am 493dad96: libcutils: Add abstracted support for setting scheduler policies... (07a554bf) · Commits · e / os / android_system_core

include/cutils/sched_policy.h

0 → 100644

+35 −0

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		/*
		* Copyright (C) 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
		*
		* 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
		* limitations under the License.
		*/

		#ifndef __CUTILS_SCHED_POLICY_H
		#define __CUTILS_SCHED_POLICY_H

		#ifdef __cplusplus
		extern "C" {
		#endif

		typedef enum {
		SP_BACKGROUND = 0,
		SP_FOREGROUND = 1,
		} SchedPolicy;

		extern int set_sched_policy(int tid, SchedPolicy policy);

		#ifdef __cplusplus
		}
		#endif

		#endif /* __CUTILS_SCHED_POLICY_H */

libcutils/Android.mk

+2 −1

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		@@ -36,7 +36,8 @@ commonSources := \
		record_stream.c \
		process_name.c \
		properties.c \
		threads.c
		threads.c \
		sched_policy.c

		commonHostSources := \
		ashmem-host.c

libcutils/sched_policy.c

0 → 100644

+84 −0

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		/* libs/cutils/sched_policy.c
		**
		** 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
		**
		** 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
		** limitations under the License.
		*/

		#include <stdio.h>
		#include <stdlib.h>
		#include <unistd.h>
		#include <string.h>
		#include <errno.h>
		#include <fcntl.h>
		#include <sched.h>
		#include <linux/sched.h>

		#include <cutils/sched_policy.h>

		static int add_tid_to_cgroup(int tid, const char *grp_name)
		{
		int fd;
		char path[255];
		char text[64];

		sprintf(path, "/dev/cpuctl/%s/tasks", grp_name);

		if ((fd = open(path, O_WRONLY)) < 0)
		return -1;

		sprintf(text, "%d", tid);
		if (write(fd, text, strlen(text)) < 0) {
		close(fd);
		return -1;
		}

		close(fd);
		return 0;
		}

		int set_sched_policy(int tid, 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_tid_to_cgroup(tid, grp)) {
		if (errno != ESRCH && errno != ENOENT)
		return -errno;
		}
		} else {
		struct sched_param param;

		param.sched_priority = 0;
		sched_setscheduler(tid,
		(policy == SP_BACKGROUND) ?
		SCHED_BATCH : SCHED_NORMAL,
		&param);
		}

		return 0;
		}