From bcb6419fc9ac4c33aa1429092df4428e8e3836df Mon Sep 17 00:00:00 2001
From: Wei Wang <wvw@google.com>
Date: Wed, 29 Mar 2017 12:57:51 -0700
Subject: [PATCH] libcutils: remove schedgroup fds [DO NOT MERGE]

After removing bg_non_interactive cgroup, there is only a ROOT cgroup.
This CL removes the no-op trying to set cgroup.
It also removes the attempt to open non-exist bg_non_interactive cgroup.

Bug: 36649832
Test: marlin boosts and cgroup ROOT task looks normal
Change-Id: Idef1dfdaa71fde63c98c73a3d37f65416aa6f2e2
---
 libcutils/sched_policy.c | 32 +++-----------------------------
 1 file changed, 3 insertions(+), 29 deletions(-)

diff --git a/libcutils/sched_policy.c b/libcutils/sched_policy.c
index 6d905898a..e11eb2e9e 100644
--- a/libcutils/sched_policy.c
+++ b/libcutils/sched_policy.c
@@ -56,10 +56,6 @@ static pthread_once_t the_once = PTHREAD_ONCE_INIT;
 
 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;
-
 #ifdef USE_CPUSETS
 // File descriptors open to /dev/cpuset/../tasks, setup by initialize, or -1 on error
 static int system_bg_cpuset_fd = -1;
@@ -73,6 +69,7 @@ static int bg_schedboost_fd = -1;
 static int fg_schedboost_fd = -1;
 static int ta_schedboost_fd = -1;
 
+#if defined(USE_CPUSETS) || defined(USE_SCHEDBOOST)
 /* Add tid to the scheduling group defined by the policy */
 static int add_tid_to_cgroup(int tid, int fd)
 {
@@ -107,30 +104,18 @@ static int add_tid_to_cgroup(int tid, int fd)
 
     return 0;
 }
+#endif //defined(USE_CPUSETS) || defined(USE_SCHEDBOOST)
 
 static void __initialize(void) {
-    char* filename;
     if (!access("/dev/cpuctl/tasks", F_OK)) {
         __sys_supports_schedgroups = 1;
-
-        filename = "/dev/cpuctl/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/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));
-        }
     } else {
         __sys_supports_schedgroups = 0;
     }
 
 #ifdef USE_CPUSETS
     if (!access("/dev/cpuset/tasks", F_OK)) {
-
+        char* filename;
         filename = "/dev/cpuset/foreground/tasks";
         fg_cpuset_fd = open(filename, O_WRONLY | O_CLOEXEC);
         filename = "/dev/cpuset/background/tasks";
@@ -380,35 +365,24 @@ int set_sched_policy(int tid, SchedPolicy policy)
 #endif
 
     if (__sys_supports_schedgroups) {
-        int fd = -1;
         int boost_fd = -1;
         switch (policy) {
         case SP_BACKGROUND:
-            fd = bg_cgroup_fd;
             boost_fd = bg_schedboost_fd;
             break;
         case SP_FOREGROUND:
         case SP_AUDIO_APP:
         case SP_AUDIO_SYS:
-            fd = fg_cgroup_fd;
             boost_fd = fg_schedboost_fd;
             break;
         case SP_TOP_APP:
-            fd = fg_cgroup_fd;
             boost_fd = ta_schedboost_fd;
             break;
         default:
-            fd = -1;
             boost_fd = -1;
             break;
         }
 
-
-        if (fd > 0 && add_tid_to_cgroup(tid, fd) != 0) {
-            if (errno != ESRCH && errno != ENOENT)
-                return -errno;
-        }
-
 #ifdef USE_SCHEDBOOST
         if (boost_fd > 0 && add_tid_to_cgroup(tid, boost_fd) != 0) {
             if (errno != ESRCH && errno != ENOENT)