diff options
Diffstat (limited to 'lmkd')
-rw-r--r-- | lmkd/lmkd.c | 88 |
1 files changed, 73 insertions, 15 deletions
diff --git a/lmkd/lmkd.c b/lmkd/lmkd.c index 6b0d8be56..72e3251c9 100644 --- a/lmkd/lmkd.c +++ b/lmkd/lmkd.c @@ -171,6 +171,11 @@ struct proc { struct proc *pidhash_next; }; +struct reread_data { + const char* const filename; + int fd; +}; + #ifdef LMKD_LOG_STATS static bool enable_stats_log; static android_log_context log_ctx; @@ -186,12 +191,27 @@ static struct adjslot_list procadjslot_list[ADJTOSLOT(OOM_SCORE_ADJ_MAX) + 1]; /* PAGE_SIZE / 1024 */ static long page_k; +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; +} + +/* + * 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 = read(fd, buf, max_len); + ssize_t r = TEMP_FAILURE_RETRY(pread(fd, buf, max_len, offset)); if (r == 0) { break; } @@ -200,12 +220,44 @@ static ssize_t read_all(int fd, char *buf, size_t max_len) } 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 int reread_file(struct reread_data *data, char *buf, size_t buf_size) { + ssize_t size; + + if (data->fd == -1) { + data->fd = open(data->filename, O_RDONLY | O_CLOEXEC); + if (data->fd == -1) { + ALOGE("%s open: %s", data->filename, strerror(errno)); + return -1; + } + } + + 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 -1; + } + ALOG_ASSERT((size_t)size < buf_size - 1, data->filename " too large"); + buf[size] = 0; + + return 0; +} + static struct proc *pid_lookup(int pid) { struct proc *procp; @@ -442,7 +494,7 @@ static void ctrl_data_close(int dsock_idx) { static int ctrl_data_read(int dsock_idx, char *buf, size_t bufsz) { int ret = 0; - ret = read(data_sock[dsock_idx].sock, buf, bufsz); + ret = TEMP_FAILURE_RETRY(read(data_sock[dsock_idx].sock, buf, bufsz)); if (ret == -1) { ALOGE("control data socket read failed; errno=%d", errno); @@ -803,23 +855,19 @@ static int find_and_kill_processes(enum vmpressure_level level, return pages_freed; } -static int64_t get_memory_usage(const char* path) { +static int64_t get_memory_usage(struct reread_data *file_data) { int ret; int64_t mem_usage; char buf[32]; - int fd = open(path, O_RDONLY | O_CLOEXEC); - if (fd == -1) { - ALOGE("%s open: errno=%d", path, errno); + + if (reread_file(file_data, buf, sizeof(buf)) < 0) { return -1; } - ret = read_all(fd, buf, sizeof(buf) - 1); - close(fd); - if (ret < 0) { - ALOGE("%s error: errno=%d", path, errno); + if (!parse_int64(buf, &mem_usage)) { + ALOGE("%s parse error", file_data->filename); return -1; } - sscanf(buf, "%" SCNd64, &mem_usage); if (mem_usage == 0) { ALOGE("No memory!"); return -1; @@ -879,6 +927,14 @@ static void mp_event_common(int data, uint32_t events __unused) { static struct timeval last_report_tm; static unsigned long skip_count = 0; enum vmpressure_level level = (enum vmpressure_level)data; + 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, + }; /* * Check all event counters from low to critical @@ -887,7 +943,8 @@ static void mp_event_common(int data, uint32_t events __unused) { */ for (lvl = VMPRESS_LEVEL_LOW; lvl < VMPRESS_LEVEL_COUNT; lvl++) { if (mpevfd[lvl] != -1 && - read(mpevfd[lvl], &evcount, sizeof(evcount)) > 0 && + TEMP_FAILURE_RETRY(read(mpevfd[lvl], + &evcount, sizeof(evcount))) > 0 && evcount > 0 && lvl > level) { level = lvl; } @@ -924,9 +981,10 @@ static void mp_event_common(int data, uint32_t events __unused) { return; } - mem_usage = get_memory_usage(MEMCG_MEMORY_USAGE); - memsw_usage = get_memory_usage(MEMCG_MEMORYSW_USAGE); - if (memsw_usage < 0 || mem_usage < 0) { + 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; } |