From 6647bb51301ea101b73e7431888f70bb35a4fabb Mon Sep 17 00:00:00 2001
From: Tim Murray <timmurray@google.com>
Date: Mon, 11 Jan 2016 16:16:35 -0800
Subject: [PATCH] Enable top-app cpuset support.

Allows ActivityManager to use the top-app cpuset to grant the currently
focused app exclusive access to a CPU core.

Change-Id: I45bca5170477e413dec6e5889338399d0859706c
---
 include/cutils/sched_policy.h |  1 +
 libcutils/sched_policy.c      | 10 ++++++++++
 rootdir/init.rc               |  7 +++++++
 3 files changed, 18 insertions(+)

diff --git a/include/cutils/sched_policy.h b/include/cutils/sched_policy.h
index 6a8d570b2..591bd4478 100644
--- a/include/cutils/sched_policy.h
+++ b/include/cutils/sched_policy.h
@@ -29,6 +29,7 @@ typedef enum {
     SP_SYSTEM     = 2,  // can't be used with set_sched_policy()
     SP_AUDIO_APP  = 3,
     SP_AUDIO_SYS  = 4,
+    SP_TOP_APP    = 5,
     SP_CNT,
     SP_MAX        = SP_CNT - 1,
     SP_SYSTEM_DEFAULT = SP_FOREGROUND,
diff --git a/libcutils/sched_policy.c b/libcutils/sched_policy.c
index 280a0834b..54d112290 100644
--- a/libcutils/sched_policy.c
+++ b/libcutils/sched_policy.c
@@ -65,6 +65,7 @@ static int fg_cgroup_fd = -1;
 static int system_bg_cpuset_fd = -1;
 static int bg_cpuset_fd = -1;
 static int fg_cpuset_fd = -1;
+static int ta_cpuset_fd = -1; // special cpuset for top app
 static int bg_schedboost_fd = -1;
 static int fg_schedboost_fd = -1;
 #endif
@@ -133,6 +134,8 @@ static void __initialize(void) {
         bg_cpuset_fd = open(filename, O_WRONLY | O_CLOEXEC);
         filename = "/dev/cpuset/system-background/tasks";
         system_bg_cpuset_fd = open(filename, O_WRONLY | O_CLOEXEC);
+        filename = "/dev/cpuset/top-app/tasks";
+        ta_cpuset_fd = open(filename, O_WRONLY | O_CLOEXEC);
 
 #ifdef USE_SCHEDBOOST
         filename = "/sys/fs/cgroup/stune/foreground/tasks";
@@ -276,6 +279,10 @@ int set_cpuset_policy(int tid, SchedPolicy policy)
         fd = fg_cpuset_fd;
         boost_fd = fg_schedboost_fd;
         break;
+    case SP_TOP_APP :
+        fd = ta_cpuset_fd;
+        boost_fd = fg_schedboost_fd;
+        break;
     case SP_SYSTEM:
         fd = system_bg_cpuset_fd;
         boost_fd = bg_schedboost_fd;
@@ -337,6 +344,7 @@ int set_sched_policy(int tid, SchedPolicy policy)
     case SP_FOREGROUND:
     case SP_AUDIO_APP:
     case SP_AUDIO_SYS:
+    case SP_TOP_APP:
         SLOGD("^^^ tid %d (%s)", tid, thread_name);
         break;
     case SP_SYSTEM:
@@ -357,6 +365,7 @@ int set_sched_policy(int tid, SchedPolicy policy)
         case SP_FOREGROUND:
         case SP_AUDIO_APP:
         case SP_AUDIO_SYS:
+        case SP_TOP_APP:
             fd = fg_cgroup_fd;
             break;
         default:
@@ -411,6 +420,7 @@ const char *get_sched_policy_name(SchedPolicy policy)
        [SP_SYSTEM]     = "  ",
        [SP_AUDIO_APP]  = "aa",
        [SP_AUDIO_SYS]  = "as",
+       [SP_TOP_APP]    = "ta",
     };
     if ((policy < SP_CNT) && (strings[policy] != NULL))
         return strings[policy];
diff --git a/rootdir/init.rc b/rootdir/init.rc
index 289bdec7f..1b367c79f 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -173,17 +173,23 @@ on init
     write /dev/cpuset/system-background/cpus 0
     write /dev/cpuset/system-background/mems 0
 
+    mkdir /dev/cpuset/top-app
+    write /dev/cpuset/top-app/cpus 0
+    write /dev/cpuset/top-app/mems 0
+
     # change permissions for all cpusets we'll touch at runtime
     chown system system /dev/cpuset
     chown system system /dev/cpuset/foreground
     chown system system /dev/cpuset/foreground/boost
     chown system system /dev/cpuset/background
     chown system system /dev/cpuset/system-background
+    chown system system /dev/cpuset/top-app
     chown system system /dev/cpuset/tasks
     chown system system /dev/cpuset/foreground/tasks
     chown system system /dev/cpuset/foreground/boost/tasks
     chown system system /dev/cpuset/background/tasks
     chown system system /dev/cpuset/system-background/tasks
+    chown system system /dev/cpuset/top-app/tasks
 
     # set system-background to 0775 so SurfaceFlinger can touch it
     chmod 0775 /dev/cpuset/system-background
@@ -192,6 +198,7 @@ on init
     chmod 0664 /dev/cpuset/foreground/boost/tasks
     chmod 0664 /dev/cpuset/background/tasks
     chmod 0664 /dev/cpuset/system-background/tasks
+    chmod 0664 /dev/cpuset/top-app/tasks
     chmod 0664 /dev/cpuset/tasks