diff --git a/lmkd.c b/lmkd.c index bf0ae4d..f30608e 100644 --- a/lmkd.c +++ b/lmkd.c @@ -424,28 +424,50 @@ static ssize_t read_all(int fd, char *buf, size_t max_len) * 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) { +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) { - data->fd = open(data->filename, O_RDONLY | O_CLOEXEC); - if (data->fd == -1) { + /* First-time buffer initialization */ + if (!buf && (buf = malloc(buf_size)) == NULL) { + return NULL; + } + + data->fd = TEMP_FAILURE_RETRY(open(data->filename, O_RDONLY | O_CLOEXEC)); + if (data->fd < 0) { ALOGE("%s open: %s", data->filename, strerror(errno)); - return -1; + return NULL; } } - 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; + while (true) { + size = read_all(data->fd, buf, buf_size - 1); + if (size < 0) { + ALOGE("%s read: %s", data->filename, strerror(errno)); + close(data->fd); + data->fd = -1; + return NULL; + } + if (size < buf_size - 1) { + break; + } + /* + * Since we are reading /proc files we can't use fstat to find out + * the real size of the file. Double the buffer size and keep retrying. + */ + if ((new_buf = realloc(buf, buf_size * 2)) == NULL) { + errno = ENOMEM; + return NULL; + } + buf = new_buf; + buf_size *= 2; } - ALOG_ASSERT((size_t)size < buf_size - 1, "%s too large", data->filename); buf[size] = 0; - return 0; + return buf; } static struct proc *pid_lookup(int pid) { @@ -1200,13 +1222,13 @@ static int zoneinfo_parse(union zoneinfo *zi) { .filename = ZONEINFO_PATH, .fd = -1, }; - char buf[PAGE_SIZE]; + char *buf; char *save_ptr; char *line; memset(zi, 0, sizeof(union zoneinfo)); - if (reread_file(&file_data, buf, sizeof(buf)) < 0) { + if ((buf = reread_file(&file_data)) == NULL) { return -1; } @@ -1254,13 +1276,13 @@ static int meminfo_parse(union meminfo *mi) { .filename = MEMINFO_PATH, .fd = -1, }; - char buf[PAGE_SIZE]; + char *buf; char *save_ptr; char *line; memset(mi, 0, sizeof(union meminfo)); - if (reread_file(&file_data, buf, sizeof(buf)) < 0) { + if ((buf = reread_file(&file_data)) == NULL) { return -1; } @@ -1542,9 +1564,9 @@ static int find_and_kill_process(int min_score_adj) { static int64_t get_memory_usage(struct reread_data *file_data) { int ret; int64_t mem_usage; - char buf[32]; + char *buf; - if (reread_file(file_data, buf, sizeof(buf)) < 0) { + if ((buf = reread_file(file_data)) == NULL) { return -1; } @@ -2014,6 +2036,10 @@ static void init_poll_kernel() { #endif static int init(void) { + struct reread_data file_data = { + .filename = ZONEINFO_PATH, + .fd = -1, + }; struct epoll_event epev; int i; int ret; @@ -2091,6 +2117,14 @@ static int init(void) { 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)); + } + return 0; }