gems-kernel/source/THIRDPARTY/xnu/bsd/kern/kern_memorystatus_notify.c
2024-06-03 11:29:39 -05:00

2026 lines
66 KiB
C

/*
* Copyright (c) 2006-2018 Apple 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 <sys/kern_event.h>
#include <kern/sched_prim.h>
#include <kern/assert.h>
#include <kern/debug.h>
#include <kern/locks.h>
#include <kern/task.h>
#include <kern/thread.h>
#include <kern/thread_call.h>
#include <kern/host.h>
#include <kern/policy_internal.h>
#include <kern/thread_group.h>
#include <IOKit/IOBSD.h>
#include <libkern/libkern.h>
#include <libkern/coreanalytics/coreanalytics.h>
#include <mach/coalition.h>
#include <mach/clock_types.h>
#include <mach/mach_time.h>
#include <mach/task.h>
#include <mach/host_priv.h>
#include <mach/mach_host.h>
#include <os/log.h>
#include <pexpert/pexpert.h>
#include <sys/coalition.h>
#include <sys/kern_event.h>
#include <sys/proc.h>
#include <sys/proc_info.h>
#include <sys/reason.h>
#include <sys/signal.h>
#include <sys/signalvar.h>
#include <sys/sysctl.h>
#include <sys/sysproto.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <sys/tree.h>
#include <sys/priv.h>
#include <vm/vm_pageout.h>
#include <vm/vm_protos.h>
#include <mach/machine/sdt.h>
#include <libkern/section_keywords.h>
#include <stdatomic.h>
#if CONFIG_FREEZE
#include <vm/vm_map.h>
#endif /* CONFIG_FREEZE */
#include <kern/kern_memorystatus_internal.h>
#include <sys/kern_memorystatus.h>
#include <sys/kern_memorystatus_notify.h>
/*
* Memorystatus klist structures
*/
struct klist memorystatus_klist;
static lck_mtx_t memorystatus_klist_mutex;
static void memorystatus_klist_lock(void);
static void memorystatus_klist_unlock(void);
/*
* Memorystatus kevent filter routines
*/
static int filt_memorystatusattach(struct knote *kn, struct kevent_qos_s *kev);
static void filt_memorystatusdetach(struct knote *kn);
static int filt_memorystatus(struct knote *kn, long hint);
static int filt_memorystatustouch(struct knote *kn, struct kevent_qos_s *kev);
static int filt_memorystatusprocess(struct knote *kn, struct kevent_qos_s *kev);
SECURITY_READ_ONLY_EARLY(struct filterops) memorystatus_filtops = {
.f_attach = filt_memorystatusattach,
.f_detach = filt_memorystatusdetach,
.f_event = filt_memorystatus,
.f_touch = filt_memorystatustouch,
.f_process = filt_memorystatusprocess,
};
/*
* Memorystatus notification events
*/
enum {
kMemorystatusNoPressure = 0x1,
kMemorystatusPressure = 0x2,
kMemorystatusLowSwap = 0x4,
kMemorystatusProcLimitWarn = 0x8,
kMemorystatusProcLimitCritical = 0x10
};
#define INTER_NOTIFICATION_DELAY (250000) /* .25 second */
#define VM_PRESSURE_DECREASED_SMOOTHING_PERIOD 5000 /* milliseconds */
#define WARNING_NOTIFICATION_RESTING_PERIOD 25 /* seconds */
#define CRITICAL_NOTIFICATION_RESTING_PERIOD 25 /* seconds */
/*
* Memorystatus notification helper routines
*/
static vm_pressure_level_t convert_internal_pressure_level_to_dispatch_level(vm_pressure_level_t);
static boolean_t is_knote_registered_modify_task_pressure_bits(struct knote*, int, task_t, vm_pressure_level_t, vm_pressure_level_t);
static void memorystatus_klist_reset_all_for_level(vm_pressure_level_t pressure_level_to_clear);
static struct knote *vm_pressure_select_optimal_candidate_to_notify(struct klist *candidate_list, int level, boolean_t target_foreground_process, uint64_t *next_telemetry_update);
static void vm_dispatch_memory_pressure(void);
kern_return_t memorystatus_update_vm_pressure(boolean_t target_foreground_process);
#if VM_PRESSURE_EVENTS
/*
* This value is the threshold that a process must meet to be considered for scavenging.
*/
#if XNU_TARGET_OS_OSX
#define VM_PRESSURE_MINIMUM_RSIZE 10 /* MB */
#else /* XNU_TARGET_OS_OSX */
#define VM_PRESSURE_MINIMUM_RSIZE 6 /* MB */
#endif /* XNU_TARGET_OS_OSX */
static uint32_t vm_pressure_task_footprint_min = VM_PRESSURE_MINIMUM_RSIZE;
#if DEVELOPMENT || DEBUG
SYSCTL_UINT(_kern, OID_AUTO, memorystatus_vm_pressure_task_footprint_min, CTLFLAG_RW | CTLFLAG_LOCKED, &vm_pressure_task_footprint_min, 0, "");
#endif /* DEVELOPMENT || DEBUG */
vm_pressure_level_t memorystatus_vm_pressure_level = kVMPressureNormal;
/*
* 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;
#endif /* VM_PRESSURE_EVENTS */
#if CONFIG_JETSAM
extern unsigned int memorystatus_available_pages;
extern unsigned int memorystatus_available_pages_pressure;
extern unsigned int memorystatus_available_pages_critical;
extern unsigned int memorystatus_available_pages_critical_base;
extern unsigned int memorystatus_available_pages_critical_idle_offset;
#else /* CONFIG_JETSAM */
extern uint64_t memorystatus_available_pages;
extern uint64_t memorystatus_available_pages_pressure;
extern uint64_t memorystatus_available_pages_critical;
#endif /* CONFIG_JETSAM */
extern lck_mtx_t memorystatus_jetsam_fg_band_lock;
uint32_t memorystatus_jetsam_fg_band_waiters = 0;
static uint64_t memorystatus_jetsam_fg_band_timestamp_ns = 0; /* nanosec */
static uint64_t memorystatus_jetsam_fg_band_delay_ns = 5ull * 1000 * 1000 * 1000; /* nanosec */
extern boolean_t(*volatile consider_buffer_cache_collect)(int);
#if DEVELOPMENT || DEBUG
SYSCTL_QUAD(_kern, OID_AUTO, memorystatus_jetsam_fg_band_delay_ns, CTLFLAG_RW | CTLFLAG_LOCKED,
&memorystatus_jetsam_fg_band_delay_ns, "");
#endif
static int
filt_memorystatusattach(struct knote *kn, __unused struct kevent_qos_s *kev)
{
int error;
kn->kn_flags |= EV_CLEAR; /* automatically set */
kn->kn_sdata = 0; /* incoming data is ignored */
memset(&kn->kn_ext, 0, sizeof(kn->kn_ext));
error = memorystatus_knote_register(kn);
if (error) {
knote_set_error(kn, error);
}
return 0;
}
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;
case kMemorystatusProcLimitWarn:
if (kn->kn_sfflags & NOTE_MEMORYSTATUS_PROC_LIMIT_WARN) {
kn->kn_fflags = NOTE_MEMORYSTATUS_PROC_LIMIT_WARN;
}
break;
case kMemorystatusProcLimitCritical:
if (kn->kn_sfflags & NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL) {
kn->kn_fflags = NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL;
}
break;
default:
break;
}
}
#if 0
if (kn->kn_fflags != 0) {
proc_t knote_proc = knote_get_kq(kn)->kq_p;
pid_t knote_pid = proc_getpid(knote_proc);
printf("filt_memorystatus: sending kn 0x%lx (event 0x%x) for pid (%d)\n",
(unsigned long)kn, kn->kn_fflags, knote_pid);
}
#endif
return kn->kn_fflags != 0;
}
static int
filt_memorystatustouch(struct knote *kn, struct kevent_qos_s *kev)
{
int res;
int prev_kn_sfflags = 0;
memorystatus_klist_lock();
/*
* copy in new kevent settings
* (saving the "desired" data and fflags).
*/
prev_kn_sfflags = kn->kn_sfflags;
kn->kn_sfflags = (kev->fflags & EVFILT_MEMORYSTATUS_ALL_MASK);
#if XNU_TARGET_OS_OSX
/*
* Only on desktop do we restrict notifications to
* one per active/inactive state (soft limits only).
*/
if (kn->kn_sfflags & NOTE_MEMORYSTATUS_PROC_LIMIT_WARN) {
/*
* Is there previous state to preserve?
*/
if (prev_kn_sfflags & NOTE_MEMORYSTATUS_PROC_LIMIT_WARN) {
/*
* This knote was previously interested in proc_limit_warn,
* so yes, preserve previous state.
*/
if (prev_kn_sfflags & NOTE_MEMORYSTATUS_PROC_LIMIT_WARN_ACTIVE) {
kn->kn_sfflags |= NOTE_MEMORYSTATUS_PROC_LIMIT_WARN_ACTIVE;
}
if (prev_kn_sfflags & NOTE_MEMORYSTATUS_PROC_LIMIT_WARN_INACTIVE) {
kn->kn_sfflags |= NOTE_MEMORYSTATUS_PROC_LIMIT_WARN_INACTIVE;
}
} else {
/*
* This knote was not previously interested in proc_limit_warn,
* but it is now. Set both states.
*/
kn->kn_sfflags |= NOTE_MEMORYSTATUS_PROC_LIMIT_WARN_ACTIVE;
kn->kn_sfflags |= NOTE_MEMORYSTATUS_PROC_LIMIT_WARN_INACTIVE;
}
}
if (kn->kn_sfflags & NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL) {
/*
* Is there previous state to preserve?
*/
if (prev_kn_sfflags & NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL) {
/*
* This knote was previously interested in proc_limit_critical,
* so yes, preserve previous state.
*/
if (prev_kn_sfflags & NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL_ACTIVE) {
kn->kn_sfflags |= NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL_ACTIVE;
}
if (prev_kn_sfflags & NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL_INACTIVE) {
kn->kn_sfflags |= NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL_INACTIVE;
}
} else {
/*
* This knote was not previously interested in proc_limit_critical,
* but it is now. Set both states.
*/
kn->kn_sfflags |= NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL_ACTIVE;
kn->kn_sfflags |= NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL_INACTIVE;
}
}
#endif /* XNU_TARGET_OS_OSX */
/*
* reset the output flags based on a
* combination of the old events and
* the new desired event list.
*/
//kn->kn_fflags &= kn->kn_sfflags;
res = (kn->kn_fflags != 0);
memorystatus_klist_unlock();
return res;
}
static int
filt_memorystatusprocess(struct knote *kn, struct kevent_qos_s *kev)
{
int res = 0;
memorystatus_klist_lock();
if (kn->kn_fflags) {
knote_fill_kevent(kn, kev, 0);
res = 1;
}
memorystatus_klist_unlock();
return res;
}
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();
/*
* Support only userspace visible flags.
*/
if ((kn->kn_sfflags & EVFILT_MEMORYSTATUS_ALL_MASK) == (unsigned int) kn->kn_sfflags) {
#if XNU_TARGET_OS_OSX
if (kn->kn_sfflags & NOTE_MEMORYSTATUS_PROC_LIMIT_WARN) {
kn->kn_sfflags |= NOTE_MEMORYSTATUS_PROC_LIMIT_WARN_ACTIVE;
kn->kn_sfflags |= NOTE_MEMORYSTATUS_PROC_LIMIT_WARN_INACTIVE;
}
if (kn->kn_sfflags & NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL) {
kn->kn_sfflags |= NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL_ACTIVE;
kn->kn_sfflags |= NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL_INACTIVE;
}
#endif /* XNU_TARGET_OS_OSX */
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 VM_PRESSURE_EVENTS
#if CONFIG_JETSAM
static thread_call_t sustained_pressure_handler_thread_call;
int memorystatus_should_kill_on_sustained_pressure = 1;
/* Count the number of sustained pressure kills we've done since boot. */
uint64_t memorystatus_kill_on_sustained_pressure_count = 0;
uint64_t memorystatus_kill_on_sustained_pressure_window_s = 60 * 10; /* 10 Minutes */
uint64_t memorystatus_kill_on_sustained_pressure_delay_ms = 500; /* .5 seconds */
#if DEVELOPMENT || DEBUG
SYSCTL_INT(_kern, OID_AUTO, memorystatus_should_kill_on_sustained_pressure, CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED, &memorystatus_should_kill_on_sustained_pressure, 0, "");
#endif /* DEVELOPMENT || DEBUG */
SYSCTL_QUAD(_kern, OID_AUTO, memorystatus_kill_on_sustained_pressure_count, CTLFLAG_RD | CTLFLAG_LOCKED, &memorystatus_kill_on_sustained_pressure_count, "");
SYSCTL_QUAD(_kern, OID_AUTO, memorystatus_kill_on_sustained_pressure_window_s, CTLFLAG_RW | CTLFLAG_LOCKED, &memorystatus_kill_on_sustained_pressure_window_s, "");
SYSCTL_QUAD(_kern, OID_AUTO, memorystatus_kill_on_sustained_pressure_delay_ms, CTLFLAG_RW | CTLFLAG_LOCKED, &memorystatus_kill_on_sustained_pressure_delay_ms, "");
static void sustained_pressure_handler(void*, void*);
#endif /* CONFIG_JETSAM */
static thread_call_t memorystatus_notify_update_telemetry_thread_call;
static void update_footprints_for_telemetry(void*, void*);
void
memorystatus_notify_init()
{
#if CONFIG_JETSAM
sustained_pressure_handler_thread_call = thread_call_allocate_with_options(sustained_pressure_handler, NULL, THREAD_CALL_PRIORITY_KERNEL_HIGH, THREAD_CALL_OPTIONS_ONCE);
#endif /* CONFIG_JETSAM */
memorystatus_notify_update_telemetry_thread_call = thread_call_allocate_with_options(update_footprints_for_telemetry, NULL, THREAD_CALL_PRIORITY_USER, THREAD_CALL_OPTIONS_ONCE);
}
#if CONFIG_MEMORYSTATUS
inline int
memorystatus_send_note(int event_code, void *data, uint32_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) {
memorystatus_log_error("%s: kev_post_msg() failed, err %d\n", __func__, ret);
}
return ret;
}
boolean_t
memorystatus_warn_process(const proc_t p, __unused boolean_t is_active, __unused boolean_t is_fatal, boolean_t limit_exceeded)
{
/*
* This function doesn't take a reference to p or lock it. So it better be the current process.
*/
assert(p == current_proc());
pid_t pid = proc_getpid(p);
boolean_t ret = FALSE;
boolean_t found_knote = FALSE;
struct knote *kn = NULL;
int send_knote_count = 0;
uint32_t platform;
platform = proc_platform(p);
/*
* See comment in sysctl_memorystatus_vm_pressure_send.
*/
memorystatus_klist_lock();
SLIST_FOREACH(kn, &memorystatus_klist, kn_selnext) {
proc_t knote_proc = knote_get_kq(kn)->kq_p;
pid_t knote_pid = proc_getpid(knote_proc);
if (knote_pid == pid) {
/*
* 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().
*/
/*
* The type of notification and the frequency are different between
* embedded and desktop.
*
* Embedded processes register for global pressure notifications
* (NOTE_MEMORYSTATUS_PRESSURE_WARN | NOTE_MEMORYSTATUS_PRESSURE_CRITICAL) via UIKit
* (see applicationDidReceiveMemoryWarning in UIKit). We'll warn them here if
* they are near there memory limit. filt_memorystatus() will warn them based
* on the system pressure level.
*
* On desktop, (NOTE_MEMORYSTATUS_PRESSURE_WARN | NOTE_MEMORYSTATUS_PRESSURE_CRITICAL)
* are only expected to fire for system level warnings. Desktop procesess
* register for NOTE_MEMORYSTATUS_PROC_LIMIT_WARN
* if they want to be warned when they approach their limit
* and for NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL to be warned when they
* exceed their limit.
*
* On embedded we continuously warn processes that are approaching their
* memory limit. However on desktop, we only send one warning while
* the process is active/inactive if the limit is soft..
*
*/
if (platform == PLATFORM_MACOS || platform == PLATFORM_MACCATALYST || platform == PLATFORM_DRIVERKIT) {
if (!limit_exceeded) {
if (kn->kn_sfflags & NOTE_MEMORYSTATUS_PROC_LIMIT_WARN) {
found_knote = TRUE;
if (!is_fatal) {
/*
* Restrict proc_limit_warn notifications when
* non-fatal (soft) limit is at play.
*/
if (is_active) {
if (kn->kn_sfflags & NOTE_MEMORYSTATUS_PROC_LIMIT_WARN_ACTIVE) {
/*
* Mark this knote for delivery.
*/
kn->kn_fflags = NOTE_MEMORYSTATUS_PROC_LIMIT_WARN;
/*
* And suppress it from future notifications.
*/
kn->kn_sfflags &= ~NOTE_MEMORYSTATUS_PROC_LIMIT_WARN_ACTIVE;
send_knote_count++;
}
} else {
if (kn->kn_sfflags & NOTE_MEMORYSTATUS_PROC_LIMIT_WARN_INACTIVE) {
/*
* Mark this knote for delivery.
*/
kn->kn_fflags = NOTE_MEMORYSTATUS_PROC_LIMIT_WARN;
/*
* And suppress it from future notifications.
*/
kn->kn_sfflags &= ~NOTE_MEMORYSTATUS_PROC_LIMIT_WARN_INACTIVE;
send_knote_count++;
}
}
} else {
/*
* No restriction on proc_limit_warn notifications when
* fatal (hard) limit is at play.
*/
kn->kn_fflags = NOTE_MEMORYSTATUS_PROC_LIMIT_WARN;
send_knote_count++;
}
}
} else {
/*
* Send this notification when a process has exceeded a soft limit,
*/
if (kn->kn_sfflags & NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL) {
found_knote = TRUE;
if (!is_fatal) {
/*
* Restrict critical notifications for soft limits.
*/
if (is_active) {
if (kn->kn_sfflags & NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL_ACTIVE) {
/*
* Suppress future proc_limit_critical notifications
* for the active soft limit.
*/
kn->kn_sfflags &= ~NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL_ACTIVE;
kn->kn_fflags = NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL;
send_knote_count++;
}
} else {
if (kn->kn_sfflags & NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL_INACTIVE) {
/*
* Suppress future proc_limit_critical_notifications
* for the inactive soft limit.
*/
kn->kn_sfflags &= ~NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL_INACTIVE;
kn->kn_fflags = NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL;
send_knote_count++;
}
}
} else {
/*
* We should never be trying to send a critical notification for
* a hard limit... the process would be killed before it could be
* received.
*/
panic("Caught sending pid %d a critical warning for a fatal limit.", pid);
}
}
}
} else {
if (!limit_exceeded) {
/*
* Intentionally set either the unambiguous limit warning,
* the system-wide critical or the system-wide warning
* notification bit.
*/
if (kn->kn_sfflags & NOTE_MEMORYSTATUS_PROC_LIMIT_WARN) {
kn->kn_fflags = NOTE_MEMORYSTATUS_PROC_LIMIT_WARN;
found_knote = TRUE;
send_knote_count++;
} else if (kn->kn_sfflags & NOTE_MEMORYSTATUS_PRESSURE_CRITICAL) {
kn->kn_fflags = NOTE_MEMORYSTATUS_PRESSURE_CRITICAL;
found_knote = TRUE;
send_knote_count++;
} else if (kn->kn_sfflags & NOTE_MEMORYSTATUS_PRESSURE_WARN) {
kn->kn_fflags = NOTE_MEMORYSTATUS_PRESSURE_WARN;
found_knote = TRUE;
send_knote_count++;
}
} else {
/*
* Send this notification when a process has exceeded a soft limit.
*/
if (kn->kn_sfflags & NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL) {
kn->kn_fflags = NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL;
found_knote = TRUE;
send_knote_count++;
}
}
}
}
}
if (found_knote) {
if (send_knote_count > 0) {
KNOTE(&memorystatus_klist, 0);
}
ret = TRUE;
}
memorystatus_klist_unlock();
return ret;
}
/*
* Can only be set by the current task on itself.
*/
int
memorystatus_low_mem_privileged_listener(uint32_t op_flags)
{
boolean_t set_privilege = FALSE;
/*
* Need an entitlement check here?
*/
if (op_flags == MEMORYSTATUS_CMD_PRIVILEGED_LISTENER_ENABLE) {
set_privilege = TRUE;
} else if (op_flags == MEMORYSTATUS_CMD_PRIVILEGED_LISTENER_DISABLE) {
set_privilege = FALSE;
} else {
return EINVAL;
}
return task_low_mem_privileged_listener(current_task(), set_privilege, NULL);
}
int
memorystatus_send_pressure_note(pid_t pid)
{
memorystatus_log_debug("memorystatus_send_pressure_note(): pid %d\n", pid);
return memorystatus_send_note(kMemorystatusPressureNote, &pid, sizeof(pid));
}
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);
}
/*
* This is meant for stackshot and kperf -- it does not take the proc_list_lock
* to access the p_memstat_dirty field.
*/
void
memorystatus_proc_flags_unsafe(void * v, boolean_t *is_dirty, boolean_t *is_dirty_tracked, boolean_t *allow_idle_exit)
{
if (!v) {
*is_dirty = FALSE;
*is_dirty_tracked = FALSE;
*allow_idle_exit = FALSE;
} else {
proc_t p = (proc_t)v;
*is_dirty = (p->p_memstat_dirty & P_DIRTY_IS_DIRTY) != 0;
*is_dirty_tracked = (p->p_memstat_dirty & P_DIRTY_TRACK) != 0;
*allow_idle_exit = (p->p_memstat_dirty & P_DIRTY_ALLOW_IDLE_EXIT) != 0;
}
}
boolean_t
memorystatus_bg_pressure_eligible(proc_t p)
{
boolean_t eligible = FALSE;
proc_list_lock();
memorystatus_log_debug("memorystatus_bg_pressure_eligible: pid %d, state 0x%x\n", proc_getpid(p), 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;
}
if (p->p_memstat_effectivepriority < JETSAM_PRIORITY_BACKGROUND_OPPORTUNISTIC) {
/*
* IDLE and IDLE_DEFERRED bands contain processes
* that have dropped memory to be under their inactive
* memory limits. And so they can't really give back
* anything.
*/
eligible = FALSE;
}
proc_list_unlock();
return eligible;
}
void
memorystatus_send_low_swap_note(void)
{
struct knote *kn = NULL;
memorystatus_klist_lock();
SLIST_FOREACH(kn, &memorystatus_klist, kn_selnext) {
/* We call is_knote_registered_modify_task_pressure_bits to check if the sfflags for the
* current note contain NOTE_MEMORYSTATUS_LOW_SWAP. Once we find one note in the memorystatus_klist
* that has the NOTE_MEMORYSTATUS_LOW_SWAP flags in its sfflags set, we call KNOTE with
* kMemoryStatusLowSwap as the hint to process and update all knotes on the memorystatus_klist accordingly. */
if (is_knote_registered_modify_task_pressure_bits(kn, NOTE_MEMORYSTATUS_LOW_SWAP, NULL, 0, 0) == TRUE) {
KNOTE(&memorystatus_klist, kMemorystatusLowSwap);
break;
}
}
memorystatus_klist_unlock();
}
#endif /* CONFIG_MEMORYSTATUS */
/*
* Notification telemetry
*/
CA_EVENT(memorystatus_pressure_interval,
CA_INT, num_processes_registered,
CA_INT, num_notifications_sent,
CA_INT, max_level,
CA_INT, num_transitions,
CA_INT, num_kills,
CA_INT, duration);
static CA_EVENT_TYPE(memorystatus_pressure_interval) memorystatus_pressure_interval_telemetry;
CA_EVENT(memorystatus_proc_notification,
CA_INT, footprint_before_notification,
CA_INT, footprint_1_min_after_first_warning,
CA_INT, footprint_5_min_after_first_warning,
CA_INT, footprint_20_min_after_first_warning,
CA_INT, footprint_1_min_after_first_critical,
CA_INT, footprint_5_min_after_first_critical,
CA_INT, footprint_20_min_after_first_critical,
CA_INT, order_within_list,
CA_INT, num_notifications_sent,
CA_INT, time_between_warning_and_critical,
CA_STATIC_STRING(CA_PROCNAME_LEN), proc_name);
/* The send timestamps for the first notifications are stored in the knote's kn_sdata field */
#define KNOTE_SEND_TIMESTAMP_WARNING_INDEX 0
#define KNOTE_SEND_TIMESTAMP_CRITICAL_INDEX 1
/* The footprint history for this task is stored in the knote's kn_ext array. */
struct knote_footprint_history {
uint32_t kfh_starting_footprint;
uint32_t kfh_footprint_after_warn_1; /* 1 minute after first warning notification */
uint32_t kfh_footprint_after_warn_5; /* 5 minutes after first warning notification */
uint32_t kfh_footprint_after_warn_20; /* 20 minutes after first warning notification */
uint32_t kfh_footprint_after_critical_1; /* 1 minute after first critical notification */
uint32_t kfh_footprint_after_critical_5; /* 5 minutes after first critical notification */
uint32_t kfh_footprint_after_critical_20; /* 20 minutes after first critical notification */
uint16_t kfh_num_notifications;
uint16_t kfh_notification_order;
} __attribute__((packed));
static_assert(sizeof(struct knote_footprint_history) <= sizeof(uint64_t) * 4, "footprint history fits in knote extensions");
static void
mark_knote_send_time(struct knote *kn, task_t task, int knote_pressure_level, uint16_t order_within_list)
{
uint32_t *timestamps;
uint32_t index;
uint64_t curr_ts, curr_ts_seconds;
struct knote_footprint_history *footprint_history = (struct knote_footprint_history *)kn->kn_ext;
if (knote_pressure_level != NOTE_MEMORYSTATUS_PRESSURE_NORMAL) {
timestamps = (uint32_t *)&(kn->kn_sdata);
index = knote_pressure_level == NOTE_MEMORYSTATUS_PRESSURE_WARN ?
KNOTE_SEND_TIMESTAMP_WARNING_INDEX : KNOTE_SEND_TIMESTAMP_CRITICAL_INDEX;
if (timestamps[index] == 0) {
/* First notification for this level since pressure elevated from normal. */
curr_ts = mach_absolute_time();
curr_ts_seconds = 0;
absolutetime_to_nanoseconds(curr_ts, &curr_ts_seconds);
curr_ts_seconds /= NSEC_PER_SEC;
timestamps[index] = (uint32_t)MIN(UINT32_MAX, curr_ts_seconds);
/* Record task initial footprint */
if (timestamps[index == KNOTE_SEND_TIMESTAMP_WARNING_INDEX ? KNOTE_SEND_TIMESTAMP_CRITICAL_INDEX : KNOTE_SEND_TIMESTAMP_WARNING_INDEX] == 0) {
/*
* First notification at any level since pressure elevated from normal.
* Record the footprint and our order in the notification list.
*/
footprint_history->kfh_starting_footprint = (uint32_t) MIN(UINT32_MAX, get_task_phys_footprint(task) / (2UL << 20));
footprint_history->kfh_notification_order = order_within_list;
}
}
}
footprint_history->kfh_num_notifications++;
}
/*
* Records the current footprint for this task in the knote telemetry.
*
* Returns the soonest absolutetime when this footprint history should be updated again.
*/
static uint64_t
update_knote_footprint_history(struct knote *kn, task_t task, uint64_t curr_ts)
{
uint32_t *timestamps = (uint32_t *)&(kn->kn_sdata);
struct knote_footprint_history *footprint_history = (struct knote_footprint_history *)kn->kn_ext;
uint64_t warning_send_time, critical_send_time, minutes_since_warning = UINT64_MAX, minutes_since_critical = UINT64_MAX;
warning_send_time = timestamps[KNOTE_SEND_TIMESTAMP_WARNING_INDEX];
critical_send_time = timestamps[KNOTE_SEND_TIMESTAMP_CRITICAL_INDEX];
uint32_t task_phys_footprint_mb = (uint32_t) MIN(UINT32_MAX, get_task_phys_footprint(task) / (2UL << 20));
uint64_t next_run = UINT64_MAX, absolutetime_in_minute = 0, minutes_since_last_notification = 0, curr_ts_s;
absolutetime_to_nanoseconds(curr_ts, &curr_ts_s);
nanoseconds_to_absolutetime(60 * NSEC_PER_SEC, &absolutetime_in_minute);
curr_ts_s /= NSEC_PER_SEC;
if (warning_send_time != 0) {
/* This task received a warning notification. */
minutes_since_warning = (curr_ts_s - warning_send_time) / 60;
if (footprint_history->kfh_footprint_after_warn_1 == 0 && minutes_since_warning >= 1) {
footprint_history->kfh_footprint_after_warn_1 = task_phys_footprint_mb;
}
if (footprint_history->kfh_footprint_after_warn_5 == 0 && minutes_since_warning >= 5) {
footprint_history->kfh_footprint_after_warn_5 = task_phys_footprint_mb;
}
if (footprint_history->kfh_footprint_after_warn_20 == 0 && minutes_since_warning >= 20) {
footprint_history->kfh_footprint_after_warn_20 = task_phys_footprint_mb;
}
}
if (critical_send_time != 0) {
/* This task received a critical notification. */
minutes_since_critical = (curr_ts_s - critical_send_time) / 60;
if (footprint_history->kfh_footprint_after_critical_1 == 0 && minutes_since_critical >= 1) {
footprint_history->kfh_footprint_after_critical_1 = task_phys_footprint_mb;
}
if (footprint_history->kfh_footprint_after_critical_5 == 0 && minutes_since_critical >= 5) {
footprint_history->kfh_footprint_after_critical_5 = task_phys_footprint_mb;
}
if (footprint_history->kfh_footprint_after_critical_20 == 0 && minutes_since_critical >= 20) {
footprint_history->kfh_footprint_after_critical_20 = task_phys_footprint_mb;
}
}
minutes_since_last_notification = MIN(minutes_since_warning, minutes_since_critical);
if (minutes_since_last_notification < 20) {
if (minutes_since_last_notification < 5) {
if (minutes_since_last_notification < 1) {
next_run = curr_ts + absolutetime_in_minute;
} else {
next_run = curr_ts + (absolutetime_in_minute * 5);
}
} else {
next_run = curr_ts + (absolutetime_in_minute * 20);
}
}
return next_run;
}
extern char *proc_name_address(void *p);
/*
* Attempt to send the given level telemetry event.
* Finalizes the duration.
* Clears the src_event struct.
*/
static void
memorystatus_pressure_interval_send(CA_EVENT_TYPE(memorystatus_pressure_interval) *src_event)
{
uint64_t duration_nanoseconds = 0;
uint64_t curr_ts = mach_absolute_time();
src_event->duration = curr_ts - src_event->duration;
absolutetime_to_nanoseconds(src_event->duration, &duration_nanoseconds);
src_event->duration = (int64_t) (duration_nanoseconds / NSEC_PER_SEC);
/*
* Drop the event rather than block for memory. We should be in a normal pressure level now,
* but we don't want to end up blocked in page_wait if there's a sudden spike in pressure.
*/
ca_event_t event_wrapper = CA_EVENT_ALLOCATE_FLAGS(memorystatus_pressure_interval, Z_NOWAIT);
if (event_wrapper) {
memcpy(event_wrapper->data, src_event, sizeof(CA_EVENT_TYPE(memorystatus_pressure_interval)));
CA_EVENT_SEND(event_wrapper);
}
src_event->num_processes_registered = 0;
src_event->num_notifications_sent = 0;
src_event->max_level = 0;
src_event->num_transitions = 0;
src_event->num_kills = 0;
src_event->duration = 0;
}
/*
* Attempt to send the per-proc telemetry events.
* Clears the footprint histories on the knotes.
*/
static void
memorystatus_pressure_proc_telemetry_send(void)
{
struct knote *kn = NULL;
memorystatus_klist_lock();
SLIST_FOREACH(kn, &memorystatus_klist, kn_selnext) {
proc_t p = PROC_NULL;
struct knote_footprint_history *footprint_history = (struct knote_footprint_history *)kn->kn_ext;
uint32_t *timestamps = (uint32_t *)&(kn->kn_sdata);
uint32_t warning_send_time = timestamps[KNOTE_SEND_TIMESTAMP_WARNING_INDEX];
uint32_t critical_send_time = timestamps[KNOTE_SEND_TIMESTAMP_CRITICAL_INDEX];
CA_EVENT_TYPE(memorystatus_proc_notification) * event = NULL;
if (warning_send_time != 0 || critical_send_time != 0) {
/*
* Drop the event rather than block for memory. We should be in a normal pressure level now,
* but we don't want to end up blocked in page_wait if there's a sudden spike in pressure.
*/
ca_event_t event_wrapper = CA_EVENT_ALLOCATE_FLAGS(memorystatus_proc_notification, Z_NOWAIT | Z_ZERO);
if (event_wrapper) {
event = event_wrapper->data;
event->footprint_before_notification = footprint_history->kfh_starting_footprint;
event->footprint_1_min_after_first_warning = footprint_history->kfh_footprint_after_warn_1;
event->footprint_5_min_after_first_warning = footprint_history->kfh_footprint_after_warn_5;
event->footprint_20_min_after_first_warning = footprint_history->kfh_footprint_after_warn_20;
event->footprint_1_min_after_first_critical = footprint_history->kfh_footprint_after_critical_1;
event->footprint_5_min_after_first_critical = footprint_history->kfh_footprint_after_critical_5;
event->footprint_20_min_after_first_critical = footprint_history->kfh_footprint_after_critical_20;
event->num_notifications_sent = footprint_history->kfh_num_notifications;
if (warning_send_time != 0 && critical_send_time != 0) {
event->time_between_warning_and_critical = (critical_send_time - warning_send_time) / 60; // Minutes
}
event->order_within_list = footprint_history->kfh_notification_order;
p = proc_ref(knote_get_kq(kn)->kq_p, false);
if (p == NULL) {
CA_EVENT_DEALLOCATE(event_wrapper);
continue;
}
strlcpy(event->proc_name, proc_name_address(p), sizeof(event->proc_name));
proc_rele(p);
CA_EVENT_SEND(event_wrapper);
}
}
memset(footprint_history, 0, sizeof(*footprint_history));
timestamps[KNOTE_SEND_TIMESTAMP_WARNING_INDEX] = 0;
timestamps[KNOTE_SEND_TIMESTAMP_CRITICAL_INDEX] = 0;
}
memorystatus_klist_unlock();
}
/*
* Send all telemetry associated with the increased pressure interval.
*/
static void
memorystatus_pressure_telemetry_send(void)
{
LCK_MTX_ASSERT(&memorystatus_klist_mutex, LCK_MTX_ASSERT_NOTOWNED);
memorystatus_pressure_interval_send(&memorystatus_pressure_interval_telemetry);
memorystatus_pressure_proc_telemetry_send();
}
/*
* 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.
*
*/
static 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 (pressure_level_to_clear && 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;
}
static void
memorystatus_klist_reset_all_for_level(vm_pressure_level_t pressure_level_to_clear)
{
struct knote *kn = NULL;
memorystatus_klist_lock();
SLIST_FOREACH(kn, &memorystatus_klist, kn_selnext) {
proc_t p = knote_get_kq(kn)->kq_p;
if (p == proc_ref(p, false)) {
task_clear_has_been_notified(proc_task(p), pressure_level_to_clear);
proc_rele(p);
}
}
memorystatus_klist_unlock();
}
/*
* Used by the vm_pressure_thread which is
* signalled from within vm_pageout_scan().
*/
void
consider_vm_pressure_events(void)
{
vm_dispatch_memory_pressure();
}
static void
vm_dispatch_memory_pressure(void)
{
memorystatus_update_vm_pressure(FALSE);
}
static struct knote *
vm_pressure_select_optimal_candidate_to_notify(struct klist *candidate_list, int level, boolean_t target_foreground_process, uint64_t *next_telemetry_update)
{
struct knote *kn = NULL, *kn_max = NULL;
uint64_t resident_max = 0;/* MB */
int selected_task_importance = 0;
static int pressure_snapshot = -1;
boolean_t pressure_increase = FALSE;
uint64_t curr_ts = mach_absolute_time();
*next_telemetry_update = UINT64_MAX;
if (pressure_snapshot == -1) {
/*
* Initial snapshot.
*/
pressure_snapshot = level;
pressure_increase = TRUE;
} else {
if (level && (level >= pressure_snapshot)) {
pressure_increase = TRUE;
} else {
pressure_increase = FALSE;
}
pressure_snapshot = level;
}
if (pressure_increase == TRUE) {
/*
* We'll start by considering the largest
* unimportant task in our list.
*/
selected_task_importance = INT_MAX;
} else {
/*
* We'll start by considering the largest
* important task in our list.
*/
selected_task_importance = 0;
}
SLIST_FOREACH(kn, candidate_list, kn_selnext) {
uint64_t resident_size = 0;/* MB */
proc_t p = PROC_NULL;
struct task* t = TASK_NULL;
int curr_task_importance = 0;
uint64_t telemetry_update = 0;
boolean_t consider_knote = FALSE;
boolean_t privileged_listener = FALSE;
p = proc_ref(knote_get_kq(kn)->kq_p, false);
if (p == PROC_NULL) {
continue;
}
#if CONFIG_MEMORYSTATUS
if (target_foreground_process == TRUE && !memorystatus_is_foreground_locked(p)) {
/*
* Skip process not marked foreground.
*/
proc_rele(p);
continue;
}
#endif /* CONFIG_MEMORYSTATUS */
t = (struct task *)(proc_task(p));
telemetry_update = update_knote_footprint_history(kn, t, curr_ts);
*next_telemetry_update = MIN(*next_telemetry_update, telemetry_update);
vm_pressure_level_t dispatch_level = convert_internal_pressure_level_to_dispatch_level(level);
if ((kn->kn_sfflags & dispatch_level) == 0) {
proc_rele(p);
continue;
}
#if CONFIG_MEMORYSTATUS
if (target_foreground_process == FALSE && !memorystatus_bg_pressure_eligible(p)) {
VM_PRESSURE_DEBUG(1, "[vm_pressure] skipping process %d\n", proc_getpid(p));
proc_rele(p);
continue;
}
#endif /* CONFIG_MEMORYSTATUS */
#if XNU_TARGET_OS_OSX
curr_task_importance = task_importance_estimate(t);
#else /* XNU_TARGET_OS_OSX */
curr_task_importance = p->p_memstat_effectivepriority;
#endif /* XNU_TARGET_OS_OSX */
/*
* Privileged listeners are only considered in the multi-level pressure scheme
* AND only if the pressure is increasing.
*/
if (level > 0) {
if (task_has_been_notified(t, level) == FALSE) {
/*
* Is this a privileged listener?
*/
if (task_low_mem_privileged_listener(t, FALSE, &privileged_listener) == 0) {
if (privileged_listener) {
kn_max = kn;
proc_rele(p);
goto done_scanning;
}
}
} else {
proc_rele(p);
continue;
}
} else if (level == 0) {
/*
* Task wasn't notified when the pressure was increasing and so
* no need to notify it that the pressure is decreasing.
*/
if ((task_has_been_notified(t, kVMPressureWarning) == FALSE) && (task_has_been_notified(t, kVMPressureCritical) == FALSE)) {
proc_rele(p);
continue;
}
}
/*
* We don't want a small process to block large processes from
* being notified again. <rdar://problem/7955532>
*/
resident_size = (get_task_phys_footprint(t)) / (1024 * 1024ULL); /* MB */
if (resident_size >= vm_pressure_task_footprint_min) {
if (level > 0) {
/*
* Warning or Critical Pressure.
*/
if (pressure_increase) {
if ((curr_task_importance < selected_task_importance) ||
((curr_task_importance == selected_task_importance) && (resident_size > resident_max))) {
/*
* We have found a candidate process which is:
* a) at a lower importance than the current selected process
* OR
* b) has importance equal to that of the current selected process but is larger
*/
consider_knote = TRUE;
}
} else {
if ((curr_task_importance > selected_task_importance) ||
((curr_task_importance == selected_task_importance) && (resident_size > resident_max))) {
/*
* We have found a candidate process which is:
* a) at a higher importance than the current selected process
* OR
* b) has importance equal to that of the current selected process but is larger
*/
consider_knote = TRUE;
}
}
} else if (level == 0) {
/*
* Pressure back to normal.
*/
if ((curr_task_importance > selected_task_importance) ||
((curr_task_importance == selected_task_importance) && (resident_size > resident_max))) {
consider_knote = TRUE;
}
}
if (consider_knote) {
resident_max = resident_size;
kn_max = kn;
selected_task_importance = curr_task_importance;
consider_knote = FALSE; /* reset for the next candidate */
}
} else {
/* There was no candidate with enough resident memory to scavenge */
VM_PRESSURE_DEBUG(0, "[vm_pressure] threshold failed for pid %d with %llu resident...\n", proc_getpid(p), resident_size);
}
proc_rele(p);
}
done_scanning:
if (kn_max) {
VM_DEBUG_CONSTANT_EVENT(vm_pressure_event, VM_PRESSURE_EVENT, DBG_FUNC_NONE, proc_getpid(knote_get_kq(kn_max)->kq_p), resident_max, 0, 0);
VM_PRESSURE_DEBUG(1, "[vm_pressure] sending event to pid %d with %llu resident\n", proc_getpid(knote_get_kq(kn_max)->kq_p), resident_max);
}
return kn_max;
}
/*
* To avoid notification storms in a system with sawtooth behavior of pressure levels eg:
* Normal -> warning (notify clients) -> critical (notify) -> warning (notify) -> critical (notify) -> warning (notify)...
*
* We have 'resting' periods: WARNING_NOTIFICATION_RESTING_PERIOD and CRITICAL_NOTIFICATION_RESTING_PERIOD
*
* So it would look like:-
* Normal -> warning (notify) -> critical (notify) -> warning (notify if it has been RestPeriod since last warning) -> critical (notify if it has been RestPeriod since last critical) -> ...
*
* That's what these 2 timestamps below signify.
*/
uint64_t next_warning_notification_sent_at_ts = 0;
uint64_t next_critical_notification_sent_at_ts = 0;
boolean_t memorystatus_manual_testing_on = FALSE;
vm_pressure_level_t memorystatus_manual_testing_level = kVMPressureNormal;
unsigned int memorystatus_sustained_pressure_maximum_band = JETSAM_PRIORITY_IDLE;
#if DEVELOPMENT || DEBUG
SYSCTL_INT(_kern, OID_AUTO, memorystatus_sustained_pressure_maximum_band, CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED, &memorystatus_sustained_pressure_maximum_band, 0, "");
#endif /* DEVELOPMENT || DEBUG */
#if CONFIG_JETSAM
/*
* TODO(jason): The memorystatus thread should be responsible for this
* It can just check how long the pressure level has been at warning and the timestamp
* of the last sustained pressure kill.
*/
static void
sustained_pressure_handler(void* arg0 __unused, void* arg1 __unused)
{
int max_kills = 0, kill_count = 0;
/*
* Pressure has been elevated for too long.
* We don't want to leave the system in this state as it can delay background
* work indefinitely & drain battery.
*
* Try to return the system to normal via jetsam.
* We'll run through the idle band up to 2 times.
* If the pressure hasn't been relieved by then, the problem is memory
* consumption in a higher band and this churn is probably doing more harm than good.
*/
max_kills = memorystatus_get_proccnt_upto_priority(memorystatus_sustained_pressure_maximum_band) * 2;
memorystatus_log("memorystatus: Pressure level has been elevated for too long. killing up to %d idle processes\n", max_kills);
while (memorystatus_vm_pressure_level != kVMPressureNormal && kill_count < max_kills) {
boolean_t killed = memorystatus_kill_on_sustained_pressure();
if (killed) {
/*
* Pause before our next kill & see if pressure reduces.
*/
delay((int)(memorystatus_kill_on_sustained_pressure_delay_ms * NSEC_PER_MSEC / NSEC_PER_USEC));
kill_count++;
memorystatus_kill_on_sustained_pressure_count++;
/* TODO(jason): Should use os_atomic but requires rdar://76310894. */
memorystatus_pressure_interval_telemetry.num_kills++;
} else {
/* Nothing left to kill */
break;
}
}
if (memorystatus_vm_pressure_level != kVMPressureNormal) {
memorystatus_log("memorystatus: Killed %d idle processes due to sustained pressure, but device didn't quiesce. Giving up.\n", kill_count);
}
}
#endif /* CONFIG_JETSAM */
/*
* Returns the number of processes registered for notifications at this level.
*/
static size_t
memorystatus_klist_length(int level)
{
LCK_MTX_ASSERT(&memorystatus_klist_mutex, LCK_MTX_ASSERT_OWNED);
struct knote *kn;
size_t count = 0;
int knote_pressure_level = convert_internal_pressure_level_to_dispatch_level(level);
SLIST_FOREACH(kn, &memorystatus_klist, kn_selnext) {
if (kn->kn_sfflags & knote_pressure_level) {
count++;
}
}
return count;
}
/*
* Updates the footprint telemetry for procs that have received notifications.
*/
static void
update_footprints_for_telemetry(void* arg0 __unused, void* arg1 __unused)
{
uint64_t curr_ts = mach_absolute_time(), next_telemetry_update = UINT64_MAX;
struct knote *kn;
memorystatus_klist_lock();
SLIST_FOREACH(kn, &memorystatus_klist, kn_selnext) {
proc_t p = PROC_NULL;
struct task* t = TASK_NULL;
uint64_t telemetry_update;
p = proc_ref(knote_get_kq(kn)->kq_p, false);
if (p == PROC_NULL) {
continue;
}
t = (struct task *)(proc_task(p));
proc_rele(p);
p = PROC_NULL;
telemetry_update = update_knote_footprint_history(kn, t, curr_ts);
next_telemetry_update = MIN(next_telemetry_update, telemetry_update);
}
memorystatus_klist_unlock();
if (next_telemetry_update != UINT64_MAX) {
uint64_t next_update_seconds;
absolutetime_to_nanoseconds(next_telemetry_update, &next_update_seconds);
next_update_seconds /= NSEC_PER_SEC;
thread_call_enter_delayed(memorystatus_notify_update_telemetry_thread_call, next_telemetry_update);
}
}
kern_return_t
memorystatus_update_vm_pressure(boolean_t target_foreground_process)
{
struct knote *kn_max = NULL;
struct knote *kn_cur = NULL, *kn_temp = NULL;/* for safe list traversal */
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};
int64_t elapsed_msecs = 0;
uint64_t curr_ts = mach_absolute_time(), next_telemetry_update = UINT64_MAX;
uint64_t logging_now;
absolutetime_to_nanoseconds(curr_ts, &logging_now);
#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++;
if (memorystatus_manual_testing_on == TRUE) {
/*
* Skip the delay when testing
* the pressure notification scheme.
*/
} else {
delay(1000000); /* 1 second */
}
}
#endif /* !CONFIG_JETSAM */
if (level_snapshot != kVMPressureNormal) {
/*
* Check to see if we are still in the 'resting' period
* after having notified all clients interested in
* a particular pressure level.
*/
level_snapshot = memorystatus_vm_pressure_level;
if (level_snapshot == kVMPressureWarning || level_snapshot == kVMPressureUrgent) {
if (next_warning_notification_sent_at_ts) {
if (curr_ts < next_warning_notification_sent_at_ts) {
delay(INTER_NOTIFICATION_DELAY * 4 /* 1 sec */);
return KERN_SUCCESS;
}
next_warning_notification_sent_at_ts = 0;
memorystatus_klist_reset_all_for_level(kVMPressureWarning);
}
} else if (level_snapshot == kVMPressureCritical) {
if (next_critical_notification_sent_at_ts) {
if (curr_ts < next_critical_notification_sent_at_ts) {
delay(INTER_NOTIFICATION_DELAY * 4 /* 1 sec */);
return KERN_SUCCESS;
}
next_critical_notification_sent_at_ts = 0;
memorystatus_klist_reset_all_for_level(kVMPressureCritical);
}
}
}
#if CONFIG_JETSAM
if (memorystatus_vm_pressure_level == kVMPressureNormal && prev_level_snapshot != kVMPressureNormal) {
if (memorystatus_should_kill_on_sustained_pressure) {
memorystatus_log("memorystatus: Pressure has returned to level %d. Cancelling scheduled jetsam\n", memorystatus_vm_pressure_level);
thread_call_cancel(sustained_pressure_handler_thread_call);
}
} else if (memorystatus_should_kill_on_sustained_pressure && memorystatus_vm_pressure_level != kVMPressureNormal && prev_level_snapshot == kVMPressureNormal) {
/*
* Pressure has increased from normal.
* Hopefully the notifications will relieve it,
* but as a fail-safe we'll trigger jetsam
* after a configurable amount of time.
*/
memorystatus_log("memorystatus: Pressure level has increased from %d to %d. Scheduling jetsam.\n", prev_level_snapshot, memorystatus_vm_pressure_level);
uint64_t kill_time;
nanoseconds_to_absolutetime(memorystatus_kill_on_sustained_pressure_window_s * NSEC_PER_SEC, &kill_time);
kill_time += mach_absolute_time();
thread_call_enter_delayed(sustained_pressure_handler_thread_call, kill_time);
}
#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;
}
}
if (level_snapshot == kVMPressureNormal) {
memorystatus_pressure_telemetry_send();
}
prev_level_snapshot = level_snapshot;
smoothing_window_started = FALSE;
memorystatus_klist_lock();
if (level_snapshot > memorystatus_pressure_interval_telemetry.max_level) {
memorystatus_pressure_interval_telemetry.num_processes_registered = memorystatus_klist_length(level_snapshot);
memorystatus_pressure_interval_telemetry.max_level = level_snapshot;
memorystatus_pressure_interval_telemetry.num_transitions++;
if (memorystatus_pressure_interval_telemetry.duration == 0) {
/* Set the start timestamp. Duration will be finalized when we send the event. */
memorystatus_pressure_interval_telemetry.duration = curr_ts;
}
}
kn_max = vm_pressure_select_optimal_candidate_to_notify(&memorystatus_klist, level_snapshot, target_foreground_process, &next_telemetry_update);
if (kn_max == NULL) {
memorystatus_klist_unlock();
/*
* No more level-based clients to notify.
*
* Start the 'resting' window within which clients will not be re-notified.
*/
if (level_snapshot != kVMPressureNormal) {
if (level_snapshot == kVMPressureWarning || level_snapshot == kVMPressureUrgent) {
nanoseconds_to_absolutetime(WARNING_NOTIFICATION_RESTING_PERIOD * NSEC_PER_SEC, &curr_ts);
/* Next warning notification (if nothing changes) won't be sent before...*/
next_warning_notification_sent_at_ts = mach_absolute_time() + curr_ts;
}
if (level_snapshot == kVMPressureCritical) {
nanoseconds_to_absolutetime(CRITICAL_NOTIFICATION_RESTING_PERIOD * NSEC_PER_SEC, &curr_ts);
/* Next critical notification (if nothing changes) won't be sent before...*/
next_critical_notification_sent_at_ts = mach_absolute_time() + curr_ts;
}
}
absolutetime_to_nanoseconds(mach_absolute_time(), &logging_now);
if (next_telemetry_update != UINT64_MAX) {
thread_call_enter_delayed(memorystatus_notify_update_telemetry_thread_call, next_telemetry_update);
} else {
thread_call_cancel(memorystatus_notify_update_telemetry_thread_call);
}
return KERN_FAILURE;
}
target_proc = proc_ref(knote_get_kq(kn_max)->kq_p, false);
if (target_proc == PROC_NULL) {
memorystatus_klist_unlock();
continue;
}
target_pid = proc_getpid(target_proc);
task = (struct task *)(proc_task(target_proc));
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, 0, 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, 0, 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) {
proc_rele(target_proc);
memorystatus_klist_unlock();
continue;
}
SLIST_FOREACH_SAFE(kn_cur, &memorystatus_klist, kn_selnext, kn_temp) {
int knote_pressure_level = convert_internal_pressure_level_to_dispatch_level(level_snapshot);
if (is_knote_registered_modify_task_pressure_bits(kn_cur, knote_pressure_level, task, 0, level_snapshot) == TRUE) {
proc_t knote_proc = knote_get_kq(kn_cur)->kq_p;
pid_t knote_pid = proc_getpid(knote_proc);
if (knote_pid == target_pid) {
KNOTE_DETACH(&memorystatus_klist, kn_cur);
KNOTE_ATTACH(&dispatch_klist, kn_cur);
}
}
}
if (level_snapshot != kVMPressureNormal) {
mark_knote_send_time(kn_max, task, convert_internal_pressure_level_to_dispatch_level(level_snapshot),
(uint16_t) MIN(UINT16_MAX, memorystatus_pressure_interval_telemetry.num_notifications_sent));
memorystatus_pressure_interval_telemetry.num_notifications_sent++;
}
KNOTE(&dispatch_klist, (level_snapshot != kVMPressureNormal) ? kMemorystatusPressure : kMemorystatusNoPressure);
SLIST_FOREACH_SAFE(kn_cur, &dispatch_klist, kn_selnext, kn_temp) {
KNOTE_DETACH(&dispatch_klist, kn_cur);
KNOTE_ATTACH(&memorystatus_klist, kn_cur);
}
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;
}
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;
}
static uint32_t
convert_internal_pressure_level_to_dispatch_level(vm_pressure_level_t internal_pressure_level)
{
uint32_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;
}
/*
* Notify any kexts that are waiting for notification that jetsam
* is approaching the foreground bands. They should use this notification
* to free cached memory.
*/
void
memorystatus_issue_fg_band_notify(void)
{
uint64_t now;
lck_mtx_lock(&memorystatus_jetsam_fg_band_lock);
absolutetime_to_nanoseconds(mach_absolute_time(), &now);
if (now - memorystatus_jetsam_fg_band_timestamp_ns < memorystatus_jetsam_fg_band_delay_ns) {
lck_mtx_unlock(&memorystatus_jetsam_fg_band_lock);
return;
}
if (memorystatus_jetsam_fg_band_waiters > 0) {
thread_wakeup(&memorystatus_jetsam_fg_band_waiters);
memorystatus_jetsam_fg_band_waiters = 0;
memorystatus_jetsam_fg_band_timestamp_ns = now;
}
lck_mtx_unlock(&memorystatus_jetsam_fg_band_lock);
/* Notify the buffer cache, file systems, etc. to jetison everything they can. */
if (consider_buffer_cache_collect != NULL) {
(void)(*consider_buffer_cache_collect)(1);
}
}
/*
* Memorystatus notification debugging support
*/
static int
sysctl_memorystatus_vm_pressure_level SYSCTL_HANDLER_ARGS
{
#pragma unused(arg1, arg2, oidp)
#if !XNU_TARGET_OS_OSX
int error = 0;
error = priv_check_cred(kauth_cred_get(), PRIV_VM_PRESSURE, 0);
if (error) {
return error;
}
#endif /* !XNU_TARGET_OS_OSX */
uint32_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 */
/*
* 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
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 = vm_pageout_state.memorystatus_purge_on_warning;
} else if (pressure_level == NOTE_MEMORYSTATUS_PRESSURE_CRITICAL) {
memorystatus_manual_testing_level = kVMPressureCritical;
force_purge = vm_pageout_state.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;
}
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", "");
SYSCTL_INT(_kern, OID_AUTO, memorystatus_purge_on_warning, CTLFLAG_RW | CTLFLAG_LOCKED, &vm_pageout_state.memorystatus_purge_on_warning, 0, "");
SYSCTL_INT(_kern, OID_AUTO, memorystatus_purge_on_urgent, CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED, &vm_pageout_state.memorystatus_purge_on_urgent, 0, "");
SYSCTL_INT(_kern, OID_AUTO, memorystatus_purge_on_critical, CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED, &vm_pageout_state.memorystatus_purge_on_critical, 0, "");
extern int vm_pressure_level_transition_threshold;
SYSCTL_INT(_kern, OID_AUTO, vm_pressure_level_transition_threshold, CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED, &vm_pressure_level_transition_threshold, 0, "");
#if DEBUG || DEVELOPMENT
SYSCTL_UINT(_kern, OID_AUTO, memorystatus_vm_pressure_events_enabled, CTLFLAG_RW | CTLFLAG_LOCKED, &vm_pressure_events_enabled, 0, "");
#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 */
/*
* This routine is used for targeted notifications regardless of system memory pressure
* and regardless of whether or not the process has already been notified.
* It bypasses and has no effect on the only-one-notification per soft-limit policy.
*
* "memnote" is the current user.
*/
static int
sysctl_memorystatus_vm_pressure_send SYSCTL_HANDLER_ARGS
{
#pragma unused(arg1, arg2)
/* Need to be root or have memorystatus entitlement */
if (!kauth_cred_issuser(kauth_cred_get()) && !IOCurrentTaskHasEntitlement(MEMORYSTATUS_ENTITLEMENT)) {
return EPERM;
}
int error = 0, pid = 0;
struct knote *kn = NULL;
boolean_t found_knote = FALSE;
int fflags = 0; /* filter flags for EVFILT_MEMORYSTATUS */
uint64_t value = 0;
error = sysctl_handle_quad(oidp, &value, 0, req);
if (error || !req->newptr) {
return error;
}
/*
* Find the pid in the low 32 bits of value passed in.
*/
pid = (int)(value & 0xFFFFFFFF);
/*
* Find notification in the high 32 bits of the value passed in.
*/
fflags = (int)((value >> 32) & 0xFFFFFFFF);
/*
* For backwards compatibility, when no notification is
* passed in, default to the NOTE_MEMORYSTATUS_PRESSURE_WARN
*/
if (fflags == 0) {
fflags = NOTE_MEMORYSTATUS_PRESSURE_WARN;
// printf("memorystatus_vm_pressure_send: using default notification [0x%x]\n", fflags);
}
/* wake up everybody waiting for kVMPressureJetsam */
if (fflags == NOTE_MEMORYSTATUS_JETSAM_FG_BAND) {
memorystatus_issue_fg_band_notify();
return error;
}
/*
* See event.h ... fflags for EVFILT_MEMORYSTATUS
*/
if (!((fflags == NOTE_MEMORYSTATUS_PRESSURE_NORMAL) ||
(fflags == NOTE_MEMORYSTATUS_PRESSURE_WARN) ||
(fflags == NOTE_MEMORYSTATUS_PRESSURE_CRITICAL) ||
(fflags == NOTE_MEMORYSTATUS_LOW_SWAP) ||
(fflags == NOTE_MEMORYSTATUS_PROC_LIMIT_WARN) ||
(fflags == NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL) ||
(((fflags & NOTE_MEMORYSTATUS_MSL_STATUS) != 0 &&
((fflags & ~NOTE_MEMORYSTATUS_MSL_STATUS) == 0))))) {
memorystatus_log_error("memorystatus_vm_pressure_send: notification [0x%x] not supported\n", fflags);
error = 1;
return error;
}
/*
* Forcibly send pid a memorystatus notification.
*/
memorystatus_klist_lock();
SLIST_FOREACH(kn, &memorystatus_klist, kn_selnext) {
proc_t knote_proc = knote_get_kq(kn)->kq_p;
pid_t knote_pid = proc_getpid(knote_proc);
if (knote_pid == pid) {
/*
* Forcibly send this pid a memorystatus notification.
*/
kn->kn_fflags = fflags;
found_knote = TRUE;
}
}
if (found_knote) {
KNOTE(&memorystatus_klist, 0);
memorystatus_log_debug("memorystatus_vm_pressure_send: (value 0x%llx) notification [0x%x] sent to process [%d]\n", value, fflags, pid);
error = 0;
} else {
memorystatus_log_error("memorystatus_vm_pressure_send: (value 0x%llx) notification [0x%x] not sent to process [%d] (none registered?)\n", value, fflags, pid);
error = 1;
}
memorystatus_klist_unlock();
return error;
}
SYSCTL_PROC(_kern, OID_AUTO, memorystatus_vm_pressure_send, CTLTYPE_QUAD | CTLFLAG_WR | CTLFLAG_LOCKED | CTLFLAG_MASKED | CTLFLAG_ANYBODY,
0, 0, &sysctl_memorystatus_vm_pressure_send, "Q", "");
#endif /* DEBUG || DEVELOPMENT */
#endif /* VM_PRESSURE_EVENTS */