am e43c2483: More fixes to Binder perf regression from Eclair (218faa30) · Commits · e / os / android_system_core

libcutils/sched_policy.c

+47 −32

Original line number	Diff line number	Diff line
		@@ -22,6 +22,7 @@
		#include <string.h>
		#include <errno.h>
		#include <fcntl.h>
		#include <pthread.h>

		#define LOG_TAG "SchedPolicy"
		#include "cutils/log.h"
		@@ -42,15 +43,28 @@

		#define POLICY_DEBUG 0

		static pthread_once_t the_once = PTHREAD_ONCE_INIT;

		static int __sys_supports_schedgroups = -1;

		/* Add tid to the group defined by dev_path ("/dev/cpuctl/.../tasks") */
		static int add_tid_to_cgroup(int tid, const char *dev_path)
		// File descriptors open to /dev/cpuctl/../tasks, setup by initialize, or -1 on error.
		static int normal_cgroup_fd = -1;
		static int bg_cgroup_fd = -1;

		/* Add tid to the scheduling group defined by the policy */
		static int add_tid_to_cgroup(int tid, SchedPolicy policy)
		{
		int fd;
		if ((fd = open(dev_path, O_WRONLY)) < 0) {
		SLOGE("add_tid_to_cgroup failed to open '%s' (%s)\n", dev_path,
		strerror(errno));

		if (policy == SP_BACKGROUND) {
		fd = bg_cgroup_fd;
		} else {
		fd = normal_cgroup_fd;
		}

		if (fd < 0) {
		SLOGE("add_tid_to_cgroup failed; background=%d\n",
		policy == SP_BACKGROUND ? 1 : 0);
		return -1;
		}

		@@ -65,32 +79,40 @@ static int add_tid_to_cgroup(int tid, const char *dev_path)
		}

		if (write(fd, ptr, end - ptr) < 0) {
		close(fd);
		/*
		* If the thread is in the process of exiting,
		* don't flag an error
		*/
		if (errno == ESRCH)
		return 0;
		SLOGW("add_tid_to_cgroup failed to write '%s' to '%s' (%s)\n",
		ptr, dev_path, strerror(errno));
		SLOGW("add_tid_to_cgroup failed to write '%s' (%s); background=%d\n",
		ptr, strerror(errno), policy == SP_BACKGROUND ? 1 : 0);
		return -1;
		}

		close(fd);
		return 0;
		}

		static inline void initialize()
		{
		if (__sys_supports_schedgroups < 0) {
		static void __initialize(void) {
		char* filename;
		if (!access("/dev/cpuctl/tasks", F_OK)) {
		__sys_supports_schedgroups = 1;

		filename = "/dev/cpuctl/tasks";
		normal_cgroup_fd = open(filename, O_WRONLY);
		if (normal_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);
		if (bg_cgroup_fd < 0) {
		SLOGE("open of %s failed: %s\n", filename, strerror(errno));
		}
		} else {
		__sys_supports_schedgroups = 0;
		}
		}
		}

		/*
		* Try to get the scheduler group.
		@@ -166,7 +188,7 @@ static int getSchedulerGroup(int tid, char* buf, size_t bufLen)

		int get_sched_policy(int tid, SchedPolicy *policy)
		{
		initialize();
		pthread_once(&the_once, __initialize);

		if (__sys_supports_schedgroups) {
		char grpBuf[32];
		@@ -198,7 +220,7 @@ int get_sched_policy(int tid, SchedPolicy *policy)

		int set_sched_policy(int tid, SchedPolicy policy)
		{
		initialize();
		pthread_once(&the_once, __initialize);

		#if POLICY_DEBUG
		char statfile[64];
		@@ -233,14 +255,7 @@ int set_sched_policy(int tid, SchedPolicy policy)
		#endif

		if (__sys_supports_schedgroups) {
		const char *dev_path;
		if (policy == SP_BACKGROUND) {
		dev_path = "/dev/cpuctl/bg_non_interactive/tasks";
		} else {
		dev_path = "/dev/cpuctl/tasks";
		}

		if (add_tid_to_cgroup(tid, dev_path)) {
		if (add_tid_to_cgroup(tid, policy)) {
		if (errno != ESRCH && errno != ENOENT)
		return -errno;
		}