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lmkd: Add support for psi monitors

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With new psi monitor support in the kernel lmkd can use it to register
custom pressure levels. Add lmkd support for psi monitors when they are
provided by the kernel and use them by default. When kernel does not
support psi lmkd will fall back to vmpressure usage.
Add ability to poll memory status after the initial psi event is triggered
because kernel throttles psi memory pressure events to one per PSI tracking
window (currently set to 1sec). Current implementation polls every 200ms
for 1sec duration after the initial event is triggered.
If ro.lmk.use_psi is set to false psi logic will be disabled even when psi
is supported in kernel.

Bug: 111308141
Test: lmkd_unit_test
Change-Id: I685774b176f393bab7412161773f5c9af51e0163
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
This commit is contained in:
Suren Baghdasaryan 2019-01-08 12:54:48 -08:00
parent 59a0149939
commit 77122e5780
2 changed files with 140 additions and 14 deletions
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1
lmkd/Android.bp
View file

@ -6,6 +6,7 @@ cc_binary {
"libcutils",
"liblog",
"libprocessgroup",
"libpsi",
],
static_libs: [
"libstatslogc",

153
lmkd/lmkd.c
View file

@ -44,6 +44,7 @@
#include <log/log.h>
#include <log/log_event_list.h>
#include <log/log_time.h>
#include <psi/psi.h>
#include <system/thread_defs.h>
#ifdef LMKD_LOG_STATS
@ -93,6 +94,7 @@
#define TARGET_UPDATE_MIN_INTERVAL_MS 1000
#define NS_PER_MS (NS_PER_SEC / MS_PER_SEC)
#define US_PER_MS (US_PER_SEC / MS_PER_SEC)
/* Defined as ProcessList.SYSTEM_ADJ in ProcessList.java */
#define SYSTEM_ADJ (-900)
@ -100,6 +102,18 @@
#define STRINGIFY(x) STRINGIFY_INTERNAL(x)
#define STRINGIFY_INTERNAL(x) #x
/*
* PSI monitor tracking window size.
* PSI monitor generates events at most once per window,
* therefore we poll memory state for the duration of
* PSI_WINDOW_SIZE_MS after the event happens.
*/
#define PSI_WINDOW_SIZE_MS 1000
/* Polling period after initial PSI signal */
#define PSI_POLL_PERIOD_MS 200
/* Poll for the duration of one window after initial PSI signal */
#define PSI_POLL_COUNT (PSI_WINDOW_SIZE_MS / PSI_POLL_PERIOD_MS)
#define min(a, b) (((a) < (b)) ? (a) : (b))
#define FAIL_REPORT_RLIMIT_MS 1000
@ -127,6 +141,11 @@ struct {
int64_t max_nr_free_pages;
} low_pressure_mem = { -1, -1 };
struct psi_threshold {
enum psi_stall_type stall_type;
int threshold_ms;
};
static int level_oomadj[VMPRESS_LEVEL_COUNT];
static int mpevfd[VMPRESS_LEVEL_COUNT] = { -1, -1, -1 };
static bool debug_process_killing;
@ -139,6 +158,12 @@ static unsigned long kill_timeout_ms;
static bool use_minfree_levels;
static bool per_app_memcg;
static int swap_free_low_percentage;
static bool use_psi_monitors = false;
static struct psi_threshold psi_thresholds[VMPRESS_LEVEL_COUNT] = {
{ PSI_SOME, 70 }, /* 70ms out of 1sec for partial stall */
{ PSI_SOME, 100 }, /* 100ms out of 1sec for partial stall */
{ PSI_FULL, 70 }, /* 70ms out of 1sec for complete stall */
};
static android_log_context ctx;
@ -1524,17 +1549,23 @@ static void mp_event_common(int data, uint32_t events __unused) {
.fd = -1,
};
/*
* Check all event counters from low to critical
* and upgrade to the highest priority one. By reading
* eventfd we also reset the event counters.
*/
for (lvl = VMPRESS_LEVEL_LOW; lvl < VMPRESS_LEVEL_COUNT; lvl++) {
if (mpevfd[lvl] != -1 &&
TEMP_FAILURE_RETRY(read(mpevfd[lvl],
&evcount, sizeof(evcount))) > 0 &&
evcount > 0 && lvl > level) {
level = lvl;
if (debug_process_killing) {
ALOGI("%s memory pressure event is triggered", level_name[level]);
}
if (!use_psi_monitors) {
/*
* Check all event counters from low to critical
* and upgrade to the highest priority one. By reading
* eventfd we also reset the event counters.
*/
for (lvl = VMPRESS_LEVEL_LOW; lvl < VMPRESS_LEVEL_COUNT; lvl++) {
if (mpevfd[lvl] != -1 &&
TEMP_FAILURE_RETRY(read(mpevfd[lvl],
&evcount, sizeof(evcount))) > 0 &&
evcount > 0 && lvl > level) {
level = lvl;
}
}
}
@ -1722,6 +1753,54 @@ do_kill:
}
}
static bool init_mp_psi(enum vmpressure_level level) {
int fd = init_psi_monitor(psi_thresholds[level].stall_type,
psi_thresholds[level].threshold_ms * US_PER_MS,
PSI_WINDOW_SIZE_MS * US_PER_MS);
if (fd < 0) {
return false;
}
vmpressure_hinfo[level].handler = mp_event_common;
vmpressure_hinfo[level].data = level;
if (register_psi_monitor(epollfd, fd, &vmpressure_hinfo[level]) < 0) {
destroy_psi_monitor(fd);
return false;
}
maxevents++;
mpevfd[level] = fd;
return true;
}
static void destroy_mp_psi(enum vmpressure_level level) {
int fd = mpevfd[level];
if (unregister_psi_monitor(epollfd, fd) < 0) {
ALOGE("Failed to unregister psi monitor for %s memory pressure; errno=%d",
level_name[level], errno);
}
destroy_psi_monitor(fd);
mpevfd[level] = -1;
}
static bool init_psi_monitors() {
if (!init_mp_psi(VMPRESS_LEVEL_LOW)) {
return false;
}
if (!init_mp_psi(VMPRESS_LEVEL_MEDIUM)) {
destroy_mp_psi(VMPRESS_LEVEL_LOW);
return false;
}
if (!init_mp_psi(VMPRESS_LEVEL_CRITICAL)) {
destroy_mp_psi(VMPRESS_LEVEL_MEDIUM);
destroy_mp_psi(VMPRESS_LEVEL_LOW);
return false;
}
return true;
}
static bool init_mp_common(enum vmpressure_level level) {
int mpfd;
int evfd;
@ -1837,12 +1916,22 @@ static int init(void) {
if (use_inkernel_interface) {
ALOGI("Using in-kernel low memory killer interface");
} else {
if (!init_mp_common(VMPRESS_LEVEL_LOW) ||
/* Try to use psi monitor first if kernel has it */
use_psi_monitors = property_get_bool("ro.lmk.use_psi", true) &&
init_psi_monitors();
/* Fall back to vmpressure */
if (!use_psi_monitors &&
(!init_mp_common(VMPRESS_LEVEL_LOW) ||
!init_mp_common(VMPRESS_LEVEL_MEDIUM) ||
!init_mp_common(VMPRESS_LEVEL_CRITICAL)) {
!init_mp_common(VMPRESS_LEVEL_CRITICAL))) {
ALOGE("Kernel does not support memory pressure events or in-kernel low memory killer");
return -1;
}
if (use_psi_monitors) {
ALOGI("Using psi monitors for memory pressure detection");
} else {
ALOGI("Using vmpressure for memory pressure detection");
}
}
for (i = 0; i <= ADJTOSLOT(OOM_SCORE_ADJ_MAX); i++) {
@ -1857,14 +1946,39 @@ static int init(void) {
static void mainloop(void) {
struct event_handler_info* handler_info;
struct event_handler_info* poll_handler = NULL;
struct timespec last_report_tm, curr_tm;
struct epoll_event *evt;
long delay = -1;
int polling = 0;
while (1) {
struct epoll_event events[maxevents];
int nevents;
int i;
nevents = epoll_wait(epollfd, events, maxevents, -1);
if (polling) {
/* Calculate next timeout */
clock_gettime(CLOCK_MONOTONIC_COARSE, &curr_tm);
delay = get_time_diff_ms(&last_report_tm, &curr_tm);
delay = (delay < PSI_POLL_PERIOD_MS) ?
PSI_POLL_PERIOD_MS - delay : PSI_POLL_PERIOD_MS;
/* Wait for events until the next polling timeout */
nevents = epoll_wait(epollfd, events, maxevents, delay);
clock_gettime(CLOCK_MONOTONIC_COARSE, &curr_tm);
if (get_time_diff_ms(&last_report_tm, &curr_tm) >= PSI_POLL_PERIOD_MS) {
if (polling) {
polling--;
poll_handler->handler(poll_handler->data, 0);
last_report_tm = curr_tm;
}
}
} else {
/* Wait for events with no timeout */
nevents = epoll_wait(epollfd, events, maxevents, -1);
}
if (nevents == -1) {
if (errno == EINTR)
@ -1899,6 +2013,17 @@ static void mainloop(void) {
if (evt->data.ptr) {
handler_info = (struct event_handler_info*)evt->data.ptr;
handler_info->handler(handler_info->data, evt->events);
if (use_psi_monitors && handler_info->handler == mp_event_common) {
/*
* Poll for the duration of PSI_WINDOW_SIZE_MS after the
* initial PSI event because psi events are rate-limited
* at one per sec.
*/
polling = PSI_POLL_COUNT;
poll_handler = handler_info;
clock_gettime(CLOCK_MONOTONIC_COARSE, &last_report_tm);
}
}
}
}