add cpuset support to libcutils
bug 21782794
Change-Id: I249531754fb29442dc3c7434d77dbb103f4220a7
diff --git a/include/cutils/sched_policy.h b/include/cutils/sched_policy.h
index ba84ce3..6a8d570 100644
--- a/include/cutils/sched_policy.h
+++ b/include/cutils/sched_policy.h
@@ -34,6 +34,8 @@
SP_SYSTEM_DEFAULT = SP_FOREGROUND,
} SchedPolicy;
+extern int set_cpuset_policy(int tid, SchedPolicy policy);
+
/* Assign thread tid to the cgroup associated with the specified policy.
* If the thread is a thread group leader, that is it's gettid() == getpid(),
* then the other threads in the same thread group are _not_ affected.
diff --git a/libcutils/Android.mk b/libcutils/Android.mk
index 9dc15d1..0963076 100644
--- a/libcutils/Android.mk
+++ b/libcutils/Android.mk
@@ -125,6 +125,9 @@
LOCAL_C_INCLUDES := $(libcutils_c_includes)
LOCAL_STATIC_LIBRARIES := liblog
+ifneq ($(ENABLE_CPUSETS),)
+LOCAL_CFLAGS += -DUSE_CPUSETS
+endif
LOCAL_CFLAGS += -Werror -std=gnu90
include $(BUILD_STATIC_LIBRARY)
@@ -134,6 +137,9 @@
# liblog symbols present in libcutils.
LOCAL_WHOLE_STATIC_LIBRARIES := libcutils liblog
LOCAL_SHARED_LIBRARIES := liblog
+ifneq ($(ENABLE_CPUSETS),)
+LOCAL_CFLAGS += -DUSE_CPUSETS
+endif
LOCAL_CFLAGS += -Werror
LOCAL_C_INCLUDES := $(libcutils_c_includes)
include $(BUILD_SHARED_LIBRARY)
diff --git a/libcutils/sched_policy.c b/libcutils/sched_policy.c
index dfc8777..a7ff85e 100644
--- a/libcutils/sched_policy.c
+++ b/libcutils/sched_policy.c
@@ -1,16 +1,16 @@
/*
** Copyright 2007, The Android Open Source Project
**
-** Licensed under the Apache License, Version 2.0 (the "License");
-** you may not use this file except in compliance with the License.
-** You may obtain a copy of the License at
+** Licensed under the Apache License, Version 2.0 (the "License");
+** you may not use this file except in compliance with the License.
+** You may obtain a copy of the License at
**
-** http://www.apache.org/licenses/LICENSE-2.0
+** http://www.apache.org/licenses/LICENSE-2.0
**
-** Unless required by applicable law or agreed to in writing, software
-** distributed under the License is distributed on an "AS IS" BASIS,
-** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-** See the License for the specific language governing permissions and
+** Unless required by applicable law or agreed to in writing, software
+** distributed under the License is distributed on an "AS IS" BASIS,
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+** See the License for the specific language governing permissions and
** limitations under the License.
*/
@@ -59,27 +59,16 @@
static int bg_cgroup_fd = -1;
static int fg_cgroup_fd = -1;
+// File descriptors open to /dev/cpuset/../tasks, setup by initialize, or -1 on error
+static int bg_cpuset_fd = -1;
+static int fg_cpuset_fd = -1;
+
/* Add tid to the scheduling group defined by the policy */
-static int add_tid_to_cgroup(int tid, SchedPolicy policy)
+static int add_tid_to_cgroup(int tid, int fd)
{
- int fd;
-
- switch (policy) {
- case SP_BACKGROUND:
- fd = bg_cgroup_fd;
- break;
- case SP_FOREGROUND:
- case SP_AUDIO_APP:
- case SP_AUDIO_SYS:
- fd = fg_cgroup_fd;
- break;
- default:
- fd = -1;
- break;
- }
-
if (fd < 0) {
- SLOGE("add_tid_to_cgroup failed; policy=%d\n", policy);
+ SLOGE("add_tid_to_cgroup failed; fd=%d\n", fd);
+ errno = EINVAL;
return -1;
}
@@ -100,8 +89,9 @@
*/
if (errno == ESRCH)
return 0;
- SLOGW("add_tid_to_cgroup failed to write '%s' (%s); policy=%d\n",
- ptr, strerror(errno), policy);
+ SLOGW("add_tid_to_cgroup failed to write '%s' (%s); fd=%d\n",
+ ptr, strerror(errno), fd);
+ errno = EINVAL;
return -1;
}
@@ -127,6 +117,17 @@
} else {
__sys_supports_schedgroups = 0;
}
+
+#ifdef USE_CPUSETS
+ if (!access("/dev/cpuset/tasks", F_OK)) {
+
+ filename = "/dev/cpuset/foreground/tasks";
+ fg_cpuset_fd = open(filename, O_WRONLY | O_CLOEXEC);
+ filename = "/dev/cpuset/background/tasks";
+ bg_cpuset_fd = open(filename, O_WRONLY | O_CLOEXEC);
+ }
+#endif
+
}
/*
@@ -236,6 +237,45 @@
return 0;
}
+int set_cpuset_policy(int tid, SchedPolicy policy)
+{
+ // in the absence of cpusets, use the old sched policy
+#ifndef USE_CPUSETS
+ return set_sched_policy(tid, policy);
+#else
+ if (tid == 0) {
+ tid = gettid();
+ }
+ policy = _policy(policy);
+ pthread_once(&the_once, __initialize);
+
+ int fd;
+ switch (policy) {
+ case SP_BACKGROUND:
+ fd = bg_cpuset_fd;
+ break;
+ case SP_FOREGROUND:
+ case SP_AUDIO_APP:
+ case SP_AUDIO_SYS:
+ fd = fg_cpuset_fd;
+ break;
+ default:
+ fd = -1;
+ break;
+ }
+
+ if (add_tid_to_cgroup(tid, fd) != 0) {
+ if (errno != ESRCH && errno != ENOENT)
+ return -errno;
+ }
+
+ // we do both setting of cpuset and setting of cgroup
+ // ensures that backgrounded apps are actually deprioritized
+ // including on core 0
+ return set_sched_policy(tid, policy);
+#endif
+}
+
int set_sched_policy(int tid, SchedPolicy policy)
{
if (tid == 0) {
@@ -286,7 +326,23 @@
#endif
if (__sys_supports_schedgroups) {
- if (add_tid_to_cgroup(tid, policy)) {
+ int fd;
+ switch (policy) {
+ case SP_BACKGROUND:
+ fd = bg_cgroup_fd;
+ break;
+ case SP_FOREGROUND:
+ case SP_AUDIO_APP:
+ case SP_AUDIO_SYS:
+ fd = fg_cgroup_fd;
+ break;
+ default:
+ fd = -1;
+ break;
+ }
+
+
+ if (add_tid_to_cgroup(tid, fd) != 0) {
if (errno != ESRCH && errno != ENOENT)
return -errno;
}
@@ -296,7 +352,7 @@
param.sched_priority = 0;
sched_setscheduler(tid,
(policy == SP_BACKGROUND) ?
- SCHED_BATCH : SCHED_NORMAL,
+ SCHED_BATCH : SCHED_NORMAL,
¶m);
}
@@ -337,4 +393,3 @@
else
return "error";
}
-
diff --git a/rootdir/init.rc b/rootdir/init.rc
index 2fbac23..acca097 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -125,6 +125,28 @@
write /dev/cpuctl/bg_non_interactive/cpu.rt_runtime_us 700000
write /dev/cpuctl/bg_non_interactive/cpu.rt_period_us 1000000
+ # sets up initial cpusets for ActivityManager
+ mkdir /dev/cpuset
+ mount cpuset none /dev/cpuset
+ mkdir /dev/cpuset/foreground
+ mkdir /dev/cpuset/background
+ # this ensures that the cpusets are present and usable, but the device's
+ # init.rc must actually set the correct cpus
+ write /dev/cpuset/foreground/cpus 0
+ write /dev/cpuset/background/cpus 0
+ write /dev/cpuset/foreground/mems 0
+ write /dev/cpuset/background/mems 0
+ chown system system /dev/cpuset
+ chown system system /dev/cpuset/foreground
+ chown system system /dev/cpuset/background
+ chown system system /dev/cpuset/tasks
+ chown system system /dev/cpuset/foreground/tasks
+ chown system system /dev/cpuset/background/tasks
+ chmod 0644 /dev/cpuset/foreground/tasks
+ chmod 0644 /dev/cpuset/background/tasks
+ chmod 0644 /dev/cpuset/tasks
+
+
# qtaguid will limit access to specific data based on group memberships.
# net_bw_acct grants impersonation of socket owners.
# net_bw_stats grants access to other apps' detailed tagged-socket stats.