLIMIT_BACKGROUND) {
				p->p_memstat_state &= ~P_MEMSTAT_FATAL_MEMLIMIT;
			}
		}

		p = memorystatus_get_next_proc_locked(&b, p, TRUE);
	}

	memorystatus_highwater_enabled = enable;

	proc_list_unlock();

	return 0;
}

SYSCTL_INT(_kern, OID_AUTO, memorystatus_idle_snapshot, CTLFLAG_RW|CTLFLAG_LOCKED, &memorystatus_idle_snapshot, 0, "");

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, "");
SYSCTL_UINT(_kern, OID_AUTO, memorystatus_available_pages_critical_idle_offset, CTLFLAG_RW|CTLFLAG_LOCKED, &memorystatus_available_pages_critical_idle_offset, 0, "");

/* 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
{
#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;

	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();

	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();

	if (changed) {
		printf("%s\n", diagnosticStrings[val]);
	}

	return (0);
}

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, "");


/*
 * This routine is used for targeted notifications
 * regardless of system memory pressure.
 * "memnote" is the current user.
 */

static int
sysctl_memorystatus_vm_pressure_send SYSCTL_HANDLER_ARGS
{
#pragma unused(arg1, arg2)

	int error = 0, pid = 0;
	int ret = 0;
	struct knote *kn = NULL;

	error = sysctl_handle_int(oidp, &pid, 0, req);
	if (error || !req->newptr)
		return (error);

	/*
	 * We inspect 3 lists here for targeted notifications:
	 * - memorystatus_klist
	 * - vm_pressure_klist
	 * - vm_pressure_dormant_klist
	 *
	 * The vm_pressure_* lists are tied to the old VM_PRESSURE
	 * notification mechanism. We intend to stop using that
	 * mechanism and, in turn, get rid of the 2 lists and
	 * vm_dispatch_pressure_note_to_pid() too.
	 */

	memorystatus_klist_lock();
	kn = vm_find_knote_from_pid(pid, &memorystatus_klist);
	if (kn) {
		/*
		 * Forcibly send this pid a "warning" memory pressure notification.
		 */
		kn->kn_fflags |= NOTE_MEMORYSTATUS_PRESSURE_WARN;
    		KNOTE(&memorystatus_klist, kMemorystatusPressure);
    		ret = 0;
	} else {
		ret = vm_dispatch_pressure_note_to_pid(pid, FALSE);
	}
	memorystatus_klist_unlock();

	return ret;
}

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 */

#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, "");

/*
 * Manual trigger of freeze and thaw for dev / debug kernels only.
 */
static int
sysctl_memorystatus_freeze SYSCTL_HANDLER_ARGS
{
#pragma unused(arg1, arg2)

	int error, pid = 0;
	proc_t p;

	if (memorystatus_freeze_enabled == FALSE) {
		return ENOTSUP;
	}

	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_SWAPBACKED) {
			max_pages = MIN(default_pager_swap_pages_free(), memorystatus_freeze_pages_max);
		} else {
			max_pages = UINT32_MAX - 1;
		}
		error = task_freeze(p->task, &purgeable, &wired, &clean, &dirty, max_pages, &shared, FALSE);
		proc_rele(p);

		if (error)
			error = EIO;
		return error;
	}
	return EINVAL;
}

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
{
#pragma unused(arg1, arg2)

	int error, pid = 0;
	proc_t p;

	if (memorystatus_freeze_enabled == FALSE) {
		return ENOTSUP;
	}

	error = sysctl_handle_int(oidp, &pid, 0, req);
	if (error || !req->newptr)
		return (error);

	p = proc_find(pid);
	if (p != NULL) {
		error = task_thaw(p->task);
		proc_rele(p);

		if (error)
			error = EIO;
		return error;
	}

	return EINVAL;
}

SYSCTL_PROC(_kern, OID_AUTO, memorystatus_thaw, CTLTYPE_INT|CTLFLAG_WR|CTLFLAG_LOCKED|CTLFLAG_MASKED,
    0, 0, &sysctl_memorystatus_available_pages_thaw, "I", "");

#endif /* CONFIG_FREEZE */

#endif /* DEVELOPMENT || DEBUG */

extern kern_return_t kernel_thread_start_priority(thread_continue_t continuation,
                                                  void *parameter,
                                                  integer_t priority,
                                                  thread_t *new_thread);

#if CONFIG_JETSAM
/*
 * Sort processes by size for a single jetsam bucket.
 */

static void memorystatus_sort_by_largest_process_locked(unsigned int bucket_index)
{
	proc_t p = NULL, insert_after_proc = NULL, max_proc = NULL;
	uint32_t pages = 0, max_pages = 0;
	memstat_bucket_t *current_bucket;

	if (bucket_index >= MEMSTAT_BUCKET_COUNT) {
		return;
	}

	current_bucket = &memstat_bucket[bucket_index];

	p = TAILQ_FIRST(&current_bucket->list);

	if (p) {
		memorystatus_get_task_page_counts(p->task, &pages, NULL, NULL, NULL);
		max_pages = pages;
		insert_after_proc = NULL;

		p = TAILQ_NEXT(p, p_memstat_list);

restart:
		while (p) {

			memorystatus_get_task_page_counts(p->task, &pages, NULL, NULL, NULL);

			if (pages > max_pages) {
				max_pages = pages;
				max_proc = p;
			}

			p = TAILQ_NEXT(p, p_memstat_list);
		}

		if (max_proc) {

			TAILQ_REMOVE(&current_bucket->list, max_proc, p_memstat_list);

			if (insert_after_proc == NULL) {
				TAILQ_INSERT_HEAD(&current_bucket->list, max_proc, p_memstat_list);
			} else {
				TAILQ_INSERT_AFTER(&current_bucket->list, insert_after_proc, max_proc, p_memstat_list);
			}

			insert_after_proc = max_proc;

			/* Reset parameters for the new search. */
			p = TAILQ_NEXT(max_proc, p_memstat_list);
			if (p) {
				memorystatus_get_task_page_counts(p->task, &pages, NULL, NULL, NULL);
				max_pages = pages;
			}
			max_proc = NULL;

			goto restart;
		}
	}
}

#endif /* CONFIG_JETSAM */

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 ((*bucket_index) >= MEMSTAT_BUCKET_COUNT) {
		return NULL;
	}

	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;
}

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;
	}

	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;
}

__private_extern__ void
memorystatus_init(void)
{
	thread_t thread = THREAD_NULL;
	kern_return_t result;
	int i;

#if CONFIG_FREEZE
	memorystatus_freeze_pages_min = FREEZE_PAGES_MIN;
	memorystatus_freeze_pages_max = FREEZE_PAGES_MAX;
#endif

	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);

	/* 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;
	memorystatus_available_pages_critical_idle_offset = idle_offset_percentage * atop_64(max_mem) / 100;
	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");
	}
}

/* Centralised for the purposes of allowing panic-on-jetsam */
extern void
vm_wake_compactor_swapper(void);

/*
 * The jetsam no frills kill call
 * 	Return: 0 on success
 *		error code on failure (EINVAL...)
 */
static int
jetsam_do_kill(proc_t p, int jetsam_flags) {
	int error = 0;
	error = exit1_internal(p, W_EXITCODE(0, SIGKILL), (int *)NULL, FALSE, FALSE, jetsam_flags);
	return(error);
}

/*
 * Wrapper for processes exiting with memorystatus details
 */
static boolean_t
memorystatus_do_kill(proc_t p, uint32_t cause) {

	int error = 0;
	__unused pid_t victim_pid = p->p_pid;

	KERNEL_DEBUG_CONSTANT( (BSDDBG_CODE(DBG_BSD_MEMSTAT, BSD_MEMSTAT_DO_KILL)) | DBG_FUNC_START,
			       victim_pid, cause, vm_page_free_count, 0, 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 kMemorystatusKilledFCThrashing:		jetsam_flags |= P_JETSAM_FCTHRASHING; break;
		case kMemorystatusKilledPerProcessLimit:	jetsam_flags |= P_JETSAM_PID; break;
		case kMemorystatusKilledIdleExit:		jetsam_flags |= P_JETSAM_IDLEEXIT; break;
	}
	error = jetsam_do_kill(p, jetsam_flags);

	KERNEL_DEBUG_CONSTANT( (BSDDBG_CODE(DBG_BSD_MEMSTAT, BSD_MEMSTAT_DO_KILL)) | DBG_FUNC_END,
			       victim_pid, cause, vm_page_free_count, error, 0);

	if (COMPRESSED_PAGER_IS_ACTIVE || DEFAULT_FREEZER_COMPRESSED_PAGER_IS_ACTIVE) {
 		vm_wake_compactor_swapper();
 	}

	return (error == 0);
}

/*
 * 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)
{
	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();

	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 [%s] to idle band, but never dirtied (0x%x)!\n",
					p->p_pid, (p->p_comm ? p->p_comm : "(unknown)"), p->p_memstat_dirty);
			}
#endif
			memorystatus_invalidate_idle_demotion_locked(p, TRUE);
			memorystatus_update_priority_locked(p, JETSAM_PRIORITY_IDLE, false);

			// The prior process has moved out of the demotion bucket, so grab the new head and continue
			p = TAILQ_FIRST(&demotion_bucket->list);
			continue;
		}

		// No further candidates
		break;
	}

	memorystatus_reschedule_idle_demotion_locked();

	proc_list_unlock();

	KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_MEMSTAT, BSD_MEMSTAT_IDLE_DEMOTE) | DBG_FUNC_END, 0, 0, 0, 0, 0);
}

static void
memorystatus_schedule_idle_demotion_locked(proc_t p, boolean_t set_state)
{
	boolean_t present_in_deferred_bucket = FALSE;

	if (p->p_memstat_effectivepriority == JETSAM_PRIORITY_IDLE_DEFERRED) {
		present_in_deferred_bucket = TRUE;
	}

	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);

	assert((p->p_memstat_dirty & P_DIRTY_IDLE_EXIT_ENABLED) == P_DIRTY_IDLE_EXIT_ENABLED);

	if (set_state) {
		assert(p->p_memstat_idledeadline == 0);
		p->p_memstat_dirty |= P_DIRTY_DEFER_IN_PROGRESS;
		p->p_memstat_idledeadline = mach_absolute_time() + memorystatus_idle_delay_time;
	}

	assert(p->p_memstat_idledeadline);

 	if (present_in_deferred_bucket == FALSE) {
		memorystatus_scheduled_idle_demotions++;
	}
}

static void
memorystatus_invalidate_idle_demotion_locked(proc_t p, boolean_t clear_state)
{
	boolean_t present_in_deferred_bucket = FALSE;

	if (p->p_memstat_effectivepriority == JETSAM_PRIORITY_IDLE_DEFERRED) {
		present_in_deferred_bucket = TRUE;
		assert(p->p_memstat_idledeadline);
	}

	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);


	if (clear_state) {
 		p->p_memstat_idledeadline = 0;
 		p->p_memstat_dirty &= ~P_DIRTY_DEFER_IN_PROGRESS;
	}

 	if (present_in_deferred_bucket == TRUE) {
		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;
		}
 	}
}

/*
 * List manipulation
 */

int
memorystatus_add(proc_t p, boolean_t locked)
{
	memstat_bucket_t *bucket;

	MEMORYSTATUS_DEBUG(1, "memorystatus_list_add(): adding process %d with priority %d.\n", p->p_pid, p->p_memstat_effectivepriority);

	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];

	if (p->p_memstat_effectivepriority == JETSAM_PRIORITY_IDLE_DEFERRED) {
		assert(bucket->count == memorystatus_scheduled_idle_demotions);
	}

	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;
}

static void
memorystatus_update_priority_locked(proc_t p, int priority, boolean_t head_insert)
{
	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;
	}

	MEMORYSTATUS_DEBUG(1, "memorystatus_update_priority_locked(): setting process %d to priority %d, inserting at %s\n",
	                   p->p_pid, priority, head_insert ? "head" : "tail");

	old_bucket = &memstat_bucket[p->p_memstat_effectivepriority];
	if (p->p_memstat_effectivepriority == JETSAM_PRIORITY_IDLE_DEFERRED) {
		assert(old_bucket->count == (memorystatus_scheduled_idle_demotions + 1));
	}

	TAILQ_REMOVE(&old_bucket->list, p, p_memstat_list);
	old_bucket->count--;

	new_bucket = &memstat_bucket[priority];
	if (head_insert)
		TAILQ_INSERT_HEAD(&new_bucket->list, p, p_memstat_list);
	else
		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)) {

		/*
		 * Adjust memory limit based on if the task is going to/from foreground and 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);

			if (memlimit <= 0) {
		        	p->p_memstat_state |= P_MEMSTAT_FATAL_MEMLIMIT;
			} else {
	        		p->p_memstat_state &= ~P_MEMSTAT_FATAL_MEMLIMIT;
			}
		}
	}
#endif

	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, boolean_t is_fatal_limit)
{
	int ret;
	boolean_t head_insert = false;

#if !CONFIG_JETSAM
#pragma unused(update_memlimit, memlimit, memlimit_background, is_fatal_limit)
#endif

	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 == JETSAM_PRIORITY_IDLE_HEAD) {
		/* JETSAM_PRIORITY_IDLE_HEAD inserts at the head of the idle queue */
		priority = JETSAM_PRIORITY_IDLE;
		head_insert = true;
	} 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", p->p_pid);
		goto out;
	}

	if ((p->p_memstat_state & P_MEMSTAT_TERMINATED) || ((p->p_listflag & P_LIST_EXITED) != 0)) {
		/*
		 * This could happen when a process calling posix_spawn() is exiting on the jetsam thread.
		 */
		ret = EBUSY;
		proc_list_unlock();
		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;

			/* Cannot have a background memory limit and be fatal. */
			is_fatal_limit = FALSE;

		} else {
			/* Otherwise, apply now */
			if (memorystatus_highwater_enabled) {
				task_set_phys_footprint_limit_internal(p->task, (memlimit  > 0) ? memlimit : -1, NULL, TRUE);
			}
		}

		if (is_fatal_limit || memlimit <= 0) {
	        	p->p_memstat_state |= P_MEMSTAT_FATAL_MEMLIMIT;
		} else {
	        	p->p_memstat_state &= ~P_MEMSTAT_FATAL_MEMLIMIT;
		}
	}
#endif

	/*
	 * We can't add to the JETSAM_PRIORITY_IDLE_DEFERRED bucket here.
	 * But, we could be removing it from the bucket.
	 * Check and take appropriate steps if so.
	 */

	if (p->p_memstat_effectivepriority == JETSAM_PRIORITY_IDLE_DEFERRED) {

		memorystatus_invalidate_idle_demotion_locked(p, TRUE);
	}

	memorystatus_update_priority_locked(p, priority, head_insert);

	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;
}

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", p->p_pid);

   	if (!locked) {
   	   	proc_list_lock();
   	}

	assert(!(p->p_memstat_state & P_MEMSTAT_INTERNAL));

	bucket = &memstat_bucket[p->p_memstat_effectivepriority];
	if (p->p_memstat_effectivepriority == JETSAM_PRIORITY_IDLE_DEFERRED) {
		assert(bucket->count == memorystatus_scheduled_idle_demotions);
	}

	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;
	}

	/* 'Launch in progress' tracking requires that process have enabled dirty tracking too. */
	if ((pcontrol & PROC_DIRTY_LAUNCH_IN_PROGRESS) &&
	   !(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;
	}

	if (priority != p->p_memstat_effectivepriority) {
		memorystatus_update_priority_locked(p, priority, false);
	}
}

/*
 * 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;
	boolean_t already_deferred = FALSE;
	boolean_t defer_now = FALSE;
	int ret;

	KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_MEMSTAT, BSD_MEMSTAT_DIRTY_TRACK),
		p->p_pid, p->p_memstat_dirty, pcontrol, 0, 0);

	proc_list_lock();

	if ((p->p_listflag & P_LIST_EXITED) != 0) {
		/*
		 * Process is on its way out.
		 */
		ret = EBUSY;
		goto exit;
	}

	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;
	}

	if (pcontrol & PROC_DIRTY_LAUNCH_IN_PROGRESS) {
		p->p_memstat_dirty |= P_DIRTY_LAUNCH_IN_PROGRESS;
	}

	if (old_dirty & P_DIRTY_DEFER_IN_PROGRESS) {
		already_deferred = TRUE;
	}

	/* This can be set and cleared exactly once. */
	if (pcontrol & PROC_DIRTY_DEFER) {

	       	if ( !(old_dirty & P_DIRTY_DEFER)) {
			p->p_memstat_dirty |= P_DIRTY_DEFER;
		}

		defer_now = TRUE;
	}

	MEMORYSTATUS_DEBUG(1, "memorystatus_on_track_dirty(): set idle-exit %s / defer %s / dirty %s for process %d\n",
		((p->p_memstat_dirty & P_DIRTY_IDLE_EXIT_ENABLED) == P_DIRTY_IDLE_EXIT_ENABLED) ? "Y" : "N",
		defer_now ? "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) &&
			defer_now && !already_deferred) {

			/*
			 * Request to defer a clean process that's idle-exit enabled
			 * and not already in the jetsam deferred band.
			 */
			memorystatus_schedule_idle_demotion_locked(p, TRUE);
			reschedule = TRUE;

		} else if (!defer_now && already_deferred) {

			/*
			 * Either the process is no longer idle-exit enabled OR
			 * there's a request to cancel a currently active deferral.
			 */
			memorystatus_invalidate_idle_demotion_locked(p, TRUE);
			reschedule = TRUE;
		}
	} else {

		/*
		 * We are trying to operate on a dirty process. Dirty processes have to
		 * be removed from the deferred band. The question is do we reset the
		 * deferred state or not?
		 *
		 * This could be a legal request like:
		 * - this process had opted into the JETSAM_DEFERRED band
		 * - but it's now dirty and requests to opt out.
		 * In this case, we remove the process from the band and reset its
		 * state too. It'll opt back in properly when needed.
		 *
		 * OR, this request could be a user-space bug. E.g.:
		 * - this process had opted into the JETSAM_DEFERRED band when clean
		 * - and, then issues another request to again put it into the band except
		 *   this time the process is dirty.
		 * The process going dirty, as a transition in memorystatus_dirty_set(), will pull the process out of
		 * the deferred band with its state intact. So our request below is no-op.
		 * But we do it here anyways for coverage.
		 *
		 * memorystatus_update_idle_priority_locked()
		 * single-mindedly treats a dirty process as "cannot be in the deferred band".
		 */

		if (!defer_now && already_deferred) {
			memorystatus_invalidate_idle_demotion_locked(p, TRUE);
			reschedule = TRUE;
		} else {
			memorystatus_invalidate_idle_demotion_locked(p, FALSE);
			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);

	KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_MEMSTAT, BSD_MEMSTAT_DIRTY_SET), p->p_pid, self, pcontrol, 0, 0);

	proc_list_lock();

	if ((p->p_listflag & P_LIST_EXITED) != 0) {
		/*
		 * Process is on its way out.
		 */
		ret = EBUSY;
		goto exit;
	}

	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)) {

			/*
			 * P_DIRTY_DEFER_IN_PROGRESS means the process is in the deferred band OR it might be heading back
			 * there once it's clean again and has some protection window left.
			 */

			if (p->p_memstat_dirty & P_DIRTY_IS_DIRTY) {
				/*
				 * New dirty process i.e. "was_dirty == FALSE && now_dirty == TRUE"
				 *
				 * The process will move from the deferred band to its higher requested
				 * jetsam band. But we don't clear its state i.e. we want to remember that
				 * this process was part of the "deferred" band and will return to it.
				 *
				 * This way, we don't let it age beyond the protection
				 * window when it returns to "clean". All the while giving
				 * it a chance to perform its work while "dirty".
				 *
				 */
				memorystatus_invalidate_idle_demotion_locked(p, FALSE);
				reschedule = TRUE;
			} else {

				/*
				 * Process is back from "dirty" to "clean".
				 *
				 * Is its timer up OR does it still have some protection
				 * window left?
				 */

				if (mach_absolute_time() >= p->p_memstat_idledeadline) {
					/*
				 	 * The process' deadline has expired. It currently
					 * does not reside in the DEFERRED bucket.
					 *
					 * It's on its way to the JETSAM_PRIORITY_IDLE
					 * bucket via memorystatus_update_idle_priority_locked()
					 * below.

					 * So all we need to do is reset all the state on the
					 * process that's related to the DEFERRED bucket i.e.
					 * the DIRTY_DEFER_IN_PROGRESS flag and the timer deadline.
					 *
				 	 */

					memorystatus_invalidate_idle_demotion_locked(p, TRUE);
					reschedule = TRUE;
				} else {
					/*
					 * It still has some protection window left and so
					 * we just re-arm the timer without modifying any
					 * state on the process.
					 */
					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_clear(proc_t p, uint32_t pcontrol) {

	int ret = 0;

	MEMORYSTATUS_DEBUG(1, "memorystatus_dirty_clear(): %d 0x%x 0x%x\n", p->p_pid, pcontrol, p->p_memstat_dirty);

	KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_MEMSTAT, BSD_MEMSTAT_DIRTY_CLEAR), p->p_pid, pcontrol, 0, 0, 0);

	proc_list_lock();

	if ((p->p_listflag & P_LIST_EXITED) != 0) {
		/*
		 * Process is on its way out.
		 */
		ret = EBUSY;
		goto exit;
	}

	if (p->p_memstat_state & P_MEMSTAT_INTERNAL) {
		ret = EPERM;
		goto exit;
	}

	if (!(p->p_memstat_dirty & P_DIRTY_TRACK)) {
		/* Dirty tracking not enabled */
		ret = EINVAL;
		goto exit;
	}

	if (!pcontrol || (pcontrol & (PROC_DIRTY_LAUNCH_IN_PROGRESS | PROC_DIRTY_DEFER)) == 0) {
		ret = EINVAL;
		goto exit;
	}

	if (pcontrol & PROC_DIRTY_LAUNCH_IN_PROGRESS) {
		p->p_memstat_dirty &= ~P_DIRTY_LAUNCH_IN_PROGRESS;
	}

	/* This can be set and cleared exactly once. */
	if (pcontrol & PROC_DIRTY_DEFER) {

	       	if (p->p_memstat_dirty & P_DIRTY_DEFER) {

			p->p_memstat_dirty &= ~P_DIRTY_DEFER;

			memorystatus_invalidate_idle_demotion_locked(p, TRUE);
			memorystatus_update_idle_priority_locked(p);
			memorystatus_reschedule_idle_demotion_locked();
		}
	}

	ret = 0;
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;
		}
		if (p->p_memstat_dirty & P_DIRTY_LAUNCH_IN_PROGRESS) {
			ret |= PROC_DIRTY_LAUNCH_IS_IN_PROGRESS;
		}
	}

	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, NULL, 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

#if CONFIG_JETSAM
static void
memorystatus_thread_wake(void) {
	thread_wakeup((event_t)&memorystatus_wakeup);
}
#endif /* CONFIG_JETSAM */

extern void vm_pressure_response(void);

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);
}

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;
	uint32_t hwm_kill = 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);

	/*
	 * Jetsam aware version.
	 *
	 * The VM pressure notification thread is working it's way through clients in parallel.
	 *
	 * So, while the pressure notification thread is targeting processes in order of
	 * increasing jetsam priority, we can hopefully reduce / stop it's work by killing
	 * any processes that have exceeded their highwater mark.
	 *
	 * If we run out of HWM processes and our available pages drops below the critical threshold, then,
	 * we target the least recently used process in order of increasing jetsam priority (exception: the FG band).
	 */
	while (is_thrashing(kill_under_pressure_cause) ||
	       memorystatus_available_pages <= memorystatus_available_pages_pressure) {
		boolean_t killed;
		int32_t priority;
		uint32_t cause;

		if (kill_under_pressure_cause) {
			cause = kill_under_pressure_cause;
		} else {
			cause = kMemorystatusKilledVMPageShortage;
		}

#if LEGACY_HIWATER
		/* Highwater */
		killed = memorystatus_kill_hiwat_proc(&errors);
		if (killed) {
			hwm_kill++;
			post_snapshot = TRUE;
			goto done;
		} else {
			memorystatus_hwm_candidates = FALSE;
		}

		/* No highwater processes to kill. Continue or stop for now? */
		if (!is_thrashing(kill_under_pressure_cause) &&
		    (memorystatus_available_pages > memorystatus_available_pages_critical)) {
			/*
			 * We are _not_ out of pressure but we are above the critical threshold and there's:
			 * - no compressor thrashing
			 * - no more HWM processes left.
			 * For now, don't kill any other processes.
			 */

			if (hwm_kill == 0) {
 				memorystatus_thread_wasted_wakeup++;
			}

			break;
		}
#endif

		/* LRU */
		killed = memorystatus_kill_top_process(TRUE, cause, &priority, &errors);
		if (killed) {
			/* Don't generate logs for steady-state idle-exit kills (unless overridden for debug) */
			if ((priority != JETSAM_PRIORITY_IDLE) || memorystatus_idle_snapshot) {
        			post_snapshot = TRUE;
			}
			goto done;
		}

		if (memorystatus_available_pages <= memorystatus_available_pages_critical) {
			/* Under pressure and unable to kill a process - panic */
			panic("memorystatus_jetsam_thread: no victim! available pages:%d\n", memorystatus_available_pages);
		}

done:

		/*
		 * We do not want to over-kill when thrashing has been detected.
		 * To avoid that, we reset the flag here and notify the
		 * compressor.
		 */
		if (is_thrashing(kill_under_pressure_cause)) {
			kill_under_pressure_cause = 0;
			vm_thrashing_jetsam_done();
		}
	}

	kill_under_pressure_cause = 0;

	if (errors) {
		memorystatus_clear_errors();
	}

#if VM_PRESSURE_EVENTS
	/*
	 * LD: We used to target the foreground process first and foremost here.
	 * Now, we target all processes, starting from the non-suspended, background
	 * processes first. We will target foreground too.
	 *
	 * memorystatus_update_vm_pressure(TRUE);
	 */
	//vm_pressure_response();
#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 */

	/*
	 * Jetsam not enabled
	 */

#endif /* CONFIG_JETSAM */

	memorystatus_thread_block(0, memorystatus_thread);
}

#if !CONFIG_JETSAM
/*
 * Returns TRUE:
 * 	when an idle-exitable proc was killed
 * Returns FALSE:
 *	when there are no more idle-exitable procs found
 * 	when the attempt to kill an idle-exitable proc failed
 */
boolean_t memorystatus_idle_exit_from_VM(void) {
	return(kill_idle_exit_proc());
}
#endif /* !CONFIG_JETSAM */

#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 task memory limits.
 */
void
memorystatus_on_ledger_footprint_exceeded(boolean_t warning, const int max_footprint_mb)
{
	proc_t p = current_proc();

    if (warning == FALSE) {
		printf("process %d (%s) exceeded physical memory footprint limit of %d MB\n",
		       p->p_pid, p->p_comm, max_footprint_mb);
	}

#if VM_PRESSURE_EVENTS
	if (warning == TRUE) {
		if (memorystatus_warn_process(p->p_pid, TRUE /* critical? */) != 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, or no handler registered?).\n");
		}
		return;
	}
#endif /* VM_PRESSURE_EVENTS */

	if ((p->p_memstat_state & P_MEMSTAT_FATAL_MEMLIMIT) == P_MEMSTAT_FATAL_MEMLIMIT) {
		/*
		 * If this process has no high watermark or has a fatal task limit, then we have been invoked because the task
		 * has violated either the system-wide per-task memory limit OR its own task limit.
		 */
		if (memorystatus_kill_process_sync(p->p_pid, kMemorystatusKilledPerProcessLimit) != TRUE) {
			printf("task_exceeded_footprint: failed to kill the current task (exiting?).\n");
		}
	} else {
		/*
		 * HWM offender exists. Done without locks or synchronization.
		 * See comment near its declaration for more details.
		 */
		memorystatus_hwm_candidates = TRUE;
	}
}

/*
 * This is invoked when cpulimits have been exceeded while in fatal mode.
 * The jetsam_flags do not apply as those are for memory related kills.
 * We call this routine so that the offending process is killed with
 * a non-zero exit status.
 */
void
jetsam_on_ledger_cpulimit_exceeded(void)
{
	int retval = 0;
	int jetsam_flags = 0;  /* make it obvious */
	proc_t p = current_proc();

	printf("task_exceeded_cpulimit: killing pid %d [%s]\n",
	       p->p_pid, (p->p_comm ? p->p_comm : "(unknown)"));

	retval = jetsam_do_kill(p, jetsam_flags);

	if (retval) {
		printf("task_exceeded_cpulimit: failed to kill current task (exiting?).\n");
	}
}

static void
memorystatus_get_task_page_counts(task_t task, uint32_t *footprint, uint32_t *max_footprint, uint32_t *max_footprint_lifetime, uint32_t *purgeable_pages)
{
	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);
	}
	if (max_footprint_lifetime) {
		*max_footprint_lifetime = (uint32_t)(get_task_resident_max(task) / PAGE_SIZE_64);
	}
	if (purgeable_pages) {
		*purgeable_pages = (uint32_t)(get_task_purgeable_size(task) / PAGE_SIZE_64);
	}
}


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)
{
	memorystatus_available_pages = pages_avail;

#if VM_PRESSURE_EVENTS
	/*
	 * Since memorystatus_available_pages changes, we should
	 * re-evaluate the pressure levels on the system and
	 * check if we need to wake the pressure thread.
	 * We also update memorystatus_level in that routine.
	 */
	vm_pressure_response();

	if (memorystatus_available_pages <= memorystatus_available_pages_pressure) {

		if (memorystatus_hwm_candidates || (memorystatus_available_pages <= memorystatus_available_pages_critical)) {
			memorystatus_thread_wake();
		}
	}
#else /* VM_PRESSURE_EVENTS */

	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_level = memorystatus_available_pages * 100 / atop_64(max_mem);
		memorystatus_thread_wake();
	}
#endif /* VM_PRESSURE_EVENTS */
}

static boolean_t
memorystatus_get_snapshot_properties_for_proc_locked(proc_t p, memorystatus_jetsam_snapshot_entry_t *entry)
{
	clock_sec_t                     tv_sec;
	clock_usec_t                    tv_usec;

	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->max_pages_lifetime, &entry->purgeable_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));
	entry->fds = p->p_fd->fd_nfiles;

	absolutetime_to_microtime(get_task_cpu_time(p->task), &tv_sec, &tv_usec);
	entry->cpu_time.tv_sec = tv_sec;
	entry->cpu_time.tv_usec = tv_usec;

	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] (%s) - memorystatus_available_pages: %d\n",
		victim_pid, (p->p_comm ? p->p_comm : "(unknown)"),
	        jetsam_kill_cause_name[cause], 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();

	memorystatus_sort_by_largest_process_locked(JETSAM_PRIORITY_FOREGROUND);

	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 (cause == kMemorystatusKilledVnodes)
		{
			/*
			 * If the system runs out of vnodes, we systematically jetsam
			 * processes in hopes of stumbling onto a vnode gain that helps
			 * the system recover.  The process that happens to trigger
			 * this path has no known relationship to the vnode consumption.
			 * We attempt to safeguard that process e.g: do not jetsam it.
			 */

			if (p == current_proc()) {
				/* do not jetsam the current process */
				continue;
			}
		}

#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) &&
                		(memorystatus_idle_snapshot || ((!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: %s %d [%s] (%s) - memorystatus_available_pages: %d\n",
					    ((p->p_memstat_effectivepriority == JETSAM_PRIORITY_IDLE) ?
					    "idle exiting pid" : "jetsam killing pid"),
					    aPid, (p->p_comm ? p->p_comm : "(unknown)"),
					    jetsam_kill_cause_name[cause], 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();
	memorystatus_sort_by_largest_process_locked(JETSAM_PRIORITY_FOREGROUND);

	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 Mb > 1 (%d Mb)\n",
				(memorystatus_jetsam_policy & kPolicyDiagnoseActive) ? "suspending": "killing", aPid, p->p_comm, footprint, p->p_memstat_memlimit);

			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 &&
				   cause != kMemorystatusKilledFCThrashing)) {
		return FALSE;
	}

	kill_under_pressure_cause = cause;
	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_FC_thrashing(boolean_t async) {
	if (async) {
		return memorystatus_kill_process_async(-1, kMemorystatusKilledFCThrashing);
	} else {
		return memorystatus_kill_process_sync(-1, kMemorystatusKilledFCThrashing);
	}
}

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, NULL, NULL);
		if (pages < memorystatus_freeze_pages_min) {
			continue; // with lock held
		}

		if (DEFAULT_FREEZER_IS_ACTIVE || DEFAULT_FREEZER_COMPRESSED_PAGER_IS_SWAPBACKED) {
			/* 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 or we're not backed by swap. */
			if (DEFAULT_FREEZER_COMPRESSED_PAGER_IS_SWAPLESS ||
				!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 VM_PRESSURE_EVENTS

#if CONFIG_MEMORYSTATUS

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;
}

boolean_t
memorystatus_warn_process(pid_t pid, boolean_t critical) {

	boolean_t ret = FALSE;
	struct knote *kn = NULL;

	/*
	 * See comment in sysctl_memorystatus_vm_pressure_send.
	 */

	memorystatus_klist_lock();
	kn = vm_find_knote_from_pid(pid, &memorystatus_klist);
	if (kn) {
		/*
		 * By setting the "fflags" here, we are forcing
		 * a process to deal with the case where it's
		 * bumping up into its memory limits. If we don't
		 * do this here, we will end up depending on the
		 * system pressure snapshot evaluation in
		 * filt_memorystatus().
		 */

		if (critical) {
			kn->kn_fflags |= NOTE_MEMORYSTATUS_PRESSURE_CRITICAL;
		} else {
			kn->kn_fflags |= NOTE_MEMORYSTATUS_PRESSURE_WARN;
		}
    		KNOTE(&memorystatus_klist, kMemorystatusPressure);
    		ret = TRUE;
	} else {
		if (vm_dispatch_pressure_note_to_pid(pid, FALSE) == 0) {
			ret = TRUE;
		}
	}
	memorystatus_klist_unlock();

	return ret;
}

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));
}

void
memorystatus_send_low_swap_note(void) {

	struct knote *kn = NULL;

	memorystatus_klist_lock();
	SLIST_FOREACH(kn, &memorystatus_klist, kn_selnext) {
		if (is_knote_registered_modify_task_pressure_bits(kn, NOTE_MEMORYSTATUS_LOW_SWAP, NULL, 0, 0) == TRUE) {
    			KNOTE(&memorystatus_klist, kMemorystatusLowSwap);
		}
	}
	memorystatus_klist_unlock();
}

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));
}
#endif /* CONFIG_MEMORYSTATUS */

/*
 * 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, boolean_t);

extern
kern_return_t vm_pressure_notification_without_levels(boolean_t);

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 *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(boolean_t target_foreground_process);

#define VM_PRESSURE_DECREASED_SMOOTHING_PERIOD		5000	/* milliseconds */

kern_return_t
memorystatus_update_vm_pressure(boolean_t target_foreground_process)
{
	struct knote			*kn_max = NULL;
        pid_t				target_pid = -1;
        struct klist			dispatch_klist = { NULL };
	proc_t				target_proc = PROC_NULL;
	struct task			*task = NULL;
	boolean_t			found_candidate = FALSE;

	static vm_pressure_level_t 	level_snapshot = kVMPressureNormal;
	static vm_pressure_level_t	prev_level_snapshot = kVMPressureNormal;
	boolean_t			smoothing_window_started = FALSE;
	struct timeval			smoothing_window_start_tstamp = {0, 0};
	struct timeval			curr_tstamp = {0, 0};
	int				elapsed_msecs = 0;

#if !CONFIG_JETSAM
#define MAX_IDLE_KILLS 100	/* limit the number of idle kills allowed */

	int	idle_kill_counter = 0;

	/*
	 * On desktop we take this opportunity to free up memory pressure
	 * by immediately killing idle exitable processes. We use a delay
	 * to avoid overkill.  And we impose a max counter as a fail safe
	 * in case daemons re-launch too fast.
	 */
	while ((memorystatus_vm_pressure_level != kVMPressureNormal) && (idle_kill_counter < MAX_IDLE_KILLS)) {
		if (memorystatus_idle_exit_from_VM() == FALSE) {
			/* No idle exitable processes left to kill */
			break;
		}
		idle_kill_counter++;
		delay(1000000);    /* 1 second */
	}
#endif /* !CONFIG_JETSAM */

	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;

		if (prev_level_snapshot > level_snapshot) {
			/*
			 * Pressure decreased? Let's take a little breather
			 * and see if this condition stays.
			 */
			if (smoothing_window_started == FALSE) {

				smoothing_window_started = TRUE;
				microuptime(&smoothing_window_start_tstamp);
			}

			microuptime(&curr_tstamp);
			timevalsub(&curr_tstamp, &smoothing_window_start_tstamp);
			elapsed_msecs = curr_tstamp.tv_sec * 1000 + curr_tstamp.tv_usec / 1000;

			if (elapsed_msecs < VM_PRESSURE_DECREASED_SMOOTHING_PERIOD) {

				delay(INTER_NOTIFICATION_DELAY);
				continue;
			}
		}

		prev_level_snapshot = level_snapshot;
		smoothing_window_started = FALSE;

		memorystatus_klist_lock();
		kn_max = vm_pressure_select_optimal_candidate_to_notify(&memorystatus_klist, level_snapshot, target_foreground_process);

        	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 (memorystatus_manual_testing_on == TRUE && target_foreground_process == TRUE) {
			break;
		}

try_dispatch_vm_clients:
		if (kn_max == NULL && level_snapshot != kVMPressureNormal) {
			/*
			 * We will exit this loop when we are done with
			 * notification clients (level and non-level based).
			 */
			if ((vm_pressure_notify_dispatch_vm_clients(target_foreground_process) == 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;
			}
		}

		/*
		 * LD: This block of code below used to be invoked in the older memory notification scheme on embedded everytime
		 * a process was sent a memory pressure notification. The "memorystatus_klist" list was used to hold these
		 * privileged listeners. But now we have moved to the newer scheme and are trying to move away from the extra
		 * notifications. So the code is here in case we break compat. and need to send out notifications to the privileged
		 * apps.
		 */
#if 0
#endif /* 0 */

		if (memorystatus_manual_testing_on == TRUE) {
			/*
			 * Testing out the pressure notification scheme.
			 * No need for delays etc.
			 */
		} else {

			uint32_t sleep_interval = INTER_NOTIFICATION_DELAY;
#if CONFIG_JETSAM
			unsigned int page_delta = 0;
			unsigned int skip_delay_page_threshold = 0;

			assert(memorystatus_available_pages_pressure >= memorystatus_available_pages_critical_base);

			page_delta = (memorystatus_available_pages_pressure - memorystatus_available_pages_critical_base) / 2;
			skip_delay_page_threshold = memorystatus_available_pages_pressure - page_delta;

			if (memorystatus_available_pages <= skip_delay_page_threshold) {
				/*
				 * We are nearing the critcal mark fast and can't afford to wait between
				 * notifications.
				 */
				sleep_interval = 0;
			}
#endif /* CONFIG_JETSAM */

			if (sleep_interval) {
				delay(sleep_interval);
			}
		}
	}

	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));
}

#if DEBUG || DEVELOPMENT

SYSCTL_PROC(_kern, OID_AUTO, memorystatus_vm_pressure_level, CTLTYPE_INT|CTLFLAG_RD|CTLFLAG_LOCKED,
    0, 0, &sysctl_memorystatus_vm_pressure_level, "I", "");

#else /* DEBUG || DEVELOPMENT */

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", "");

#endif /* DEBUG || DEVELOPMENT */

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(FALSE);
		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 /* 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 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;

		if (memorystatus_available_pages_critical  > memorystatus_available_pages_pressure ) {
			/*
			 * The critical threshold must never exceed the pressure threshold
			 */
			memorystatus_available_pages_critical = memorystatus_available_pages_pressure;
		}
	}

#if DEBUG || DEVELOPMENT
	if (memorystatus_jetsam_policy & kPolicyDiagnoseActive) {
		memorystatus_available_pages_critical += memorystatus_jetsam_policy_offset_pages_diagnostic;

		if (memorystatus_available_pages_critical > memorystatus_available_pages_pressure ) {
			/*
			 * The critical threshold must never exceed the pressure threshold
			 */
			memorystatus_available_pages_critical = memorystatus_available_pages_pressure;
		}
	}
#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;
}

/*
 * 	Routine:	memorystatus_cmd_grp_set_properties
 *	Purpose:	Update properties for a group of processes.
 *
 *	Supported Properties:
 *	[priority]
 *		Move each process out of its effective priority
 *		band and into a new priority band.
 *		Maintains relative order from lowest to highest priority.
 *		In single band, maintains relative order from head to tail.
 *
 *		eg: before	[effectivepriority | pid]
 *				[18 | p101              ]
 *				[17 | p55, p67, p19     ]
 *				[12 | p103 p10          ]
 *				[ 7 | p25               ]
 *			 	[ 0 | p71, p82,         ]
 *
 *		after	[ new band | pid]
 *			[ xxx | p71, p82, p25, p103, p10, p55, p67, p19, p101]
 *
 *	Returns:  0 on success, else non-zero.
 *
 *	Caveat:   We know there is a race window regarding recycled pids.
 *		  A process could be killed before the kernel can act on it here.
 *		  If a pid cannot be found in any of the jetsam priority bands,
 *		  then we simply ignore it.  No harm.
 *		  But, if the pid has been recycled then it could be an issue.
 *		  In that scenario, we might move an unsuspecting process to the new
 *		  priority band. It's not clear how the kernel can safeguard
 *		  against this, but it would be an extremely rare case anyway.
 *		  The caller of this api might avoid such race conditions by
 *		  ensuring that the processes passed in the pid list are suspended.
 */


/* This internal structure can expand when we add support for more properties */
typedef	struct memorystatus_internal_properties
{
	proc_t proc;
	int32_t priority;  /* see memorytstatus_priority_entry_t : priority */
} memorystatus_internal_properties_t;


static int
memorystatus_cmd_grp_set_properties(int32_t flags, user_addr_t buffer, size_t buffer_size, __unused int32_t *retval) {

#pragma unused (flags)

	/*
	 * We only handle setting priority
	 * per process
	 */

	int error = 0;
	memorystatus_priority_entry_t *entries = NULL;
	uint32_t entry_count = 0;

	/* This will be the ordered proc list */
	memorystatus_internal_properties_t *table = NULL;
	size_t table_size = 0;
	uint32_t table_count = 0;

	uint32_t i = 0;
	uint32_t bucket_index = 0;
	boolean_t head_insert;
	int32_t new_priority;

	proc_t p;

	/* Verify inputs */
	if ((buffer == USER_ADDR_NULL) || (buffer_size == 0) || ((buffer_size % sizeof(memorystatus_priority_entry_t)) != 0)) {
		error = EINVAL;
		goto out;
	}

	entry_count = (buffer_size / sizeof(memorystatus_priority_entry_t));
	if ((entries = (memorystatus_priority_entry_t *)kalloc(buffer_size)) == NULL) {
		error = ENOMEM;
		goto out;
	}

	KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_MEMSTAT, BSD_MEMSTAT_GRP_SET_PROP) | DBG_FUNC_START, entry_count, 0, 0, 0, 0);

	if ((error = copyin(buffer, entries, buffer_size)) != 0) {
		goto out;
	}

	/* Verify sanity of input priorities */
	for (i=0; i < entry_count; i++) {
		if (entries[i].priority == -1) {
			/* Use as shorthand for default priority */
			entries[i].priority = JETSAM_PRIORITY_DEFAULT;
		} else if (entries[i].priority == JETSAM_PRIORITY_IDLE_DEFERRED) {
			/* JETSAM_PRIORITY_IDLE_DEFERRED is reserved for internal use;
			 * if requested, adjust to JETSAM_PRIORITY_IDLE. */
			entries[i].priority = JETSAM_PRIORITY_IDLE;
	        } else if (entries[i].priority == JETSAM_PRIORITY_IDLE_HEAD) {
			/* JETSAM_PRIORITY_IDLE_HEAD inserts at the head of the idle
			 * queue */
			/* Deal with this later */
		} else if ((entries[i].priority < 0) || (entries[i].priority >= MEMSTAT_BUCKET_COUNT)) {
			/* Sanity check */
			error = EINVAL;
			goto out;
		}
	}

	table_size = sizeof(memorystatus_internal_properties_t) * entry_count;
	if ( (table = (memorystatus_internal_properties_t *)kalloc(table_size)) == NULL) {
		error = ENOMEM;
		goto out;
	}
	memset(table, 0, table_size);


	/*
	 * For each jetsam bucket entry, spin through the input property list.
	 * When a matching pid is found, populate an adjacent table with the
	 * appropriate proc pointer and new property values.
	 * This traversal automatically preserves order from lowest
	 * to highest priority.
	 */

	bucket_index=0;

	proc_list_lock();

	/* Create the ordered table */
	p = memorystatus_get_first_proc_locked(&bucket_index, TRUE);
	while (p && (table_count < entry_count)) {
		for (i=0; i < entry_count; i++ ) {
			if (p->p_pid == entries[i].pid) {
				/* Build the table data  */
				table[table_count].proc = p;
				table[table_count].priority = entries[i].priority;
				table_count++;
				break;
			}
		}
		p = memorystatus_get_next_proc_locked(&bucket_index, p, TRUE);
	}

	/* We now have ordered list of procs ready to move */
	for (i=0; i < table_count; i++) {
		p = table[i].proc;
		assert(p != NULL);

		/* Allow head inserts -- but relative order is now  */
		if (table[i].priority == JETSAM_PRIORITY_IDLE_HEAD) {
			new_priority = JETSAM_PRIORITY_IDLE;
			head_insert = true;
		} else {
			new_priority = table[i].priority;
			head_insert = false;
		}

		/* Not allowed */
		if (p->p_memstat_state & P_MEMSTAT_INTERNAL) {
			continue;
		}

		/*
		 * Take appropriate steps if moving proc out of the
		 * JETSAM_PRIORITY_IDLE_DEFERRED band.
		 */
		if (p->p_memstat_effectivepriority == JETSAM_PRIORITY_IDLE_DEFERRED) {
			memorystatus_invalidate_idle_demotion_locked(p, TRUE);
		}

		memorystatus_update_priority_locked(p, new_priority, head_insert);
	}

	proc_list_unlock();

	/*
	 * if (table_count != entry_count)
	 * then some pids were not found in a jetsam band.
	 * harmless but interesting...
	 */
	KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_MEMSTAT, BSD_MEMSTAT_GRP_SET_PROP) | DBG_FUNC_END, entry_count, table_count, 0, 0, 0);

out:
	if (entries)
		kfree(entries, buffer_size);
	if (table)
		kfree(table, table_size);

	return (error);
}


/*
 * This routine is meant solely for the purpose of adjusting jetsam priorities and bands.
 * It is _not_ meant to be used for the setting of memory limits, especially, since we can't
 * tell if the memory limit being set is fatal or not.
 *
 * So the the last 5 args to the memorystatus_update() call below, related to memory limits,  are all 0 or FALSE.
 */

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, FALSE);
		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;
}

/*
 * Every process, including a P_MEMSTAT_INTERNAL process (currently only pid 1), is allowed to set a HWM.
 */

static int
memorystatus_cmd_set_jetsam_memory_limit(pid_t pid, int32_t high_water_mark, __unused int32_t *retval, boolean_t is_fatal_limit) {
	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();

	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, false);

        		/*
			 * The update priority call above takes care to set/reset the fatal memory limit state
			 * IF the process is transitioning between foreground <-> background and has a background
			 * memory limit.
			 * Here, however, the process won't be doing any such transitions and so we explicitly tackle
			 * the fatal limit state.
			 */
			is_fatal_limit = FALSE;

        	} else {
        		error = (task_set_phys_footprint_limit_internal(p->task, high_water_mark, NULL, TRUE) == 0) ? 0 : EINVAL;
        	}
	}

	if (error == 0) {
		if (is_fatal_limit == TRUE) {
        		p->p_memstat_state |= P_MEMSTAT_FATAL_MEMLIMIT;
		} else {
        		p->p_memstat_state &= ~P_MEMSTAT_FATAL_MEMLIMIT;
		}
	}

	proc_list_unlock();
	proc_rele(p);

	return error;
}

/*
 * Returns the jetsam priority (effective or requested) of the process
 * associated with this task.
 */
int
proc_get_memstat_priority(proc_t p, boolean_t effective_priority)
{
	if (p) {
		if (effective_priority) {
			return p->p_memstat_effectivepriority;
		} else {
			return p->p_memstat_requestedpriority;
		}
	}
	return 0;
}
#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_GRP_SET_PROPERTIES:
		error = memorystatus_cmd_grp_set_properties((int32_t)args->flags, 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:
		error = memorystatus_cmd_set_jetsam_memory_limit(args->pid, (int32_t)args->flags, ret, FALSE);
		break;
	case MEMORYSTATUS_CMD_SET_JETSAM_TASK_LIMIT:
		error = memorystatus_cmd_set_jetsam_memory_limit(args->pid, (int32_t)args->flags, ret, TRUE);
		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;
		case kMemorystatusLowSwap:
			if (kn->kn_sfflags & NOTE_MEMORYSTATUS_LOW_SWAP) {
				kn->kn_fflags |= NOTE_MEMORYSTATUS_LOW_SWAP;
			}
			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 | NOTE_MEMORYSTATUS_LOW_SWAP)) {

		if (kn->kn_sfflags & NOTE_MEMORYSTATUS_LOW_SWAP) {
			error = suser(kauth_cred_get(), 0);
		}

		if (error == 0) {
			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 0
#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 */
#endif /* 0 */