commit aba4d2b72516a2a6a9082b90883bdfd4d0157f3b
author Suren Baghdasaryan <surenb@google.com> Tue Jun 19 18:38:12 2018 -0700
committer Minchan Kim <minchan@google.com> Thu Jun 21 10:36:55 2018 +0900
tree 83ea6105d672b0390a2d35a0d06cba26687f8681
parent af7492e5745af22a3fd63ed04a4554a8c4187638

lmkd: Disable memory.stat usage when per-application memcgs are not used

Per-application memory.stat files are not available when per-application
memcgs are not used (per_app_memcg=false). Disable its usage based on
ro.config.per_app_memcg property.

minchan:
* correct indentation of memory_stat_parse
* move per_app_memcg check into memory_stat_parse inside
* change low_ram_device to per_app_memcg

Bug: 110384555
Test: manual test to see lkmd log message with memory hogger
Change-Id: Ib6dd7586d3ef1c64cb04d16e2d2b21fa9c8e6a3a
Signed-off-by: Minchan Kim <minchan@google.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>

lmkd/lmkd.c

diff --git a/lmkd/lmkd.c b/lmkd/lmkd.c
index b20f4ef..c093246 100644
--- a/lmkd/lmkd.c
+++ b/lmkd/lmkd.c
@@ -118,6 +118,7 @@
 static bool kill_heaviest_task;
 static unsigned long kill_timeout_ms;
 static bool use_minfree_levels;
+static bool per_app_memcg;
 
 /* data required to handle events */
 struct event_handler_info {
@@ -484,7 +485,7 @@
         return;
     }
 
-    if (low_ram_device) {
+    if (per_app_memcg) {
         if (params.oomadj >= 900) {
             soft_limit_mult = 0;
         } else if (params.oomadj >= 800) {
@@ -754,24 +755,31 @@
 }
 
 static int memory_stat_parse(struct memory_stat *mem_st,  int pid, uid_t uid) {
-   FILE *fp;
-   char buf[PATH_MAX];
+    FILE *fp;
+    char buf[PATH_MAX];
 
-   snprintf(buf, sizeof(buf), MEMCG_PROCESS_MEMORY_STAT_PATH, uid, pid);
+    /*
+     * Per-application memory.stat files are available only when
+     * per-application memcgs are enabled.
+     */
+    if (!per_app_memcg)
+        return -1;
 
-   fp = fopen(buf, "r");
+    snprintf(buf, sizeof(buf), MEMCG_PROCESS_MEMORY_STAT_PATH, uid, pid);
 
-   if (fp == NULL) {
-       ALOGE("%s open failed: %s", buf, strerror(errno));
-       return -1;
-   }
+    fp = fopen(buf, "r");
 
-   while (fgets(buf, PAGE_SIZE, fp) != NULL ) {
-       memory_stat_parse_line(buf, mem_st);
-   }
-   fclose(fp);
+    if (fp == NULL) {
+        ALOGE("%s open failed: %s", buf, strerror(errno));
+        return -1;
+    }
 
-   return 0;
+    while (fgets(buf, PAGE_SIZE, fp) != NULL ) {
+        memory_stat_parse_line(buf, mem_st);
+    }
+    fclose(fp);
+
+    return 0;
 }
 #endif
 
@@ -1580,6 +1588,8 @@
         (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);
 
 #ifdef LMKD_LOG_STATS
     statslog_init(&log_ctx, &enable_stats_log);