Merge changes I8e27f8b9,I78d2dc79 into pi-dev
* changes:
lmkd: Optimize frequent file reads by keeping file descriptors open
lmkd: Fix usage of ro.lmk.kill_heaviest_task property
diff --git a/lmkd/lmkd.c b/lmkd/lmkd.c
index 5f27dfc..72e3251 100644
--- a/lmkd/lmkd.c
+++ b/lmkd/lmkd.c
@@ -171,6 +171,11 @@
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 @@
/* 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 @@
}
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 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);
@@ -771,10 +823,8 @@
struct proc *procp;
while (true) {
- if (low_ram_device)
- procp = proc_adj_lru(i);
- else
- procp = proc_get_heaviest(i);
+ procp = kill_heaviest_task ?
+ proc_get_heaviest(i) : proc_adj_lru(i);
if (!procp)
break;
@@ -805,23 +855,19 @@
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;
@@ -881,6 +927,14 @@
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
@@ -889,7 +943,8 @@
*/
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;
}
@@ -926,9 +981,10 @@
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;
}
@@ -1198,7 +1254,7 @@
downgrade_pressure =
(int64_t)property_get_int32("ro.lmk.downgrade_pressure", 100);
kill_heaviest_task =
- property_get_bool("ro.lmk.kill_heaviest_task", true);
+ 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);