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platform_system_core/lmkd/lmkd.c
Greg Kaiser 5670fabb94 lmkd: Remove unnecessary conditional 
We want poll_handler to be handler_info, so it's more efficient
to just unconditionally assign it.

Test: TreeHugger
Change-Id: I55b5164da1817ef77b5d455eb618f9a2471afc5c
2019-10-10 06:52:23 -07:00

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/*
* Copyright (C) 2013 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#define LOG_TAG "lowmemorykiller"
#include <dirent.h>
#include <errno.h>
#include <inttypes.h>
#include <pwd.h>
#include <sched.h>
#include <signal.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <sys/cdefs.h>
#include <sys/epoll.h>
#include <sys/eventfd.h>
#include <sys/mman.h>
#include <sys/resource.h>
#include <sys/socket.h>
#include <sys/syscall.h>
#include <sys/sysinfo.h>
#include <sys/time.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>
#include <cutils/properties.h>
#include <cutils/sched_policy.h>
#include <cutils/sockets.h>
#include <lmkd.h>
#include <log/log.h>
#include <log/log_event_list.h>
#include <log/log_time.h>
#include <psi/psi.h>
#include <system/thread_defs.h>
#include "statslog.h"
/*
* Define LMKD_TRACE_KILLS to record lmkd kills in kernel traces
* to profile and correlate with OOM kills
*/
#ifdef LMKD_TRACE_KILLS
#define ATRACE_TAG ATRACE_TAG_ALWAYS
#include <cutils/trace.h>
#define TRACE_KILL_START(pid) ATRACE_INT(__FUNCTION__, pid);
#define TRACE_KILL_END() ATRACE_INT(__FUNCTION__, 0);
#else /* LMKD_TRACE_KILLS */
#define TRACE_KILL_START(pid) ((void)(pid))
#define TRACE_KILL_END() ((void)0)
#endif /* LMKD_TRACE_KILLS */
#ifndef __unused
#define __unused __attribute__((__unused__))
#endif
#define MEMCG_SYSFS_PATH "/dev/memcg/"
#define MEMCG_MEMORY_USAGE "/dev/memcg/memory.usage_in_bytes"
#define MEMCG_MEMORYSW_USAGE "/dev/memcg/memory.memsw.usage_in_bytes"
#define ZONEINFO_PATH "/proc/zoneinfo"
#define MEMINFO_PATH "/proc/meminfo"
#define VMSTAT_PATH "/proc/vmstat"
#define PROC_STATUS_TGID_FIELD "Tgid:"
#define LINE_MAX 128
#define PERCEPTIBLE_APP_ADJ 200
/* Android Logger event logtags (see event.logtags) */
#define KILLINFO_LOG_TAG 10195355
/* gid containing AID_SYSTEM required */
#define INKERNEL_MINFREE_PATH "/sys/module/lowmemorykiller/parameters/minfree"
#define INKERNEL_ADJ_PATH "/sys/module/lowmemorykiller/parameters/adj"
#define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x)))
#define EIGHT_MEGA (1 << 23)
#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)
#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 PSI signal when pressure is high */
#define PSI_POLL_PERIOD_SHORT_MS 10
/* Polling period after PSI signal when pressure is low */
#define PSI_POLL_PERIOD_LONG_MS 100
#define min(a, b) (((a) < (b)) ? (a) : (b))
#define max(a, b) (((a) > (b)) ? (a) : (b))
#define FAIL_REPORT_RLIMIT_MS 1000
/*
* System property defaults
*/
/* ro.lmk.swap_free_low_percentage property defaults */
#define DEF_LOW_SWAP_LOWRAM 10
#define DEF_LOW_SWAP 20
/* ro.lmk.thrashing_limit property defaults */
#define DEF_THRASHING_LOWRAM 30
#define DEF_THRASHING 100
/* ro.lmk.thrashing_limit_decay property defaults */
#define DEF_THRASHING_DECAY_LOWRAM 50
#define DEF_THRASHING_DECAY 10
/* ro.lmk.psi_partial_stall_ms property defaults */
#define DEF_PARTIAL_STALL_LOWRAM 200
#define DEF_PARTIAL_STALL 70
/* ro.lmk.psi_complete_stall_ms property defaults */
#define DEF_COMPLETE_STALL 700
static inline int sys_pidfd_open(pid_t pid, unsigned int flags) {
return syscall(__NR_pidfd_open, pid, flags);
}
static inline int sys_pidfd_send_signal(int pidfd, int sig, siginfo_t *info,
unsigned int flags) {
return syscall(__NR_pidfd_send_signal, pidfd, sig, info, flags);
}
/* default to old in-kernel interface if no memory pressure events */
static bool use_inkernel_interface = true;
static bool has_inkernel_module;
/* memory pressure levels */
enum vmpressure_level {
VMPRESS_LEVEL_LOW = 0,
VMPRESS_LEVEL_MEDIUM,
VMPRESS_LEVEL_CRITICAL,
VMPRESS_LEVEL_COUNT
};
static const char *level_name[] = {
"low",
"medium",
"critical"
};
struct {
int64_t min_nr_free_pages; /* recorded but not used yet */
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 pidfd_supported;
static int last_kill_pid_or_fd = -1;
static struct timespec last_kill_tm;
/* lmkd configurable parameters */
static bool debug_process_killing;
static bool enable_pressure_upgrade;
static int64_t upgrade_pressure;
static int64_t downgrade_pressure;
static bool low_ram_device;
static bool kill_heaviest_task;
static unsigned long kill_timeout_ms;
static bool use_minfree_levels;
static bool per_app_memcg;
static int swap_free_low_percentage;
static int psi_partial_stall_ms;
static int psi_complete_stall_ms;
static int thrashing_limit_pct;
static int thrashing_limit_decay_pct;
static bool use_psi_monitors = false;
static struct kernel_poll_info kpoll_info;
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;
enum polling_update {
POLLING_DO_NOT_CHANGE,
POLLING_START,
POLLING_STOP,
POLLING_PAUSE,
POLLING_RESUME,
};
/*
* Data used for periodic polling for the memory state of the device.
* Note that when system is not polling poll_handler is set to NULL,
* when polling starts poll_handler gets set and is reset back to
* NULL when polling stops.
*/
struct polling_params {
struct event_handler_info* poll_handler;
struct event_handler_info* paused_handler;
struct timespec poll_start_tm;
struct timespec last_poll_tm;
int polling_interval_ms;
enum polling_update update;
};
/* data required to handle events */
struct event_handler_info {
int data;
void (*handler)(int data, uint32_t events, struct polling_params *poll_params);
};
/* data required to handle socket events */
struct sock_event_handler_info {
int sock;
struct event_handler_info handler_info;
};
/* max supported number of data connections */
#define MAX_DATA_CONN 2
/* socket event handler data */
static struct sock_event_handler_info ctrl_sock;
static struct sock_event_handler_info data_sock[MAX_DATA_CONN];
/* vmpressure event handler data */
static struct event_handler_info vmpressure_hinfo[VMPRESS_LEVEL_COUNT];
/*
* 1 ctrl listen socket, 2 ctrl data socket, 3 memory pressure levels,
* 1 lmk events + 1 fd to wait for process death
*/
#define MAX_EPOLL_EVENTS (1 + MAX_DATA_CONN + VMPRESS_LEVEL_COUNT + 1 + 1)
static int epollfd;
static int maxevents;
/* OOM score values used by both kernel and framework */
#define OOM_SCORE_ADJ_MIN (-1000)
#define OOM_SCORE_ADJ_MAX 1000
static int lowmem_adj[MAX_TARGETS];
static int lowmem_minfree[MAX_TARGETS];
static int lowmem_targets_size;
/* Fields to parse in /proc/zoneinfo */
/* zoneinfo per-zone fields */
enum zoneinfo_zone_field {
ZI_ZONE_NR_FREE_PAGES = 0,
ZI_ZONE_MIN,
ZI_ZONE_LOW,
ZI_ZONE_HIGH,
ZI_ZONE_PRESENT,
ZI_ZONE_NR_FREE_CMA,
ZI_ZONE_FIELD_COUNT
};
static const char* const zoneinfo_zone_field_names[ZI_ZONE_FIELD_COUNT] = {
"nr_free_pages",
"min",
"low",
"high",
"present",
"nr_free_cma",
};
/* zoneinfo per-zone special fields */
enum zoneinfo_zone_spec_field {
ZI_ZONE_SPEC_PROTECTION = 0,
ZI_ZONE_SPEC_PAGESETS,
ZI_ZONE_SPEC_FIELD_COUNT,
};
static const char* const zoneinfo_zone_spec_field_names[ZI_ZONE_SPEC_FIELD_COUNT] = {
"protection:",
"pagesets",
};
/* see __MAX_NR_ZONES definition in kernel mmzone.h */
#define MAX_NR_ZONES 6
union zoneinfo_zone_fields {
struct {
int64_t nr_free_pages;
int64_t min;
int64_t low;
int64_t high;
int64_t present;
int64_t nr_free_cma;
} field;
int64_t arr[ZI_ZONE_FIELD_COUNT];
};
struct zoneinfo_zone {
union zoneinfo_zone_fields fields;
int64_t protection[MAX_NR_ZONES];
int64_t max_protection;
};
/* zoneinfo per-node fields */
enum zoneinfo_node_field {
ZI_NODE_NR_INACTIVE_FILE = 0,
ZI_NODE_NR_ACTIVE_FILE,
ZI_NODE_WORKINGSET_REFAULT,
ZI_NODE_FIELD_COUNT
};
static const char* const zoneinfo_node_field_names[ZI_NODE_FIELD_COUNT] = {
"nr_inactive_file",
"nr_active_file",
"workingset_refault",
};
union zoneinfo_node_fields {
struct {
int64_t nr_inactive_file;
int64_t nr_active_file;
int64_t workingset_refault;
} field;
int64_t arr[ZI_NODE_FIELD_COUNT];
};
struct zoneinfo_node {
int id;
int zone_count;
struct zoneinfo_zone zones[MAX_NR_ZONES];
union zoneinfo_node_fields fields;
};
/* for now two memory nodes is more than enough */
#define MAX_NR_NODES 2
struct zoneinfo {
int node_count;
struct zoneinfo_node nodes[MAX_NR_NODES];
int64_t totalreserve_pages;
int64_t total_inactive_file;
int64_t total_active_file;
int64_t total_workingset_refault;
};
/* Fields to parse in /proc/meminfo */
enum meminfo_field {
MI_NR_FREE_PAGES = 0,
MI_CACHED,
MI_SWAP_CACHED,
MI_BUFFERS,
MI_SHMEM,
MI_UNEVICTABLE,
MI_TOTAL_SWAP,
MI_FREE_SWAP,
MI_ACTIVE_ANON,
MI_INACTIVE_ANON,
MI_ACTIVE_FILE,
MI_INACTIVE_FILE,
MI_SRECLAIMABLE,
MI_SUNRECLAIM,
MI_KERNEL_STACK,
MI_PAGE_TABLES,
MI_ION_HELP,
MI_ION_HELP_POOL,
MI_CMA_FREE,
MI_FIELD_COUNT
};
static const char* const meminfo_field_names[MI_FIELD_COUNT] = {
"MemFree:",
"Cached:",
"SwapCached:",
"Buffers:",
"Shmem:",
"Unevictable:",
"SwapTotal:",
"SwapFree:",
"Active(anon):",
"Inactive(anon):",
"Active(file):",
"Inactive(file):",
"SReclaimable:",
"SUnreclaim:",
"KernelStack:",
"PageTables:",
"ION_heap:",
"ION_heap_pool:",
"CmaFree:",
};
union meminfo {
struct {
int64_t nr_free_pages;
int64_t cached;
int64_t swap_cached;
int64_t buffers;
int64_t shmem;
int64_t unevictable;
int64_t total_swap;
int64_t free_swap;
int64_t active_anon;
int64_t inactive_anon;
int64_t active_file;
int64_t inactive_file;
int64_t sreclaimable;
int64_t sunreclaimable;
int64_t kernel_stack;
int64_t page_tables;
int64_t ion_heap;
int64_t ion_heap_pool;
int64_t cma_free;
/* fields below are calculated rather than read from the file */
int64_t nr_file_pages;
} field;
int64_t arr[MI_FIELD_COUNT];
};
/* Fields to parse in /proc/vmstat */
enum vmstat_field {
VS_FREE_PAGES,
VS_INACTIVE_FILE,
VS_ACTIVE_FILE,
VS_WORKINGSET_REFAULT,
VS_PGSCAN_KSWAPD,
VS_PGSCAN_DIRECT,
VS_PGSCAN_DIRECT_THROTTLE,
VS_FIELD_COUNT
};
static const char* const vmstat_field_names[MI_FIELD_COUNT] = {
"nr_free_pages",
"nr_inactive_file",
"nr_active_file",
"workingset_refault",
"pgscan_kswapd",
"pgscan_direct",
"pgscan_direct_throttle",
};
union vmstat {
struct {
int64_t nr_free_pages;
int64_t nr_inactive_file;
int64_t nr_active_file;
int64_t workingset_refault;
int64_t pgscan_kswapd;
int64_t pgscan_direct;
int64_t pgscan_direct_throttle;
} field;
int64_t arr[VS_FIELD_COUNT];
};
enum field_match_result {
NO_MATCH,
PARSE_FAIL,
PARSE_SUCCESS
};
struct adjslot_list {
struct adjslot_list *next;
struct adjslot_list *prev;
};
struct proc {
struct adjslot_list asl;
int pid;
int pidfd;
uid_t uid;
int oomadj;
struct proc *pidhash_next;
};
struct reread_data {
const char* const filename;
int fd;
};
#define PIDHASH_SZ 1024
static struct proc *pidhash[PIDHASH_SZ];
#define pid_hashfn(x) ((((x) >> 8) ^ (x)) & (PIDHASH_SZ - 1))
#define ADJTOSLOT(adj) ((adj) + -OOM_SCORE_ADJ_MIN)
#define ADJTOSLOT_COUNT (ADJTOSLOT(OOM_SCORE_ADJ_MAX) + 1)
static struct adjslot_list procadjslot_list[ADJTOSLOT_COUNT];
#define MAX_DISTINCT_OOM_ADJ 32
#define KILLCNT_INVALID_IDX 0xFF
/*
* Because killcnt array is sparse a two-level indirection is used
* to keep the size small. killcnt_idx stores index of the element in
* killcnt array. Index KILLCNT_INVALID_IDX indicates an unused slot.
*/
static uint8_t killcnt_idx[ADJTOSLOT_COUNT];
static uint16_t killcnt[MAX_DISTINCT_OOM_ADJ];
static int killcnt_free_idx = 0;
static uint32_t killcnt_total = 0;
/* PAGE_SIZE / 1024 */
static long page_k;
static int clamp(int low, int high, int value) {
return max(min(value, high), low);
}
static bool parse_int64(const char* str, int64_t* ret) {
char* endptr;
long long val = strtoll(str, &endptr, 10);
if (str == endptr || val > INT64_MAX) {
return false;
}
*ret = (int64_t)val;
return true;
}
static int find_field(const char* name, const char* const field_names[], int field_count) {
for (int i = 0; i < field_count; i++) {
if (!strcmp(name, field_names[i])) {
return i;
}
}
return -1;
}
static enum field_match_result match_field(const char* cp, const char* ap,
const char* const field_names[],
int field_count, int64_t* field,
int *field_idx) {
int i = find_field(cp, field_names, field_count);
if (i < 0) {
return NO_MATCH;
}
*field_idx = i;
return parse_int64(ap, field) ? PARSE_SUCCESS : PARSE_FAIL;
}
/*
* Read file content from the beginning up to max_len bytes or EOF
* whichever happens first.
*/
static ssize_t read_all(int fd, char *buf, size_t max_len)
{
ssize_t ret = 0;
off_t offset = 0;
while (max_len > 0) {
ssize_t r = TEMP_FAILURE_RETRY(pread(fd, buf, max_len, offset));
if (r == 0) {
break;
}
if (r == -1) {
return -1;
}
ret += r;
buf += r;
offset += r;
max_len -= r;
}
return ret;
}
/*
* Read a new or already opened file from the beginning.
* If the file has not been opened yet data->fd should be set to -1.
* To be used with files which are read often and possibly during high
* memory pressure to minimize file opening which by itself requires kernel
* memory allocation and might result in a stall on memory stressed system.
*/
static char *reread_file(struct reread_data *data) {
/* start with page-size buffer and increase if needed */
static ssize_t buf_size = PAGE_SIZE;
static char *new_buf, *buf = NULL;
ssize_t size;
if (data->fd == -1) {
/* First-time buffer initialization */
if (!buf && (buf = malloc(buf_size)) == NULL) {
return NULL;
}
data->fd = TEMP_FAILURE_RETRY(open(data->filename, O_RDONLY | O_CLOEXEC));
if (data->fd < 0) {
ALOGE("%s open: %s", data->filename, strerror(errno));
return NULL;
}
}
while (true) {
size = read_all(data->fd, buf, buf_size - 1);
if (size < 0) {
ALOGE("%s read: %s", data->filename, strerror(errno));
close(data->fd);
data->fd = -1;
return NULL;
}
if (size < buf_size - 1) {
break;
}
/*
* Since we are reading /proc files we can't use fstat to find out
* the real size of the file. Double the buffer size and keep retrying.
*/
if ((new_buf = realloc(buf, buf_size * 2)) == NULL) {
errno = ENOMEM;
return NULL;
}
buf = new_buf;
buf_size *= 2;
}
buf[size] = 0;
return buf;
}
static struct proc *pid_lookup(int pid) {
struct proc *procp;
for (procp = pidhash[pid_hashfn(pid)]; procp && procp->pid != pid;
procp = procp->pidhash_next)
;
return procp;
}
static void adjslot_insert(struct adjslot_list *head, struct adjslot_list *new)
{
struct adjslot_list *next = head->next;
new->prev = head;
new->next = next;
next->prev = new;
head->next = new;
}
static void adjslot_remove(struct adjslot_list *old)
{
struct adjslot_list *prev = old->prev;
struct adjslot_list *next = old->next;
next->prev = prev;
prev->next = next;
}
static struct adjslot_list *adjslot_tail(struct adjslot_list *head) {
struct adjslot_list *asl = head->prev;
return asl == head ? NULL : asl;
}
static void proc_slot(struct proc *procp) {
int adjslot = ADJTOSLOT(procp->oomadj);
adjslot_insert(&procadjslot_list[adjslot], &procp->asl);
}
static void proc_unslot(struct proc *procp) {
adjslot_remove(&procp->asl);
}
static void proc_insert(struct proc *procp) {
int hval = pid_hashfn(procp->pid);
procp->pidhash_next = pidhash[hval];
pidhash[hval] = procp;
proc_slot(procp);
}
static int pid_remove(int pid) {
int hval = pid_hashfn(pid);
struct proc *procp;
struct proc *prevp;
for (procp = pidhash[hval], prevp = NULL; procp && procp->pid != pid;
procp = procp->pidhash_next)
prevp = procp;
if (!procp)
return -1;
if (!prevp)
pidhash[hval] = procp->pidhash_next;
else
prevp->pidhash_next = procp->pidhash_next;
proc_unslot(procp);
/*
* Close pidfd here if we are not waiting for corresponding process to die,
* in which case stop_wait_for_proc_kill() will close the pidfd later
*/
if (procp->pidfd >= 0 && procp->pidfd != last_kill_pid_or_fd) {
close(procp->pidfd);
}
free(procp);
return 0;
}
/*
* Write a string to a file.
* Returns false if the file does not exist.
*/
static bool writefilestring(const char *path, const char *s,
bool err_if_missing) {
int fd = open(path, O_WRONLY | O_CLOEXEC);
ssize_t len = strlen(s);
ssize_t ret;
if (fd < 0) {
if (err_if_missing) {
ALOGE("Error opening %s; errno=%d", path, errno);
}
return false;
}
ret = TEMP_FAILURE_RETRY(write(fd, s, len));
if (ret < 0) {
ALOGE("Error writing %s; errno=%d", path, errno);
} else if (ret < len) {
ALOGE("Short write on %s; length=%zd", path, ret);
}
close(fd);
return true;
}
static inline long get_time_diff_ms(struct timespec *from,
struct timespec *to) {
return (to->tv_sec - from->tv_sec) * (long)MS_PER_SEC +
(to->tv_nsec - from->tv_nsec) / (long)NS_PER_MS;
}
static int proc_get_tgid(int pid) {
char path[PATH_MAX];
char buf[PAGE_SIZE];
int fd;
ssize_t size;
char *pos;
int64_t tgid = -1;
snprintf(path, PATH_MAX, "/proc/%d/status", pid);
fd = open(path, O_RDONLY | O_CLOEXEC);
if (fd < 0) {
return -1;
}
size = read_all(fd, buf, sizeof(buf) - 1);
if (size < 0) {
goto out;
}
buf[size] = 0;
pos = buf;
while (true) {
pos = strstr(pos, PROC_STATUS_TGID_FIELD);
/* Stop if TGID tag not found or found at the line beginning */
if (pos == NULL || pos == buf || pos[-1] == '\n') {
break;
}
pos++;
}
if (pos == NULL) {
goto out;
}
pos += strlen(PROC_STATUS_TGID_FIELD);
while (*pos == ' ') pos++;
parse_int64(pos, &tgid);
out:
close(fd);
return (int)tgid;
}
static int proc_get_size(int pid) {
char path[PATH_MAX];
char line[LINE_MAX];
int fd;
int rss = 0;
int total;
ssize_t ret;
/* gid containing AID_READPROC required */
snprintf(path, PATH_MAX, "/proc/%d/statm", pid);
fd = open(path, O_RDONLY | O_CLOEXEC);
if (fd == -1)
return -1;
ret = read_all(fd, line, sizeof(line) - 1);
if (ret < 0) {
close(fd);
return -1;
}
line[ret] = '\0';
sscanf(line, "%d %d ", &total, &rss);
close(fd);
return rss;
}
static char *proc_get_name(int pid, char *buf, size_t buf_size) {
char path[PATH_MAX];
int fd;
char *cp;
ssize_t ret;
/* gid containing AID_READPROC required */
snprintf(path, PATH_MAX, "/proc/%d/cmdline", pid);
fd = open(path, O_RDONLY | O_CLOEXEC);
if (fd == -1) {
return NULL;
}
ret = read_all(fd, buf, buf_size - 1);
close(fd);
if (ret < 0) {
return NULL;
}
buf[ret] = '\0';
cp = strchr(buf, ' ');
if (cp) {
*cp = '\0';
}
return buf;
}
static void cmd_procprio(LMKD_CTRL_PACKET packet) {
struct proc *procp;
char path[LINE_MAX];
char val[20];
int soft_limit_mult;
struct lmk_procprio params;
bool is_system_server;
struct passwd *pwdrec;
int tgid;
lmkd_pack_get_procprio(packet, &params);
if (params.oomadj < OOM_SCORE_ADJ_MIN ||
params.oomadj > OOM_SCORE_ADJ_MAX) {
ALOGE("Invalid PROCPRIO oomadj argument %d", params.oomadj);
return;
}
/* Check if registered process is a thread group leader */
tgid = proc_get_tgid(params.pid);
if (tgid >= 0 && tgid != params.pid) {
ALOGE("Attempt to register a task that is not a thread group leader (tid %d, tgid %d)",
params.pid, tgid);
return;
}
/* gid containing AID_READPROC required */
/* CAP_SYS_RESOURCE required */
/* CAP_DAC_OVERRIDE required */
snprintf(path, sizeof(path), "/proc/%d/oom_score_adj", params.pid);
snprintf(val, sizeof(val), "%d", params.oomadj);
if (!writefilestring(path, val, false)) {
ALOGW("Failed to open %s; errno=%d: process %d might have been killed",
path, errno, params.pid);
/* If this file does not exist the process is dead. */
return;
}
if (use_inkernel_interface) {
stats_store_taskname(params.pid, proc_get_name(params.pid, path, sizeof(path)),
kpoll_info.poll_fd);
return;
}
if (per_app_memcg) {
if (params.oomadj >= 900) {
soft_limit_mult = 0;
} else if (params.oomadj >= 800) {
soft_limit_mult = 0;
} else if (params.oomadj >= 700) {
soft_limit_mult = 0;
} else if (params.oomadj >= 600) {
// Launcher should be perceptible, don't kill it.
params.oomadj = 200;
soft_limit_mult = 1;
} else if (params.oomadj >= 500) {
soft_limit_mult = 0;
} else if (params.oomadj >= 400) {
soft_limit_mult = 0;
} else if (params.oomadj >= 300) {
soft_limit_mult = 1;
} else if (params.oomadj >= 200) {
soft_limit_mult = 8;
} else if (params.oomadj >= 100) {
soft_limit_mult = 10;
} else if (params.oomadj >= 0) {
soft_limit_mult = 20;
} else {
// Persistent processes will have a large
// soft limit 512MB.
soft_limit_mult = 64;
}
snprintf(path, sizeof(path), MEMCG_SYSFS_PATH
"apps/uid_%d/pid_%d/memory.soft_limit_in_bytes",
params.uid, params.pid);
snprintf(val, sizeof(val), "%d", soft_limit_mult * EIGHT_MEGA);
/*
* system_server process has no memcg under /dev/memcg/apps but should be
* registered with lmkd. This is the best way so far to identify it.
*/
is_system_server = (params.oomadj == SYSTEM_ADJ &&
(pwdrec = getpwnam("system")) != NULL &&
params.uid == pwdrec->pw_uid);
writefilestring(path, val, !is_system_server);
}
procp = pid_lookup(params.pid);
if (!procp) {
int pidfd = -1;
if (pidfd_supported) {
pidfd = TEMP_FAILURE_RETRY(sys_pidfd_open(params.pid, 0));
if (pidfd < 0) {
ALOGE("pidfd_open for pid %d failed; errno=%d", params.pid, errno);
return;
}
}
procp = calloc(1, sizeof(struct proc));
if (!procp) {
// Oh, the irony. May need to rebuild our state.
return;
}
procp->pid = params.pid;
procp->pidfd = pidfd;
procp->uid = params.uid;
procp->oomadj = params.oomadj;
proc_insert(procp);
} else {
proc_unslot(procp);
procp->oomadj = params.oomadj;
proc_slot(procp);
}
}
static void cmd_procremove(LMKD_CTRL_PACKET packet) {
struct lmk_procremove params;
lmkd_pack_get_procremove(packet, &params);
if (use_inkernel_interface) {
stats_remove_taskname(params.pid, kpoll_info.poll_fd);
return;
}
/*
* WARNING: After pid_remove() procp is freed and can't be used!
* Therefore placed at the end of the function.
*/
pid_remove(params.pid);
}
static void cmd_procpurge() {
int i;
struct proc *procp;
struct proc *next;
if (use_inkernel_interface) {
stats_purge_tasknames();
return;
}
for (i = 0; i <= ADJTOSLOT(OOM_SCORE_ADJ_MAX); i++) {
procadjslot_list[i].next = &procadjslot_list[i];
procadjslot_list[i].prev = &procadjslot_list[i];
}
for (i = 0; i < PIDHASH_SZ; i++) {
procp = pidhash[i];
while (procp) {
next = procp->pidhash_next;
free(procp);
procp = next;
}
}
memset(&pidhash[0], 0, sizeof(pidhash));
}
static void inc_killcnt(int oomadj) {
int slot = ADJTOSLOT(oomadj);
uint8_t idx = killcnt_idx[slot];
if (idx == KILLCNT_INVALID_IDX) {
/* index is not assigned for this oomadj */
if (killcnt_free_idx < MAX_DISTINCT_OOM_ADJ) {
killcnt_idx[slot] = killcnt_free_idx;
killcnt[killcnt_free_idx] = 1;
killcnt_free_idx++;
} else {
ALOGW("Number of distinct oomadj levels exceeds %d",
MAX_DISTINCT_OOM_ADJ);
}
} else {
/*
* wraparound is highly unlikely and is detectable using total
* counter because it has to be equal to the sum of all counters
*/
killcnt[idx]++;
}
/* increment total kill counter */
killcnt_total++;
}
static int get_killcnt(int min_oomadj, int max_oomadj) {
int slot;
int count = 0;
if (min_oomadj > max_oomadj)
return 0;
/* special case to get total kill count */
if (min_oomadj > OOM_SCORE_ADJ_MAX)
return killcnt_total;
while (min_oomadj <= max_oomadj &&
(slot = ADJTOSLOT(min_oomadj)) < ADJTOSLOT_COUNT) {
uint8_t idx = killcnt_idx[slot];
if (idx != KILLCNT_INVALID_IDX) {
count += killcnt[idx];
}
min_oomadj++;
}
return count;
}
static int cmd_getkillcnt(LMKD_CTRL_PACKET packet) {
struct lmk_getkillcnt params;
if (use_inkernel_interface) {
/* kernel driver does not expose this information */
return 0;
}
lmkd_pack_get_getkillcnt(packet, &params);
return get_killcnt(params.min_oomadj, params.max_oomadj);
}
static void cmd_target(int ntargets, LMKD_CTRL_PACKET packet) {
int i;
struct lmk_target target;
char minfree_str[PROPERTY_VALUE_MAX];
char *pstr = minfree_str;
char *pend = minfree_str + sizeof(minfree_str);
static struct timespec last_req_tm;
struct timespec curr_tm;
if (ntargets < 1 || ntargets > (int)ARRAY_SIZE(lowmem_adj))
return;
/*
* Ratelimit minfree updates to once per TARGET_UPDATE_MIN_INTERVAL_MS
* to prevent DoS attacks
*/
if (clock_gettime(CLOCK_MONOTONIC_COARSE, &curr_tm) != 0) {
ALOGE("Failed to get current time");
return;
}
if (get_time_diff_ms(&last_req_tm, &curr_tm) <
TARGET_UPDATE_MIN_INTERVAL_MS) {
ALOGE("Ignoring frequent updated to lmkd limits");
return;
}
last_req_tm = curr_tm;
for (i = 0; i < ntargets; i++) {
lmkd_pack_get_target(packet, i, &target);
lowmem_minfree[i] = target.minfree;
lowmem_adj[i] = target.oom_adj_score;
pstr += snprintf(pstr, pend - pstr, "%d:%d,", target.minfree,
target.oom_adj_score);
if (pstr >= pend) {
/* if no more space in the buffer then terminate the loop */
pstr = pend;
break;
}
}
lowmem_targets_size = ntargets;
/* Override the last extra comma */
pstr[-1] = '\0';
property_set("sys.lmk.minfree_levels", minfree_str);
if (has_inkernel_module) {
char minfreestr[128];
char killpriostr[128];
minfreestr[0] = '\0';
killpriostr[0] = '\0';
for (i = 0; i < lowmem_targets_size; i++) {
char val[40];
if (i) {
strlcat(minfreestr, ",", sizeof(minfreestr));
strlcat(killpriostr, ",", sizeof(killpriostr));
}
snprintf(val, sizeof(val), "%d", use_inkernel_interface ? lowmem_minfree[i] : 0);
strlcat(minfreestr, val, sizeof(minfreestr));
snprintf(val, sizeof(val), "%d", use_inkernel_interface ? lowmem_adj[i] : 0);
strlcat(killpriostr, val, sizeof(killpriostr));
}
writefilestring(INKERNEL_MINFREE_PATH, minfreestr, true);
writefilestring(INKERNEL_ADJ_PATH, killpriostr, true);
}
}
static void ctrl_data_close(int dsock_idx) {
struct epoll_event epev;
ALOGI("closing lmkd data connection");
if (epoll_ctl(epollfd, EPOLL_CTL_DEL, data_sock[dsock_idx].sock, &epev) == -1) {
// Log a warning and keep going
ALOGW("epoll_ctl for data connection socket failed; errno=%d", errno);
}
maxevents--;
close(data_sock[dsock_idx].sock);
data_sock[dsock_idx].sock = -1;
}
static int ctrl_data_read(int dsock_idx, char *buf, size_t bufsz) {
int ret = 0;
ret = TEMP_FAILURE_RETRY(read(data_sock[dsock_idx].sock, buf, bufsz));
if (ret == -1) {
ALOGE("control data socket read failed; errno=%d", errno);
} else if (ret == 0) {
ALOGE("Got EOF on control data socket");
ret = -1;
}
return ret;
}
static int ctrl_data_write(int dsock_idx, char *buf, size_t bufsz) {
int ret = 0;
ret = TEMP_FAILURE_RETRY(write(data_sock[dsock_idx].sock, buf, bufsz));
if (ret == -1) {
ALOGE("control data socket write failed; errno=%d", errno);
} else if (ret == 0) {
ALOGE("Got EOF on control data socket");
ret = -1;
}
return ret;
}
static void ctrl_command_handler(int dsock_idx) {
LMKD_CTRL_PACKET packet;
int len;
enum lmk_cmd cmd;
int nargs;
int targets;
int kill_cnt;
len = ctrl_data_read(dsock_idx, (char *)packet, CTRL_PACKET_MAX_SIZE);
if (len <= 0)
return;
if (len < (int)sizeof(int)) {
ALOGE("Wrong control socket read length len=%d", len);
return;
}
cmd = lmkd_pack_get_cmd(packet);
nargs = len / sizeof(int) - 1;
if (nargs < 0)
goto wronglen;
switch(cmd) {
case LMK_TARGET:
targets = nargs / 2;
if (nargs & 0x1 || targets > (int)ARRAY_SIZE(lowmem_adj))
goto wronglen;
cmd_target(targets, packet);
break;
case LMK_PROCPRIO:
if (nargs != 3)
goto wronglen;
cmd_procprio(packet);
break;
case LMK_PROCREMOVE:
if (nargs != 1)
goto wronglen;
cmd_procremove(packet);
break;
case LMK_PROCPURGE:
if (nargs != 0)
goto wronglen;
cmd_procpurge();
break;
case LMK_GETKILLCNT:
if (nargs != 2)
goto wronglen;
kill_cnt = cmd_getkillcnt(packet);
len = lmkd_pack_set_getkillcnt_repl(packet, kill_cnt);
if (ctrl_data_write(dsock_idx, (char *)packet, len) != len)
return;
break;
default:
ALOGE("Received unknown command code %d", cmd);
return;
}
return;
wronglen:
ALOGE("Wrong control socket read length cmd=%d len=%d", cmd, len);
}
static void ctrl_data_handler(int data, uint32_t events,
struct polling_params *poll_params __unused) {
if (events & EPOLLIN) {
ctrl_command_handler(data);
}
}
static int get_free_dsock() {
for (int i = 0; i < MAX_DATA_CONN; i++) {
if (data_sock[i].sock < 0) {
return i;
}
}
return -1;
}
static void ctrl_connect_handler(int data __unused, uint32_t events __unused,
struct polling_params *poll_params __unused) {
struct epoll_event epev;
int free_dscock_idx = get_free_dsock();
if (free_dscock_idx < 0) {
/*
* Number of data connections exceeded max supported. This should not
* happen but if it does we drop all existing connections and accept
* the new one. This prevents inactive connections from monopolizing
* data socket and if we drop ActivityManager connection it will
* immediately reconnect.
*/
for (int i = 0; i < MAX_DATA_CONN; i++) {
ctrl_data_close(i);
}
free_dscock_idx = 0;
}
data_sock[free_dscock_idx].sock = accept(ctrl_sock.sock, NULL, NULL);
if (data_sock[free_dscock_idx].sock < 0) {
ALOGE("lmkd control socket accept failed; errno=%d", errno);
return;
}
ALOGI("lmkd data connection established");
/* use data to store data connection idx */
data_sock[free_dscock_idx].handler_info.data = free_dscock_idx;
data_sock[free_dscock_idx].handler_info.handler = ctrl_data_handler;
epev.events = EPOLLIN;
epev.data.ptr = (void *)&(data_sock[free_dscock_idx].handler_info);
if (epoll_ctl(epollfd, EPOLL_CTL_ADD, data_sock[free_dscock_idx].sock, &epev) == -1) {
ALOGE("epoll_ctl for data connection socket failed; errno=%d", errno);
ctrl_data_close(free_dscock_idx);
return;
}
maxevents++;
}
/*
* /proc/zoneinfo parsing routines
* Expected file format is:
*
* Node <node_id>, zone <zone_name>
* (
* per-node stats
* (<per-node field name> <value>)+
* )?
* (pages free <value>
* (<per-zone field name> <value>)+
* pagesets
* (<unused fields>)*
* )+
* ...
*/
static void zoneinfo_parse_protection(char *buf, struct zoneinfo_zone *zone) {
int zone_idx;
int64_t max = 0;
char *save_ptr;
for (buf = strtok_r(buf, "(), ", &save_ptr), zone_idx = 0;
buf && zone_idx < MAX_NR_ZONES;
buf = strtok_r(NULL, "), ", &save_ptr), zone_idx++) {
long long zoneval = strtoll(buf, &buf, 0);
if (zoneval > max) {
max = (zoneval > INT64_MAX) ? INT64_MAX : zoneval;
}
zone->protection[zone_idx] = zoneval;
}
zone->max_protection = max;
}
static int zoneinfo_parse_zone(char **buf, struct zoneinfo_zone *zone) {
for (char *line = strtok_r(NULL, "\n", buf); line;
line = strtok_r(NULL, "\n", buf)) {
char *cp;
char *ap;
char *save_ptr;
int64_t val;
int field_idx;
enum field_match_result match_res;
cp = strtok_r(line, " ", &save_ptr);
if (!cp) {
return false;
}
field_idx = find_field(cp, zoneinfo_zone_spec_field_names, ZI_ZONE_SPEC_FIELD_COUNT);
if (field_idx >= 0) {
/* special field */
if (field_idx == ZI_ZONE_SPEC_PAGESETS) {
/* no mode fields we are interested in */
return true;
}
/* protection field */
ap = strtok_r(NULL, ")", &save_ptr);
if (ap) {
zoneinfo_parse_protection(ap, zone);
}
continue;
}
ap = strtok_r(NULL, " ", &save_ptr);
if (!ap) {
continue;
}
match_res = match_field(cp, ap, zoneinfo_zone_field_names, ZI_ZONE_FIELD_COUNT,
&val, &field_idx);
if (match_res == PARSE_FAIL) {
return false;
}
if (match_res == PARSE_SUCCESS) {
zone->fields.arr[field_idx] = val;
}
if (field_idx == ZI_ZONE_PRESENT && val == 0) {
/* zone is not populated, stop parsing it */
return true;
}
}
return false;
}
static int zoneinfo_parse_node(char **buf, struct zoneinfo_node *node) {
int fields_to_match = ZI_NODE_FIELD_COUNT;
for (char *line = strtok_r(NULL, "\n", buf); line;
line = strtok_r(NULL, "\n", buf)) {
char *cp;
char *ap;
char *save_ptr;
int64_t val;
int field_idx;
enum field_match_result match_res;
cp = strtok_r(line, " ", &save_ptr);
if (!cp) {
return false;
}
ap = strtok_r(NULL, " ", &save_ptr);
if (!ap) {
return false;
}
match_res = match_field(cp, ap, zoneinfo_node_field_names, ZI_NODE_FIELD_COUNT,
&val, &field_idx);
if (match_res == PARSE_FAIL) {
return false;
}
if (match_res == PARSE_SUCCESS) {
node->fields.arr[field_idx] = val;
fields_to_match--;
if (!fields_to_match) {
return true;
}
}
}
return false;
}
static int zoneinfo_parse(struct zoneinfo *zi) {
static struct reread_data file_data = {
.filename = ZONEINFO_PATH,
.fd = -1,
};
char *buf;
char *save_ptr;
char *line;
char zone_name[LINE_MAX + 1];
struct zoneinfo_node *node = NULL;
int node_idx = 0;
int zone_idx = 0;
memset(zi, 0, sizeof(struct zoneinfo));
if ((buf = reread_file(&file_data)) == NULL) {
return -1;
}
for (line = strtok_r(buf, "\n", &save_ptr); line;
line = strtok_r(NULL, "\n", &save_ptr)) {
int node_id;
if (sscanf(line, "Node %d, zone %" STRINGIFY(LINE_MAX) "s", &node_id, zone_name) == 2) {
if (!node || node->id != node_id) {
/* new node is found */
if (node) {
node->zone_count = zone_idx + 1;
node_idx++;
if (node_idx == MAX_NR_NODES) {
/* max node count exceeded */
ALOGE("%s parse error", file_data.filename);
return -1;
}
}
node = &zi->nodes[node_idx];
node->id = node_id;
zone_idx = 0;
if (!zoneinfo_parse_node(&save_ptr, node)) {
ALOGE("%s parse error", file_data.filename);
return -1;
}
} else {
/* new zone is found */
zone_idx++;
}
if (!zoneinfo_parse_zone(&save_ptr, &node->zones[zone_idx])) {
ALOGE("%s parse error", file_data.filename);
return -1;
}
}
}
if (!node) {
ALOGE("%s parse error", file_data.filename);
return -1;
}
node->zone_count = zone_idx + 1;
zi->node_count = node_idx + 1;
/* calculate totals fields */
for (node_idx = 0; node_idx < zi->node_count; node_idx++) {
node = &zi->nodes[node_idx];
for (zone_idx = 0; zone_idx < node->zone_count; zone_idx++) {
struct zoneinfo_zone *zone = &zi->nodes[node_idx].zones[zone_idx];
zi->totalreserve_pages += zone->max_protection + zone->fields.field.high;
}
zi->total_inactive_file += node->fields.field.nr_inactive_file;
zi->total_active_file += node->fields.field.nr_active_file;
zi->total_workingset_refault += node->fields.field.workingset_refault;
}
return 0;
}
/* /proc/meminfo parsing routines */
static bool meminfo_parse_line(char *line, union meminfo *mi) {
char *cp = line;
char *ap;
char *save_ptr;
int64_t val;
int field_idx;
enum field_match_result match_res;
cp = strtok_r(line, " ", &save_ptr);
if (!cp) {
return false;
}
ap = strtok_r(NULL, " ", &save_ptr);
if (!ap) {
return false;
}
match_res = match_field(cp, ap, meminfo_field_names, MI_FIELD_COUNT,
&val, &field_idx);
if (match_res == PARSE_SUCCESS) {
mi->arr[field_idx] = val / page_k;
}
return (match_res != PARSE_FAIL);
}
static int meminfo_parse(union meminfo *mi) {
static struct reread_data file_data = {
.filename = MEMINFO_PATH,
.fd = -1,
};
char *buf;
char *save_ptr;
char *line;
memset(mi, 0, sizeof(union meminfo));
if ((buf = reread_file(&file_data)) == NULL) {
return -1;
}
for (line = strtok_r(buf, "\n", &save_ptr); line;
line = strtok_r(NULL, "\n", &save_ptr)) {
if (!meminfo_parse_line(line, mi)) {
ALOGE("%s parse error", file_data.filename);
return -1;
}
}
mi->field.nr_file_pages = mi->field.cached + mi->field.swap_cached +
mi->field.buffers;
return 0;
}
/* /proc/vmstat parsing routines */
static bool vmstat_parse_line(char *line, union vmstat *vs) {
char *cp;
char *ap;
char *save_ptr;
int64_t val;
int field_idx;
enum field_match_result match_res;
cp = strtok_r(line, " ", &save_ptr);
if (!cp) {
return false;
}
ap = strtok_r(NULL, " ", &save_ptr);
if (!ap) {
return false;
}
match_res = match_field(cp, ap, vmstat_field_names, VS_FIELD_COUNT,
&val, &field_idx);
if (match_res == PARSE_SUCCESS) {
vs->arr[field_idx] = val;
}
return (match_res != PARSE_FAIL);
}
static int vmstat_parse(union vmstat *vs) {
static struct reread_data file_data = {
.filename = VMSTAT_PATH,
.fd = -1,
};
char *buf;
char *save_ptr;
char *line;
memset(vs, 0, sizeof(union vmstat));
if ((buf = reread_file(&file_data)) == NULL) {
return -1;
}
for (line = strtok_r(buf, "\n", &save_ptr); line;
line = strtok_r(NULL, "\n", &save_ptr)) {
if (!vmstat_parse_line(line, vs)) {
ALOGE("%s parse error", file_data.filename);
return -1;
}
}
return 0;
}
static void killinfo_log(struct proc* procp, int min_oom_score, int tasksize,
int kill_reason, union meminfo *mi) {
/* log process information */
android_log_write_int32(ctx, procp->pid);
android_log_write_int32(ctx, procp->uid);
android_log_write_int32(ctx, procp->oomadj);
android_log_write_int32(ctx, min_oom_score);
android_log_write_int32(ctx, (int32_t)min(tasksize * page_k, INT32_MAX));
android_log_write_int32(ctx, kill_reason);
/* log meminfo fields */
for (int field_idx = 0; field_idx < MI_FIELD_COUNT; field_idx++) {
android_log_write_int32(ctx, (int32_t)min(mi->arr[field_idx] * page_k, INT32_MAX));
}
android_log_write_list(ctx, LOG_ID_EVENTS);
android_log_reset(ctx);
}
static struct proc *proc_adj_lru(int oomadj) {
return (struct proc *)adjslot_tail(&procadjslot_list[ADJTOSLOT(oomadj)]);
}
static struct proc *proc_get_heaviest(int oomadj) {
struct adjslot_list *head = &procadjslot_list[ADJTOSLOT(oomadj)];
struct adjslot_list *curr = head->next;
struct proc *maxprocp = NULL;
int maxsize = 0;
while (curr != head) {
int pid = ((struct proc *)curr)->pid;
int tasksize = proc_get_size(pid);
if (tasksize <= 0) {
struct adjslot_list *next = curr->next;
pid_remove(pid);
curr = next;
} else {
if (tasksize > maxsize) {
maxsize = tasksize;
maxprocp = (struct proc *)curr;
}
curr = curr->next;
}
}
return maxprocp;
}
static void set_process_group_and_prio(int pid, SchedPolicy sp, int prio) {
DIR* d;
char proc_path[PATH_MAX];
struct dirent* de;
snprintf(proc_path, sizeof(proc_path), "/proc/%d/task", pid);
if (!(d = opendir(proc_path))) {
ALOGW("Failed to open %s; errno=%d: process pid(%d) might have died", proc_path, errno,
pid);
return;
}
while ((de = readdir(d))) {
int t_pid;
if (de->d_name[0] == '.') continue;
t_pid = atoi(de->d_name);
if (!t_pid) {
ALOGW("Failed to get t_pid for '%s' of pid(%d)", de->d_name, pid);
continue;
}
if (setpriority(PRIO_PROCESS, t_pid, prio) && errno != ESRCH) {
ALOGW("Unable to raise priority of killing t_pid (%d): errno=%d", t_pid, errno);
}
if (set_cpuset_policy(t_pid, sp)) {
ALOGW("Failed to set_cpuset_policy on pid(%d) t_pid(%d) to %d", pid, t_pid, (int)sp);
continue;
}
}
closedir(d);
}
static bool is_kill_pending(void) {
char buf[24];
if (last_kill_pid_or_fd < 0) {
return false;
}
if (pidfd_supported) {
return true;
}
/* when pidfd is not supported base the decision on /proc/<pid> existence */
snprintf(buf, sizeof(buf), "/proc/%d/", last_kill_pid_or_fd);
if (access(buf, F_OK) == 0) {
return true;
}
return false;
}
static bool is_waiting_for_kill(void) {
return pidfd_supported && last_kill_pid_or_fd >= 0;
}
static void stop_wait_for_proc_kill(bool finished) {
struct epoll_event epev;
if (last_kill_pid_or_fd < 0) {
return;
}
if (debug_process_killing) {
struct timespec curr_tm;
if (clock_gettime(CLOCK_MONOTONIC_COARSE, &curr_tm) != 0) {
/*
* curr_tm is used here merely to report kill duration, so this failure is not fatal.
* Log an error and continue.
*/
ALOGE("Failed to get current time");
}
if (finished) {
ALOGI("Process got killed in %ldms",
get_time_diff_ms(&last_kill_tm, &curr_tm));
} else {
ALOGI("Stop waiting for process kill after %ldms",
get_time_diff_ms(&last_kill_tm, &curr_tm));
}
}
if (pidfd_supported) {
/* unregister fd */
if (epoll_ctl(epollfd, EPOLL_CTL_DEL, last_kill_pid_or_fd, &epev) != 0) {
ALOGE("epoll_ctl for last killed process failed; errno=%d", errno);
return;
}
maxevents--;
close(last_kill_pid_or_fd);
}
last_kill_pid_or_fd = -1;
}
static void kill_done_handler(int data __unused, uint32_t events __unused,
struct polling_params *poll_params) {
stop_wait_for_proc_kill(true);
poll_params->update = POLLING_RESUME;
}
static void start_wait_for_proc_kill(int pid_or_fd) {
static struct event_handler_info kill_done_hinfo = { 0, kill_done_handler };
struct epoll_event epev;
if (last_kill_pid_or_fd >= 0) {
/* Should not happen but if it does we should stop previous wait */
ALOGE("Attempt to wait for a kill while another wait is in progress");
stop_wait_for_proc_kill(false);
}
last_kill_pid_or_fd = pid_or_fd;
if (!pidfd_supported) {
/* If pidfd is not supported just store PID and exit */
return;
}
epev.events = EPOLLIN;
epev.data.ptr = (void *)&kill_done_hinfo;
if (epoll_ctl(epollfd, EPOLL_CTL_ADD, last_kill_pid_or_fd, &epev) != 0) {
ALOGE("epoll_ctl for last kill failed; errno=%d", errno);
close(last_kill_pid_or_fd);
last_kill_pid_or_fd = -1;
return;
}
maxevents++;
}
/* Kill one process specified by procp. Returns the size of the process killed */
static int kill_one_process(struct proc* procp, int min_oom_score, int kill_reason,
const char *kill_desc, union meminfo *mi, struct timespec *tm) {
int pid = procp->pid;
int pidfd = procp->pidfd;
uid_t uid = procp->uid;
int tgid;
char *taskname;
int tasksize;
int r;
int result = -1;
struct memory_stat *mem_st;
char buf[LINE_MAX];
tgid = proc_get_tgid(pid);
if (tgid >= 0 && tgid != pid) {
ALOGE("Possible pid reuse detected (pid %d, tgid %d)!", pid, tgid);
goto out;
}
taskname = proc_get_name(pid, buf, sizeof(buf));
if (!taskname) {
goto out;
}
tasksize = proc_get_size(pid);
if (tasksize <= 0) {
goto out;
}
mem_st = stats_read_memory_stat(per_app_memcg, pid, uid);
TRACE_KILL_START(pid);
/* CAP_KILL required */
if (pidfd < 0) {
start_wait_for_proc_kill(pid);
r = kill(pid, SIGKILL);
} else {
start_wait_for_proc_kill(pidfd);
r = sys_pidfd_send_signal(pidfd, SIGKILL, NULL, 0);
}
TRACE_KILL_END();
if (r) {
stop_wait_for_proc_kill(false);
ALOGE("kill(%d): errno=%d", pid, errno);
/* Delete process record even when we fail to kill so that we don't get stuck on it */
goto out;
}
set_process_group_and_prio(pid, SP_FOREGROUND, ANDROID_PRIORITY_HIGHEST);
last_kill_tm = *tm;
inc_killcnt(procp->oomadj);
killinfo_log(procp, min_oom_score, tasksize, kill_reason, mi);
if (kill_desc) {
ALOGI("Kill '%s' (%d), uid %d, oom_adj %d to free %ldkB; reason: %s", taskname, pid,
uid, procp->oomadj, tasksize * page_k, kill_desc);
} else {
ALOGI("Kill '%s' (%d), uid %d, oom_adj %d to free %ldkB", taskname, pid,
uid, procp->oomadj, tasksize * page_k);
}
stats_write_lmk_kill_occurred(LMK_KILL_OCCURRED, uid, taskname,
procp->oomadj, min_oom_score, tasksize, mem_st);
result = tasksize;
out:
/*
* WARNING: After pid_remove() procp is freed and can't be used!
* Therefore placed at the end of the function.
*/
pid_remove(pid);
return result;
}
/*
* Find one process to kill at or above the given oom_adj level.
* Returns size of the killed process.
*/
static int find_and_kill_process(int min_score_adj, int kill_reason, const char *kill_desc,
union meminfo *mi, struct timespec *tm) {
int i;
int killed_size = 0;
bool lmk_state_change_start = false;
for (i = OOM_SCORE_ADJ_MAX; i >= min_score_adj; i--) {
struct proc *procp;
while (true) {
procp = kill_heaviest_task ?
proc_get_heaviest(i) : proc_adj_lru(i);
if (!procp)
break;
killed_size = kill_one_process(procp, min_score_adj, kill_reason, kill_desc, mi, tm);
if (killed_size >= 0) {
if (!lmk_state_change_start) {
lmk_state_change_start = true;
stats_write_lmk_state_changed(LMK_STATE_CHANGED,
LMK_STATE_CHANGE_START);
}
break;
}
}
if (killed_size) {
break;
}
}
if (lmk_state_change_start) {
stats_write_lmk_state_changed(LMK_STATE_CHANGED, LMK_STATE_CHANGE_STOP);
}
return killed_size;
}
static int64_t get_memory_usage(struct reread_data *file_data) {
int ret;
int64_t mem_usage;
char *buf;
if ((buf = reread_file(file_data)) == NULL) {
return -1;
}
if (!parse_int64(buf, &mem_usage)) {
ALOGE("%s parse error", file_data->filename);
return -1;
}
if (mem_usage == 0) {
ALOGE("No memory!");
return -1;
}
return mem_usage;
}
void record_low_pressure_levels(union meminfo *mi) {
if (low_pressure_mem.min_nr_free_pages == -1 ||
low_pressure_mem.min_nr_free_pages > mi->field.nr_free_pages) {
if (debug_process_killing) {
ALOGI("Low pressure min memory update from %" PRId64 " to %" PRId64,
low_pressure_mem.min_nr_free_pages, mi->field.nr_free_pages);
}
low_pressure_mem.min_nr_free_pages = mi->field.nr_free_pages;
}
/*
* Free memory at low vmpressure events occasionally gets spikes,
* possibly a stale low vmpressure event with memory already
* freed up (no memory pressure should have been reported).
* Ignore large jumps in max_nr_free_pages that would mess up our stats.
*/
if (low_pressure_mem.max_nr_free_pages == -1 ||
(low_pressure_mem.max_nr_free_pages < mi->field.nr_free_pages &&
mi->field.nr_free_pages - low_pressure_mem.max_nr_free_pages <
low_pressure_mem.max_nr_free_pages * 0.1)) {
if (debug_process_killing) {
ALOGI("Low pressure max memory update from %" PRId64 " to %" PRId64,
low_pressure_mem.max_nr_free_pages, mi->field.nr_free_pages);
}
low_pressure_mem.max_nr_free_pages = mi->field.nr_free_pages;
}
}
enum vmpressure_level upgrade_level(enum vmpressure_level level) {
return (enum vmpressure_level)((level < VMPRESS_LEVEL_CRITICAL) ?
level + 1 : level);
}
enum vmpressure_level downgrade_level(enum vmpressure_level level) {
return (enum vmpressure_level)((level > VMPRESS_LEVEL_LOW) ?
level - 1 : level);
}
enum zone_watermark {
WMARK_MIN = 0,
WMARK_LOW,
WMARK_HIGH,
WMARK_NONE
};
struct zone_watermarks {
long high_wmark;
long low_wmark;
long min_wmark;
};
/*
* Returns lowest breached watermark or WMARK_NONE.
*/
static enum zone_watermark get_lowest_watermark(union meminfo *mi,
struct zone_watermarks *watermarks)
{
int64_t nr_free_pages = mi->field.nr_free_pages - mi->field.cma_free;
if (nr_free_pages < watermarks->min_wmark) {
return WMARK_MIN;
}
if (nr_free_pages < watermarks->low_wmark) {
return WMARK_LOW;
}
if (nr_free_pages < watermarks->high_wmark) {
return WMARK_HIGH;
}
return WMARK_NONE;
}
void calc_zone_watermarks(struct zoneinfo *zi, struct zone_watermarks *watermarks) {
memset(watermarks, 0, sizeof(struct zone_watermarks));
for (int node_idx = 0; node_idx < zi->node_count; node_idx++) {
struct zoneinfo_node *node = &zi->nodes[node_idx];
for (int zone_idx = 0; zone_idx < node->zone_count; zone_idx++) {
struct zoneinfo_zone *zone = &node->zones[zone_idx];
if (!zone->fields.field.present) {
continue;
}
watermarks->high_wmark += zone->max_protection + zone->fields.field.high;
watermarks->low_wmark += zone->max_protection + zone->fields.field.low;
watermarks->min_wmark += zone->max_protection + zone->fields.field.min;
}
}
}
static void mp_event_psi(int data, uint32_t events, struct polling_params *poll_params) {
enum kill_reasons {
NONE = -1, /* To denote no kill condition */
PRESSURE_AFTER_KILL = 0,
NOT_RESPONDING,
LOW_SWAP_AND_THRASHING,
LOW_MEM_AND_SWAP,
LOW_MEM_AND_THRASHING,
DIRECT_RECL_AND_THRASHING,
KILL_REASON_COUNT
};
enum reclaim_state {
NO_RECLAIM = 0,
KSWAPD_RECLAIM,
DIRECT_RECLAIM,
};
static int64_t init_ws_refault;
static int64_t base_file_lru;
static int64_t init_pgscan_kswapd;
static int64_t init_pgscan_direct;
static int64_t swap_low_threshold;
static bool killing;
static int thrashing_limit;
static bool in_reclaim;
static struct zone_watermarks watermarks;
static struct timespec wmark_update_tm;
union meminfo mi;
union vmstat vs;
struct timespec curr_tm;
int64_t thrashing = 0;
bool swap_is_low = false;
enum vmpressure_level level = (enum vmpressure_level)data;
enum kill_reasons kill_reason = NONE;
bool cycle_after_kill = false;
enum reclaim_state reclaim = NO_RECLAIM;
enum zone_watermark wmark = WMARK_NONE;
char kill_desc[LINE_MAX];
bool cut_thrashing_limit = false;
int min_score_adj = 0;
/* Skip while still killing a process */
if (is_kill_pending()) {
goto no_kill;
}
/*
* Process is dead, stop waiting. This has no effect if pidfds are supported and
* death notification already caused waiting to stop.
*/
stop_wait_for_proc_kill(true);
if (clock_gettime(CLOCK_MONOTONIC_COARSE, &curr_tm) != 0) {
ALOGE("Failed to get current time");
return;
}
if (vmstat_parse(&vs) < 0) {
ALOGE("Failed to parse vmstat!");
return;
}
if (meminfo_parse(&mi) < 0) {
ALOGE("Failed to parse meminfo!");
return;
}
/* Reset states after process got killed */
if (killing) {
killing = false;
cycle_after_kill = true;
/* Reset file-backed pagecache size and refault amounts after a kill */
base_file_lru = vs.field.nr_inactive_file + vs.field.nr_active_file;
init_ws_refault = vs.field.workingset_refault;
}
/* Check free swap levels */
if (swap_free_low_percentage) {
if (!swap_low_threshold) {
swap_low_threshold = mi.field.total_swap * swap_free_low_percentage / 100;
}
swap_is_low = mi.field.free_swap < swap_low_threshold;
}
/* Identify reclaim state */
if (vs.field.pgscan_direct > init_pgscan_direct) {
init_pgscan_direct = vs.field.pgscan_direct;
init_pgscan_kswapd = vs.field.pgscan_kswapd;
reclaim = DIRECT_RECLAIM;
} else if (vs.field.pgscan_kswapd > init_pgscan_kswapd) {
init_pgscan_kswapd = vs.field.pgscan_kswapd;
reclaim = KSWAPD_RECLAIM;
} else {
in_reclaim = false;
/* Skip if system is not reclaiming */
goto no_kill;
}
if (!in_reclaim) {
/* Record file-backed pagecache size when entering reclaim cycle */
base_file_lru = vs.field.nr_inactive_file + vs.field.nr_active_file;
init_ws_refault = vs.field.workingset_refault;
thrashing_limit = thrashing_limit_pct;
} else {
/* Calculate what % of the file-backed pagecache refaulted so far */
thrashing = (vs.field.workingset_refault - init_ws_refault) * 100 / base_file_lru;
}
in_reclaim = true;
/*
* Refresh watermarks once per min in case user updated one of the margins.
* TODO: b/140521024 replace this periodic update with an API for AMS to notify LMKD
* that zone watermarks were changed by the system software.
*/
if (watermarks.high_wmark == 0 || get_time_diff_ms(&wmark_update_tm, &curr_tm) > 60000) {
struct zoneinfo zi;
if (zoneinfo_parse(&zi) < 0) {
ALOGE("Failed to parse zoneinfo!");
return;
}
calc_zone_watermarks(&zi, &watermarks);
wmark_update_tm = curr_tm;
}
/* Find out which watermark is breached if any */
wmark = get_lowest_watermark(&mi, &watermarks);
/*
* TODO: move this logic into a separate function
* Decide if killing a process is necessary and record the reason
*/
if (cycle_after_kill && wmark < WMARK_LOW) {
/*
* Prevent kills not freeing enough memory which might lead to OOM kill.
* This might happen when a process is consuming memory faster than reclaim can
* free even after a kill. Mostly happens when running memory stress tests.
*/
kill_reason = PRESSURE_AFTER_KILL;
strncpy(kill_desc, "min watermark is breached even after kill", sizeof(kill_desc));
} else if (level == VMPRESS_LEVEL_CRITICAL && events != 0) {
/*
* Device is too busy reclaiming memory which might lead to ANR.
* Critical level is triggered when PSI complete stall (all tasks are blocked because
* of the memory congestion) breaches the configured threshold.
*/
kill_reason = NOT_RESPONDING;
strncpy(kill_desc, "device is not responding", sizeof(kill_desc));
} else if (swap_is_low && thrashing > thrashing_limit_pct) {
/* Page cache is thrashing while swap is low */
kill_reason = LOW_SWAP_AND_THRASHING;
snprintf(kill_desc, sizeof(kill_desc), "device is low on swap (%" PRId64
"kB < %" PRId64 "kB) and thrashing (%" PRId64 "%%)",
mi.field.free_swap * page_k, swap_low_threshold * page_k, thrashing);
} else if (swap_is_low && wmark < WMARK_HIGH) {
/* Both free memory and swap are low */
kill_reason = LOW_MEM_AND_SWAP;
snprintf(kill_desc, sizeof(kill_desc), "%s watermark is breached and swap is low (%"
PRId64 "kB < %" PRId64 "kB)", wmark > WMARK_LOW ? "min" : "low",
mi.field.free_swap * page_k, swap_low_threshold * page_k);
} else if (wmark < WMARK_HIGH && thrashing > thrashing_limit) {
/* Page cache is thrashing while memory is low */
kill_reason = LOW_MEM_AND_THRASHING;
snprintf(kill_desc, sizeof(kill_desc), "%s watermark is breached and thrashing (%"
PRId64 "%%)", wmark > WMARK_LOW ? "min" : "low", thrashing);
cut_thrashing_limit = true;
/* Do not kill perceptible apps because of thrashing */
min_score_adj = PERCEPTIBLE_APP_ADJ;
} else if (reclaim == DIRECT_RECLAIM && thrashing > thrashing_limit) {
/* Page cache is thrashing while in direct reclaim (mostly happens on lowram devices) */
kill_reason = DIRECT_RECL_AND_THRASHING;
snprintf(kill_desc, sizeof(kill_desc), "device is in direct reclaim and thrashing (%"
PRId64 "%%)", thrashing);
cut_thrashing_limit = true;
/* Do not kill perceptible apps because of thrashing */
min_score_adj = PERCEPTIBLE_APP_ADJ;
}
/* Kill a process if necessary */
if (kill_reason != NONE) {
int pages_freed = find_and_kill_process(min_score_adj, kill_reason, kill_desc, &mi,
&curr_tm);
if (pages_freed > 0) {
killing = true;
if (cut_thrashing_limit) {
/*
* Cut thrasing limit by thrashing_limit_decay_pct percentage of the current
* thrashing limit until the system stops thrashing.
*/
thrashing_limit = (thrashing_limit * (100 - thrashing_limit_decay_pct)) / 100;
}
}
}
no_kill:
/* Do not poll if kernel supports pidfd waiting */
if (is_waiting_for_kill()) {
/* Pause polling if we are waiting for process death notification */
poll_params->update = POLLING_PAUSE;
return;
}
/*
* Start polling after initial PSI event;
* extend polling while device is in direct reclaim or process is being killed;
* do not extend when kswapd reclaims because that might go on for a long time
* without causing memory pressure
*/
if (events || killing || reclaim == DIRECT_RECLAIM) {
poll_params->update = POLLING_START;
}
/* Decide the polling interval */
if (swap_is_low || killing) {
/* Fast polling during and after a kill or when swap is low */
poll_params->polling_interval_ms = PSI_POLL_PERIOD_SHORT_MS;
} else {
/* By default use long intervals */
poll_params->polling_interval_ms = PSI_POLL_PERIOD_LONG_MS;
}
}
static void mp_event_common(int data, uint32_t events, struct polling_params *poll_params) {
int ret;
unsigned long long evcount;
int64_t mem_usage, memsw_usage;
int64_t mem_pressure;
enum vmpressure_level lvl;
union meminfo mi;
struct zoneinfo zi;
struct timespec curr_tm;
static unsigned long kill_skip_count = 0;
enum vmpressure_level level = (enum vmpressure_level)data;
long other_free = 0, other_file = 0;
int min_score_adj;
int minfree = 0;
static struct reread_data mem_usage_file_data = {
.filename = MEMCG_MEMORY_USAGE,
.fd = -1,
};
static struct reread_data memsw_usage_file_data = {
.filename = MEMCG_MEMORYSW_USAGE,
.fd = -1,
};
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;
}
}
}
/* Start polling after initial PSI event */
if (use_psi_monitors && events) {
/* Override polling params only if current event is more critical */
if (!poll_params->poll_handler || data > poll_params->poll_handler->data) {
poll_params->polling_interval_ms = PSI_POLL_PERIOD_SHORT_MS;
poll_params->update = POLLING_START;
}
}
if (clock_gettime(CLOCK_MONOTONIC_COARSE, &curr_tm) != 0) {
ALOGE("Failed to get current time");
return;
}
if (kill_timeout_ms && get_time_diff_ms(&last_kill_tm, &curr_tm) < kill_timeout_ms) {
/*
* If we're within the no-kill timeout, see if there's pending reclaim work
* from the last killed process. If so, skip killing for now.
*/
if (is_kill_pending()) {
kill_skip_count++;
return;
}
/*
* Process is dead, stop waiting. This has no effect if pidfds are supported and
* death notification already caused waiting to stop.
*/
stop_wait_for_proc_kill(true);
} else {
/*
* Killing took longer than no-kill timeout. Stop waiting for the last process
* to die because we are ready to kill again.
*/
stop_wait_for_proc_kill(false);
}
if (kill_skip_count > 0) {
ALOGI("%lu memory pressure events were skipped after a kill!",
kill_skip_count);
kill_skip_count = 0;
}
if (meminfo_parse(&mi) < 0 || zoneinfo_parse(&zi) < 0) {
ALOGE("Failed to get free memory!");
return;
}
if (use_minfree_levels) {
int i;
other_free = mi.field.nr_free_pages - zi.totalreserve_pages;
if (mi.field.nr_file_pages > (mi.field.shmem + mi.field.unevictable + mi.field.swap_cached)) {
other_file = (mi.field.nr_file_pages - mi.field.shmem -
mi.field.unevictable - mi.field.swap_cached);
} else {
other_file = 0;
}
min_score_adj = OOM_SCORE_ADJ_MAX + 1;
for (i = 0; i < lowmem_targets_size; i++) {
minfree = lowmem_minfree[i];
if (other_free < minfree && other_file < minfree) {
min_score_adj = lowmem_adj[i];
break;
}
}
if (min_score_adj == OOM_SCORE_ADJ_MAX + 1) {
if (debug_process_killing) {
ALOGI("Ignore %s memory pressure event "
"(free memory=%ldkB, cache=%ldkB, limit=%ldkB)",
level_name[level], other_free * page_k, other_file * page_k,
(long)lowmem_minfree[lowmem_targets_size - 1] * page_k);
}
return;
}
goto do_kill;
}
if (level == VMPRESS_LEVEL_LOW) {
record_low_pressure_levels(&mi);
}
if (level_oomadj[level] > OOM_SCORE_ADJ_MAX) {
/* Do not monitor this pressure level */
return;
}
if ((mem_usage = get_memory_usage(&mem_usage_file_data)) < 0) {
goto do_kill;
}
if ((memsw_usage = get_memory_usage(&memsw_usage_file_data)) < 0) {
goto do_kill;
}
// Calculate percent for swappinness.
mem_pressure = (mem_usage * 100) / memsw_usage;
if (enable_pressure_upgrade && level != VMPRESS_LEVEL_CRITICAL) {
// We are swapping too much.
if (mem_pressure < upgrade_pressure) {
level = upgrade_level(level);
if (debug_process_killing) {
ALOGI("Event upgraded to %s", level_name[level]);
}
}
}
// If we still have enough swap space available, check if we want to
// ignore/downgrade pressure events.
if (mi.field.free_swap >=
mi.field.total_swap * swap_free_low_percentage / 100) {
// If the pressure is larger than downgrade_pressure lmk will not
// kill any process, since enough memory is available.
if (mem_pressure > downgrade_pressure) {
if (debug_process_killing) {
ALOGI("Ignore %s memory pressure", level_name[level]);
}
return;
} else if (level == VMPRESS_LEVEL_CRITICAL && mem_pressure > upgrade_pressure) {
if (debug_process_killing) {
ALOGI("Downgrade critical memory pressure");
}
// Downgrade event, since enough memory available.
level = downgrade_level(level);
}
}
do_kill:
if (low_ram_device) {
/* For Go devices kill only one task */
if (find_and_kill_process(level_oomadj[level], -1, NULL, &mi, &curr_tm) == 0) {
if (debug_process_killing) {
ALOGI("Nothing to kill");
}
}
} else {
int pages_freed;
static struct timespec last_report_tm;
static unsigned long report_skip_count = 0;
if (!use_minfree_levels) {
/* Free up enough memory to downgrate the memory pressure to low level */
if (mi.field.nr_free_pages >= low_pressure_mem.max_nr_free_pages) {
if (debug_process_killing) {
ALOGI("Ignoring pressure since more memory is "
"available (%" PRId64 ") than watermark (%" PRId64 ")",
mi.field.nr_free_pages, low_pressure_mem.max_nr_free_pages);
}
return;
}
min_score_adj = level_oomadj[level];
}
pages_freed = find_and_kill_process(min_score_adj, -1, NULL, &mi, &curr_tm);
if (pages_freed == 0) {
/* Rate limit kill reports when nothing was reclaimed */
if (get_time_diff_ms(&last_report_tm, &curr_tm) < FAIL_REPORT_RLIMIT_MS) {
report_skip_count++;
return;
}
}
/* Log whenever we kill or when report rate limit allows */
if (use_minfree_levels) {
ALOGI("Reclaimed %ldkB, cache(%ldkB) and "
"free(%" PRId64 "kB)-reserved(%" PRId64 "kB) below min(%ldkB) for oom_adj %d",
pages_freed * page_k,
other_file * page_k, mi.field.nr_free_pages * page_k,
zi.totalreserve_pages * page_k,
minfree * page_k, min_score_adj);
} else {
ALOGI("Reclaimed %ldkB at oom_adj %d",
pages_freed * page_k, min_score_adj);
}
if (report_skip_count > 0) {
ALOGI("Suppressed %lu failed kill reports", report_skip_count);
report_skip_count = 0;
}
last_report_tm = curr_tm;
}
if (is_waiting_for_kill()) {
/* pause polling if we are waiting for process death notification */
poll_params->update = POLLING_PAUSE;
}
}
static bool init_mp_psi(enum vmpressure_level level, bool use_new_strategy) {
int fd;
/* Do not register a handler if threshold_ms is not set */
if (!psi_thresholds[level].threshold_ms) {
return true;
}
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 = use_new_strategy ? mp_event_psi : 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() {
/*
* When PSI is used on low-ram devices or on high-end devices without memfree levels
* use new kill strategy based on zone watermarks, free swap and thrashing stats
*/
bool use_new_strategy =
property_get_bool("ro.lmk.use_new_strategy", low_ram_device || !use_minfree_levels);
/* In default PSI mode override stall amounts using system properties */
if (use_new_strategy) {
/* Do not use low pressure level */
psi_thresholds[VMPRESS_LEVEL_LOW].threshold_ms = 0;
psi_thresholds[VMPRESS_LEVEL_MEDIUM].threshold_ms = psi_partial_stall_ms;
psi_thresholds[VMPRESS_LEVEL_CRITICAL].threshold_ms = psi_complete_stall_ms;
}
if (!init_mp_psi(VMPRESS_LEVEL_LOW, use_new_strategy)) {
return false;
}
if (!init_mp_psi(VMPRESS_LEVEL_MEDIUM, use_new_strategy)) {
destroy_mp_psi(VMPRESS_LEVEL_LOW);
return false;
}
if (!init_mp_psi(VMPRESS_LEVEL_CRITICAL, use_new_strategy)) {
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;
int evctlfd;
char buf[256];
struct epoll_event epev;
int ret;
int level_idx = (int)level;
const char *levelstr = level_name[level_idx];
/* gid containing AID_SYSTEM required */
mpfd = open(MEMCG_SYSFS_PATH "memory.pressure_level", O_RDONLY | O_CLOEXEC);
if (mpfd < 0) {
ALOGI("No kernel memory.pressure_level support (errno=%d)", errno);
goto err_open_mpfd;
}
evctlfd = open(MEMCG_SYSFS_PATH "cgroup.event_control", O_WRONLY | O_CLOEXEC);
if (evctlfd < 0) {
ALOGI("No kernel memory cgroup event control (errno=%d)", errno);
goto err_open_evctlfd;
}
evfd = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
if (evfd < 0) {
ALOGE("eventfd failed for level %s; errno=%d", levelstr, errno);
goto err_eventfd;
}
ret = snprintf(buf, sizeof(buf), "%d %d %s", evfd, mpfd, levelstr);
if (ret >= (ssize_t)sizeof(buf)) {
ALOGE("cgroup.event_control line overflow for level %s", levelstr);
goto err;
}
ret = TEMP_FAILURE_RETRY(write(evctlfd, buf, strlen(buf) + 1));
if (ret == -1) {
ALOGE("cgroup.event_control write failed for level %s; errno=%d",
levelstr, errno);
goto err;
}
epev.events = EPOLLIN;
/* use data to store event level */
vmpressure_hinfo[level_idx].data = level_idx;
vmpressure_hinfo[level_idx].handler = mp_event_common;
epev.data.ptr = (void *)&vmpressure_hinfo[level_idx];
ret = epoll_ctl(epollfd, EPOLL_CTL_ADD, evfd, &epev);
if (ret == -1) {
ALOGE("epoll_ctl for level %s failed; errno=%d", levelstr, errno);
goto err;
}
maxevents++;
mpevfd[level] = evfd;
close(evctlfd);
return true;
err:
close(evfd);
err_eventfd:
close(evctlfd);
err_open_evctlfd:
close(mpfd);
err_open_mpfd:
return false;
}
static void kernel_event_handler(int data __unused, uint32_t events __unused,
struct polling_params *poll_params __unused) {
kpoll_info.handler(kpoll_info.poll_fd);
}
static int init(void) {
static struct event_handler_info kernel_poll_hinfo = { 0, kernel_event_handler };
struct reread_data file_data = {
.filename = ZONEINFO_PATH,
.fd = -1,
};
struct epoll_event epev;
int pidfd;
int i;
int ret;
page_k = sysconf(_SC_PAGESIZE);
if (page_k == -1)
page_k = PAGE_SIZE;
page_k /= 1024;
epollfd = epoll_create(MAX_EPOLL_EVENTS);
if (epollfd == -1) {
ALOGE("epoll_create failed (errno=%d)", errno);
return -1;
}
// mark data connections as not connected
for (int i = 0; i < MAX_DATA_CONN; i++) {
data_sock[i].sock = -1;
}
ctrl_sock.sock = android_get_control_socket("lmkd");
if (ctrl_sock.sock < 0) {
ALOGE("get lmkd control socket failed");
return -1;
}
ret = listen(ctrl_sock.sock, MAX_DATA_CONN);
if (ret < 0) {
ALOGE("lmkd control socket listen failed (errno=%d)", errno);
return -1;
}
epev.events = EPOLLIN;
ctrl_sock.handler_info.handler = ctrl_connect_handler;
epev.data.ptr = (void *)&(ctrl_sock.handler_info);
if (epoll_ctl(epollfd, EPOLL_CTL_ADD, ctrl_sock.sock, &epev) == -1) {
ALOGE("epoll_ctl for lmkd control socket failed (errno=%d)", errno);
return -1;
}
maxevents++;
has_inkernel_module = !access(INKERNEL_MINFREE_PATH, W_OK);
use_inkernel_interface = has_inkernel_module;
if (use_inkernel_interface) {
ALOGI("Using in-kernel low memory killer interface");
if (init_poll_kernel(&kpoll_info)) {
epev.events = EPOLLIN;
epev.data.ptr = (void*)&kernel_poll_hinfo;
if (epoll_ctl(epollfd, EPOLL_CTL_ADD, kpoll_info.poll_fd, &epev) != 0) {
ALOGE("epoll_ctl for lmk events failed (errno=%d)", errno);
close(kpoll_info.poll_fd);
kpoll_info.poll_fd = -1;
} else {
maxevents++;
}
}
} else {
/* 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))) {
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++) {
procadjslot_list[i].next = &procadjslot_list[i];
procadjslot_list[i].prev = &procadjslot_list[i];
}
memset(killcnt_idx, KILLCNT_INVALID_IDX, sizeof(killcnt_idx));
/*
* Read zoneinfo as the biggest file we read to create and size the initial
* read buffer and avoid memory re-allocations during memory pressure
*/
if (reread_file(&file_data) == NULL) {
ALOGE("Failed to read %s: %s", file_data.filename, strerror(errno));
}
/* check if kernel supports pidfd_open syscall */
pidfd = TEMP_FAILURE_RETRY(sys_pidfd_open(getpid(), 0));
if (pidfd < 0) {
pidfd_supported = (errno != ENOSYS);
} else {
pidfd_supported = true;
close(pidfd);
}
ALOGI("Process polling is %s", pidfd_supported ? "supported" : "not supported" );
return 0;
}
static void call_handler(struct event_handler_info* handler_info,
struct polling_params *poll_params, uint32_t events) {
struct timespec curr_tm;
handler_info->handler(handler_info->data, events, poll_params);
clock_gettime(CLOCK_MONOTONIC_COARSE, &curr_tm);
poll_params->last_poll_tm = curr_tm;
switch (poll_params->update) {
case POLLING_START:
/*
* Poll for the duration of PSI_WINDOW_SIZE_MS after the
* initial PSI event because psi events are rate-limited
* at one per sec.
*/
poll_params->poll_start_tm = curr_tm;
poll_params->poll_handler = handler_info;
break;
case POLLING_STOP:
poll_params->poll_handler = NULL;
break;
case POLLING_PAUSE:
poll_params->paused_handler = handler_info;
poll_params->poll_handler = NULL;
break;
case POLLING_RESUME:
poll_params->poll_start_tm = curr_tm;
poll_params->poll_handler = poll_params->paused_handler;
break;
case POLLING_DO_NOT_CHANGE:
if (get_time_diff_ms(&poll_params->poll_start_tm, &curr_tm) > PSI_WINDOW_SIZE_MS) {
/* Polled for the duration of PSI window, time to stop */
poll_params->poll_handler = NULL;
}
/* WARNING: skipping the rest of the function */
return;
}
poll_params->update = POLLING_DO_NOT_CHANGE;
}
static void mainloop(void) {
struct event_handler_info* handler_info;
struct polling_params poll_params;
struct timespec curr_tm;
struct epoll_event *evt;
long delay = -1;
poll_params.poll_handler = NULL;
poll_params.update = POLLING_DO_NOT_CHANGE;
while (1) {
struct epoll_event events[maxevents];
int nevents;
int i;
if (poll_params.poll_handler) {
bool poll_now;
clock_gettime(CLOCK_MONOTONIC_COARSE, &curr_tm);
if (poll_params.poll_handler == poll_params.paused_handler) {
/*
* Just transitioned into POLLING_RESUME. Reset paused_handler
* and poll immediately
*/
poll_params.paused_handler = NULL;
poll_now = true;
nevents = 0;
} else {
/* Calculate next timeout */
delay = get_time_diff_ms(&poll_params.last_poll_tm, &curr_tm);
delay = (delay < poll_params.polling_interval_ms) ?
poll_params.polling_interval_ms - delay : poll_params.polling_interval_ms;
/* Wait for events until the next polling timeout */
nevents = epoll_wait(epollfd, events, maxevents, delay);
/* Update current time after wait */
clock_gettime(CLOCK_MONOTONIC_COARSE, &curr_tm);
poll_now = (get_time_diff_ms(&poll_params.last_poll_tm, &curr_tm) >=
poll_params.polling_interval_ms);
}
if (poll_now) {
call_handler(poll_params.poll_handler, &poll_params, 0);
}
} else {
/* Wait for events with no timeout */
nevents = epoll_wait(epollfd, events, maxevents, -1);
}
if (nevents == -1) {
if (errno == EINTR)
continue;
ALOGE("epoll_wait failed (errno=%d)", errno);
continue;
}
/*
* First pass to see if any data socket connections were dropped.
* Dropped connection should be handled before any other events
* to deallocate data connection and correctly handle cases when
* connection gets dropped and reestablished in the same epoll cycle.
* In such cases it's essential to handle connection closures first.
*/
for (i = 0, evt = &events[0]; i < nevents; ++i, evt++) {
if ((evt->events & EPOLLHUP) && evt->data.ptr) {
ALOGI("lmkd data connection dropped");
handler_info = (struct event_handler_info*)evt->data.ptr;
ctrl_data_close(handler_info->data);
}
}
/* Second pass to handle all other events */
for (i = 0, evt = &events[0]; i < nevents; ++i, evt++) {
if (evt->events & EPOLLERR) {
ALOGD("EPOLLERR on event #%d", i);
}
if (evt->events & EPOLLHUP) {
/* This case was handled in the first pass */
continue;
}
if (evt->data.ptr) {
handler_info = (struct event_handler_info*)evt->data.ptr;
call_handler(handler_info, &poll_params, evt->events);
}
}
}
}
int main(int argc __unused, char **argv __unused) {
struct sched_param param = {
.sched_priority = 1,
};
/* By default disable low level vmpressure events */
level_oomadj[VMPRESS_LEVEL_LOW] =
property_get_int32("ro.lmk.low", OOM_SCORE_ADJ_MAX + 1);
level_oomadj[VMPRESS_LEVEL_MEDIUM] =
property_get_int32("ro.lmk.medium", 800);
level_oomadj[VMPRESS_LEVEL_CRITICAL] =
property_get_int32("ro.lmk.critical", 0);
debug_process_killing = property_get_bool("ro.lmk.debug", false);
/* By default disable upgrade/downgrade logic */
enable_pressure_upgrade =
property_get_bool("ro.lmk.critical_upgrade", false);
upgrade_pressure =
(int64_t)property_get_int32("ro.lmk.upgrade_pressure", 100);
downgrade_pressure =
(int64_t)property_get_int32("ro.lmk.downgrade_pressure", 100);
kill_heaviest_task =
property_get_bool("ro.lmk.kill_heaviest_task", false);
low_ram_device = property_get_bool("ro.config.low_ram", false);
kill_timeout_ms =
(unsigned long)property_get_int32("ro.lmk.kill_timeout_ms", 0);
use_minfree_levels =
property_get_bool("ro.lmk.use_minfree_levels", false);
per_app_memcg =
property_get_bool("ro.config.per_app_memcg", low_ram_device);
swap_free_low_percentage = clamp(0, 100, property_get_int32("ro.lmk.swap_free_low_percentage",
low_ram_device ? DEF_LOW_SWAP_LOWRAM : DEF_LOW_SWAP));
psi_partial_stall_ms = property_get_int32("ro.lmk.psi_partial_stall_ms",
low_ram_device ? DEF_PARTIAL_STALL_LOWRAM : DEF_PARTIAL_STALL);
psi_complete_stall_ms = property_get_int32("ro.lmk.psi_complete_stall_ms",
DEF_COMPLETE_STALL);
thrashing_limit_pct = max(0, property_get_int32("ro.lmk.thrashing_limit",
low_ram_device ? DEF_THRASHING_LOWRAM : DEF_THRASHING));
thrashing_limit_decay_pct = clamp(0, 100, property_get_int32("ro.lmk.thrashing_limit_decay",
low_ram_device ? DEF_THRASHING_DECAY_LOWRAM : DEF_THRASHING_DECAY));
ctx = create_android_logger(KILLINFO_LOG_TAG);
statslog_init();
if (!init()) {
if (!use_inkernel_interface) {
/*
* MCL_ONFAULT pins pages as they fault instead of loading
* everything immediately all at once. (Which would be bad,
* because as of this writing, we have a lot of mapped pages we
* never use.) Old kernels will see MCL_ONFAULT and fail with
* EINVAL; we ignore this failure.
*
* N.B. read the man page for mlockall. MCL_CURRENT | MCL_ONFAULT
* pins ⊆ MCL_CURRENT, converging to just MCL_CURRENT as we fault
* in pages.
*/
/* CAP_IPC_LOCK required */
if (mlockall(MCL_CURRENT | MCL_FUTURE | MCL_ONFAULT) && (errno != EINVAL)) {
ALOGW("mlockall failed %s", strerror(errno));
}
/* CAP_NICE required */
if (sched_setscheduler(0, SCHED_FIFO, &param)) {
ALOGW("set SCHED_FIFO failed %s", strerror(errno));
}
}
mainloop();
}
statslog_destroy();
android_log_destroy(&ctx);
ALOGI("exiting");
return 0;
}
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