Process: Add support for using scheduler policies instead of cgroups.
Preference is given to cgroups if available.
Signed-off-by: San Mehat <san@google.com>
diff --git a/core/jni/android_util_Process.cpp b/core/jni/android_util_Process.cpp
index 723fd4b..7748aba 100644
--- a/core/jni/android_util_Process.cpp
+++ b/core/jni/android_util_Process.cpp
@@ -50,14 +50,6 @@
#undef __KERNEL__
#endif
-/*
- * List of cgroup names which map to ANDROID_TGROUP_ values in Thread.h
- * and Process.java
- * These names are used to construct the path to the cgroup control dir
- */
-
-static const char *cgroup_names[] = { NULL, "bg_non_interactive", "fg_boost" };
-
using namespace android;
static void signalExceptionForPriorityError(JNIEnv* env, jobject obj, int err)
@@ -194,14 +186,13 @@
return -1;
}
-static int add_pid_to_cgroup(int pid, int grp)
+static int add_pid_to_cgroup(int pid, const char *grp_name)
{
int fd;
char path[255];
char text[64];
- sprintf(path, "/dev/cpuctl/%s/tasks",
- (cgroup_names[grp] ? cgroup_names[grp] : ""));
+ sprintf(path, "/dev/cpuctl/%s/tasks", grp_name);
if ((fd = open(path, O_WRONLY)) < 0)
return -1;
@@ -216,6 +207,37 @@
return 0;
}
+void setSchedPolicy(JNIEnv* env, jobject clazz, int pid, SchedPolicy policy)
+{
+ static int __sys_supports_schedgroups = -1;
+
+ if (__sys_supports_schedgroups < 0) {
+ if (!access("/dev/cpuctl/tasks", F_OK)) {
+ __sys_supports_schedgroups = 1;
+ } else {
+ __sys_supports_schedgroups = 0;
+ }
+ }
+
+ if (__sys_supports_schedgroups) {
+ const char *grp = NULL;
+
+ if (policy == SP_BACKGROUND) {
+ grp = "bg_non_interactive";
+ }
+
+ if (add_pid_to_cgroup(pid, grp)) {
+ if (errno != ESRCH && errno != ENOENT)
+ signalExceptionForGroupError(env, clazz, errno);
+ }
+ } else {
+ struct sched_param param;
+
+ param.sched_priority = 0;
+ sched_setscheduler(pid, (policy == SP_BACKGROUND) ? 5 : 0, ¶m);
+ }
+}
+
void android_os_Process_setThreadGroup(JNIEnv* env, jobject clazz, int pid, jint grp)
{
if (grp > ANDROID_TGROUP_MAX || grp < 0) {
@@ -223,11 +245,9 @@
return;
}
- if (add_pid_to_cgroup(pid, grp)) {
- // If the thread exited on us, don't generate an exception
- if (errno != ESRCH && errno != ENOENT)
- signalExceptionForGroupError(env, clazz, errno);
- }
+ setSchedPolicy(env, clazz, pid,
+ (grp == ANDROID_TGROUP_BG_NONINTERACT) ?
+ SP_BACKGROUND : SP_FOREGROUND);
}
void android_os_Process_setProcessGroup(JNIEnv* env, jobject clazz, int pid, jint grp)
@@ -271,14 +291,9 @@
continue;
}
- if (add_pid_to_cgroup(t_pid, grp)) {
- // If the thread exited on us, ignore it and keep going
- if (errno != ESRCH && errno != ENOENT) {
- signalExceptionForGroupError(env, clazz, errno);
- closedir(d);
- return;
- }
- }
+ setSchedPolicy(env, clazz, t_pid,
+ (grp == ANDROID_TGROUP_BG_NONINTERACT) ?
+ SP_BACKGROUND : SP_FOREGROUND);
}
closedir(d);
}
@@ -287,9 +302,9 @@
jint pid, jint pri)
{
if (pri >= ANDROID_PRIORITY_BACKGROUND) {
- add_pid_to_cgroup(pid, ANDROID_TGROUP_BG_NONINTERACT);
+ setSchedPolicy(env, clazz, pid, SP_BACKGROUND);
} else if (getpriority(PRIO_PROCESS, pid) >= ANDROID_PRIORITY_BACKGROUND) {
- add_pid_to_cgroup(pid, ANDROID_TGROUP_DEFAULT);
+ setSchedPolicy(env, clazz, pid, SP_FOREGROUND);
}
if (setpriority(PRIO_PROCESS, pid, pri) < 0) {
diff --git a/include/utils/threads.h b/include/utils/threads.h
index 0fc533f..f5304f7 100644
--- a/include/utils/threads.h
+++ b/include/utils/threads.h
@@ -90,6 +90,11 @@
ANDROID_TGROUP_MAX = ANDROID_TGROUP_FG_BOOST,
};
+typedef enum {
+ SP_BACKGROUND = 0,
+ SP_FOREGROUND = 1,
+} SchedPolicy;
+
// Create and run a new thread.
extern int androidCreateThread(android_thread_func_t, void *);