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android/platform/system/memory/lmkd/refs/heads/main/./lmkd.cpp
blob: 3cb458d57dccefadb1327d7caea0026a899fdc05 [file] [edit]
/*
* 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 <errno.h>
#include <inttypes.h>
#include <pwd.h>
#include <sched.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/pidfd.h>
#include <sys/socket.h>
#include <sys/syscall.h>
#include <sys/sysinfo.h>
#include <time.h>
#include <unistd.h>
#include <algorithm>
#include <array>
#include <memory>
#include <shared_mutex>
#include <vector>
#include <BpfSyscallWrappers.h>
#include <android-base/unique_fd.h>
#include <bpf/WaitForProgsLoaded.h>
#include <cutils/properties.h>
#include <cutils/sockets.h>
#include <liblmkd_utils.h>
#include <lmkd.h>
#include <lmkd_hooks.h>
#include <log/log.h>
#include <log/log_event_list.h>
#include <log/log_time.h>
#include <memevents/memevents.h>
#include <private/android_filesystem_config.h>
#include <processgroup/processgroup.h>
#include <psi/psi.h>
#include "reaper.h"
#include "statslog.h"
#include "watchdog.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>
static inline void trace_kill_start(const char *desc) {
ATRACE_BEGIN(desc);
}
static inline void trace_kill_end() {
ATRACE_END();
}
#else /* LMKD_TRACE_KILLS */
static inline void trace_kill_start(const char *) {}
static inline void trace_kill_end() {}
#endif /* LMKD_TRACE_KILLS */
#ifndef __unused
#define __unused __attribute__((__unused__))
#endif
#define ZONEINFO_PATH "/proc/zoneinfo"
#define MEMINFO_PATH "/proc/meminfo"
#define VMSTAT_PATH "/proc/vmstat"
#define PROC_STATUS_TGID_FIELD "Tgid:"
#define PROC_STATUS_RSS_FIELD "VmRSS:"
#define PROC_STATUS_SWAP_FIELD "VmSwap:"
#define NODE_STATS_MARKER " per-node stats"
#define PERCEPTIBLE_APP_ADJ 200
#define PREVIOUS_APP_ADJ 700
/* 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 EIGHT_MEGA (1 << 23)
#define TARGET_UPDATE_MIN_INTERVAL_MS 1000
#define THRASHING_RESET_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
#define PROCFS_PATH_MAX 64
/*
* Read lmk property with persist.device_config.lmkd_native.<name> overriding ro.lmk.<name>
* persist.device_config.lmkd_native.* properties are being set by experiments. If a new property
* can be controlled by an experiment then use GET_LMK_PROPERTY instead of property_get_xxx and
* add "on property" triggers in lmkd.rc to react to the experiment flag changes.
*/
#define GET_LMK_PROPERTY(type, name, def) \
property_get_##type("persist.device_config.lmkd_native." name, \
property_get_##type("ro.lmk." name, def))
/*
* 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 FAIL_REPORT_RLIMIT_MS 1000
/*
* System property defaults
*/
/* ro.lmk.swap_free_low_percentage property defaults */
#define DEF_LOW_SWAP 10
/* 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
/* ro.lmk.direct_reclaim_threshold_ms property defaults */
#define DEF_DIRECT_RECL_THRESH_MS 0
/* ro.lmk.swap_compression_ratio property defaults */
#define DEF_SWAP_COMP_RATIO 1
/* ro.lmk.lowmem_min_oom_score defaults */
#define DEF_LOWMEM_MIN_SCORE (PREVIOUS_APP_ADJ + 1)
#define LMKD_REINIT_PROP "lmkd.reinit"
#define WATCHDOG_TIMEOUT_SEC 2
/* 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;
};
/* Listener for direct reclaim and kswapd state changes */
static std::unique_ptr<android::bpf::memevents::MemEventListener> memevent_listener(nullptr);
static struct timespec direct_reclaim_start_tm;
static struct timespec kswapd_start_tm;
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;
enum vmpressure_level prev_level = VMPRESS_LEVEL_LOW;
static bool monitors_initialized;
static bool boot_completed_handled = false;
static bool mem_event_update_zoneinfo_supported;
/* 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 int pressure_after_kill_min_score;
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 int thrashing_critical_pct;
static int swap_util_max;
static int64_t filecache_min_kb;
static int64_t stall_limit_critical;
static bool use_psi_monitors = false;
static int kpoll_fd;
static bool delay_monitors_until_boot;
static int direct_reclaim_threshold_ms;
static int swap_compression_ratio;
static int lowmem_min_oom_score;
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 uint64_t mp_event_count;
static android_log_context ctx;
static Reaper reaper;
static int reaper_comm_fd[2];
enum polling_update {
POLLING_DO_NOT_CHANGE,
POLLING_START,
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;
pid_t pid;
uint32_t async_event_mask;
struct event_handler_info handler_info;
};
/* max supported number of data connections (AMS, init, tests) */
#define MAX_DATA_CONN 3
/* 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, 3 ctrl data socket, 3 memory pressure levels,
* 1 lmk events + 1 fd to wait for process death + 1 fd to receive kill failure notifications
* + 1 fd to receive memevent_listener notifications
*/
#define MAX_EPOLL_EVENTS (1 + MAX_DATA_CONN + VMPRESS_LEVEL_COUNT + 1 + 1 + 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 std::array<int, MAX_TARGETS> lowmem_adj;
static std::array<int, MAX_TARGETS> lowmem_minfree;
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_FIELD_COUNT
};
static const char* const zoneinfo_node_field_names[ZI_NODE_FIELD_COUNT] = {
"nr_inactive_file",
"nr_active_file",
};
union zoneinfo_node_fields {
struct {
int64_t nr_inactive_file;
int64_t nr_active_file;
} 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;
};
/* 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;
int64_t total_gpu_kb;
int64_t easy_available;
} 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_WORKINGSET_REFAULT_FILE,
VS_PGSCAN_KSWAPD,
VS_PGSCAN_DIRECT,
VS_PGSCAN_DIRECT_THROTTLE,
VS_PGREFILL,
VS_FIELD_COUNT
};
static const char* const vmstat_field_names[VS_FIELD_COUNT] = {
"nr_free_pages",
"nr_inactive_file",
"nr_active_file",
"workingset_refault",
"workingset_refault_file",
"pgscan_kswapd",
"pgscan_direct",
"pgscan_direct_throttle",
"pgrefill",
};
union vmstat {
struct {
int64_t nr_free_pages;
int64_t nr_inactive_file;
int64_t nr_active_file;
int64_t workingset_refault;
int64_t workingset_refault_file;
int64_t pgscan_kswapd;
int64_t pgscan_direct;
int64_t pgscan_direct_throttle;
int64_t pgrefill;
} 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;
pid_t reg_pid; /* PID of the process that registered this record */
bool valid;
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)
// protects procadjslot_list from concurrent access
static std::shared_mutex adjslot_list_lock;
// procadjslot_list should be modified only from the main thread while exclusively holding
// adjslot_list_lock. Readers from non-main threads should hold adjslot_list_lock shared lock.
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;
static int pagesize;
static long page_k; /* page size in kB */
static bool update_props();
static bool init_monitors();
static void destroy_monitors();
static bool init_memevent_listener_monitoring();
static int clamp(int low, int high, int value) {
return std::max(std::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 = pagesize;
static char *new_buf, *buf = NULL;
ssize_t size;
if (data->fd == -1) {
/* First-time buffer initialization */
if (!buf && (buf = static_cast<char*>(malloc(buf_size))) == nullptr) {
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 = static_cast<char*>(realloc(buf, buf_size * 2))) == nullptr) {
errno = ENOMEM;
return NULL;
}
buf = new_buf;
buf_size *= 2;
}
buf[size] = 0;
return buf;
}
static bool claim_record(struct proc* procp, pid_t pid) {
if (procp->reg_pid == pid) {
/* Record already belongs to the registrant */
return true;
}
if (procp->reg_pid == 0) {
/* Old registrant is gone, claim the record */
procp->reg_pid = pid;
return true;
}
/* The record is owned by another registrant */
return false;
}
static void remove_claims(pid_t pid) {
int i;
for (i = 0; i < PIDHASH_SZ; i++) {
struct proc* procp = pidhash[i];
while (procp) {
if (procp->reg_pid == pid) {
procp->reg_pid = 0;
}
procp = procp->pidhash_next;
}
}
}
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;
/* Mark all records of the old registrant as unclaimed */
remove_claims(data_sock[dsock_idx].pid);
}
static ssize_t ctrl_data_read(int dsock_idx, char* buf, size_t bufsz, struct ucred* sender_cred) {
struct iovec iov = {buf, bufsz};
char control[CMSG_SPACE(sizeof(struct ucred))];
struct msghdr hdr = {
NULL, 0, &iov, 1, control, sizeof(control), 0,
};
ssize_t ret;
ret = TEMP_FAILURE_RETRY(recvmsg(data_sock[dsock_idx].sock, &hdr, 0));
if (ret == -1) {
ALOGE("control data socket read failed; %s", strerror(errno));
return -1;
}
if (ret == 0) {
ALOGE("Got EOF on control data socket");
return -1;
}
struct ucred* cred = NULL;
struct cmsghdr* cmsg = CMSG_FIRSTHDR(&hdr);
while (cmsg != NULL) {
if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_CREDENTIALS) {
cred = (struct ucred*)CMSG_DATA(cmsg);
break;
}
cmsg = CMSG_NXTHDR(&hdr, cmsg);
}
if (cred == NULL) {
ALOGE("Failed to retrieve sender credentials");
/* Close the connection */
ctrl_data_close(dsock_idx);
return -1;
}
memcpy(sender_cred, cred, sizeof(struct ucred));
/* Store PID of the peer */
data_sock[dsock_idx].pid = cred->pid;
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;
}
/*
* Write the pid/uid pair over the data socket, note: all active clients
* will receive this unsolicited notification.
*/
static void ctrl_data_write_lmk_kill_occurred(pid_t pid, uid_t uid, int64_t rss_kb) {
LMKD_CTRL_PACKET packet;
size_t len = lmkd_pack_set_prockills(packet, pid, uid, static_cast<int>(rss_kb));
for (int i = 0; i < MAX_DATA_CONN; i++) {
if (data_sock[i].sock >= 0 && data_sock[i].async_event_mask & 1 << LMK_ASYNC_EVENT_KILL) {
ctrl_data_write(i, (char*)packet, len);
}
}
}
/*
* Write the kill_stat/memory_stat over the data socket to be propagated via AMS to statsd
*/
static void stats_write_lmk_kill_occurred(struct kill_stat *kill_st,
struct memory_stat *mem_st) {
LMK_KILL_OCCURRED_PACKET packet;
const size_t len = lmkd_pack_set_kill_occurred(packet, kill_st, mem_st);
if (len == 0) {
return;
}
for (int i = 0; i < MAX_DATA_CONN; i++) {
if (data_sock[i].sock >= 0 && data_sock[i].async_event_mask & 1 << LMK_ASYNC_EVENT_STAT) {
ctrl_data_write(i, packet, len);
}
}
}
static void stats_write_lmk_kill_occurred_pid(int pid, struct kill_stat *kill_st,
struct memory_stat *mem_st) {
kill_st->taskname = stats_get_task_name(pid);
if (kill_st->taskname != NULL) {
stats_write_lmk_kill_occurred(kill_st, mem_st);
}
}
static void poll_kernel(int poll_fd) {
if (poll_fd == -1) {
// not waiting
return;
}
while (1) {
char rd_buf[256];
int bytes_read = TEMP_FAILURE_RETRY(pread(poll_fd, (void*)rd_buf, sizeof(rd_buf) - 1, 0));
if (bytes_read <= 0) break;
rd_buf[bytes_read] = '\0';
int64_t pid;
int64_t uid;
int64_t group_leader_pid;
int64_t rss_in_pages;
struct memory_stat mem_st = {};
int16_t oom_score_adj;
int16_t min_score_adj;
int64_t starttime;
char* taskname = 0;
int64_t rss_kb;
int fields_read =
sscanf(rd_buf,
"%" SCNd64 " %" SCNd64 " %" SCNd64 " %" SCNd64 " %" SCNd64 " %" SCNd64
" %" SCNd16 " %" SCNd16 " %" SCNd64 "\n%m[^\n]",
&pid, &uid, &group_leader_pid, &mem_st.pgfault, &mem_st.pgmajfault,
&rss_in_pages, &oom_score_adj, &min_score_adj, &starttime, &taskname);
/* only the death of the group leader process is logged */
if (fields_read == 10 && group_leader_pid == pid) {
mem_st.rss_in_bytes = rss_in_pages * pagesize;
rss_kb = mem_st.rss_in_bytes >> 10;
ctrl_data_write_lmk_kill_occurred((pid_t)pid, (uid_t)uid, rss_kb);
mem_st.process_start_time_ns = starttime * (NS_PER_SEC / sysconf(_SC_CLK_TCK));
struct kill_stat kill_st = {
.uid = static_cast<int32_t>(uid),
.kill_reason = NONE,
.oom_score = oom_score_adj,
.min_oom_score = min_score_adj,
.free_mem_kb = 0,
.free_swap_kb = 0,
};
stats_write_lmk_kill_occurred_pid(pid, &kill_st, &mem_st);
}
free(taskname);
}
}
static bool init_poll_kernel() {
kpoll_fd = TEMP_FAILURE_RETRY(open("/proc/lowmemorykiller", O_RDONLY | O_NONBLOCK | O_CLOEXEC));
if (kpoll_fd < 0) {
ALOGE("kernel lmk event file could not be opened; errno=%d", errno);
return false;
}
return true;
}
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_element)
{
struct adjslot_list *next = head->next;
new_element->prev = head;
new_element->next = next;
next->prev = new_element;
head->next = new_element;
}
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;
}
// Should be modified only from the main thread.
static void proc_slot(struct proc *procp) {
int adjslot = ADJTOSLOT(procp->oomadj);
std::scoped_lock lock(adjslot_list_lock);
adjslot_insert(&procadjslot_list[adjslot], &procp->asl);
}
// Should be modified only from the main thread.
static void proc_unslot(struct proc *procp) {
std::scoped_lock lock(adjslot_list_lock);
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);
}
// Can be called only from the main thread.
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;
}
static void pid_invalidate(int pid) {
std::shared_lock lock(adjslot_list_lock);
struct proc *procp = pid_lookup(pid);
if (procp) {
procp->valid = false;
}
}
/*
* 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;
}
/* Reads /proc/pid/status into buf. */
static bool read_proc_status(int pid, char *buf, size_t buf_sz) {
char path[PROCFS_PATH_MAX];
int fd;
ssize_t size;
snprintf(path, PROCFS_PATH_MAX, "/proc/%d/status", pid);
fd = open(path, O_RDONLY | O_CLOEXEC);
if (fd < 0) {
return false;
}
size = read_all(fd, buf, buf_sz - 1);
close(fd);
if (size <= 0) {
return false;
}
buf[size] = 0;
return true;
}
/* Looks for tag in buf and parses the first integer */
static bool parse_status_tag(char *buf, const char *tag, int64_t *out) {
char *pos = buf;
while (true) {
pos = strstr(pos, tag);
/* Stop if tag not found or found at the line beginning */
if (pos == NULL || pos == buf || pos[-1] == '\n') {
break;
}
pos++;
}
if (pos == NULL) {
return false;
}
pos += strlen(tag);
while (*pos == ' ') ++pos;
return parse_int64(pos, out);
}
static int proc_get_size(int pid) {
char path[PROCFS_PATH_MAX];
char line[LINE_MAX];
int fd;
int rss = 0;
int total;
ssize_t ret;
/* gid containing AID_READPROC required */
snprintf(path, PROCFS_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[PROCFS_PATH_MAX];
int fd;
char *cp;
ssize_t ret;
/* gid containing AID_READPROC required */
snprintf(path, PROCFS_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 register_oom_adj_proc(const struct lmk_procprio& proc, struct ucred* cred) {
char val[20];
int soft_limit_mult;
bool is_system_server;
struct passwd *pwdrec;
struct proc* procp;
int oom_adj_score = proc.oomadj;
/* lmkd should not change soft limits for services */
if (proc.ptype == PROC_TYPE_APP && per_app_memcg) {
if (proc.oomadj >= 900) {
soft_limit_mult = 0;
} else if (proc.oomadj >= 800) {
soft_limit_mult = 0;
} else if (proc.oomadj >= 700) {
soft_limit_mult = 0;
} else if (proc.oomadj >= 600) {
// Launcher should be perceptible, don't kill it.
oom_adj_score = 200;
soft_limit_mult = 1;
} else if (proc.oomadj >= 500) {
soft_limit_mult = 0;
} else if (proc.oomadj >= 400) {
soft_limit_mult = 0;
} else if (proc.oomadj >= 300) {
soft_limit_mult = 1;
} else if (proc.oomadj >= 200) {
soft_limit_mult = 8;
} else if (proc.oomadj >= 100) {
soft_limit_mult = 10;
} else if (proc.oomadj >= 0) {
soft_limit_mult = 20;
} else {
// Persistent processes will have a large
// soft limit 512MB.
soft_limit_mult = 64;
}
std::string soft_limit_path;
if (!CgroupGetAttributePathForTask("MemSoftLimit", proc.pid, &soft_limit_path)) {
ALOGE("Querying MemSoftLimit path failed");
return;
}
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 = (oom_adj_score == SYSTEM_ADJ && (pwdrec = getpwnam("system")) != NULL &&
proc.uid == pwdrec->pw_uid);
writefilestring(soft_limit_path.c_str(), val, !is_system_server);
}
procp = pid_lookup(proc.pid);
if (!procp) {
int pidfd = -1;
if (pidfd_supported) {
pidfd = TEMP_FAILURE_RETRY(pidfd_open(proc.pid, 0));
if (pidfd < 0) {
ALOGE("pidfd_open for pid %d failed; errno=%d", proc.pid, errno);
return;
}
}
procp = static_cast<struct proc*>(calloc(1, sizeof(struct proc)));
if (!procp) {
// Oh, the irony. May need to rebuild our state.
return;
}
procp->pid = proc.pid;
procp->pidfd = pidfd;
procp->uid = proc.uid;
procp->reg_pid = cred->pid;
procp->oomadj = oom_adj_score;
procp->valid = true;
proc_insert(procp);
} else {
if (!claim_record(procp, cred->pid)) {
char buf[LINE_MAX];
char *taskname = proc_get_name(cred->pid, buf, sizeof(buf));
/* Only registrant of the record can remove it */
ALOGE("%s (%d, %d) attempts to modify a process registered by another client",
taskname ? taskname : "A process ", cred->uid, cred->pid);
return;
}
proc_unslot(procp);
procp->oomadj = oom_adj_score;
proc_slot(procp);
}
}
static void apply_proc_prio(const struct lmk_procprio& params, struct ucred* cred) {
char path[PROCFS_PATH_MAX];
char val[20];
int64_t tgid;
char buf[pagesize];
if (params.oomadj < OOM_SCORE_ADJ_MIN || params.oomadj > OOM_SCORE_ADJ_MAX) {
ALOGE("Invalid PROCPRIO oomadj argument %d", params.oomadj);
return;
}
if (params.ptype < PROC_TYPE_FIRST || params.ptype >= PROC_TYPE_COUNT) {
ALOGE("Invalid PROCPRIO process type argument %d", params.ptype);
return;
}
/* Check if registered process is a thread group leader */
if (read_proc_status(params.pid, buf, sizeof(buf))) {
if (parse_status_tag(buf, PROC_STATUS_TGID_FIELD, &tgid) && tgid != params.pid) {
ALOGE("Attempt to register a task that is not a thread group leader "
"(tid %d, tgid %" PRId64 ")",
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)));
return;
}
register_oom_adj_proc(params, cred);
}
static void cmd_procprio(LMKD_CTRL_PACKET packet, int field_count, struct ucred* cred) {
struct lmk_procprio proc_prio;
lmkd_pack_get_procprio(packet, field_count, &proc_prio);
apply_proc_prio(proc_prio, cred);
}
static void cmd_procremove(LMKD_CTRL_PACKET packet, struct ucred *cred) {
struct lmk_procremove params;
struct proc *procp;
lmkd_pack_get_procremove(packet, &params);
if (use_inkernel_interface) {
/*
* Perform an extra check before the pid is removed, after which it
* will be impossible for poll_kernel to get the taskname. poll_kernel()
* is potentially a long-running blocking function; however this method
* handles AMS requests but does not block AMS.
*/
poll_kernel(kpoll_fd);
stats_remove_taskname(params.pid);
return;
}
procp = pid_lookup(params.pid);
if (!procp) {
return;
}
if (!claim_record(procp, cred->pid)) {
char buf[LINE_MAX];
char *taskname = proc_get_name(cred->pid, buf, sizeof(buf));
/* Only registrant of the record can remove it */
ALOGE("%s (%d, %d) attempts to unregister a process registered by another client",
taskname ? taskname : "A process ", cred->uid, cred->pid);
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(struct ucred *cred) {
int i;
struct proc *procp;
struct proc *next;
if (use_inkernel_interface) {
stats_purge_tasknames();
return;
}
for (i = 0; i < PIDHASH_SZ; i++) {
procp = pidhash[i];
while (procp) {
next = procp->pidhash_next;
/* Purge only records created by the requestor */
if (claim_record(procp, cred->pid)) {
pid_remove(procp->pid);
}
procp = next;
}
}
}
static void cmd_subscribe(int dsock_idx, LMKD_CTRL_PACKET packet) {
struct lmk_subscribe params;
lmkd_pack_get_subscribe(packet, &params);
data_sock[dsock_idx].async_event_mask |= 1 << params.evt_type;
}
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)lowmem_adj.size()) {
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 cmd_procs_prio(LMKD_CTRL_PACKET packet, const int field_count, struct ucred* cred) {
struct lmk_procs_prio params;
const int procs_count = lmkd_pack_get_procs_prio(packet, &params, field_count);
if (procs_count < 0) {
ALOGE("LMK_PROCS_PRIO received invalid packet format");
return;
}
for (int i = 0; i < procs_count; i++) {
apply_proc_prio(params.procs[i], cred);
}
}
static void ctrl_command_handler(int dsock_idx) {
LMKD_CTRL_PACKET packet;
struct ucred cred;
int len;
enum lmk_cmd cmd;
int nargs;
int targets;
int kill_cnt;
int result;
len = ctrl_data_read(dsock_idx, (char *)packet, CTRL_PACKET_MAX_SIZE, &cred);
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)lowmem_adj.size()) {
goto wronglen;
}
cmd_target(targets, packet);
break;
case LMK_PROCPRIO:
/* process type field is optional for backward compatibility */
if (nargs < 3 || nargs > 4)
goto wronglen;
cmd_procprio(packet, nargs, &cred);
break;
case LMK_PROCREMOVE:
if (nargs != 1)
goto wronglen;
cmd_procremove(packet, &cred);
break;
case LMK_PROCPURGE:
if (nargs != 0)
goto wronglen;
cmd_procpurge(&cred);
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;
case LMK_SUBSCRIBE:
if (nargs != 1)
goto wronglen;
cmd_subscribe(dsock_idx, packet);
break;
case LMK_PROCKILL:
/* This command code is NOT expected at all */
ALOGE("Received unexpected command code %d", cmd);
break;
case LMK_UPDATE_PROPS:
if (nargs != 0)
goto wronglen;
result = -1;
if (update_props()) {
if (!use_inkernel_interface && monitors_initialized) {
/* Reinitialize monitors to apply new settings */
destroy_monitors();
if (init_monitors()) {
result = 0;
}
} else {
result = 0;
}
if (direct_reclaim_threshold_ms > 0 && !memevent_listener) {
ALOGW("Kernel support for direct_reclaim_threshold_ms is not found");
direct_reclaim_threshold_ms = 0;
}
}
len = lmkd_pack_set_update_props_repl(packet, result);
if (ctrl_data_write(dsock_idx, (char *)packet, len) != len) {
ALOGE("Failed to report operation results");
}
if (!result) {
ALOGI("Properties reinitilized");
} else {
/* New settings can't be supported, crash to be restarted */
ALOGE("New configuration is not supported. Exiting...");
exit(1);
}
break;
case LMK_START_MONITORING:
if (nargs != 0)
goto wronglen;
// Registration is needed only if it was skipped earlier.
if (monitors_initialized)
return;
if (!property_get_bool("sys.boot_completed", false)) {
ALOGE("LMK_START_MONITORING cannot be handled before boot completed");
return;
}
if (!init_monitors()) {
/* Failure to start psi monitoring, crash to be restarted */
ALOGE("Failure to initialize monitoring. Exiting...");
exit(1);
}
ALOGI("Initialized monitors after boot completed.");
break;
case LMK_BOOT_COMPLETED:
if (nargs != 0) goto wronglen;
if (boot_completed_handled) {
/* Notify we have already handled post boot-up operations */
result = 1;
} else if (!property_get_bool("sys.boot_completed", false)) {
ALOGE("LMK_BOOT_COMPLETED cannot be handled before boot completed");
result = -1;
} else {
/*
* Initialize the memevent listener after boot is completed to prevent
* waiting, during boot-up, for BPF programs to be loaded.
*/
if (init_memevent_listener_monitoring()) {
ALOGI("Using memevents for direct reclaim and kswapd detection");
} else {
ALOGI("Using vmstats for direct reclaim and kswapd detection");
if (direct_reclaim_threshold_ms > 0) {
ALOGW("Kernel support for direct_reclaim_threshold_ms is not found");
direct_reclaim_threshold_ms = 0;
}
}
result = 0;
boot_completed_handled = true;
}
len = lmkd_pack_set_boot_completed_notif_repl(packet, result);
if (ctrl_data_write(dsock_idx, (char*)packet, len) != len) {
ALOGE("Failed to report boot-completed operation results");
}
break;
case LMK_PROCS_PRIO:
cmd_procs_prio(packet, nargs, &cred);
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;
data_sock[free_dscock_idx].async_event_mask = 0;
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) {
line = strtok_r(NULL, "\n", &save_ptr);
if (strncmp(line, NODE_STATS_MARKER, strlen(NODE_STATS_MARKER)) != 0) {
/*
* per-node stats are only present in the first non-empty zone of
* the node.
*/
continue;
}
/* 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;
}
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 int64_t read_gpu_total_kb() {
static android::base::unique_fd fd(
android::bpf::mapRetrieveRO("/sys/fs/bpf/map_gpuMem_gpu_mem_total_map"));
static constexpr uint64_t kBpfKeyGpuTotalUsage = 0;
uint64_t value;
if (!fd.ok()) {
return 0;
}
return android::bpf::findMapEntry(fd, &kBpfKeyGpuTotalUsage, &value)
? 0
: (int32_t)(value / 1024);
}
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;
mi->field.total_gpu_kb = read_gpu_total_kb();
mi->field.easy_available = mi->field.nr_free_pages + mi->field.inactive_file;
return 0;
}
// In the case of ZRAM, mi->field.free_swap can't be used directly because swap space is taken
// from the free memory or reclaimed. Use the lowest of free_swap and easily available memory to
// measure free swap because they represent how much swap space the system will consider to use
// and how much it can actually use.
// Swap compression ratio in the calculation can be adjusted using swap_compression_ratio tunable.
// By setting swap_compression_ratio to 0, available memory can be ignored.
static inline int64_t get_free_swap(union meminfo *mi) {
if (swap_compression_ratio)
return std::min(mi->field.free_swap, mi->field.easy_available * swap_compression_ratio);
return mi->field.free_swap;
}
/* /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 int psi_parse(struct reread_data *file_data, struct psi_stats stats[], bool full) {
char *buf;
char *save_ptr;
char *line;
if ((buf = reread_file(file_data)) == NULL) {
return -1;
}
line = strtok_r(buf, "\n", &save_ptr);
if (parse_psi_line(line, PSI_SOME, stats)) {
return -1;
}
if (full) {
line = strtok_r(NULL, "\n", &save_ptr);
if (parse_psi_line(line, PSI_FULL, stats)) {
return -1;
}
}
return 0;
}
static int psi_parse_mem(struct psi_data *psi_data) {
static struct reread_data file_data = {
.filename = psi_resource_file[PSI_MEMORY],
.fd = -1,
};
return psi_parse(&file_data, psi_data->mem_stats, true);
}
static int psi_parse_io(struct psi_data *psi_data) {
static struct reread_data file_data = {
.filename = psi_resource_file[PSI_IO],
.fd = -1,
};
return psi_parse(&file_data, psi_data->io_stats, true);
}
static int psi_parse_cpu(struct psi_data *psi_data) {
static struct reread_data file_data = {
.filename = psi_resource_file[PSI_CPU],
.fd = -1,
};
return psi_parse(&file_data, psi_data->cpu_stats, false);
}
enum wakeup_reason {
Event,
Polling
};
struct wakeup_info {
struct timespec wakeup_tm;
struct timespec prev_wakeup_tm;
struct timespec last_event_tm;
int wakeups_since_event;
int skipped_wakeups;
};
/*
* After the initial memory pressure event is received lmkd schedules periodic wakeups to check
* the memory conditions and kill if needed (polling). This is done because pressure events are
* rate-limited and memory conditions can change in between events. Therefore after the initial
* event there might be multiple wakeups. This function records the wakeup information such as the
* timestamps of the last event and the last wakeup, the number of wakeups since the last event
* and how many of those wakeups were skipped (some wakeups are skipped if previously killed
* process is still freeing its memory).
*/
static void record_wakeup_time(struct timespec *tm, enum wakeup_reason reason,
struct wakeup_info *wi) {
wi->prev_wakeup_tm = wi->wakeup_tm;
wi->wakeup_tm = *tm;
if (reason == Event) {
wi->last_event_tm = *tm;
wi->wakeups_since_event = 0;
wi->skipped_wakeups = 0;
} else {
wi->wakeups_since_event++;
}
}
struct kill_info {
enum kill_reasons kill_reason;
const char *kill_desc;
int thrashing;
int max_thrashing;
};
static void killinfo_log(struct proc* procp, int min_oom_score, int rss_kb,
int swap_kb, struct kill_info *ki, union meminfo *mi,
struct wakeup_info *wi, struct timespec *tm, struct psi_data *pd) {
/* 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, std::min(rss_kb, (int)INT32_MAX));
android_log_write_int32(ctx, ki ? ki->kill_reason : NONE);
/* log meminfo fields */
for (int field_idx = 0; field_idx < MI_FIELD_COUNT; field_idx++) {
android_log_write_int32(ctx,
mi ? std::min(mi->arr[field_idx] * page_k, (int64_t)INT32_MAX) : 0);
}
/* log lmkd wakeup information */
if (wi) {
android_log_write_int32(ctx, (int32_t)get_time_diff_ms(&wi->last_event_tm, tm));
android_log_write_int32(ctx, (int32_t)get_time_diff_ms(&wi->prev_wakeup_tm, tm));
android_log_write_int32(ctx, wi->wakeups_since_event);
android_log_write_int32(ctx, wi->skipped_wakeups);
} else {
android_log_write_int32(ctx, 0);
android_log_write_int32(ctx, 0);
android_log_write_int32(ctx, 0);
android_log_write_int32(ctx, 0);
}
android_log_write_int32(ctx, std::min(swap_kb, (int)INT32_MAX));
android_log_write_int32(ctx, mi ? (int32_t)mi->field.total_gpu_kb : 0);
if (ki) {
android_log_write_int32(ctx, ki->thrashing);
android_log_write_int32(ctx, ki->max_thrashing);
} else {
android_log_write_int32(ctx, 0);
android_log_write_int32(ctx, 0);
}
if (pd) {
android_log_write_float32(ctx, pd->mem_stats[PSI_SOME].avg10);
android_log_write_float32(ctx, pd->mem_stats[PSI_FULL].avg10);
android_log_write_float32(ctx, pd->io_stats[PSI_SOME].avg10);
android_log_write_float32(ctx, pd->io_stats[PSI_FULL].avg10);
android_log_write_float32(ctx, pd->cpu_stats[PSI_SOME].avg10);
} else {
for (int i = 0; i < 5; i++) {
android_log_write_float32(ctx, 0);
}
}
android_log_write_list(ctx, LOG_ID_EVENTS);
android_log_reset(ctx);
}
// Note: returned entry is only an anchor and does not hold a valid process info.
// When called from a non-main thread, adjslot_list_lock read lock should be taken.
static struct proc *proc_adj_head(int oomadj) {
return (struct proc *)&procadjslot_list[ADJTOSLOT(oomadj)];
}
// When called from a non-main thread, adjslot_list_lock read lock should be taken.
static struct proc *proc_adj_tail(int oomadj) {
return (struct proc *)adjslot_tail(&procadjslot_list[ADJTOSLOT(oomadj)]);
}
// When called from a non-main thread, adjslot_list_lock read lock should be taken.
static struct proc *proc_adj_prev(int oomadj, int pid) {
struct adjslot_list *head = &procadjslot_list[ADJTOSLOT(oomadj)];
struct adjslot_list *curr = adjslot_tail(&procadjslot_list[ADJTOSLOT(oomadj)]);
while (curr != head) {
if (((struct proc *)curr)->pid == pid) {
return (struct proc *)curr->prev;
}
curr = curr->prev;
}
return NULL;
}
// Can be called only from the main thread.
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;
if ((curr != head) && (curr->next == head)) {
// Our list only has one process.  No need to access procfs for its size.
return (struct proc *)curr;
}
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 bool find_victim(int oom_score, int prev_pid, struct proc &target_proc) {
struct proc *procp;
std::shared_lock lock(adjslot_list_lock);
if (!prev_pid) {
procp = proc_adj_tail(oom_score);
} else {
procp = proc_adj_prev(oom_score, prev_pid);
if (!procp) {
// pid was removed, restart at the tail
procp = proc_adj_tail(oom_score);
}
}
// the list is empty at this oom_score or we looped through it
if (!procp || procp == proc_adj_head(oom_score)) {
return false;
}
// make a copy because original might be destroyed after adjslot_list_lock is released
target_proc = *procp;
return true;
}
static void watchdog_callback() {
int prev_pid = 0;
ALOGW("lmkd watchdog timed out!");
for (int oom_score = OOM_SCORE_ADJ_MAX; oom_score >= 0;) {
struct proc target;
if (!find_victim(oom_score, prev_pid, target)) {
oom_score--;
prev_pid = 0;
continue;
}
if (target.valid && reaper.kill({ target.pidfd, target.pid, target.uid }, true) == 0) {
ALOGW("lmkd watchdog killed process %d, oom_score_adj %d", target.pid, oom_score);
killinfo_log(&target, 0, 0, 0, NULL, NULL, NULL, NULL, NULL);
// Can't call pid_remove() from non-main thread, therefore just invalidate the record
pid_invalidate(target.pid);
break;
}
prev_pid = target.pid;
}
}
static Watchdog watchdog(WATCHDOG_TIMEOUT_SEC, watchdog_callback);
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)) {
// Log an error and keep going
ALOGE("epoll_ctl for last killed process failed; errno=%d", errno);
}
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 kill_fail_handler(int data __unused, uint32_t events __unused,
struct polling_params *poll_params) {
int pid;
// Extract pid from the communication pipe. Clearing the pipe this way allows further
// epoll_wait calls to sleep until the next event.
if (TEMP_FAILURE_RETRY(read(reaper_comm_fd[0], &pid, sizeof(pid))) != sizeof(pid)) {
ALOGE("thread communication read failed: %s", strerror(errno));
}
stop_wait_for_proc_kill(false);
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 (in pages) of the process killed */
static int kill_one_process(struct proc* procp, int min_oom_score, struct kill_info *ki,
union meminfo *mi, struct wakeup_info *wi, struct timespec *tm,
struct psi_data *pd) {
int pid = procp->pid;
int pidfd = procp->pidfd;
uid_t uid = procp->uid;
char *taskname;
int kill_result;
int result = -1;
struct memory_stat *mem_st;
struct kill_stat kill_st;
int64_t tgid;
int64_t rss_kb;
int64_t swap_kb;
char buf[pagesize];
char desc[LINE_MAX];
if (!procp->valid || !read_proc_status(pid, buf, sizeof(buf))) {
goto out;
}
if (!parse_status_tag(buf, PROC_STATUS_TGID_FIELD, &tgid)) {
ALOGE("Unable to parse tgid from /proc/%d/status", pid);
goto out;
}
if (tgid != pid) {
ALOGE("Possible pid reuse detected (pid %d, tgid %" PRId64 ")!", pid, tgid);
goto out;
}
// Zombie processes will not have RSS / Swap fields.
if (!parse_status_tag(buf, PROC_STATUS_RSS_FIELD, &rss_kb)) {
goto out;
}
if (!parse_status_tag(buf, PROC_STATUS_SWAP_FIELD, &swap_kb)) {
goto out;
}
taskname = proc_get_name(pid, buf, sizeof(buf));
// taskname will point inside buf, do not reuse buf onwards.
if (!taskname) {
goto out;
}
mem_st = stats_read_memory_stat(per_app_memcg, pid, uid, rss_kb * 1024, swap_kb * 1024);
snprintf(desc, sizeof(desc), "lmk,%d,%d,%d,%d,%d", pid, ki ? (int)ki->kill_reason : -1,
procp->oomadj, min_oom_score, ki ? ki->max_thrashing : -1);
result = lmkd_free_memory_before_kill_hook(procp, rss_kb / page_k, procp->oomadj,
ki ? (int)ki->kill_reason : -1);
if (result > 0) {
/*
* Memory was freed elsewhere; no need to kill. Note: intentionally do not
* pid_remove(pid) since it was not killed.
*/
ALOGI("Skipping kill; %ld kB freed elsewhere.", result * page_k);
return result;
}
trace_kill_start(desc);
start_wait_for_proc_kill(pidfd < 0 ? pid : pidfd);
kill_result = reaper.kill({ pidfd, pid, uid }, false);
trace_kill_end();
if (kill_result) {
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;
}
last_kill_tm = *tm;
inc_killcnt(procp->oomadj);
if (ki) {
kill_st.kill_reason = ki->kill_reason;
kill_st.thrashing = ki->thrashing;
kill_st.max_thrashing = ki->max_thrashing;
ALOGI("Kill '%s' (%d), uid %d, oom_score_adj %d to free %" PRId64 "kB rss, %" PRId64
"kB swap; reason: %s", taskname, pid, uid, procp->oomadj, rss_kb, swap_kb,
ki->kill_desc);
} else {
kill_st.kill_reason = NONE;
kill_st.thrashing = 0;
kill_st.max_thrashing = 0;
ALOGI("Kill '%s' (%d), uid %d, oom_score_adj %d to free %" PRId64 "kB rss, %" PRId64
"kb swap", taskname, pid, uid, procp->oomadj, rss_kb, swap_kb);
}
killinfo_log(procp, min_oom_score, rss_kb, swap_kb, ki, mi, wi, tm, pd);
kill_st.uid = static_cast<int32_t>(uid);
kill_st.taskname = taskname;
kill_st.oom_score = procp->oomadj;
kill_st.min_oom_score = min_oom_score;
kill_st.free_mem_kb = mi->field.nr_free_pages * page_k;
kill_st.free_swap_kb = get_free_swap(mi) * page_k;
stats_write_lmk_kill_occurred(&kill_st, mem_st);
ctrl_data_write_lmk_kill_occurred((pid_t)pid, uid, rss_kb);
result = rss_kb / page_k;
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_score_adj level.
* Returns size of the killed process.
*/
static int find_and_kill_process(int min_score_adj, struct kill_info *ki, union meminfo *mi,
struct wakeup_info *wi, struct timespec *tm,
struct psi_data *pd) {
int i;
int killed_size = 0;
bool choose_heaviest_task = kill_heaviest_task;
for (i = OOM_SCORE_ADJ_MAX; i >= min_score_adj; i--) {
struct proc *procp;
if (!choose_heaviest_task && i <= PERCEPTIBLE_APP_ADJ) {
/*
* If we have to choose a perceptible process, choose the heaviest one to
* hopefully minimize the number of victims.
*/
choose_heaviest_task = true;
}
while (true) {
procp = choose_heaviest_task ?
proc_get_heaviest(i) : proc_adj_tail(i);
if (!procp)
break;
killed_size = kill_one_process(procp, min_score_adj, ki, mi, wi, tm, pd);
if (killed_size >= 0) {
break;
}
}
if (killed_size) {
break;
}
}
return killed_size;
}
static int64_t get_memory_usage(struct reread_data *file_data) {
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;
};
static struct zone_watermarks watermarks;
/*
* 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 int update_zoneinfo_watermarks(struct zoneinfo *zi) {
if (zoneinfo_parse(zi) < 0) {
ALOGE("Failed to parse zoneinfo!");
return -1;
}
calc_zone_watermarks(zi, &watermarks);
return 0;
}
static int calc_swap_utilization(union meminfo *mi) {
int64_t swap_used = mi->field.total_swap - get_free_swap(mi);
int64_t total_swappable = mi->field.active_anon + mi->field.inactive_anon +
mi->field.shmem + swap_used;
return total_swappable > 0 ? (swap_used * 100) / total_swappable : 0;
}
enum event_source {
PSI,
VENDOR,
};
union psi_event_data {
enum vmpressure_level level;
mem_event_t vendor_event;
};
static void __mp_event_psi(enum event_source source, union psi_event_data data,
uint32_t events, struct polling_params *poll_params) {
enum reclaim_state {
NO_RECLAIM = 0,
KSWAPD_RECLAIM,
DIRECT_RECLAIM,
};
static int64_t init_ws_refault;
static int64_t prev_workingset_refault;
static int64_t base_file_lru;
static int64_t init_pgscan_kswapd;
static int64_t init_pgscan_direct;
static int64_t init_pgrefill;
static bool killing;
static int thrashing_limit = thrashing_limit_pct;
static struct timespec wmark_update_tm;
static struct wakeup_info wi;
static struct timespec thrashing_reset_tm;
static int64_t prev_thrash_growth = 0;
static bool check_filecache = false;
static int max_thrashing = 0;
union meminfo mi;
union vmstat vs;
struct psi_data psi_data;
struct timespec curr_tm;
int64_t thrashing = 0;
bool swap_is_low = false;
enum vmpressure_level level = (source == PSI) ? data.level: (enum vmpressure_level)0;
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;
int swap_util = 0;
int64_t swap_low_threshold;
long since_thrashing_reset_ms;
int64_t workingset_refault_file;
bool critical_stall = false;
bool in_direct_reclaim;
long direct_reclaim_duration_ms;
bool in_kswapd_reclaim;
mp_event_count++;
if (debug_process_killing) {
if (source == PSI)
ALOGI("%s memory pressure event #%" PRIu64 " is triggered",
level_name[level], mp_event_count);
else
ALOGI("vendor kill event #%" PRIu64 " is triggered", mp_event_count);
}
if (clock_gettime(CLOCK_MONOTONIC_COARSE, &curr_tm) != 0) {
ALOGE("Failed to get current time");
return;
}
if (source == PSI) {
if (events > 0 ) {
/* Ignore a lower event within the first polling window. */
if (level < prev_level) {
if (debug_process_killing)
ALOGI("Ignoring %s pressure event; occurred too soon.",
level_name[level]);
return;
}
prev_level = level;
} else {
/* Reset event level after the first polling window. */
prev_level = VMPRESS_LEVEL_LOW;
}
record_wakeup_time(&curr_tm, events ? Event : Polling, &wi);
}
bool kill_pending = is_kill_pending();
if (kill_pending && (kill_timeout_ms == 0 ||
get_time_diff_ms(&last_kill_tm, &curr_tm) < static_cast<long>(kill_timeout_ms))) {
/* Skip while still killing a process */
wi.skipped_wakeups++;
goto no_kill;
}
/*
* Process is dead or kill timeout is over, stop waiting. This has no effect if pidfds are
* supported and death notification already caused waiting to stop.
*/
stop_wait_for_proc_kill(!kill_pending);
if (vmstat_parse(&vs) < 0) {
ALOGE("Failed to parse vmstat!");
return;
}
/* Starting 5.9 kernel workingset_refault vmstat field was renamed workingset_refault_file */
workingset_refault_file = vs.field.workingset_refault ? : vs.field.workingset_refault_file;
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 = workingset_refault_file;
thrashing_reset_tm = curr_tm;
prev_thrash_growth = 0;
}
/* Check free swap levels */
if (swap_free_low_percentage) {
swap_low_threshold = mi.field.total_swap * swap_free_low_percentage / 100;
swap_is_low = get_free_swap(&mi) < swap_low_threshold;
} else {
swap_low_threshold = 0;
}
if (memevent_listener) {
in_direct_reclaim =
direct_reclaim_start_tm.tv_sec != 0 || direct_reclaim_start_tm.tv_nsec != 0;
in_kswapd_reclaim = kswapd_start_tm.tv_sec != 0 || kswapd_start_tm.tv_nsec != 0;
} else {
in_direct_reclaim = vs.field.pgscan_direct != init_pgscan_direct;
in_kswapd_reclaim = (vs.field.pgscan_kswapd != init_pgscan_kswapd) ||
(vs.field.pgrefill != init_pgrefill);
}
/* Identify reclaim state */
if (in_direct_reclaim) {
init_pgscan_direct = vs.field.pgscan_direct;
init_pgscan_kswapd = vs.field.pgscan_kswapd;
init_pgrefill = vs.field.pgrefill;
direct_reclaim_duration_ms = get_time_diff_ms(&direct_reclaim_start_tm, &curr_tm);
reclaim = DIRECT_RECLAIM;
} else if (in_kswapd_reclaim) {
init_pgscan_kswapd = vs.field.pgscan_kswapd;
init_pgrefill = vs.field.pgrefill;
reclaim = KSWAPD_RECLAIM;
} else if ((workingset_refault_file == prev_workingset_refault) &&
(source == PSI)) {
/*
* Device is not thrashing and not reclaiming, bail out early until we see these stats
* changing
*/
goto no_kill;
}
prev_workingset_refault = workingset_refault_file;
/*
* It's possible we fail to find an eligible process to kill (ex. no process is
* above oom_adj_min). When this happens, we should retry to find a new process
* for a kill whenever a new eligible process is available. This is especially
* important for a slow growing refault case. While retrying, we should keep
* monitoring new thrashing counter as someone could release the memory to mitigate
* the thrashing. Thus, when thrashing reset window comes, we decay the prev thrashing
* counter by window counts. If the counter is still greater than thrashing limit,
* we preserve the current prev_thrash counter so we will retry kill again. Otherwise,
* we reset the prev_thrash counter so we will stop retrying.
*/
since_thrashing_reset_ms = get_time_diff_ms(&thrashing_reset_tm, &curr_tm);
if (since_thrashing_reset_ms > THRASHING_RESET_INTERVAL_MS) {
long windows_passed;
/* Calculate prev_thrash_growth if we crossed THRASHING_RESET_INTERVAL_MS */
prev_thrash_growth = (workingset_refault_file - init_ws_refault) * 100
/ (base_file_lru + 1);
windows_passed = (since_thrashing_reset_ms / THRASHING_RESET_INTERVAL_MS);
/*
* Decay prev_thrashing unless over-the-limit thrashing was registered in the window we
* just crossed, which means there were no eligible processes to kill. We preserve the
* counter in that case to ensure a kill if a new eligible process appears.
*/
if (windows_passed > 1 || prev_thrash_growth < thrashing_limit) {
prev_thrash_growth >>= windows_passed;
}
/* Record file-backed pagecache size when crossing THRASHING_RESET_INTERVAL_MS */
base_file_lru = vs.field.nr_inactive_file + vs.field.nr_active_file;
init_ws_refault = workingset_refault_file;
thrashing_reset_tm = curr_tm;
thrashing_limit = thrashing_limit_pct;
} else {
/* Calculate what % of the file-backed pagecache refaulted so far */
thrashing = (workingset_refault_file - init_ws_refault) * 100 / (base_file_lru + 1);
}
/* Add previous cycle's decayed thrashing amount */
thrashing += prev_thrash_growth;
if (max_thrashing < thrashing) {
max_thrashing = thrashing;
}
update_watermarks:
/*
* Refresh watermarks:
* 1. watermarks haven't been initialized (high_wmark == 0)
* 2. per min in case user updated one of the margins if mem_event update_zoneinfo is NOT
* supported.
*/
if (watermarks.high_wmark == 0 || (!mem_event_update_zoneinfo_supported &&
get_time_diff_ms(&wmark_update_tm, &curr_tm) > 60000)) {
struct zoneinfo zi;
if (update_zoneinfo_watermarks(&zi) < 0) {
return;
}
wmark_update_tm = curr_tm;
}
/* Find out which watermark is breached if any */
wmark = get_lowest_watermark(&mi, &watermarks);
if (!psi_parse_mem(&psi_data)) {
critical_stall = psi_data.mem_stats[PSI_FULL].avg10 > (float)stall_limit_critical;
}
/*
* TODO: move this logic into a separate function
* Decide if killing a process is necessary and record the reason
*/
if (source == VENDOR) {
int vendor_kill_reason = data.vendor_event.event_data.vendor_kill.reason;
short vendor_kill_min_oom_score_adj =
data.vendor_event.event_data.vendor_kill.min_oom_score_adj;
if (vendor_kill_reason < 0 ||
vendor_kill_reason > VENDOR_KILL_REASON_END ||
vendor_kill_min_oom_score_adj < 0) {
ALOGE("Invalid vendor kill reason %d, min_oom_score_adj %d",
vendor_kill_reason, vendor_kill_min_oom_score_adj);
return;
}
kill_reason = (enum kill_reasons)(vendor_kill_reason + VENDOR_KILL_REASON_BASE);
min_score_adj = vendor_kill_min_oom_score_adj;
snprintf(kill_desc, sizeof(kill_desc),
"vendor kill with the reason %d, min_score_adj %d", kill_reason, min_score_adj);
} else 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.
*/
min_score_adj = pressure_after_kill_min_score;
kill_reason = PRESSURE_AFTER_KILL;
strncpy(kill_desc, "min watermark is breached even after kill", sizeof(kill_desc));
kill_desc[sizeof(kill_desc) - 1] = '\0';
} 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));
kill_desc[sizeof(kill_desc) - 1] = '\0';
} 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 "%%)",
get_free_swap(&mi) * page_k, swap_low_threshold * page_k, thrashing);
/* Do not kill perceptible apps unless below min watermark or heavily thrashing */
if (wmark > WMARK_MIN && thrashing < thrashing_critical_pct) {
min_score_adj = PERCEPTIBLE_APP_ADJ + 1;
}
check_filecache = true;
} 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",
get_free_swap(&mi) * page_k, swap_low_threshold * page_k);
/* Do not kill perceptible apps unless below min watermark or heavily thrashing */
if (wmark > WMARK_MIN && thrashing < thrashing_critical_pct) {
min_score_adj = PERCEPTIBLE_APP_ADJ + 1;
}
} else if (wmark < WMARK_HIGH && swap_util_max < 100 &&
(swap_util = calc_swap_utilization(&mi)) > swap_util_max) {
/*
* Too much anon memory is swapped out but swap is not low.
* Non-swappable allocations created memory pressure.
*/
kill_reason = LOW_MEM_AND_SWAP_UTIL;
snprintf(kill_desc, sizeof(kill_desc), "%s watermark is breached and swap utilization"
" is high (%d%% > %d%%)", wmark < WMARK_LOW ? "min" : "low",
swap_util, swap_util_max);
} 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 unless thrashing at critical levels */
if (thrashing < thrashing_critical_pct) {
min_score_adj = PERCEPTIBLE_APP_ADJ + 1;
}
check_filecache = true;
} 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 unless thrashing at critical levels */
if (thrashing < thrashing_critical_pct) {
min_score_adj = PERCEPTIBLE_APP_ADJ + 1;
}
check_filecache = true;
} else if (reclaim == DIRECT_RECLAIM && direct_reclaim_threshold_ms > 0 &&
direct_reclaim_duration_ms > direct_reclaim_threshold_ms) {
kill_reason = DIRECT_RECL_STUCK;
snprintf(kill_desc, sizeof(kill_desc), "device is stuck in direct reclaim (%ldms > %dms)",
direct_reclaim_duration_ms, direct_reclaim_threshold_ms);
} else if (check_filecache) {
int64_t file_lru_kb = (vs.field.nr_inactive_file + vs.field.nr_active_file) * page_k;
if (file_lru_kb < filecache_min_kb) {
/* File cache is too low after thrashing, keep killing background processes */
kill_reason = LOW_FILECACHE_AFTER_THRASHING;
snprintf(kill_desc, sizeof(kill_desc),
"filecache is low (%" PRId64 "kB < %" PRId64 "kB) after thrashing",
file_lru_kb, filecache_min_kb);
min_score_adj = PERCEPTIBLE_APP_ADJ + 1;
} else {
/* File cache is big enough, stop checking */
check_filecache = false;
}
}
/* Check if a cached app should be killed */
if (kill_reason == NONE && wmark < WMARK_HIGH) {
kill_reason = LOW_MEM;
snprintf(kill_desc, sizeof(kill_desc), "%s watermark is breached",
wmark < WMARK_LOW ? "min" : "low");
min_score_adj = lowmem_min_oom_score;
}
/* Kill a process if necessary */
if (kill_reason != NONE) {
struct kill_info ki = {
.kill_reason = kill_reason,
.kill_desc = kill_desc,
.thrashing = (int)thrashing,
.max_thrashing = max_thrashing,
};
static bool first_kill = true;
/* Make sure watermarks are correct before the first kill */
if (first_kill) {
first_kill = false;
watermarks.high_wmark = 0; // force recomputation
goto update_watermarks;
}
/* Allow killing perceptible apps if the system is stalled */
if (critical_stall) {
min_score_adj = 0;
}
psi_parse_io(&psi_data);
psi_parse_cpu(&psi_data);
int pages_freed = find_and_kill_process(min_score_adj, &ki, &mi, &wi, &curr_tm, &psi_data);
if (pages_freed > 0) {
killing = true;
max_thrashing = 0;
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_psi(int data, uint32_t events, struct polling_params *poll_params) {
union psi_event_data event_data = {.level = (enum vmpressure_level)data};
__mp_event_psi(PSI, event_data, events, poll_params);
}
static std::string GetCgroupAttributePath(const char* attr) {
std::string path;
if (!CgroupGetAttributePath(attr, &path)) {
ALOGE("Unknown cgroup attribute %s", attr);
}
return path;
}
// The implementation of this function relies on memcg statistics that are only available in the
// v1 cgroup hierarchy.
static void mp_event_common(int data, uint32_t events, struct polling_params *poll_params) {
unsigned long long evcount;
int64_t mem_usage, memsw_usage;
int64_t mem_pressure;
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 const std::string mem_usage_path = GetCgroupAttributePath("MemUsage");
static struct reread_data mem_usage_file_data = {
.filename = mem_usage_path.c_str(),
.fd = -1,
};
static const std::string memsw_usage_path = GetCgroupAttributePath("MemAndSwapUsage");
static struct reread_data memsw_usage_file_data = {
.filename = memsw_usage_path.c_str(),
.fd = -1,
};
static struct wakeup_info wi;
mp_event_count++;
if (debug_process_killing) {
ALOGI("%s memory pressure event #%" PRIu64 " is triggered",
level_name[level], mp_event_count);
}
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 (int 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 = static_cast<vmpressure_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;
}
record_wakeup_time(&curr_tm, events ? Event : Polling, &wi);
if (kill_timeout_ms &&
get_time_diff_ms(&last_kill_tm, &curr_tm) < static_cast<long>(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++;
wi.skipped_wakeups++;
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 && lowmem_targets_size) {
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 (get_free_swap(&mi) >=
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(use_minfree_levels ? min_score_adj : level_oomadj[level],
NULL, &mi, &wi, &curr_tm, NULL) == 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, NULL, &mi, &wi, &curr_tm, NULL);
if (pages_freed == 0 && min_score_adj == 0) {
lmkd_no_kill_candidates_hook();
}
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_score_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_score_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 (fd < 0) {
return;
}
if (unregister_psi_monitor(epollfd, fd) < 0) {
ALOGE("Failed to unregister psi monitor for %s memory pressure; errno=%d",
level_name[level], errno);
}
maxevents--;
destroy_psi_monitor(fd);
mpevfd[level] = -1;
}
enum class MemcgVersion {
kNotFound,
kV1,
kV2,
};
static MemcgVersion __memcg_version() {
std::string cgroupv2_path, memcg_path;
if (!CgroupGetControllerPath("memory", &memcg_path)) {
return MemcgVersion::kNotFound;
}
return CgroupGetControllerPath(CGROUPV2_HIERARCHY_NAME, &cgroupv2_path) &&
cgroupv2_path == memcg_path
? MemcgVersion::kV2
: MemcgVersion::kV1;
}
static MemcgVersion memcg_version() {
static MemcgVersion version = __memcg_version();
return version;
}
static void memevent_listener_notification(int data __unused, uint32_t events __unused,
struct polling_params* poll_params) {
struct timespec curr_tm;
std::vector<mem_event_t> mem_events;
if (clock_gettime(CLOCK_MONOTONIC_COARSE, &curr_tm) != 0) {
direct_reclaim_start_tm.tv_sec = 0;
direct_reclaim_start_tm.tv_nsec = 0;
ALOGE("Failed to get current time for memevent listener notification.");
return;
}
if (!memevent_listener->getMemEvents(mem_events)) {
direct_reclaim_start_tm.tv_sec = 0;
direct_reclaim_start_tm.tv_nsec = 0;
ALOGE("Failed fetching memory listener events.");
return;
}
for (const mem_event_t& mem_event : mem_events) {
switch (mem_event.type) {
/* Direct Reclaim */
case MEM_EVENT_DIRECT_RECLAIM_BEGIN:
direct_reclaim_start_tm = curr_tm;
break;
case MEM_EVENT_DIRECT_RECLAIM_END:
direct_reclaim_start_tm.tv_sec = 0;
direct_reclaim_start_tm.tv_nsec = 0;
break;
/* kswapd */
case MEM_EVENT_KSWAPD_WAKE:
kswapd_start_tm = curr_tm;
break;
case MEM_EVENT_KSWAPD_SLEEP:
kswapd_start_tm.tv_sec = 0;
kswapd_start_tm.tv_nsec = 0;
break;
case MEM_EVENT_VENDOR_LMK_KILL: {
union psi_event_data event_data = {.vendor_event = mem_event};
__mp_event_psi(VENDOR, event_data, 0, poll_params);
break;
}
case MEM_EVENT_UPDATE_ZONEINFO: {
struct zoneinfo zi;
update_zoneinfo_watermarks(&zi);
break;
}
}
}
}
static bool init_memevent_listener_monitoring() {
static struct event_handler_info direct_reclaim_poll_hinfo = {0,
memevent_listener_notification};
if (memevent_listener) return true;
// Make sure bpf programs are loaded, else we'll wait until they are loaded
android::bpf::waitForProgsLoaded();
memevent_listener = std::make_unique<android::bpf::memevents::MemEventListener>(
android::bpf::memevents::MemEventClient::LMKD);
if (!memevent_listener->ok()) {
ALOGE("Failed to initialize memevents listener");
memevent_listener.reset();
return false;
}
if (!memevent_listener->registerEvent(MEM_EVENT_DIRECT_RECLAIM_BEGIN) ||
!memevent_listener->registerEvent(MEM_EVENT_DIRECT_RECLAIM_END)) {
ALOGE("Failed to register direct reclaim memevents");
memevent_listener.reset();
return false;
}
if (!memevent_listener->registerEvent(MEM_EVENT_KSWAPD_WAKE) ||
!memevent_listener->registerEvent(MEM_EVENT_KSWAPD_SLEEP)) {
ALOGE("Failed to register kswapd memevents");
memevent_listener.reset();
return false;
}
if (!memevent_listener->registerEvent(MEM_EVENT_VENDOR_LMK_KILL)) {
ALOGI("Failed to register android_vendor_kill memevents");
}
if (!memevent_listener->registerEvent(MEM_EVENT_UPDATE_ZONEINFO)) {
mem_event_update_zoneinfo_supported = false;
ALOGI("update_zoneinfo memevents are not supported");
} else {
mem_event_update_zoneinfo_supported = true;
}
int memevent_listener_fd = memevent_listener->getRingBufferFd();
if (memevent_listener_fd < 0) {
memevent_listener.reset();
ALOGE("Invalid memevent_listener fd: %d", memevent_listener_fd);
return false;
}
struct epoll_event epev;
epev.events = EPOLLIN;
epev.data.ptr = (void*)&direct_reclaim_poll_hinfo;
if (epoll_ctl(epollfd, EPOLL_CTL_ADD, memevent_listener_fd, &epev) < 0) {
ALOGE("Failed registering memevent_listener fd: %d; errno=%d", memevent_listener_fd, errno);
memevent_listener.reset();
return false;
}
direct_reclaim_start_tm.tv_sec = 0;
direct_reclaim_start_tm.tv_nsec = 0;
maxevents++;
return true;
}
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.
* Also use the new strategy if memcg has not been mounted in the v1 cgroups hiearchy since
* the old strategy relies on memcg attributes that are available only in the v1 cgroups
* hiearchy.
*/
bool use_new_strategy =
GET_LMK_PROPERTY(bool, "use_new_strategy", low_ram_device || !use_minfree_levels);
if (!use_new_strategy && memcg_version() != MemcgVersion::kV1) {
ALOGE("Old kill strategy can only be used with v1 cgroup hierarchy");
return false;
}
/* 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) {
// The implementation of this function relies on memcg statistics that are only available in the
// v1 cgroup hierarchy.
if (memcg_version() != MemcgVersion::kV1) {
ALOGE("%s: global monitoring is only available for the v1 cgroup hierarchy", __func__);
return false;
}
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(GetCgroupAttributePath("MemPressureLevel").c_str(), O_RDONLY | O_CLOEXEC);
if (mpfd < 0) {
ALOGI("No kernel memory.pressure_level support (errno=%d)", errno);
goto err_open_mpfd;
}
evctlfd = open(GetCgroupAttributePath("MemCgroupEventControl").c_str(), 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 destroy_mp_common(enum vmpressure_level level) {
struct epoll_event epev;
int fd = mpevfd[level];
if (fd < 0) {
return;
}
if (epoll_ctl(epollfd, EPOLL_CTL_DEL, fd, &epev)) {
// Log an error and keep going
ALOGE("epoll_ctl for level %s failed; errno=%d", level_name[level], errno);
}
maxevents--;
close(fd);
mpevfd[level] = -1;
}
static void kernel_event_handler(int data __unused, uint32_t events __unused,
struct polling_params *poll_params __unused) {
poll_kernel(kpoll_fd);
}
static bool init_monitors() {
ALOGI("Wakeup counter is reset from %" PRIu64 " to 0", mp_event_count);
mp_event_count = 0;
/* Try to use psi monitor first if kernel has it */
use_psi_monitors = GET_LMK_PROPERTY(bool, "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 false;
}
if (use_psi_monitors) {
ALOGI("Using psi monitors for memory pressure detection");
} else {
ALOGI("Using vmpressure for memory pressure detection");
}
monitors_initialized = true;
return true;
}
static void destroy_monitors() {
if (use_psi_monitors) {
destroy_mp_psi(VMPRESS_LEVEL_CRITICAL);
destroy_mp_psi(VMPRESS_LEVEL_MEDIUM);
destroy_mp_psi(VMPRESS_LEVEL_LOW);
} else {
destroy_mp_common(VMPRESS_LEVEL_CRITICAL);
destroy_mp_common(VMPRESS_LEVEL_MEDIUM);
destroy_mp_common(VMPRESS_LEVEL_LOW);
}
}
static void drop_reaper_comm() {
close(reaper_comm_fd[0]);
close(reaper_comm_fd[1]);
}
static bool setup_reaper_comm() {
if (pipe(reaper_comm_fd)) {
ALOGE("pipe failed: %s", strerror(errno));
return false;
}
// Ensure main thread never blocks on read
int flags = fcntl(reaper_comm_fd[0], F_GETFL);
if (fcntl(reaper_comm_fd[0], F_SETFL, flags | O_NONBLOCK)) {
ALOGE("fcntl failed: %s", strerror(errno));
drop_reaper_comm();
return false;
}
return true;
}
static bool init_reaper() {
if (!reaper.is_reaping_supported()) {
ALOGI("Process reaping is not supported");
return false;
}
if (!setup_reaper_comm()) {
ALOGE("Failed to create thread communication channel");
return false;
}
// Setup epoll handler
struct epoll_event epev;
static struct event_handler_info kill_failed_hinfo = { 0, kill_fail_handler };
epev.events = EPOLLIN;
epev.data.ptr = (void *)&kill_failed_hinfo;
if (epoll_ctl(epollfd, EPOLL_CTL_ADD, reaper_comm_fd[0], &epev)) {
ALOGE("epoll_ctl failed: %s", strerror(errno));
drop_reaper_comm();
return false;
}
if (!reaper.init(reaper_comm_fd[1])) {
ALOGE("Failed to initialize reaper object");
if (epoll_ctl(epollfd, EPOLL_CTL_DEL, reaper_comm_fd[0], &epev)) {
ALOGE("epoll_ctl failed: %s", strerror(errno));
}
drop_reaper_comm();
return false;
}
maxevents++;
return true;
}
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;
// Initialize page size
pagesize = getpagesize();
page_k = pagesize / 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()) {
epev.events = EPOLLIN;
epev.data.ptr = (void*)&kernel_poll_hinfo;
if (epoll_ctl(epollfd, EPOLL_CTL_ADD, kpoll_fd, &epev) != 0) {
ALOGE("epoll_ctl for lmk events failed (errno=%d)", errno);
close(kpoll_fd);
kpoll_fd = -1;
} else {
maxevents++;
/* let the others know it does support reporting kills */
property_set("sys.lmk.reportkills", "1");
}
}
} else {
// Do not register monitors until boot completed for devices configured
// for delaying monitors. This is done to save CPU cycles for low
// resource devices during boot up.
if (!delay_monitors_until_boot || property_get_bool("sys.boot_completed", false)) {
if (!init_monitors()) {
return -1;
}
}
/* let the others know it does support reporting kills */
property_set("sys.lmk.reportkills", "1");
}
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(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" );
if (!lmkd_init_hook()) {
ALOGE("Failed to initialize LMKD hooks.");
return -1;
}
return 0;
}
static bool polling_paused(struct polling_params *poll_params) {
return poll_params->paused_handler != NULL;
}
static void resume_polling(struct polling_params *poll_params, struct timespec curr_tm) {
poll_params->poll_start_tm = curr_tm;
poll_params->poll_handler = poll_params->paused_handler;
poll_params->polling_interval_ms = PSI_POLL_PERIOD_SHORT_MS;
poll_params->paused_handler = NULL;
}
static void call_handler(struct event_handler_info* handler_info,
struct polling_params *poll_params, uint32_t events) {
struct timespec curr_tm;
watchdog.start();
poll_params->update = POLLING_DO_NOT_CHANGE;
handler_info->handler(handler_info->data, events, poll_params);
clock_gettime(CLOCK_MONOTONIC_COARSE, &curr_tm);
if (poll_params->poll_handler == handler_info) {
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;
poll_params->last_poll_tm = curr_tm;
break;
case POLLING_PAUSE:
poll_params->paused_handler = handler_info;
poll_params->poll_handler = NULL;
break;
case POLLING_RESUME:
resume_polling(poll_params, curr_tm);
break;
case POLLING_DO_NOT_CHANGE:
if (poll_params->poll_handler &&
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;
}
break;
}
watchdog.stop();
}
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.paused_handler = NULL;
while (1) {
struct epoll_event events[MAX_EPOLL_EVENTS];
int nevents;
int i;
if (poll_params.poll_handler) {
bool poll_now;
clock_gettime(CLOCK_MONOTONIC_COARSE, &curr_tm);
if (poll_params.update == POLLING_RESUME) {
/* Just transitioned into POLLING_RESUME, poll immediately. */
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 {
if (kill_timeout_ms && is_waiting_for_kill()) {
clock_gettime(CLOCK_MONOTONIC_COARSE, &curr_tm);
delay = kill_timeout_ms - get_time_diff_ms(&last_kill_tm, &curr_tm);
/* Wait for pidfds notification or kill timeout to expire */
nevents = (delay > 0) ? epoll_wait(epollfd, events, maxevents, delay) : 0;
if (nevents == 0) {
/* Kill notification timed out */
stop_wait_for_proc_kill(false);
if (polling_paused(&poll_params)) {
clock_gettime(CLOCK_MONOTONIC_COARSE, &curr_tm);
poll_params.update = POLLING_RESUME;
resume_polling(&poll_params, curr_tm);
}
}
} 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) {
handler_info = (struct event_handler_info*)evt->data.ptr;
if (handler_info->handler == kill_done_handler) {
call_handler(handler_info, &poll_params, evt->events);
} else {
ALOGI("lmkd data connection dropped");
watchdog.start();
ctrl_data_close(handler_info->data);
watchdog.stop();
}
}
}
/* 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 issue_reinit() {
int sock;
sock = lmkd_connect();
if (sock < 0) {
ALOGE("failed to connect to lmkd: %s", strerror(errno));
return -1;
}
enum update_props_result res = lmkd_update_props(sock);
switch (res) {
case UPDATE_PROPS_SUCCESS:
ALOGI("lmkd updated properties successfully");
break;
case UPDATE_PROPS_SEND_ERR:
ALOGE("failed to send lmkd request: %s", strerror(errno));
break;
case UPDATE_PROPS_RECV_ERR:
ALOGE("failed to receive lmkd reply: %s", strerror(errno));
break;
case UPDATE_PROPS_FORMAT_ERR:
ALOGE("lmkd reply is invalid");
break;
case UPDATE_PROPS_FAIL:
ALOGE("lmkd failed to update its properties");
break;
}
close(sock);
return res == UPDATE_PROPS_SUCCESS ? 0 : -1;
}
static int on_boot_completed() {
int sock;
sock = lmkd_connect();
if (sock < 0) {
ALOGE("failed to connect to lmkd: %s", strerror(errno));
return -1;
}
enum boot_completed_notification_result res = lmkd_notify_boot_completed(sock);
switch (res) {
case BOOT_COMPLETED_NOTIF_SUCCESS:
break;
case BOOT_COMPLETED_NOTIF_ALREADY_HANDLED:
ALOGW("lmkd already handled boot-completed operations");
break;
case BOOT_COMPLETED_NOTIF_SEND_ERR:
ALOGE("failed to send lmkd request: %m");
break;
case BOOT_COMPLETED_NOTIF_RECV_ERR:
ALOGE("failed to receive request: %m");
break;
case BOOT_COMPLETED_NOTIF_FORMAT_ERR:
ALOGE("lmkd reply is invalid");
break;
case BOOT_COMPLETED_NOTIF_FAILS:
ALOGE("lmkd failed to receive boot-completed notification");
break;
}
close(sock);
return res == BOOT_COMPLETED_NOTIF_SUCCESS ? 0 : -1;
}
static bool update_props() {
/* By default disable low level vmpressure events */
level_oomadj[VMPRESS_LEVEL_LOW] =
GET_LMK_PROPERTY(int32, "low", OOM_SCORE_ADJ_MAX + 1);
level_oomadj[VMPRESS_LEVEL_MEDIUM] =
GET_LMK_PROPERTY(int32, "medium", 800);
level_oomadj[VMPRESS_LEVEL_CRITICAL] =
GET_LMK_PROPERTY(int32, "critical", 0);
debug_process_killing = GET_LMK_PROPERTY(bool, "debug", false);
/* By default disable upgrade/downgrade logic */
enable_pressure_upgrade =
GET_LMK_PROPERTY(bool, "critical_upgrade", false);
upgrade_pressure =
(int64_t)GET_LMK_PROPERTY(int32, "upgrade_pressure", 100);
downgrade_pressure =
(int64_t)GET_LMK_PROPERTY(int32, "downgrade_pressure", 100);
kill_heaviest_task =
GET_LMK_PROPERTY(bool, "kill_heaviest_task", false);
low_ram_device = property_get_bool("ro.config.low_ram", false);
kill_timeout_ms =
(unsigned long)GET_LMK_PROPERTY(int32, "kill_timeout_ms", 100);
pressure_after_kill_min_score =
(unsigned long)GET_LMK_PROPERTY(int32, "pressure_after_kill_min_score", 0);
use_minfree_levels =
GET_LMK_PROPERTY(bool, "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, GET_LMK_PROPERTY(int32, "swap_free_low_percentage",
DEF_LOW_SWAP));
psi_partial_stall_ms = GET_LMK_PROPERTY(int32, "psi_partial_stall_ms",
low_ram_device ? DEF_PARTIAL_STALL_LOWRAM : DEF_PARTIAL_STALL);
psi_complete_stall_ms = GET_LMK_PROPERTY(int32, "psi_complete_stall_ms",
DEF_COMPLETE_STALL);
thrashing_limit_pct =
std::max(0, GET_LMK_PROPERTY(int32, "thrashing_limit",
low_ram_device ? DEF_THRASHING_LOWRAM : DEF_THRASHING));
thrashing_limit_decay_pct = clamp(0, 100, GET_LMK_PROPERTY(int32, "thrashing_limit_decay",
low_ram_device ? DEF_THRASHING_DECAY_LOWRAM : DEF_THRASHING_DECAY));
thrashing_critical_pct = std::max(
0, GET_LMK_PROPERTY(int32, "thrashing_limit_critical", thrashing_limit_pct * 3));
swap_util_max = clamp(0, 100, GET_LMK_PROPERTY(int32, "swap_util_max", 100));
filecache_min_kb = GET_LMK_PROPERTY(int64, "filecache_min_kb", 0);
stall_limit_critical = GET_LMK_PROPERTY(int64, "stall_limit_critical", 100);
delay_monitors_until_boot = GET_LMK_PROPERTY(bool, "delay_monitors_until_boot", false);
direct_reclaim_threshold_ms =
GET_LMK_PROPERTY(int64, "direct_reclaim_threshold_ms", DEF_DIRECT_RECL_THRESH_MS);
swap_compression_ratio =
GET_LMK_PROPERTY(int64, "swap_compression_ratio", DEF_SWAP_COMP_RATIO);
lowmem_min_oom_score =
std::max(PERCEPTIBLE_APP_ADJ + 1,
GET_LMK_PROPERTY(int32, "lowmem_min_oom_score", DEF_LOWMEM_MIN_SCORE));
reaper.enable_debug(debug_process_killing);
/* Call the update props hook */
if (!lmkd_update_props_hook()) {
ALOGE("Failed to update LMKD hook props.");
return false;
}
return true;
}
int main(int argc, char **argv) {
if ((argc > 1) && argv[1]) {
if (!strcmp(argv[1], "--reinit")) {
if (property_set(LMKD_REINIT_PROP, "")) {
ALOGE("Failed to reset " LMKD_REINIT_PROP " property");
}
return issue_reinit();
} else if (!strcmp(argv[1], "--boot_completed")) {
return on_boot_completed();
}
}
if (!update_props()) {
ALOGE("Failed to initialize props, exiting.");
return -1;
}
ctx = create_android_logger(KILLINFO_LOG_TAG);
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 */
struct sched_param param = {
.sched_priority = 1,
};
if (sched_setscheduler(0, SCHED_FIFO, &param)) {
ALOGW("set SCHED_FIFO failed %s", strerror(errno));
}
}
if (init_reaper()) {
ALOGI("Process reaper initialized with %d threads in the pool",
reaper.thread_cnt());
}
if (!watchdog.init()) {
ALOGE("Failed to initialize the watchdog");
}
mainloop();
}
android_log_destroy(&ctx);
ALOGI("exiting");
return 0;
}