Build lmkd as C++
Bug: 145669697
Test: build
Change-Id: I4fb2a9a900c8a6915ee84cc3d82434596301b24b
diff --git a/lmkd.cpp b/lmkd.cpp
new file mode 100644
index 0000000..389a2de
--- /dev/null
+++ b/lmkd.cpp
@@ -0,0 +1,3109 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "lowmemorykiller"
+
+#include <dirent.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <pwd.h>
+#include <sched.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/cdefs.h>
+#include <sys/epoll.h>
+#include <sys/eventfd.h>
+#include <sys/mman.h>
+#include <sys/resource.h>
+#include <sys/socket.h>
+#include <sys/syscall.h>
+#include <sys/sysinfo.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <time.h>
+#include <unistd.h>
+
+#include <cutils/properties.h>
+#include <cutils/sched_policy.h>
+#include <cutils/sockets.h>
+#include <lmkd.h>
+#include <log/log.h>
+#include <log/log_event_list.h>
+#include <log/log_time.h>
+#include <private/android_filesystem_config.h>
+#include <psi/psi.h>
+#include <system/thread_defs.h>
+
+#include "statslog.h"
+
+/*
+ * Define LMKD_TRACE_KILLS to record lmkd kills in kernel traces
+ * to profile and correlate with OOM kills
+ */
+#ifdef LMKD_TRACE_KILLS
+
+#define ATRACE_TAG ATRACE_TAG_ALWAYS
+#include <cutils/trace.h>
+
+#define TRACE_KILL_START(pid) ATRACE_INT(__FUNCTION__, pid);
+#define TRACE_KILL_END() ATRACE_INT(__FUNCTION__, 0);
+
+#else /* LMKD_TRACE_KILLS */
+
+#define TRACE_KILL_START(pid) ((void)(pid))
+#define TRACE_KILL_END() ((void)0)
+
+#endif /* LMKD_TRACE_KILLS */
+
+#ifndef __unused
+#define __unused __attribute__((__unused__))
+#endif
+
+#define MEMCG_SYSFS_PATH "/dev/memcg/"
+#define MEMCG_MEMORY_USAGE "/dev/memcg/memory.usage_in_bytes"
+#define MEMCG_MEMORYSW_USAGE "/dev/memcg/memory.memsw.usage_in_bytes"
+#define ZONEINFO_PATH "/proc/zoneinfo"
+#define MEMINFO_PATH "/proc/meminfo"
+#define VMSTAT_PATH "/proc/vmstat"
+#define PROC_STATUS_TGID_FIELD "Tgid:"
+#define LINE_MAX 128
+
+#define PERCEPTIBLE_APP_ADJ 200
+
+/* Android Logger event logtags (see event.logtags) */
+#define KILLINFO_LOG_TAG 10195355
+
+/* gid containing AID_SYSTEM required */
+#define INKERNEL_MINFREE_PATH "/sys/module/lowmemorykiller/parameters/minfree"
+#define INKERNEL_ADJ_PATH "/sys/module/lowmemorykiller/parameters/adj"
+
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x)))
+#define EIGHT_MEGA (1 << 23)
+
+#define TARGET_UPDATE_MIN_INTERVAL_MS 1000
+
+#define NS_PER_MS (NS_PER_SEC / MS_PER_SEC)
+#define US_PER_MS (US_PER_SEC / MS_PER_SEC)
+
+/* Defined as ProcessList.SYSTEM_ADJ in ProcessList.java */
+#define SYSTEM_ADJ (-900)
+
+#define STRINGIFY(x) STRINGIFY_INTERNAL(x)
+#define STRINGIFY_INTERNAL(x) #x
+
+/*
+ * PSI monitor tracking window size.
+ * PSI monitor generates events at most once per window,
+ * therefore we poll memory state for the duration of
+ * PSI_WINDOW_SIZE_MS after the event happens.
+ */
+#define PSI_WINDOW_SIZE_MS 1000
+/* Polling period after PSI signal when pressure is high */
+#define PSI_POLL_PERIOD_SHORT_MS 10
+/* Polling period after PSI signal when pressure is low */
+#define PSI_POLL_PERIOD_LONG_MS 100
+
+#define min(a, b) (((a) < (b)) ? (a) : (b))
+#define max(a, b) (((a) > (b)) ? (a) : (b))
+
+#define FAIL_REPORT_RLIMIT_MS 1000
+
+/*
+ * System property defaults
+ */
+/* ro.lmk.swap_free_low_percentage property defaults */
+#define DEF_LOW_SWAP_LOWRAM 10
+#define DEF_LOW_SWAP 20
+/* ro.lmk.thrashing_limit property defaults */
+#define DEF_THRASHING_LOWRAM 30
+#define DEF_THRASHING 100
+/* ro.lmk.thrashing_limit_decay property defaults */
+#define DEF_THRASHING_DECAY_LOWRAM 50
+#define DEF_THRASHING_DECAY 10
+/* ro.lmk.psi_partial_stall_ms property defaults */
+#define DEF_PARTIAL_STALL_LOWRAM 200
+#define DEF_PARTIAL_STALL 70
+/* ro.lmk.psi_complete_stall_ms property defaults */
+#define DEF_COMPLETE_STALL 700
+
+static inline int sys_pidfd_open(pid_t pid, unsigned int flags) {
+ return syscall(__NR_pidfd_open, pid, flags);
+}
+
+static inline int sys_pidfd_send_signal(int pidfd, int sig, siginfo_t *info,
+ unsigned int flags) {
+ return syscall(__NR_pidfd_send_signal, pidfd, sig, info, flags);
+}
+
+/* default to old in-kernel interface if no memory pressure events */
+static bool use_inkernel_interface = true;
+static bool has_inkernel_module;
+
+/* memory pressure levels */
+enum vmpressure_level {
+ VMPRESS_LEVEL_LOW = 0,
+ VMPRESS_LEVEL_MEDIUM,
+ VMPRESS_LEVEL_CRITICAL,
+ VMPRESS_LEVEL_COUNT
+};
+
+static const char *level_name[] = {
+ "low",
+ "medium",
+ "critical"
+};
+
+struct {
+ int64_t min_nr_free_pages; /* recorded but not used yet */
+ int64_t max_nr_free_pages;
+} low_pressure_mem = { -1, -1 };
+
+struct psi_threshold {
+ enum psi_stall_type stall_type;
+ int threshold_ms;
+};
+
+static int level_oomadj[VMPRESS_LEVEL_COUNT];
+static int mpevfd[VMPRESS_LEVEL_COUNT] = { -1, -1, -1 };
+static bool pidfd_supported;
+static int last_kill_pid_or_fd = -1;
+static struct timespec last_kill_tm;
+
+/* lmkd configurable parameters */
+static bool debug_process_killing;
+static bool enable_pressure_upgrade;
+static int64_t upgrade_pressure;
+static int64_t downgrade_pressure;
+static bool low_ram_device;
+static bool kill_heaviest_task;
+static unsigned long kill_timeout_ms;
+static bool use_minfree_levels;
+static bool per_app_memcg;
+static int swap_free_low_percentage;
+static int psi_partial_stall_ms;
+static int psi_complete_stall_ms;
+static int thrashing_limit_pct;
+static int thrashing_limit_decay_pct;
+static bool use_psi_monitors = false;
+static int kpoll_fd;
+static struct psi_threshold psi_thresholds[VMPRESS_LEVEL_COUNT] = {
+ { PSI_SOME, 70 }, /* 70ms out of 1sec for partial stall */
+ { PSI_SOME, 100 }, /* 100ms out of 1sec for partial stall */
+ { PSI_FULL, 70 }, /* 70ms out of 1sec for complete stall */
+};
+
+static android_log_context ctx;
+
+enum polling_update {
+ POLLING_DO_NOT_CHANGE,
+ POLLING_START,
+ POLLING_STOP,
+ POLLING_PAUSE,
+ POLLING_RESUME,
+};
+
+/*
+ * Data used for periodic polling for the memory state of the device.
+ * Note that when system is not polling poll_handler is set to NULL,
+ * when polling starts poll_handler gets set and is reset back to
+ * NULL when polling stops.
+ */
+struct polling_params {
+ struct event_handler_info* poll_handler;
+ struct event_handler_info* paused_handler;
+ struct timespec poll_start_tm;
+ struct timespec last_poll_tm;
+ int polling_interval_ms;
+ enum polling_update update;
+};
+
+/* data required to handle events */
+struct event_handler_info {
+ int data;
+ void (*handler)(int data, uint32_t events, struct polling_params *poll_params);
+};
+
+/* data required to handle socket events */
+struct sock_event_handler_info {
+ int sock;
+ pid_t pid;
+ 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
+ */
+#define MAX_EPOLL_EVENTS (1 + MAX_DATA_CONN + VMPRESS_LEVEL_COUNT + 1 + 1)
+static int epollfd;
+static int maxevents;
+
+/* OOM score values used by both kernel and framework */
+#define OOM_SCORE_ADJ_MIN (-1000)
+#define OOM_SCORE_ADJ_MAX 1000
+
+static int lowmem_adj[MAX_TARGETS];
+static int lowmem_minfree[MAX_TARGETS];
+static int lowmem_targets_size;
+
+/* Fields to parse in /proc/zoneinfo */
+/* zoneinfo per-zone fields */
+enum zoneinfo_zone_field {
+ ZI_ZONE_NR_FREE_PAGES = 0,
+ ZI_ZONE_MIN,
+ ZI_ZONE_LOW,
+ ZI_ZONE_HIGH,
+ ZI_ZONE_PRESENT,
+ ZI_ZONE_NR_FREE_CMA,
+ ZI_ZONE_FIELD_COUNT
+};
+
+static const char* const zoneinfo_zone_field_names[ZI_ZONE_FIELD_COUNT] = {
+ "nr_free_pages",
+ "min",
+ "low",
+ "high",
+ "present",
+ "nr_free_cma",
+};
+
+/* zoneinfo per-zone special fields */
+enum zoneinfo_zone_spec_field {
+ ZI_ZONE_SPEC_PROTECTION = 0,
+ ZI_ZONE_SPEC_PAGESETS,
+ ZI_ZONE_SPEC_FIELD_COUNT,
+};
+
+static const char* const zoneinfo_zone_spec_field_names[ZI_ZONE_SPEC_FIELD_COUNT] = {
+ "protection:",
+ "pagesets",
+};
+
+/* see __MAX_NR_ZONES definition in kernel mmzone.h */
+#define MAX_NR_ZONES 6
+
+union zoneinfo_zone_fields {
+ struct {
+ int64_t nr_free_pages;
+ int64_t min;
+ int64_t low;
+ int64_t high;
+ int64_t present;
+ int64_t nr_free_cma;
+ } field;
+ int64_t arr[ZI_ZONE_FIELD_COUNT];
+};
+
+struct zoneinfo_zone {
+ union zoneinfo_zone_fields fields;
+ int64_t protection[MAX_NR_ZONES];
+ int64_t max_protection;
+};
+
+/* zoneinfo per-node fields */
+enum zoneinfo_node_field {
+ ZI_NODE_NR_INACTIVE_FILE = 0,
+ ZI_NODE_NR_ACTIVE_FILE,
+ ZI_NODE_WORKINGSET_REFAULT,
+ ZI_NODE_FIELD_COUNT
+};
+
+static const char* const zoneinfo_node_field_names[ZI_NODE_FIELD_COUNT] = {
+ "nr_inactive_file",
+ "nr_active_file",
+ "workingset_refault",
+};
+
+union zoneinfo_node_fields {
+ struct {
+ int64_t nr_inactive_file;
+ int64_t nr_active_file;
+ int64_t workingset_refault;
+ } field;
+ int64_t arr[ZI_NODE_FIELD_COUNT];
+};
+
+struct zoneinfo_node {
+ int id;
+ int zone_count;
+ struct zoneinfo_zone zones[MAX_NR_ZONES];
+ union zoneinfo_node_fields fields;
+};
+
+/* for now two memory nodes is more than enough */
+#define MAX_NR_NODES 2
+
+struct zoneinfo {
+ int node_count;
+ struct zoneinfo_node nodes[MAX_NR_NODES];
+ int64_t totalreserve_pages;
+ int64_t total_inactive_file;
+ int64_t total_active_file;
+ int64_t total_workingset_refault;
+};
+
+/* Fields to parse in /proc/meminfo */
+enum meminfo_field {
+ MI_NR_FREE_PAGES = 0,
+ MI_CACHED,
+ MI_SWAP_CACHED,
+ MI_BUFFERS,
+ MI_SHMEM,
+ MI_UNEVICTABLE,
+ MI_TOTAL_SWAP,
+ MI_FREE_SWAP,
+ MI_ACTIVE_ANON,
+ MI_INACTIVE_ANON,
+ MI_ACTIVE_FILE,
+ MI_INACTIVE_FILE,
+ MI_SRECLAIMABLE,
+ MI_SUNRECLAIM,
+ MI_KERNEL_STACK,
+ MI_PAGE_TABLES,
+ MI_ION_HELP,
+ MI_ION_HELP_POOL,
+ MI_CMA_FREE,
+ MI_FIELD_COUNT
+};
+
+static const char* const meminfo_field_names[MI_FIELD_COUNT] = {
+ "MemFree:",
+ "Cached:",
+ "SwapCached:",
+ "Buffers:",
+ "Shmem:",
+ "Unevictable:",
+ "SwapTotal:",
+ "SwapFree:",
+ "Active(anon):",
+ "Inactive(anon):",
+ "Active(file):",
+ "Inactive(file):",
+ "SReclaimable:",
+ "SUnreclaim:",
+ "KernelStack:",
+ "PageTables:",
+ "ION_heap:",
+ "ION_heap_pool:",
+ "CmaFree:",
+};
+
+union meminfo {
+ struct {
+ int64_t nr_free_pages;
+ int64_t cached;
+ int64_t swap_cached;
+ int64_t buffers;
+ int64_t shmem;
+ int64_t unevictable;
+ int64_t total_swap;
+ int64_t free_swap;
+ int64_t active_anon;
+ int64_t inactive_anon;
+ int64_t active_file;
+ int64_t inactive_file;
+ int64_t sreclaimable;
+ int64_t sunreclaimable;
+ int64_t kernel_stack;
+ int64_t page_tables;
+ int64_t ion_heap;
+ int64_t ion_heap_pool;
+ int64_t cma_free;
+ /* fields below are calculated rather than read from the file */
+ int64_t nr_file_pages;
+ } field;
+ int64_t arr[MI_FIELD_COUNT];
+};
+
+/* Fields to parse in /proc/vmstat */
+enum vmstat_field {
+ VS_FREE_PAGES,
+ VS_INACTIVE_FILE,
+ VS_ACTIVE_FILE,
+ VS_WORKINGSET_REFAULT,
+ VS_PGSCAN_KSWAPD,
+ VS_PGSCAN_DIRECT,
+ VS_PGSCAN_DIRECT_THROTTLE,
+ VS_FIELD_COUNT
+};
+
+static const char* const vmstat_field_names[MI_FIELD_COUNT] = {
+ "nr_free_pages",
+ "nr_inactive_file",
+ "nr_active_file",
+ "workingset_refault",
+ "pgscan_kswapd",
+ "pgscan_direct",
+ "pgscan_direct_throttle",
+};
+
+union vmstat {
+ struct {
+ int64_t nr_free_pages;
+ int64_t nr_inactive_file;
+ int64_t nr_active_file;
+ int64_t workingset_refault;
+ int64_t pgscan_kswapd;
+ int64_t pgscan_direct;
+ int64_t pgscan_direct_throttle;
+ } field;
+ int64_t arr[VS_FIELD_COUNT];
+};
+
+enum field_match_result {
+ NO_MATCH,
+ PARSE_FAIL,
+ PARSE_SUCCESS
+};
+
+struct adjslot_list {
+ struct adjslot_list *next;
+ struct adjslot_list *prev;
+};
+
+struct proc {
+ struct adjslot_list asl;
+ int pid;
+ int pidfd;
+ uid_t uid;
+ int oomadj;
+ pid_t reg_pid; /* PID of the process that registered this record */
+ struct proc *pidhash_next;
+};
+
+struct reread_data {
+ const char* const filename;
+ int fd;
+};
+
+#define PIDHASH_SZ 1024
+static struct proc *pidhash[PIDHASH_SZ];
+#define pid_hashfn(x) ((((x) >> 8) ^ (x)) & (PIDHASH_SZ - 1))
+
+#define ADJTOSLOT(adj) ((adj) + -OOM_SCORE_ADJ_MIN)
+#define ADJTOSLOT_COUNT (ADJTOSLOT(OOM_SCORE_ADJ_MAX) + 1)
+static struct adjslot_list procadjslot_list[ADJTOSLOT_COUNT];
+
+#define MAX_DISTINCT_OOM_ADJ 32
+#define KILLCNT_INVALID_IDX 0xFF
+/*
+ * Because killcnt array is sparse a two-level indirection is used
+ * to keep the size small. killcnt_idx stores index of the element in
+ * killcnt array. Index KILLCNT_INVALID_IDX indicates an unused slot.
+ */
+static uint8_t killcnt_idx[ADJTOSLOT_COUNT];
+static uint16_t killcnt[MAX_DISTINCT_OOM_ADJ];
+static int killcnt_free_idx = 0;
+static uint32_t killcnt_total = 0;
+
+/* PAGE_SIZE / 1024 */
+static long page_k;
+
+static int clamp(int low, int high, int value) {
+ return max(min(value, high), low);
+}
+
+static bool parse_int64(const char* str, int64_t* ret) {
+ char* endptr;
+ long long val = strtoll(str, &endptr, 10);
+ if (str == endptr || val > INT64_MAX) {
+ return false;
+ }
+ *ret = (int64_t)val;
+ return true;
+}
+
+static int find_field(const char* name, const char* const field_names[], int field_count) {
+ for (int i = 0; i < field_count; i++) {
+ if (!strcmp(name, field_names[i])) {
+ return i;
+ }
+ }
+ return -1;
+}
+
+static enum field_match_result match_field(const char* cp, const char* ap,
+ const char* const field_names[],
+ int field_count, int64_t* field,
+ int *field_idx) {
+ int i = find_field(cp, field_names, field_count);
+ if (i < 0) {
+ return NO_MATCH;
+ }
+ *field_idx = i;
+ return parse_int64(ap, field) ? PARSE_SUCCESS : PARSE_FAIL;
+}
+
+/*
+ * Read file content from the beginning up to max_len bytes or EOF
+ * whichever happens first.
+ */
+static ssize_t read_all(int fd, char *buf, size_t max_len)
+{
+ ssize_t ret = 0;
+ off_t offset = 0;
+
+ while (max_len > 0) {
+ ssize_t r = TEMP_FAILURE_RETRY(pread(fd, buf, max_len, offset));
+ if (r == 0) {
+ break;
+ }
+ if (r == -1) {
+ return -1;
+ }
+ ret += r;
+ buf += r;
+ offset += r;
+ max_len -= r;
+ }
+
+ return ret;
+}
+
+/*
+ * Read a new or already opened file from the beginning.
+ * If the file has not been opened yet data->fd should be set to -1.
+ * To be used with files which are read often and possibly during high
+ * memory pressure to minimize file opening which by itself requires kernel
+ * memory allocation and might result in a stall on memory stressed system.
+ */
+static char *reread_file(struct reread_data *data) {
+ /* start with page-size buffer and increase if needed */
+ static ssize_t buf_size = PAGE_SIZE;
+ static char *new_buf, *buf = NULL;
+ ssize_t size;
+
+ if (data->fd == -1) {
+ /* First-time buffer initialization */
+ if (!buf && (buf = 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) {
+ LMKD_CTRL_PACKET packet;
+ size_t len = lmkd_pack_set_prockills(packet, pid, uid);
+
+ for (int i = 0; i < MAX_DATA_CONN; i++) {
+ if (data_sock[i].sock >= 0) {
+ ctrl_data_write(i, (char*)packet, len);
+ }
+ }
+}
+
+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), 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;
+
+ 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) {
+ ctrl_data_write_lmk_kill_occurred((pid_t)pid, (uid_t)uid);
+ mem_st.process_start_time_ns = starttime * (NS_PER_SEC / sysconf(_SC_CLK_TCK));
+ mem_st.rss_in_bytes = rss_in_pages * PAGE_SIZE;
+ stats_write_lmk_kill_occurred_pid(LMK_KILL_OCCURRED, uid, pid, oom_score_adj,
+ min_score_adj, 0, &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;
+}
+
+static void proc_slot(struct proc *procp) {
+ int adjslot = ADJTOSLOT(procp->oomadj);
+
+ adjslot_insert(&procadjslot_list[adjslot], &procp->asl);
+}
+
+static void proc_unslot(struct proc *procp) {
+ adjslot_remove(&procp->asl);
+}
+
+static void proc_insert(struct proc *procp) {
+ int hval = pid_hashfn(procp->pid);
+
+ procp->pidhash_next = pidhash[hval];
+ pidhash[hval] = procp;
+ proc_slot(procp);
+}
+
+static int pid_remove(int pid) {
+ int hval = pid_hashfn(pid);
+ struct proc *procp;
+ struct proc *prevp;
+
+ for (procp = pidhash[hval], prevp = NULL; procp && procp->pid != pid;
+ procp = procp->pidhash_next)
+ prevp = procp;
+
+ if (!procp)
+ return -1;
+
+ if (!prevp)
+ pidhash[hval] = procp->pidhash_next;
+ else
+ prevp->pidhash_next = procp->pidhash_next;
+
+ proc_unslot(procp);
+ /*
+ * Close pidfd here if we are not waiting for corresponding process to die,
+ * in which case stop_wait_for_proc_kill() will close the pidfd later
+ */
+ if (procp->pidfd >= 0 && procp->pidfd != last_kill_pid_or_fd) {
+ close(procp->pidfd);
+ }
+ free(procp);
+ return 0;
+}
+
+/*
+ * Write a string to a file.
+ * Returns false if the file does not exist.
+ */
+static bool writefilestring(const char *path, const char *s,
+ bool err_if_missing) {
+ int fd = open(path, O_WRONLY | O_CLOEXEC);
+ ssize_t len = strlen(s);
+ ssize_t ret;
+
+ if (fd < 0) {
+ if (err_if_missing) {
+ ALOGE("Error opening %s; errno=%d", path, errno);
+ }
+ return false;
+ }
+
+ ret = TEMP_FAILURE_RETRY(write(fd, s, len));
+ if (ret < 0) {
+ ALOGE("Error writing %s; errno=%d", path, errno);
+ } else if (ret < len) {
+ ALOGE("Short write on %s; length=%zd", path, ret);
+ }
+
+ close(fd);
+ return true;
+}
+
+static inline long get_time_diff_ms(struct timespec *from,
+ struct timespec *to) {
+ return (to->tv_sec - from->tv_sec) * (long)MS_PER_SEC +
+ (to->tv_nsec - from->tv_nsec) / (long)NS_PER_MS;
+}
+
+static int proc_get_tgid(int pid) {
+ char path[PATH_MAX];
+ char buf[PAGE_SIZE];
+ int fd;
+ ssize_t size;
+ char *pos;
+ int64_t tgid = -1;
+
+ snprintf(path, PATH_MAX, "/proc/%d/status", pid);
+ fd = open(path, O_RDONLY | O_CLOEXEC);
+ if (fd < 0) {
+ return -1;
+ }
+
+ size = read_all(fd, buf, sizeof(buf) - 1);
+ if (size < 0) {
+ goto out;
+ }
+ buf[size] = 0;
+
+ pos = buf;
+ while (true) {
+ pos = strstr(pos, PROC_STATUS_TGID_FIELD);
+ /* Stop if TGID tag not found or found at the line beginning */
+ if (pos == NULL || pos == buf || pos[-1] == '\n') {
+ break;
+ }
+ pos++;
+ }
+
+ if (pos == NULL) {
+ goto out;
+ }
+
+ pos += strlen(PROC_STATUS_TGID_FIELD);
+ while (*pos == ' ') pos++;
+ parse_int64(pos, &tgid);
+
+out:
+ close(fd);
+ return (int)tgid;
+}
+
+static int proc_get_size(int pid) {
+ char path[PATH_MAX];
+ char line[LINE_MAX];
+ int fd;
+ int rss = 0;
+ int total;
+ ssize_t ret;
+
+ /* gid containing AID_READPROC required */
+ snprintf(path, PATH_MAX, "/proc/%d/statm", pid);
+ fd = open(path, O_RDONLY | O_CLOEXEC);
+ if (fd == -1)
+ return -1;
+
+ ret = read_all(fd, line, sizeof(line) - 1);
+ if (ret < 0) {
+ close(fd);
+ return -1;
+ }
+ line[ret] = '\0';
+
+ sscanf(line, "%d %d ", &total, &rss);
+ close(fd);
+ return rss;
+}
+
+static char *proc_get_name(int pid, char *buf, size_t buf_size) {
+ char path[PATH_MAX];
+ int fd;
+ char *cp;
+ ssize_t ret;
+
+ /* gid containing AID_READPROC required */
+ snprintf(path, PATH_MAX, "/proc/%d/cmdline", pid);
+ fd = open(path, O_RDONLY | O_CLOEXEC);
+ if (fd == -1) {
+ return NULL;
+ }
+ ret = read_all(fd, buf, buf_size - 1);
+ close(fd);
+ if (ret < 0) {
+ return NULL;
+ }
+ buf[ret] = '\0';
+
+ cp = strchr(buf, ' ');
+ if (cp) {
+ *cp = '\0';
+ }
+
+ return buf;
+}
+
+static void cmd_procprio(LMKD_CTRL_PACKET packet, int field_count, struct ucred *cred) {
+ struct proc *procp;
+ char path[LINE_MAX];
+ char val[20];
+ int soft_limit_mult;
+ struct lmk_procprio params;
+ bool is_system_server;
+ struct passwd *pwdrec;
+ int tgid;
+
+ lmkd_pack_get_procprio(packet, field_count, ¶ms);
+
+ 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 */
+ tgid = proc_get_tgid(params.pid);
+ if (tgid >= 0 && tgid != params.pid) {
+ ALOGE("Attempt to register a task that is not a thread group leader (tid %d, tgid %d)",
+ params.pid, tgid);
+ return;
+ }
+
+ /* gid containing AID_READPROC required */
+ /* CAP_SYS_RESOURCE required */
+ /* CAP_DAC_OVERRIDE required */
+ snprintf(path, sizeof(path), "/proc/%d/oom_score_adj", params.pid);
+ snprintf(val, sizeof(val), "%d", params.oomadj);
+ if (!writefilestring(path, val, false)) {
+ ALOGW("Failed to open %s; errno=%d: process %d might have been killed",
+ path, errno, params.pid);
+ /* If this file does not exist the process is dead. */
+ return;
+ }
+
+ if (use_inkernel_interface) {
+ stats_store_taskname(params.pid, proc_get_name(params.pid, path, sizeof(path)));
+ return;
+ }
+
+ /* lmkd should not change soft limits for services */
+ if (params.ptype == PROC_TYPE_APP && per_app_memcg) {
+ if (params.oomadj >= 900) {
+ soft_limit_mult = 0;
+ } else if (params.oomadj >= 800) {
+ soft_limit_mult = 0;
+ } else if (params.oomadj >= 700) {
+ soft_limit_mult = 0;
+ } else if (params.oomadj >= 600) {
+ // Launcher should be perceptible, don't kill it.
+ params.oomadj = 200;
+ soft_limit_mult = 1;
+ } else if (params.oomadj >= 500) {
+ soft_limit_mult = 0;
+ } else if (params.oomadj >= 400) {
+ soft_limit_mult = 0;
+ } else if (params.oomadj >= 300) {
+ soft_limit_mult = 1;
+ } else if (params.oomadj >= 200) {
+ soft_limit_mult = 8;
+ } else if (params.oomadj >= 100) {
+ soft_limit_mult = 10;
+ } else if (params.oomadj >= 0) {
+ soft_limit_mult = 20;
+ } else {
+ // Persistent processes will have a large
+ // soft limit 512MB.
+ soft_limit_mult = 64;
+ }
+
+ snprintf(path, sizeof(path), MEMCG_SYSFS_PATH
+ "apps/uid_%d/pid_%d/memory.soft_limit_in_bytes",
+ params.uid, params.pid);
+ snprintf(val, sizeof(val), "%d", soft_limit_mult * EIGHT_MEGA);
+
+ /*
+ * system_server process has no memcg under /dev/memcg/apps but should be
+ * registered with lmkd. This is the best way so far to identify it.
+ */
+ is_system_server = (params.oomadj == SYSTEM_ADJ &&
+ (pwdrec = getpwnam("system")) != NULL &&
+ params.uid == pwdrec->pw_uid);
+ writefilestring(path, val, !is_system_server);
+ }
+
+ procp = pid_lookup(params.pid);
+ if (!procp) {
+ int pidfd = -1;
+
+ if (pidfd_supported) {
+ pidfd = TEMP_FAILURE_RETRY(sys_pidfd_open(params.pid, 0));
+ if (pidfd < 0) {
+ ALOGE("pidfd_open for pid %d failed; errno=%d", params.pid, errno);
+ return;
+ }
+ }
+
+ procp = static_cast<struct proc*>(calloc(1, sizeof(struct proc)));
+ if (!procp) {
+ // Oh, the irony. May need to rebuild our state.
+ return;
+ }
+
+ procp->pid = params.pid;
+ procp->pidfd = pidfd;
+ procp->uid = params.uid;
+ procp->reg_pid = cred->pid;
+ procp->oomadj = params.oomadj;
+ proc_insert(procp);
+ } else {
+ if (!claim_record(procp, cred->pid)) {
+ char buf[LINE_MAX];
+ /* Only registrant of the record can remove it */
+ ALOGE("%s (%d, %d) attempts to modify a process registered by another client",
+ proc_get_name(cred->pid, buf, sizeof(buf)), cred->uid, cred->pid);
+ return;
+ }
+ proc_unslot(procp);
+ procp->oomadj = params.oomadj;
+ proc_slot(procp);
+ }
+}
+
+static void cmd_procremove(LMKD_CTRL_PACKET packet, struct ucred *cred) {
+ struct lmk_procremove params;
+ struct proc *procp;
+
+ lmkd_pack_get_procremove(packet, ¶ms);
+
+ 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];
+ /* Only registrant of the record can remove it */
+ ALOGE("%s (%d, %d) attempts to unregister a process registered by another client",
+ proc_get_name(cred->pid, buf, sizeof(buf)), 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 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, ¶ms);
+
+ return get_killcnt(params.min_oomadj, params.max_oomadj);
+}
+
+static void cmd_target(int ntargets, LMKD_CTRL_PACKET packet) {
+ int i;
+ struct lmk_target target;
+ char minfree_str[PROPERTY_VALUE_MAX];
+ char *pstr = minfree_str;
+ char *pend = minfree_str + sizeof(minfree_str);
+ static struct timespec last_req_tm;
+ struct timespec curr_tm;
+
+ if (ntargets < 1 || ntargets > (int)ARRAY_SIZE(lowmem_adj))
+ return;
+
+ /*
+ * Ratelimit minfree updates to once per TARGET_UPDATE_MIN_INTERVAL_MS
+ * to prevent DoS attacks
+ */
+ if (clock_gettime(CLOCK_MONOTONIC_COARSE, &curr_tm) != 0) {
+ ALOGE("Failed to get current time");
+ return;
+ }
+
+ if (get_time_diff_ms(&last_req_tm, &curr_tm) <
+ TARGET_UPDATE_MIN_INTERVAL_MS) {
+ ALOGE("Ignoring frequent updated to lmkd limits");
+ return;
+ }
+
+ last_req_tm = curr_tm;
+
+ for (i = 0; i < ntargets; i++) {
+ lmkd_pack_get_target(packet, i, &target);
+ lowmem_minfree[i] = target.minfree;
+ lowmem_adj[i] = target.oom_adj_score;
+
+ pstr += snprintf(pstr, pend - pstr, "%d:%d,", target.minfree,
+ target.oom_adj_score);
+ if (pstr >= pend) {
+ /* if no more space in the buffer then terminate the loop */
+ pstr = pend;
+ break;
+ }
+ }
+
+ lowmem_targets_size = ntargets;
+
+ /* Override the last extra comma */
+ pstr[-1] = '\0';
+ property_set("sys.lmk.minfree_levels", minfree_str);
+
+ if (has_inkernel_module) {
+ char minfreestr[128];
+ char killpriostr[128];
+
+ minfreestr[0] = '\0';
+ killpriostr[0] = '\0';
+
+ for (i = 0; i < lowmem_targets_size; i++) {
+ char val[40];
+
+ if (i) {
+ strlcat(minfreestr, ",", sizeof(minfreestr));
+ strlcat(killpriostr, ",", sizeof(killpriostr));
+ }
+
+ snprintf(val, sizeof(val), "%d", use_inkernel_interface ? lowmem_minfree[i] : 0);
+ strlcat(minfreestr, val, sizeof(minfreestr));
+ snprintf(val, sizeof(val), "%d", use_inkernel_interface ? lowmem_adj[i] : 0);
+ strlcat(killpriostr, val, sizeof(killpriostr));
+ }
+
+ writefilestring(INKERNEL_MINFREE_PATH, minfreestr, true);
+ writefilestring(INKERNEL_ADJ_PATH, killpriostr, true);
+ }
+}
+
+static void ctrl_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;
+
+ 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)ARRAY_SIZE(lowmem_adj))
+ 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_PROCKILL:
+ /* This command code is NOT expected at all */
+ ALOGE("Received unexpected command code %d", cmd);
+ break;
+ default:
+ ALOGE("Received unknown command code %d", cmd);
+ return;
+ }
+
+ return;
+
+wronglen:
+ ALOGE("Wrong control socket read length cmd=%d len=%d", cmd, len);
+}
+
+static void ctrl_data_handler(int data, uint32_t events,
+ struct polling_params *poll_params __unused) {
+ if (events & EPOLLIN) {
+ ctrl_command_handler(data);
+ }
+}
+
+static int get_free_dsock() {
+ for (int i = 0; i < MAX_DATA_CONN; i++) {
+ if (data_sock[i].sock < 0) {
+ return i;
+ }
+ }
+ return -1;
+}
+
+static void ctrl_connect_handler(int data __unused, uint32_t events __unused,
+ struct polling_params *poll_params __unused) {
+ struct epoll_event epev;
+ int free_dscock_idx = get_free_dsock();
+
+ if (free_dscock_idx < 0) {
+ /*
+ * Number of data connections exceeded max supported. This should not
+ * happen but if it does we drop all existing connections and accept
+ * the new one. This prevents inactive connections from monopolizing
+ * data socket and if we drop ActivityManager connection it will
+ * immediately reconnect.
+ */
+ for (int i = 0; i < MAX_DATA_CONN; i++) {
+ ctrl_data_close(i);
+ }
+ free_dscock_idx = 0;
+ }
+
+ data_sock[free_dscock_idx].sock = accept(ctrl_sock.sock, NULL, NULL);
+ if (data_sock[free_dscock_idx].sock < 0) {
+ ALOGE("lmkd control socket accept failed; errno=%d", errno);
+ return;
+ }
+
+ ALOGI("lmkd data connection established");
+ /* use data to store data connection idx */
+ data_sock[free_dscock_idx].handler_info.data = free_dscock_idx;
+ data_sock[free_dscock_idx].handler_info.handler = ctrl_data_handler;
+ epev.events = EPOLLIN;
+ epev.data.ptr = (void *)&(data_sock[free_dscock_idx].handler_info);
+ if (epoll_ctl(epollfd, EPOLL_CTL_ADD, data_sock[free_dscock_idx].sock, &epev) == -1) {
+ ALOGE("epoll_ctl for data connection socket failed; errno=%d", errno);
+ ctrl_data_close(free_dscock_idx);
+ return;
+ }
+ maxevents++;
+}
+
+/*
+ * /proc/zoneinfo parsing routines
+ * Expected file format is:
+ *
+ * Node <node_id>, zone <zone_name>
+ * (
+ * per-node stats
+ * (<per-node field name> <value>)+
+ * )?
+ * (pages free <value>
+ * (<per-zone field name> <value>)+
+ * pagesets
+ * (<unused fields>)*
+ * )+
+ * ...
+ */
+static void zoneinfo_parse_protection(char *buf, struct zoneinfo_zone *zone) {
+ int zone_idx;
+ int64_t max = 0;
+ char *save_ptr;
+
+ for (buf = strtok_r(buf, "(), ", &save_ptr), zone_idx = 0;
+ buf && zone_idx < MAX_NR_ZONES;
+ buf = strtok_r(NULL, "), ", &save_ptr), zone_idx++) {
+ long long zoneval = strtoll(buf, &buf, 0);
+ if (zoneval > max) {
+ max = (zoneval > INT64_MAX) ? INT64_MAX : zoneval;
+ }
+ zone->protection[zone_idx] = zoneval;
+ }
+ zone->max_protection = max;
+}
+
+static int zoneinfo_parse_zone(char **buf, struct zoneinfo_zone *zone) {
+ for (char *line = strtok_r(NULL, "\n", buf); line;
+ line = strtok_r(NULL, "\n", buf)) {
+ char *cp;
+ char *ap;
+ char *save_ptr;
+ int64_t val;
+ int field_idx;
+ enum field_match_result match_res;
+
+ cp = strtok_r(line, " ", &save_ptr);
+ if (!cp) {
+ return false;
+ }
+
+ field_idx = find_field(cp, zoneinfo_zone_spec_field_names, ZI_ZONE_SPEC_FIELD_COUNT);
+ if (field_idx >= 0) {
+ /* special field */
+ if (field_idx == ZI_ZONE_SPEC_PAGESETS) {
+ /* no mode fields we are interested in */
+ return true;
+ }
+
+ /* protection field */
+ ap = strtok_r(NULL, ")", &save_ptr);
+ if (ap) {
+ zoneinfo_parse_protection(ap, zone);
+ }
+ continue;
+ }
+
+ ap = strtok_r(NULL, " ", &save_ptr);
+ if (!ap) {
+ continue;
+ }
+
+ match_res = match_field(cp, ap, zoneinfo_zone_field_names, ZI_ZONE_FIELD_COUNT,
+ &val, &field_idx);
+ if (match_res == PARSE_FAIL) {
+ return false;
+ }
+ if (match_res == PARSE_SUCCESS) {
+ zone->fields.arr[field_idx] = val;
+ }
+ if (field_idx == ZI_ZONE_PRESENT && val == 0) {
+ /* zone is not populated, stop parsing it */
+ return true;
+ }
+ }
+ return false;
+}
+
+static int zoneinfo_parse_node(char **buf, struct zoneinfo_node *node) {
+ int fields_to_match = ZI_NODE_FIELD_COUNT;
+
+ for (char *line = strtok_r(NULL, "\n", buf); line;
+ line = strtok_r(NULL, "\n", buf)) {
+ char *cp;
+ char *ap;
+ char *save_ptr;
+ int64_t val;
+ int field_idx;
+ enum field_match_result match_res;
+
+ cp = strtok_r(line, " ", &save_ptr);
+ if (!cp) {
+ return false;
+ }
+
+ ap = strtok_r(NULL, " ", &save_ptr);
+ if (!ap) {
+ return false;
+ }
+
+ match_res = match_field(cp, ap, zoneinfo_node_field_names, ZI_NODE_FIELD_COUNT,
+ &val, &field_idx);
+ if (match_res == PARSE_FAIL) {
+ return false;
+ }
+ if (match_res == PARSE_SUCCESS) {
+ node->fields.arr[field_idx] = val;
+ fields_to_match--;
+ if (!fields_to_match) {
+ return true;
+ }
+ }
+ }
+ return false;
+}
+
+static int zoneinfo_parse(struct zoneinfo *zi) {
+ static struct reread_data file_data = {
+ .filename = ZONEINFO_PATH,
+ .fd = -1,
+ };
+ char *buf;
+ char *save_ptr;
+ char *line;
+ char zone_name[LINE_MAX + 1];
+ struct zoneinfo_node *node = NULL;
+ int node_idx = 0;
+ int zone_idx = 0;
+
+ memset(zi, 0, sizeof(struct zoneinfo));
+
+ if ((buf = reread_file(&file_data)) == NULL) {
+ return -1;
+ }
+
+ for (line = strtok_r(buf, "\n", &save_ptr); line;
+ line = strtok_r(NULL, "\n", &save_ptr)) {
+ int node_id;
+ if (sscanf(line, "Node %d, zone %" STRINGIFY(LINE_MAX) "s", &node_id, zone_name) == 2) {
+ if (!node || node->id != node_id) {
+ /* new node is found */
+ if (node) {
+ node->zone_count = zone_idx + 1;
+ node_idx++;
+ if (node_idx == MAX_NR_NODES) {
+ /* max node count exceeded */
+ ALOGE("%s parse error", file_data.filename);
+ return -1;
+ }
+ }
+ node = &zi->nodes[node_idx];
+ node->id = node_id;
+ zone_idx = 0;
+ if (!zoneinfo_parse_node(&save_ptr, node)) {
+ ALOGE("%s parse error", file_data.filename);
+ return -1;
+ }
+ } else {
+ /* new zone is found */
+ zone_idx++;
+ }
+ if (!zoneinfo_parse_zone(&save_ptr, &node->zones[zone_idx])) {
+ ALOGE("%s parse error", file_data.filename);
+ return -1;
+ }
+ }
+ }
+ if (!node) {
+ ALOGE("%s parse error", file_data.filename);
+ return -1;
+ }
+ node->zone_count = zone_idx + 1;
+ zi->node_count = node_idx + 1;
+
+ /* calculate totals fields */
+ for (node_idx = 0; node_idx < zi->node_count; node_idx++) {
+ node = &zi->nodes[node_idx];
+ for (zone_idx = 0; zone_idx < node->zone_count; zone_idx++) {
+ struct zoneinfo_zone *zone = &zi->nodes[node_idx].zones[zone_idx];
+ zi->totalreserve_pages += zone->max_protection + zone->fields.field.high;
+ }
+ zi->total_inactive_file += node->fields.field.nr_inactive_file;
+ zi->total_active_file += node->fields.field.nr_active_file;
+ zi->total_workingset_refault += node->fields.field.workingset_refault;
+ }
+ return 0;
+}
+
+/* /proc/meminfo parsing routines */
+static bool meminfo_parse_line(char *line, union meminfo *mi) {
+ char *cp = line;
+ char *ap;
+ char *save_ptr;
+ int64_t val;
+ int field_idx;
+ enum field_match_result match_res;
+
+ cp = strtok_r(line, " ", &save_ptr);
+ if (!cp) {
+ return false;
+ }
+
+ ap = strtok_r(NULL, " ", &save_ptr);
+ if (!ap) {
+ return false;
+ }
+
+ match_res = match_field(cp, ap, meminfo_field_names, MI_FIELD_COUNT,
+ &val, &field_idx);
+ if (match_res == PARSE_SUCCESS) {
+ mi->arr[field_idx] = val / page_k;
+ }
+ return (match_res != PARSE_FAIL);
+}
+
+static int meminfo_parse(union meminfo *mi) {
+ static struct reread_data file_data = {
+ .filename = MEMINFO_PATH,
+ .fd = -1,
+ };
+ char *buf;
+ char *save_ptr;
+ char *line;
+
+ memset(mi, 0, sizeof(union meminfo));
+
+ if ((buf = reread_file(&file_data)) == NULL) {
+ return -1;
+ }
+
+ for (line = strtok_r(buf, "\n", &save_ptr); line;
+ line = strtok_r(NULL, "\n", &save_ptr)) {
+ if (!meminfo_parse_line(line, mi)) {
+ ALOGE("%s parse error", file_data.filename);
+ return -1;
+ }
+ }
+ mi->field.nr_file_pages = mi->field.cached + mi->field.swap_cached +
+ mi->field.buffers;
+
+ return 0;
+}
+
+/* /proc/vmstat parsing routines */
+static bool vmstat_parse_line(char *line, union vmstat *vs) {
+ char *cp;
+ char *ap;
+ char *save_ptr;
+ int64_t val;
+ int field_idx;
+ enum field_match_result match_res;
+
+ cp = strtok_r(line, " ", &save_ptr);
+ if (!cp) {
+ return false;
+ }
+
+ ap = strtok_r(NULL, " ", &save_ptr);
+ if (!ap) {
+ return false;
+ }
+
+ match_res = match_field(cp, ap, vmstat_field_names, VS_FIELD_COUNT,
+ &val, &field_idx);
+ if (match_res == PARSE_SUCCESS) {
+ vs->arr[field_idx] = val;
+ }
+ return (match_res != PARSE_FAIL);
+}
+
+static int vmstat_parse(union vmstat *vs) {
+ static struct reread_data file_data = {
+ .filename = VMSTAT_PATH,
+ .fd = -1,
+ };
+ char *buf;
+ char *save_ptr;
+ char *line;
+
+ memset(vs, 0, sizeof(union vmstat));
+
+ if ((buf = reread_file(&file_data)) == NULL) {
+ return -1;
+ }
+
+ for (line = strtok_r(buf, "\n", &save_ptr); line;
+ line = strtok_r(NULL, "\n", &save_ptr)) {
+ if (!vmstat_parse_line(line, vs)) {
+ ALOGE("%s parse error", file_data.filename);
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
+static void killinfo_log(struct proc* procp, int min_oom_score, int tasksize,
+ int kill_reason, union meminfo *mi) {
+ /* log process information */
+ android_log_write_int32(ctx, procp->pid);
+ android_log_write_int32(ctx, procp->uid);
+ android_log_write_int32(ctx, procp->oomadj);
+ android_log_write_int32(ctx, min_oom_score);
+ android_log_write_int32(ctx, (int32_t)min(tasksize * page_k, INT32_MAX));
+ android_log_write_int32(ctx, kill_reason);
+
+ /* log meminfo fields */
+ for (int field_idx = 0; field_idx < MI_FIELD_COUNT; field_idx++) {
+ android_log_write_int32(ctx, (int32_t)min(mi->arr[field_idx] * page_k, INT32_MAX));
+ }
+
+ android_log_write_list(ctx, LOG_ID_EVENTS);
+ android_log_reset(ctx);
+}
+
+static struct proc *proc_adj_lru(int oomadj) {
+ return (struct proc *)adjslot_tail(&procadjslot_list[ADJTOSLOT(oomadj)]);
+}
+
+static struct proc *proc_get_heaviest(int oomadj) {
+ struct adjslot_list *head = &procadjslot_list[ADJTOSLOT(oomadj)];
+ struct adjslot_list *curr = head->next;
+ struct proc *maxprocp = NULL;
+ int maxsize = 0;
+ while (curr != head) {
+ int pid = ((struct proc *)curr)->pid;
+ int tasksize = proc_get_size(pid);
+ if (tasksize <= 0) {
+ struct adjslot_list *next = curr->next;
+ pid_remove(pid);
+ curr = next;
+ } else {
+ if (tasksize > maxsize) {
+ maxsize = tasksize;
+ maxprocp = (struct proc *)curr;
+ }
+ curr = curr->next;
+ }
+ }
+ return maxprocp;
+}
+
+static void set_process_group_and_prio(int pid, SchedPolicy sp, int prio) {
+ DIR* d;
+ char proc_path[PATH_MAX];
+ struct dirent* de;
+
+ snprintf(proc_path, sizeof(proc_path), "/proc/%d/task", pid);
+ if (!(d = opendir(proc_path))) {
+ ALOGW("Failed to open %s; errno=%d: process pid(%d) might have died", proc_path, errno,
+ pid);
+ return;
+ }
+
+ while ((de = readdir(d))) {
+ int t_pid;
+
+ if (de->d_name[0] == '.') continue;
+ t_pid = atoi(de->d_name);
+
+ if (!t_pid) {
+ ALOGW("Failed to get t_pid for '%s' of pid(%d)", de->d_name, pid);
+ continue;
+ }
+
+ if (setpriority(PRIO_PROCESS, t_pid, prio) && errno != ESRCH) {
+ ALOGW("Unable to raise priority of killing t_pid (%d): errno=%d", t_pid, errno);
+ }
+
+ if (set_cpuset_policy(t_pid, sp)) {
+ ALOGW("Failed to set_cpuset_policy on pid(%d) t_pid(%d) to %d", pid, t_pid, (int)sp);
+ continue;
+ }
+ }
+ closedir(d);
+}
+
+static bool is_kill_pending(void) {
+ char buf[24];
+
+ if (last_kill_pid_or_fd < 0) {
+ return false;
+ }
+
+ if (pidfd_supported) {
+ return true;
+ }
+
+ /* when pidfd is not supported base the decision on /proc/<pid> existence */
+ snprintf(buf, sizeof(buf), "/proc/%d/", last_kill_pid_or_fd);
+ if (access(buf, F_OK) == 0) {
+ return true;
+ }
+
+ return false;
+}
+
+static bool is_waiting_for_kill(void) {
+ return pidfd_supported && last_kill_pid_or_fd >= 0;
+}
+
+static void stop_wait_for_proc_kill(bool finished) {
+ struct epoll_event epev;
+
+ if (last_kill_pid_or_fd < 0) {
+ return;
+ }
+
+ if (debug_process_killing) {
+ struct timespec curr_tm;
+
+ if (clock_gettime(CLOCK_MONOTONIC_COARSE, &curr_tm) != 0) {
+ /*
+ * curr_tm is used here merely to report kill duration, so this failure is not fatal.
+ * Log an error and continue.
+ */
+ ALOGE("Failed to get current time");
+ }
+
+ if (finished) {
+ ALOGI("Process got killed in %ldms",
+ get_time_diff_ms(&last_kill_tm, &curr_tm));
+ } else {
+ ALOGI("Stop waiting for process kill after %ldms",
+ get_time_diff_ms(&last_kill_tm, &curr_tm));
+ }
+ }
+
+ if (pidfd_supported) {
+ /* unregister fd */
+ if (epoll_ctl(epollfd, EPOLL_CTL_DEL, last_kill_pid_or_fd, &epev) != 0) {
+ ALOGE("epoll_ctl for last killed process failed; errno=%d", errno);
+ return;
+ }
+ maxevents--;
+ close(last_kill_pid_or_fd);
+ }
+
+ last_kill_pid_or_fd = -1;
+}
+
+static void kill_done_handler(int data __unused, uint32_t events __unused,
+ struct polling_params *poll_params) {
+ stop_wait_for_proc_kill(true);
+ poll_params->update = POLLING_RESUME;
+}
+
+static void start_wait_for_proc_kill(int pid_or_fd) {
+ static struct event_handler_info kill_done_hinfo = { 0, kill_done_handler };
+ struct epoll_event epev;
+
+ if (last_kill_pid_or_fd >= 0) {
+ /* Should not happen but if it does we should stop previous wait */
+ ALOGE("Attempt to wait for a kill while another wait is in progress");
+ stop_wait_for_proc_kill(false);
+ }
+
+ last_kill_pid_or_fd = pid_or_fd;
+
+ if (!pidfd_supported) {
+ /* If pidfd is not supported just store PID and exit */
+ return;
+ }
+
+ epev.events = EPOLLIN;
+ epev.data.ptr = (void *)&kill_done_hinfo;
+ if (epoll_ctl(epollfd, EPOLL_CTL_ADD, last_kill_pid_or_fd, &epev) != 0) {
+ ALOGE("epoll_ctl for last kill failed; errno=%d", errno);
+ close(last_kill_pid_or_fd);
+ last_kill_pid_or_fd = -1;
+ return;
+ }
+ maxevents++;
+}
+
+/* Kill one process specified by procp. Returns the size of the process killed */
+static int kill_one_process(struct proc* procp, int min_oom_score, int kill_reason,
+ const char *kill_desc, union meminfo *mi, struct timespec *tm) {
+ int pid = procp->pid;
+ int pidfd = procp->pidfd;
+ uid_t uid = procp->uid;
+ int tgid;
+ char *taskname;
+ int tasksize;
+ int r;
+ int result = -1;
+ struct memory_stat *mem_st;
+ char buf[LINE_MAX];
+
+ tgid = proc_get_tgid(pid);
+ if (tgid >= 0 && tgid != pid) {
+ ALOGE("Possible pid reuse detected (pid %d, tgid %d)!", pid, tgid);
+ goto out;
+ }
+
+ taskname = proc_get_name(pid, buf, sizeof(buf));
+ if (!taskname) {
+ goto out;
+ }
+
+ tasksize = proc_get_size(pid);
+ if (tasksize <= 0) {
+ goto out;
+ }
+
+ mem_st = stats_read_memory_stat(per_app_memcg, pid, uid);
+
+ TRACE_KILL_START(pid);
+
+ /* CAP_KILL required */
+ if (pidfd < 0) {
+ start_wait_for_proc_kill(pid);
+ r = kill(pid, SIGKILL);
+ } else {
+ start_wait_for_proc_kill(pidfd);
+ r = sys_pidfd_send_signal(pidfd, SIGKILL, NULL, 0);
+ }
+
+ TRACE_KILL_END();
+
+ if (r) {
+ stop_wait_for_proc_kill(false);
+ ALOGE("kill(%d): errno=%d", pid, errno);
+ /* Delete process record even when we fail to kill so that we don't get stuck on it */
+ goto out;
+ }
+
+ set_process_group_and_prio(pid, SP_FOREGROUND, ANDROID_PRIORITY_HIGHEST);
+
+ last_kill_tm = *tm;
+
+ inc_killcnt(procp->oomadj);
+
+ killinfo_log(procp, min_oom_score, tasksize, kill_reason, mi);
+
+ if (kill_desc) {
+ ALOGI("Kill '%s' (%d), uid %d, oom_adj %d to free %ldkB; reason: %s", taskname, pid,
+ uid, procp->oomadj, tasksize * page_k, kill_desc);
+ } else {
+ ALOGI("Kill '%s' (%d), uid %d, oom_adj %d to free %ldkB", taskname, pid,
+ uid, procp->oomadj, tasksize * page_k);
+ }
+
+ stats_write_lmk_kill_occurred(LMK_KILL_OCCURRED, uid, taskname,
+ procp->oomadj, min_oom_score, tasksize, mem_st);
+
+ ctrl_data_write_lmk_kill_occurred((pid_t)pid, uid);
+
+ result = tasksize;
+
+out:
+ /*
+ * WARNING: After pid_remove() procp is freed and can't be used!
+ * Therefore placed at the end of the function.
+ */
+ pid_remove(pid);
+ return result;
+}
+
+/*
+ * Find one process to kill at or above the given oom_adj level.
+ * Returns size of the killed process.
+ */
+static int find_and_kill_process(int min_score_adj, int kill_reason, const char *kill_desc,
+ union meminfo *mi, struct timespec *tm) {
+ int i;
+ int killed_size = 0;
+ bool lmk_state_change_start = false;
+
+ for (i = OOM_SCORE_ADJ_MAX; i >= min_score_adj; i--) {
+ struct proc *procp;
+
+ while (true) {
+ procp = kill_heaviest_task ?
+ proc_get_heaviest(i) : proc_adj_lru(i);
+
+ if (!procp)
+ break;
+
+ killed_size = kill_one_process(procp, min_score_adj, kill_reason, kill_desc, mi, tm);
+ if (killed_size >= 0) {
+ if (!lmk_state_change_start) {
+ lmk_state_change_start = true;
+ stats_write_lmk_state_changed(LMK_STATE_CHANGED,
+ LMK_STATE_CHANGE_START);
+ }
+ break;
+ }
+ }
+ if (killed_size) {
+ break;
+ }
+ }
+
+ if (lmk_state_change_start) {
+ stats_write_lmk_state_changed(LMK_STATE_CHANGED, LMK_STATE_CHANGE_STOP);
+ }
+
+ return killed_size;
+}
+
+static int64_t get_memory_usage(struct reread_data *file_data) {
+ int ret;
+ int64_t mem_usage;
+ char *buf;
+
+ if ((buf = reread_file(file_data)) == NULL) {
+ return -1;
+ }
+
+ if (!parse_int64(buf, &mem_usage)) {
+ ALOGE("%s parse error", file_data->filename);
+ return -1;
+ }
+ if (mem_usage == 0) {
+ ALOGE("No memory!");
+ return -1;
+ }
+ return mem_usage;
+}
+
+void record_low_pressure_levels(union meminfo *mi) {
+ if (low_pressure_mem.min_nr_free_pages == -1 ||
+ low_pressure_mem.min_nr_free_pages > mi->field.nr_free_pages) {
+ if (debug_process_killing) {
+ ALOGI("Low pressure min memory update from %" PRId64 " to %" PRId64,
+ low_pressure_mem.min_nr_free_pages, mi->field.nr_free_pages);
+ }
+ low_pressure_mem.min_nr_free_pages = mi->field.nr_free_pages;
+ }
+ /*
+ * Free memory at low vmpressure events occasionally gets spikes,
+ * possibly a stale low vmpressure event with memory already
+ * freed up (no memory pressure should have been reported).
+ * Ignore large jumps in max_nr_free_pages that would mess up our stats.
+ */
+ if (low_pressure_mem.max_nr_free_pages == -1 ||
+ (low_pressure_mem.max_nr_free_pages < mi->field.nr_free_pages &&
+ mi->field.nr_free_pages - low_pressure_mem.max_nr_free_pages <
+ low_pressure_mem.max_nr_free_pages * 0.1)) {
+ if (debug_process_killing) {
+ ALOGI("Low pressure max memory update from %" PRId64 " to %" PRId64,
+ low_pressure_mem.max_nr_free_pages, mi->field.nr_free_pages);
+ }
+ low_pressure_mem.max_nr_free_pages = mi->field.nr_free_pages;
+ }
+}
+
+enum vmpressure_level upgrade_level(enum vmpressure_level level) {
+ return (enum vmpressure_level)((level < VMPRESS_LEVEL_CRITICAL) ?
+ level + 1 : level);
+}
+
+enum vmpressure_level downgrade_level(enum vmpressure_level level) {
+ return (enum vmpressure_level)((level > VMPRESS_LEVEL_LOW) ?
+ level - 1 : level);
+}
+
+enum zone_watermark {
+ WMARK_MIN = 0,
+ WMARK_LOW,
+ WMARK_HIGH,
+ WMARK_NONE
+};
+
+struct zone_watermarks {
+ long high_wmark;
+ long low_wmark;
+ long min_wmark;
+};
+
+/*
+ * Returns lowest breached watermark or WMARK_NONE.
+ */
+static enum zone_watermark get_lowest_watermark(union meminfo *mi,
+ struct zone_watermarks *watermarks)
+{
+ int64_t nr_free_pages = mi->field.nr_free_pages - mi->field.cma_free;
+
+ if (nr_free_pages < watermarks->min_wmark) {
+ return WMARK_MIN;
+ }
+ if (nr_free_pages < watermarks->low_wmark) {
+ return WMARK_LOW;
+ }
+ if (nr_free_pages < watermarks->high_wmark) {
+ return WMARK_HIGH;
+ }
+ return WMARK_NONE;
+}
+
+void calc_zone_watermarks(struct zoneinfo *zi, struct zone_watermarks *watermarks) {
+ memset(watermarks, 0, sizeof(struct zone_watermarks));
+
+ for (int node_idx = 0; node_idx < zi->node_count; node_idx++) {
+ struct zoneinfo_node *node = &zi->nodes[node_idx];
+ for (int zone_idx = 0; zone_idx < node->zone_count; zone_idx++) {
+ struct zoneinfo_zone *zone = &node->zones[zone_idx];
+
+ if (!zone->fields.field.present) {
+ continue;
+ }
+
+ watermarks->high_wmark += zone->max_protection + zone->fields.field.high;
+ watermarks->low_wmark += zone->max_protection + zone->fields.field.low;
+ watermarks->min_wmark += zone->max_protection + zone->fields.field.min;
+ }
+ }
+}
+
+static void mp_event_psi(int data, uint32_t events, struct polling_params *poll_params) {
+ enum kill_reasons {
+ NONE = -1, /* To denote no kill condition */
+ PRESSURE_AFTER_KILL = 0,
+ NOT_RESPONDING,
+ LOW_SWAP_AND_THRASHING,
+ LOW_MEM_AND_SWAP,
+ LOW_MEM_AND_THRASHING,
+ DIRECT_RECL_AND_THRASHING,
+ KILL_REASON_COUNT
+ };
+ enum reclaim_state {
+ NO_RECLAIM = 0,
+ KSWAPD_RECLAIM,
+ DIRECT_RECLAIM,
+ };
+ static int64_t init_ws_refault;
+ static int64_t base_file_lru;
+ static int64_t init_pgscan_kswapd;
+ static int64_t init_pgscan_direct;
+ static int64_t swap_low_threshold;
+ static bool killing;
+ static int thrashing_limit;
+ static bool in_reclaim;
+ static struct zone_watermarks watermarks;
+ static struct timespec wmark_update_tm;
+
+ union meminfo mi;
+ union vmstat vs;
+ struct timespec curr_tm;
+ int64_t thrashing = 0;
+ bool swap_is_low = false;
+ enum vmpressure_level level = (enum vmpressure_level)data;
+ enum kill_reasons kill_reason = NONE;
+ bool cycle_after_kill = false;
+ enum reclaim_state reclaim = NO_RECLAIM;
+ enum zone_watermark wmark = WMARK_NONE;
+ char kill_desc[LINE_MAX];
+ bool cut_thrashing_limit = false;
+ int min_score_adj = 0;
+
+ /* Skip while still killing a process */
+ if (is_kill_pending()) {
+ goto no_kill;
+ }
+ /*
+ * Process is dead, stop waiting. This has no effect if pidfds are supported and
+ * death notification already caused waiting to stop.
+ */
+ stop_wait_for_proc_kill(true);
+
+ if (clock_gettime(CLOCK_MONOTONIC_COARSE, &curr_tm) != 0) {
+ ALOGE("Failed to get current time");
+ return;
+ }
+
+ if (vmstat_parse(&vs) < 0) {
+ ALOGE("Failed to parse vmstat!");
+ return;
+ }
+
+ if (meminfo_parse(&mi) < 0) {
+ ALOGE("Failed to parse meminfo!");
+ return;
+ }
+
+ /* Reset states after process got killed */
+ if (killing) {
+ killing = false;
+ cycle_after_kill = true;
+ /* Reset file-backed pagecache size and refault amounts after a kill */
+ base_file_lru = vs.field.nr_inactive_file + vs.field.nr_active_file;
+ init_ws_refault = vs.field.workingset_refault;
+ }
+
+ /* Check free swap levels */
+ if (swap_free_low_percentage) {
+ if (!swap_low_threshold) {
+ swap_low_threshold = mi.field.total_swap * swap_free_low_percentage / 100;
+ }
+ swap_is_low = mi.field.free_swap < swap_low_threshold;
+ }
+
+ /* Identify reclaim state */
+ if (vs.field.pgscan_direct > init_pgscan_direct) {
+ init_pgscan_direct = vs.field.pgscan_direct;
+ init_pgscan_kswapd = vs.field.pgscan_kswapd;
+ reclaim = DIRECT_RECLAIM;
+ } else if (vs.field.pgscan_kswapd > init_pgscan_kswapd) {
+ init_pgscan_kswapd = vs.field.pgscan_kswapd;
+ reclaim = KSWAPD_RECLAIM;
+ } else {
+ in_reclaim = false;
+ /* Skip if system is not reclaiming */
+ goto no_kill;
+ }
+
+ if (!in_reclaim) {
+ /* Record file-backed pagecache size when entering reclaim cycle */
+ base_file_lru = vs.field.nr_inactive_file + vs.field.nr_active_file;
+ init_ws_refault = vs.field.workingset_refault;
+ thrashing_limit = thrashing_limit_pct;
+ } else {
+ /* Calculate what % of the file-backed pagecache refaulted so far */
+ thrashing = (vs.field.workingset_refault - init_ws_refault) * 100 / base_file_lru;
+ }
+ in_reclaim = true;
+
+ /*
+ * Refresh watermarks once per min in case user updated one of the margins.
+ * TODO: b/140521024 replace this periodic update with an API for AMS to notify LMKD
+ * that zone watermarks were changed by the system software.
+ */
+ if (watermarks.high_wmark == 0 || get_time_diff_ms(&wmark_update_tm, &curr_tm) > 60000) {
+ struct zoneinfo zi;
+
+ if (zoneinfo_parse(&zi) < 0) {
+ ALOGE("Failed to parse zoneinfo!");
+ return;
+ }
+
+ calc_zone_watermarks(&zi, &watermarks);
+ wmark_update_tm = curr_tm;
+ }
+
+ /* Find out which watermark is breached if any */
+ wmark = get_lowest_watermark(&mi, &watermarks);
+
+ /*
+ * TODO: move this logic into a separate function
+ * Decide if killing a process is necessary and record the reason
+ */
+ if (cycle_after_kill && wmark < WMARK_LOW) {
+ /*
+ * Prevent kills not freeing enough memory which might lead to OOM kill.
+ * This might happen when a process is consuming memory faster than reclaim can
+ * free even after a kill. Mostly happens when running memory stress tests.
+ */
+ kill_reason = PRESSURE_AFTER_KILL;
+ strncpy(kill_desc, "min watermark is breached even after kill", sizeof(kill_desc));
+ } else if (level == VMPRESS_LEVEL_CRITICAL && events != 0) {
+ /*
+ * Device is too busy reclaiming memory which might lead to ANR.
+ * Critical level is triggered when PSI complete stall (all tasks are blocked because
+ * of the memory congestion) breaches the configured threshold.
+ */
+ kill_reason = NOT_RESPONDING;
+ strncpy(kill_desc, "device is not responding", sizeof(kill_desc));
+ } else if (swap_is_low && thrashing > thrashing_limit_pct) {
+ /* Page cache is thrashing while swap is low */
+ kill_reason = LOW_SWAP_AND_THRASHING;
+ snprintf(kill_desc, sizeof(kill_desc), "device is low on swap (%" PRId64
+ "kB < %" PRId64 "kB) and thrashing (%" PRId64 "%%)",
+ mi.field.free_swap * page_k, swap_low_threshold * page_k, thrashing);
+ } else if (swap_is_low && wmark < WMARK_HIGH) {
+ /* Both free memory and swap are low */
+ kill_reason = LOW_MEM_AND_SWAP;
+ snprintf(kill_desc, sizeof(kill_desc), "%s watermark is breached and swap is low (%"
+ PRId64 "kB < %" PRId64 "kB)", wmark > WMARK_LOW ? "min" : "low",
+ mi.field.free_swap * page_k, swap_low_threshold * page_k);
+ } else if (wmark < WMARK_HIGH && thrashing > thrashing_limit) {
+ /* Page cache is thrashing while memory is low */
+ kill_reason = LOW_MEM_AND_THRASHING;
+ snprintf(kill_desc, sizeof(kill_desc), "%s watermark is breached and thrashing (%"
+ PRId64 "%%)", wmark > WMARK_LOW ? "min" : "low", thrashing);
+ cut_thrashing_limit = true;
+ /* Do not kill perceptible apps because of thrashing */
+ min_score_adj = PERCEPTIBLE_APP_ADJ;
+ } else if (reclaim == DIRECT_RECLAIM && thrashing > thrashing_limit) {
+ /* Page cache is thrashing while in direct reclaim (mostly happens on lowram devices) */
+ kill_reason = DIRECT_RECL_AND_THRASHING;
+ snprintf(kill_desc, sizeof(kill_desc), "device is in direct reclaim and thrashing (%"
+ PRId64 "%%)", thrashing);
+ cut_thrashing_limit = true;
+ /* Do not kill perceptible apps because of thrashing */
+ min_score_adj = PERCEPTIBLE_APP_ADJ;
+ }
+
+ /* Kill a process if necessary */
+ if (kill_reason != NONE) {
+ int pages_freed = find_and_kill_process(min_score_adj, kill_reason, kill_desc, &mi,
+ &curr_tm);
+ if (pages_freed > 0) {
+ killing = true;
+ if (cut_thrashing_limit) {
+ /*
+ * Cut thrasing limit by thrashing_limit_decay_pct percentage of the current
+ * thrashing limit until the system stops thrashing.
+ */
+ thrashing_limit = (thrashing_limit * (100 - thrashing_limit_decay_pct)) / 100;
+ }
+ }
+ }
+
+no_kill:
+ /* Do not poll if kernel supports pidfd waiting */
+ if (is_waiting_for_kill()) {
+ /* Pause polling if we are waiting for process death notification */
+ poll_params->update = POLLING_PAUSE;
+ return;
+ }
+
+ /*
+ * Start polling after initial PSI event;
+ * extend polling while device is in direct reclaim or process is being killed;
+ * do not extend when kswapd reclaims because that might go on for a long time
+ * without causing memory pressure
+ */
+ if (events || killing || reclaim == DIRECT_RECLAIM) {
+ poll_params->update = POLLING_START;
+ }
+
+ /* Decide the polling interval */
+ if (swap_is_low || killing) {
+ /* Fast polling during and after a kill or when swap is low */
+ poll_params->polling_interval_ms = PSI_POLL_PERIOD_SHORT_MS;
+ } else {
+ /* By default use long intervals */
+ poll_params->polling_interval_ms = PSI_POLL_PERIOD_LONG_MS;
+ }
+}
+
+static void mp_event_common(int data, uint32_t events, struct polling_params *poll_params) {
+ int ret;
+ unsigned long long evcount;
+ int64_t mem_usage, memsw_usage;
+ int64_t mem_pressure;
+ union meminfo mi;
+ struct zoneinfo zi;
+ struct timespec curr_tm;
+ static unsigned long kill_skip_count = 0;
+ enum vmpressure_level level = (enum vmpressure_level)data;
+ long other_free = 0, other_file = 0;
+ int min_score_adj;
+ int minfree = 0;
+ static struct reread_data mem_usage_file_data = {
+ .filename = MEMCG_MEMORY_USAGE,
+ .fd = -1,
+ };
+ static struct reread_data memsw_usage_file_data = {
+ .filename = MEMCG_MEMORYSW_USAGE,
+ .fd = -1,
+ };
+
+ if (debug_process_killing) {
+ ALOGI("%s memory pressure event is triggered", level_name[level]);
+ }
+
+ if (!use_psi_monitors) {
+ /*
+ * Check all event counters from low to critical
+ * and upgrade to the highest priority one. By reading
+ * eventfd we also reset the event counters.
+ */
+ for (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;
+ }
+
+ if (kill_timeout_ms && get_time_diff_ms(&last_kill_tm, &curr_tm) < kill_timeout_ms) {
+ /*
+ * If we're within the no-kill timeout, see if there's pending reclaim work
+ * from the last killed process. If so, skip killing for now.
+ */
+ if (is_kill_pending()) {
+ kill_skip_count++;
+ return;
+ }
+ /*
+ * Process is dead, stop waiting. This has no effect if pidfds are supported and
+ * death notification already caused waiting to stop.
+ */
+ stop_wait_for_proc_kill(true);
+ } else {
+ /*
+ * Killing took longer than no-kill timeout. Stop waiting for the last process
+ * to die because we are ready to kill again.
+ */
+ stop_wait_for_proc_kill(false);
+ }
+
+ if (kill_skip_count > 0) {
+ ALOGI("%lu memory pressure events were skipped after a kill!",
+ kill_skip_count);
+ kill_skip_count = 0;
+ }
+
+ if (meminfo_parse(&mi) < 0 || zoneinfo_parse(&zi) < 0) {
+ ALOGE("Failed to get free memory!");
+ return;
+ }
+
+ if (use_minfree_levels) {
+ int i;
+
+ other_free = mi.field.nr_free_pages - zi.totalreserve_pages;
+ if (mi.field.nr_file_pages > (mi.field.shmem + mi.field.unevictable + mi.field.swap_cached)) {
+ other_file = (mi.field.nr_file_pages - mi.field.shmem -
+ mi.field.unevictable - mi.field.swap_cached);
+ } else {
+ other_file = 0;
+ }
+
+ min_score_adj = OOM_SCORE_ADJ_MAX + 1;
+ for (i = 0; i < lowmem_targets_size; i++) {
+ minfree = lowmem_minfree[i];
+ if (other_free < minfree && other_file < minfree) {
+ min_score_adj = lowmem_adj[i];
+ break;
+ }
+ }
+
+ if (min_score_adj == OOM_SCORE_ADJ_MAX + 1) {
+ if (debug_process_killing) {
+ ALOGI("Ignore %s memory pressure event "
+ "(free memory=%ldkB, cache=%ldkB, limit=%ldkB)",
+ level_name[level], other_free * page_k, other_file * page_k,
+ (long)lowmem_minfree[lowmem_targets_size - 1] * page_k);
+ }
+ return;
+ }
+
+ goto do_kill;
+ }
+
+ if (level == VMPRESS_LEVEL_LOW) {
+ record_low_pressure_levels(&mi);
+ }
+
+ if (level_oomadj[level] > OOM_SCORE_ADJ_MAX) {
+ /* Do not monitor this pressure level */
+ return;
+ }
+
+ if ((mem_usage = get_memory_usage(&mem_usage_file_data)) < 0) {
+ goto do_kill;
+ }
+ if ((memsw_usage = get_memory_usage(&memsw_usage_file_data)) < 0) {
+ goto do_kill;
+ }
+
+ // Calculate percent for swappinness.
+ mem_pressure = (mem_usage * 100) / memsw_usage;
+
+ if (enable_pressure_upgrade && level != VMPRESS_LEVEL_CRITICAL) {
+ // We are swapping too much.
+ if (mem_pressure < upgrade_pressure) {
+ level = upgrade_level(level);
+ if (debug_process_killing) {
+ ALOGI("Event upgraded to %s", level_name[level]);
+ }
+ }
+ }
+
+ // If we still have enough swap space available, check if we want to
+ // ignore/downgrade pressure events.
+ if (mi.field.free_swap >=
+ mi.field.total_swap * swap_free_low_percentage / 100) {
+ // If the pressure is larger than downgrade_pressure lmk will not
+ // kill any process, since enough memory is available.
+ if (mem_pressure > downgrade_pressure) {
+ if (debug_process_killing) {
+ ALOGI("Ignore %s memory pressure", level_name[level]);
+ }
+ return;
+ } else if (level == VMPRESS_LEVEL_CRITICAL && mem_pressure > upgrade_pressure) {
+ if (debug_process_killing) {
+ ALOGI("Downgrade critical memory pressure");
+ }
+ // Downgrade event, since enough memory available.
+ level = downgrade_level(level);
+ }
+ }
+
+do_kill:
+ if (low_ram_device) {
+ /* For Go devices kill only one task */
+ if (find_and_kill_process(level_oomadj[level], -1, NULL, &mi, &curr_tm) == 0) {
+ if (debug_process_killing) {
+ ALOGI("Nothing to kill");
+ }
+ }
+ } else {
+ int pages_freed;
+ static struct timespec last_report_tm;
+ static unsigned long report_skip_count = 0;
+
+ if (!use_minfree_levels) {
+ /* Free up enough memory to downgrate the memory pressure to low level */
+ if (mi.field.nr_free_pages >= low_pressure_mem.max_nr_free_pages) {
+ if (debug_process_killing) {
+ ALOGI("Ignoring pressure since more memory is "
+ "available (%" PRId64 ") than watermark (%" PRId64 ")",
+ mi.field.nr_free_pages, low_pressure_mem.max_nr_free_pages);
+ }
+ return;
+ }
+ min_score_adj = level_oomadj[level];
+ }
+
+ pages_freed = find_and_kill_process(min_score_adj, -1, NULL, &mi, &curr_tm);
+
+ if (pages_freed == 0) {
+ /* Rate limit kill reports when nothing was reclaimed */
+ if (get_time_diff_ms(&last_report_tm, &curr_tm) < FAIL_REPORT_RLIMIT_MS) {
+ report_skip_count++;
+ return;
+ }
+ }
+
+ /* Log whenever we kill or when report rate limit allows */
+ if (use_minfree_levels) {
+ ALOGI("Reclaimed %ldkB, cache(%ldkB) and "
+ "free(%" PRId64 "kB)-reserved(%" PRId64 "kB) below min(%ldkB) for oom_adj %d",
+ pages_freed * page_k,
+ other_file * page_k, mi.field.nr_free_pages * page_k,
+ zi.totalreserve_pages * page_k,
+ minfree * page_k, min_score_adj);
+ } else {
+ ALOGI("Reclaimed %ldkB at oom_adj %d",
+ pages_freed * page_k, min_score_adj);
+ }
+
+ if (report_skip_count > 0) {
+ ALOGI("Suppressed %lu failed kill reports", report_skip_count);
+ report_skip_count = 0;
+ }
+
+ last_report_tm = curr_tm;
+ }
+ if (is_waiting_for_kill()) {
+ /* pause polling if we are waiting for process death notification */
+ poll_params->update = POLLING_PAUSE;
+ }
+}
+
+static bool init_mp_psi(enum vmpressure_level level, bool use_new_strategy) {
+ int fd;
+
+ /* Do not register a handler if threshold_ms is not set */
+ if (!psi_thresholds[level].threshold_ms) {
+ return true;
+ }
+
+ fd = init_psi_monitor(psi_thresholds[level].stall_type,
+ psi_thresholds[level].threshold_ms * US_PER_MS,
+ PSI_WINDOW_SIZE_MS * US_PER_MS);
+
+ if (fd < 0) {
+ return false;
+ }
+
+ vmpressure_hinfo[level].handler = use_new_strategy ? mp_event_psi : mp_event_common;
+ vmpressure_hinfo[level].data = level;
+ if (register_psi_monitor(epollfd, fd, &vmpressure_hinfo[level]) < 0) {
+ destroy_psi_monitor(fd);
+ return false;
+ }
+ maxevents++;
+ mpevfd[level] = fd;
+
+ return true;
+}
+
+static void destroy_mp_psi(enum vmpressure_level level) {
+ int fd = mpevfd[level];
+
+ if (unregister_psi_monitor(epollfd, fd) < 0) {
+ ALOGE("Failed to unregister psi monitor for %s memory pressure; errno=%d",
+ level_name[level], errno);
+ }
+ destroy_psi_monitor(fd);
+ mpevfd[level] = -1;
+}
+
+static bool init_psi_monitors() {
+ /*
+ * When PSI is used on low-ram devices or on high-end devices without memfree levels
+ * use new kill strategy based on zone watermarks, free swap and thrashing stats
+ */
+ bool use_new_strategy =
+ property_get_bool("ro.lmk.use_new_strategy", low_ram_device || !use_minfree_levels);
+
+ /* In default PSI mode override stall amounts using system properties */
+ if (use_new_strategy) {
+ /* Do not use low pressure level */
+ psi_thresholds[VMPRESS_LEVEL_LOW].threshold_ms = 0;
+ psi_thresholds[VMPRESS_LEVEL_MEDIUM].threshold_ms = psi_partial_stall_ms;
+ psi_thresholds[VMPRESS_LEVEL_CRITICAL].threshold_ms = psi_complete_stall_ms;
+ }
+
+ if (!init_mp_psi(VMPRESS_LEVEL_LOW, use_new_strategy)) {
+ return false;
+ }
+ if (!init_mp_psi(VMPRESS_LEVEL_MEDIUM, use_new_strategy)) {
+ destroy_mp_psi(VMPRESS_LEVEL_LOW);
+ return false;
+ }
+ if (!init_mp_psi(VMPRESS_LEVEL_CRITICAL, use_new_strategy)) {
+ destroy_mp_psi(VMPRESS_LEVEL_MEDIUM);
+ destroy_mp_psi(VMPRESS_LEVEL_LOW);
+ return false;
+ }
+ return true;
+}
+
+static bool init_mp_common(enum vmpressure_level level) {
+ int mpfd;
+ int evfd;
+ int evctlfd;
+ char buf[256];
+ struct epoll_event epev;
+ int ret;
+ int level_idx = (int)level;
+ const char *levelstr = level_name[level_idx];
+
+ /* gid containing AID_SYSTEM required */
+ mpfd = open(MEMCG_SYSFS_PATH "memory.pressure_level", O_RDONLY | O_CLOEXEC);
+ if (mpfd < 0) {
+ ALOGI("No kernel memory.pressure_level support (errno=%d)", errno);
+ goto err_open_mpfd;
+ }
+
+ evctlfd = open(MEMCG_SYSFS_PATH "cgroup.event_control", O_WRONLY | O_CLOEXEC);
+ if (evctlfd < 0) {
+ ALOGI("No kernel memory cgroup event control (errno=%d)", errno);
+ goto err_open_evctlfd;
+ }
+
+ evfd = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
+ if (evfd < 0) {
+ ALOGE("eventfd failed for level %s; errno=%d", levelstr, errno);
+ goto err_eventfd;
+ }
+
+ ret = snprintf(buf, sizeof(buf), "%d %d %s", evfd, mpfd, levelstr);
+ if (ret >= (ssize_t)sizeof(buf)) {
+ ALOGE("cgroup.event_control line overflow for level %s", levelstr);
+ goto err;
+ }
+
+ ret = TEMP_FAILURE_RETRY(write(evctlfd, buf, strlen(buf) + 1));
+ if (ret == -1) {
+ ALOGE("cgroup.event_control write failed for level %s; errno=%d",
+ levelstr, errno);
+ goto err;
+ }
+
+ epev.events = EPOLLIN;
+ /* use data to store event level */
+ vmpressure_hinfo[level_idx].data = level_idx;
+ vmpressure_hinfo[level_idx].handler = mp_event_common;
+ epev.data.ptr = (void *)&vmpressure_hinfo[level_idx];
+ ret = epoll_ctl(epollfd, EPOLL_CTL_ADD, evfd, &epev);
+ if (ret == -1) {
+ ALOGE("epoll_ctl for level %s failed; errno=%d", levelstr, errno);
+ goto err;
+ }
+ maxevents++;
+ mpevfd[level] = evfd;
+ close(evctlfd);
+ return true;
+
+err:
+ close(evfd);
+err_eventfd:
+ close(evctlfd);
+err_open_evctlfd:
+ close(mpfd);
+err_open_mpfd:
+ return false;
+}
+
+static void kernel_event_handler(int data __unused, uint32_t events __unused,
+ struct polling_params *poll_params __unused) {
+ poll_kernel(kpoll_fd);
+}
+
+static int init(void) {
+ static struct event_handler_info kernel_poll_hinfo = { 0, kernel_event_handler };
+ struct reread_data file_data = {
+ .filename = ZONEINFO_PATH,
+ .fd = -1,
+ };
+ struct epoll_event epev;
+ int pidfd;
+ int i;
+ int ret;
+
+ page_k = sysconf(_SC_PAGESIZE);
+ if (page_k == -1)
+ page_k = PAGE_SIZE;
+ page_k /= 1024;
+
+ epollfd = epoll_create(MAX_EPOLL_EVENTS);
+ if (epollfd == -1) {
+ ALOGE("epoll_create failed (errno=%d)", errno);
+ return -1;
+ }
+
+ // mark data connections as not connected
+ for (int i = 0; i < MAX_DATA_CONN; i++) {
+ data_sock[i].sock = -1;
+ }
+
+ ctrl_sock.sock = android_get_control_socket("lmkd");
+ if (ctrl_sock.sock < 0) {
+ ALOGE("get lmkd control socket failed");
+ return -1;
+ }
+
+ ret = listen(ctrl_sock.sock, MAX_DATA_CONN);
+ if (ret < 0) {
+ ALOGE("lmkd control socket listen failed (errno=%d)", errno);
+ return -1;
+ }
+
+ epev.events = EPOLLIN;
+ ctrl_sock.handler_info.handler = ctrl_connect_handler;
+ epev.data.ptr = (void *)&(ctrl_sock.handler_info);
+ if (epoll_ctl(epollfd, EPOLL_CTL_ADD, ctrl_sock.sock, &epev) == -1) {
+ ALOGE("epoll_ctl for lmkd control socket failed (errno=%d)", errno);
+ return -1;
+ }
+ maxevents++;
+
+ has_inkernel_module = !access(INKERNEL_MINFREE_PATH, W_OK);
+ use_inkernel_interface = has_inkernel_module;
+
+ if (use_inkernel_interface) {
+ ALOGI("Using in-kernel low memory killer interface");
+ if (init_poll_kernel()) {
+ 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 {
+ /* Try to use psi monitor first if kernel has it */
+ use_psi_monitors = property_get_bool("ro.lmk.use_psi", true) &&
+ init_psi_monitors();
+ /* Fall back to vmpressure */
+ if (!use_psi_monitors &&
+ (!init_mp_common(VMPRESS_LEVEL_LOW) ||
+ !init_mp_common(VMPRESS_LEVEL_MEDIUM) ||
+ !init_mp_common(VMPRESS_LEVEL_CRITICAL))) {
+ ALOGE("Kernel does not support memory pressure events or in-kernel low memory killer");
+ return -1;
+ }
+ if (use_psi_monitors) {
+ ALOGI("Using psi monitors for memory pressure detection");
+ } else {
+ ALOGI("Using vmpressure for memory pressure detection");
+ }
+ /* 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(sys_pidfd_open(getpid(), 0));
+ if (pidfd < 0) {
+ pidfd_supported = (errno != ENOSYS);
+ } else {
+ pidfd_supported = true;
+ close(pidfd);
+ }
+ ALOGI("Process polling is %s", pidfd_supported ? "supported" : "not supported" );
+
+ return 0;
+}
+
+static void call_handler(struct event_handler_info* handler_info,
+ struct polling_params *poll_params, uint32_t events) {
+ struct timespec curr_tm;
+
+ handler_info->handler(handler_info->data, events, poll_params);
+ clock_gettime(CLOCK_MONOTONIC_COARSE, &curr_tm);
+ poll_params->last_poll_tm = curr_tm;
+
+ switch (poll_params->update) {
+ case POLLING_START:
+ /*
+ * Poll for the duration of PSI_WINDOW_SIZE_MS after the
+ * initial PSI event because psi events are rate-limited
+ * at one per sec.
+ */
+ poll_params->poll_start_tm = curr_tm;
+ poll_params->poll_handler = handler_info;
+ break;
+ case POLLING_STOP:
+ poll_params->poll_handler = NULL;
+ break;
+ case POLLING_PAUSE:
+ poll_params->paused_handler = handler_info;
+ poll_params->poll_handler = NULL;
+ break;
+ case POLLING_RESUME:
+ poll_params->poll_start_tm = curr_tm;
+ poll_params->poll_handler = poll_params->paused_handler;
+ break;
+ case POLLING_DO_NOT_CHANGE:
+ if (get_time_diff_ms(&poll_params->poll_start_tm, &curr_tm) > PSI_WINDOW_SIZE_MS) {
+ /* Polled for the duration of PSI window, time to stop */
+ poll_params->poll_handler = NULL;
+ }
+ /* WARNING: skipping the rest of the function */
+ return;
+ }
+ poll_params->update = POLLING_DO_NOT_CHANGE;
+}
+
+static void mainloop(void) {
+ struct event_handler_info* handler_info;
+ struct polling_params poll_params;
+ struct timespec curr_tm;
+ struct epoll_event *evt;
+ long delay = -1;
+
+ poll_params.poll_handler = NULL;
+ poll_params.update = POLLING_DO_NOT_CHANGE;
+
+ while (1) {
+ struct epoll_event events[maxevents];
+ int nevents;
+ int i;
+
+ if (poll_params.poll_handler) {
+ bool poll_now;
+
+ clock_gettime(CLOCK_MONOTONIC_COARSE, &curr_tm);
+ if (poll_params.poll_handler == poll_params.paused_handler) {
+ /*
+ * Just transitioned into POLLING_RESUME. Reset paused_handler
+ * and poll immediately
+ */
+ poll_params.paused_handler = NULL;
+ poll_now = true;
+ nevents = 0;
+ } else {
+ /* Calculate next timeout */
+ delay = get_time_diff_ms(&poll_params.last_poll_tm, &curr_tm);
+ delay = (delay < poll_params.polling_interval_ms) ?
+ poll_params.polling_interval_ms - delay : poll_params.polling_interval_ms;
+
+ /* Wait for events until the next polling timeout */
+ nevents = epoll_wait(epollfd, events, maxevents, delay);
+
+ /* Update current time after wait */
+ clock_gettime(CLOCK_MONOTONIC_COARSE, &curr_tm);
+ poll_now = (get_time_diff_ms(&poll_params.last_poll_tm, &curr_tm) >=
+ poll_params.polling_interval_ms);
+ }
+ if (poll_now) {
+ call_handler(poll_params.poll_handler, &poll_params, 0);
+ }
+ } else {
+ /* Wait for events with no timeout */
+ nevents = epoll_wait(epollfd, events, maxevents, -1);
+ }
+
+ if (nevents == -1) {
+ if (errno == EINTR)
+ continue;
+ ALOGE("epoll_wait failed (errno=%d)", errno);
+ continue;
+ }
+
+ /*
+ * First pass to see if any data socket connections were dropped.
+ * Dropped connection should be handled before any other events
+ * to deallocate data connection and correctly handle cases when
+ * connection gets dropped and reestablished in the same epoll cycle.
+ * In such cases it's essential to handle connection closures first.
+ */
+ for (i = 0, evt = &events[0]; i < nevents; ++i, evt++) {
+ if ((evt->events & EPOLLHUP) && evt->data.ptr) {
+ ALOGI("lmkd data connection dropped");
+ handler_info = (struct event_handler_info*)evt->data.ptr;
+ ctrl_data_close(handler_info->data);
+ }
+ }
+
+ /* Second pass to handle all other events */
+ for (i = 0, evt = &events[0]; i < nevents; ++i, evt++) {
+ if (evt->events & EPOLLERR) {
+ ALOGD("EPOLLERR on event #%d", i);
+ }
+ if (evt->events & EPOLLHUP) {
+ /* This case was handled in the first pass */
+ continue;
+ }
+ if (evt->data.ptr) {
+ handler_info = (struct event_handler_info*)evt->data.ptr;
+ call_handler(handler_info, &poll_params, evt->events);
+ }
+ }
+ }
+}
+
+int main(int argc __unused, char **argv __unused) {
+ struct sched_param param = {
+ .sched_priority = 1,
+ };
+
+ /* By default disable low level vmpressure events */
+ level_oomadj[VMPRESS_LEVEL_LOW] =
+ property_get_int32("ro.lmk.low", OOM_SCORE_ADJ_MAX + 1);
+ level_oomadj[VMPRESS_LEVEL_MEDIUM] =
+ property_get_int32("ro.lmk.medium", 800);
+ level_oomadj[VMPRESS_LEVEL_CRITICAL] =
+ property_get_int32("ro.lmk.critical", 0);
+ debug_process_killing = property_get_bool("ro.lmk.debug", false);
+
+ /* By default disable upgrade/downgrade logic */
+ enable_pressure_upgrade =
+ property_get_bool("ro.lmk.critical_upgrade", false);
+ upgrade_pressure =
+ (int64_t)property_get_int32("ro.lmk.upgrade_pressure", 100);
+ downgrade_pressure =
+ (int64_t)property_get_int32("ro.lmk.downgrade_pressure", 100);
+ kill_heaviest_task =
+ property_get_bool("ro.lmk.kill_heaviest_task", false);
+ low_ram_device = property_get_bool("ro.config.low_ram", false);
+ kill_timeout_ms =
+ (unsigned long)property_get_int32("ro.lmk.kill_timeout_ms", 0);
+ use_minfree_levels =
+ property_get_bool("ro.lmk.use_minfree_levels", false);
+ per_app_memcg =
+ property_get_bool("ro.config.per_app_memcg", low_ram_device);
+ swap_free_low_percentage = clamp(0, 100, property_get_int32("ro.lmk.swap_free_low_percentage",
+ low_ram_device ? DEF_LOW_SWAP_LOWRAM : DEF_LOW_SWAP));
+ psi_partial_stall_ms = property_get_int32("ro.lmk.psi_partial_stall_ms",
+ low_ram_device ? DEF_PARTIAL_STALL_LOWRAM : DEF_PARTIAL_STALL);
+ psi_complete_stall_ms = property_get_int32("ro.lmk.psi_complete_stall_ms",
+ DEF_COMPLETE_STALL);
+ thrashing_limit_pct = max(0, property_get_int32("ro.lmk.thrashing_limit",
+ low_ram_device ? DEF_THRASHING_LOWRAM : DEF_THRASHING));
+ thrashing_limit_decay_pct = clamp(0, 100, property_get_int32("ro.lmk.thrashing_limit_decay",
+ low_ram_device ? DEF_THRASHING_DECAY_LOWRAM : DEF_THRASHING_DECAY));
+
+ ctx = create_android_logger(KILLINFO_LOG_TAG);
+
+ statslog_init();
+
+ if (!init()) {
+ if (!use_inkernel_interface) {
+ /*
+ * MCL_ONFAULT pins pages as they fault instead of loading
+ * everything immediately all at once. (Which would be bad,
+ * because as of this writing, we have a lot of mapped pages we
+ * never use.) Old kernels will see MCL_ONFAULT and fail with
+ * EINVAL; we ignore this failure.
+ *
+ * N.B. read the man page for mlockall. MCL_CURRENT | MCL_ONFAULT
+ * pins ⊆ MCL_CURRENT, converging to just MCL_CURRENT as we fault
+ * in pages.
+ */
+ /* CAP_IPC_LOCK required */
+ if (mlockall(MCL_CURRENT | MCL_FUTURE | MCL_ONFAULT) && (errno != EINVAL)) {
+ ALOGW("mlockall failed %s", strerror(errno));
+ }
+
+ /* CAP_NICE required */
+ if (sched_setscheduler(0, SCHED_FIFO, ¶m)) {
+ ALOGW("set SCHED_FIFO failed %s", strerror(errno));
+ }
+ }
+
+ mainloop();
+ }
+
+ statslog_destroy();
+
+ android_log_destroy(&ctx);
+
+ ALOGI("exiting");
+ return 0;
+}