Make the default cgroup, the foreground cgroup.

All kernel services will now be in the same cgroup as
foreground applications. This will now make kernel threads
not implicitly higher priority than android foreground
services.

Bug 17681097

Change-Id: I28e81c7aade50428d5395df86f00ce01c1e7af02

1 files changed, 3 insertions, 23 deletions

diff --git a/libcutils/sched_policy.c b/libcutils/sched_policy.c
index 2acc3c3..493511e 100644
--- a/libcutils/sched_policy.c
+++ b/libcutils/sched_policy.c
@@ -45,8 +45,6 @@ static inline SchedPolicy _policy(SchedPolicy p)
 
 #define POLICY_DEBUG 0
 
-#define CAN_SET_SP_SYSTEM 0 // non-zero means to implement set_sched_policy(tid, SP_SYSTEM)
-
 // This prctl is only available in Android kernels.
 #define PR_SET_TIMERSLACK_PID 41
 
@@ -60,9 +58,6 @@ static int __sys_supports_schedgroups = -1;
 // File descriptors open to /dev/cpuctl/../tasks, setup by initialize, or -1 on error.
 static int bg_cgroup_fd = -1;
 static int fg_cgroup_fd = -1;
-#if CAN_SET_SP_SYSTEM
-static int system_cgroup_fd = -1;
-#endif
 
 /* Add tid to the scheduling group defined by the policy */
 static int add_tid_to_cgroup(int tid, SchedPolicy policy)
@@ -78,11 +73,6 @@ static int add_tid_to_cgroup(int tid, SchedPolicy policy)
     case SP_AUDIO_SYS:
         fd = fg_cgroup_fd;
         break;
-#if CAN_SET_SP_SYSTEM
-    case SP_SYSTEM:
-        fd = system_cgroup_fd;
-        break;
-#endif
     default:
         fd = -1;
         break;
@@ -123,21 +113,13 @@ static void __initialize(void) {
     if (!access("/dev/cpuctl/tasks", F_OK)) {
         __sys_supports_schedgroups = 1;
 
-#if CAN_SET_SP_SYSTEM
         filename = "/dev/cpuctl/tasks";
-        system_cgroup_fd = open(filename, O_WRONLY | O_CLOEXEC);
-        if (system_cgroup_fd < 0) {
-            SLOGV("open of %s failed: %s\n", filename, strerror(errno));
-        }
-#endif
-
-        filename = "/dev/cpuctl/apps/tasks";
         fg_cgroup_fd = open(filename, O_WRONLY | O_CLOEXEC);
         if (fg_cgroup_fd < 0) {
             SLOGE("open of %s failed: %s\n", filename, strerror(errno));
         }
 
-        filename = "/dev/cpuctl/apps/bg_non_interactive/tasks";
+        filename = "/dev/cpuctl/bg_non_interactive/tasks";
         bg_cgroup_fd = open(filename, O_WRONLY | O_CLOEXEC);
         if (bg_cgroup_fd < 0) {
             SLOGE("open of %s failed: %s\n", filename, strerror(errno));
@@ -233,11 +215,9 @@ int get_sched_policy(int tid, SchedPolicy *policy)
         if (getSchedulerGroup(tid, grpBuf, sizeof(grpBuf)) < 0)
             return -1;
         if (grpBuf[0] == '\0') {
-            *policy = SP_SYSTEM;
-        } else if (!strcmp(grpBuf, "apps/bg_non_interactive")) {
-            *policy = SP_BACKGROUND;
-        } else if (!strcmp(grpBuf, "apps")) {
             *policy = SP_FOREGROUND;
+        } else if (!strcmp(grpBuf, "bg_non_interactive")) {
+            *policy = SP_BACKGROUND;
         } else {
             errno = ERANGE;
             return -1;