cutils: Add support for ioprio cgroup (f097d5df) · Commits · e / os / android_system_core

include/cutils/iosched_policy.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -31,6 +31,8 @@ typedef enum {
		extern int android_set_ioprio(int pid, IoSchedClass clazz, int ioprio);
		extern int android_get_ioprio(int pid, IoSchedClass clazz, int ioprio);

		extern int android_set_rt_ioprio(int pid, int rt);

		#ifdef __cplusplus
		}
		#endif

libcutils/iosched_policy.c

+89 −12

Original line number	Diff line number	Diff line
		/*
		** Copyright 2007, The Android Open Source Project
		** Copyright 2007-2014, The Android Open Source Project
		** Copyright 2015, The CyanogenMod Project
		**
		** Licensed under the Apache License, Version 2.0 (the "License");
		** you may not use this file except in compliance with the License.
		@@ -20,28 +21,30 @@
		#include <stdlib.h>
		#include <string.h>
		#include <unistd.h>
		#include <pthread.h>

		#include <cutils/iosched_policy.h>
		#define LOG_TAG "iosched_policy"
		#include <cutils/log.h>

		#define __android_unused __attribute__((__unused__))

		#ifdef HAVE_ANDROID_OS
		#include <linux/ioprio.h>
		#include <sys/syscall.h>
		#define __android_unused
		#else
		#define __android_unused __attribute__((__unused__))
		#endif
		#include <sys/stat.h>

		static int __rtio_cgroup_supported = -1;
		static pthread_once_t __rtio_init_once = PTHREAD_ONCE_INIT;

		int android_set_ioprio(int pid __android_unused, IoSchedClass clazz __android_unused, int ioprio __android_unused) {
		#ifdef HAVE_ANDROID_OS
		if (syscall(SYS_ioprio_set, IOPRIO_WHO_PROCESS, pid, ioprio \| (clazz << IOPRIO_CLASS_SHIFT))) {
		return -1;
		}
		#endif
		return 0;
		}

		int android_get_ioprio(int pid __android_unused, IoSchedClass clazz, int ioprio) {
		#ifdef HAVE_ANDROID_OS
		int rc;

		if ((rc = syscall(SYS_ioprio_get, IOPRIO_WHO_PROCESS, pid)) < 0) {
		@@ -50,9 +53,83 @@ int android_get_ioprio(int pid __android_unused, IoSchedClass clazz, int iopri

		*clazz = (rc >> IOPRIO_CLASS_SHIFT);
		*ioprio = (rc & 0xff);
		return 0;
		}

		static void __initialize_rtio(void) {
		if (!access("/sys/fs/cgroup/bfqio/tasks", W_OK) \|\|
		!access("/sys/fs/cgroup/bfqio/rt-display/tasks", W_OK)) {
		__rtio_cgroup_supported = 1;
		} else {
		__rtio_cgroup_supported = 0;
		}
		}

		int android_set_rt_ioprio(int tid, int rt) {
		int fd = -1, rc = -1;

		pthread_once(&__rtio_init_once, __initialize_rtio);
		if (__rtio_cgroup_supported != 1) {
		return -1;
		}

		if (rt) {
		fd = open("/sys/fs/cgroup/bfqio/rt-display/tasks", O_WRONLY \| O_CLOEXEC);
		} else {
		fd = open("/sys/fs/cgroup/bfqio/tasks", O_WRONLY \| O_CLOEXEC);
		}

		if (fd < 0) {
		return -1;
		}

		#ifdef HAVE_GETTID
		if (tid == 0) {
		tid = gettid();
		}
		#endif

		// specialized itoa -- works for tid > 0
		char text[22];
		char *end = text + sizeof(text) - 1;
		char *ptr = end;
		*ptr = '\0';
		while (tid > 0) {
		*--ptr = '0' + (tid % 10);
		tid = tid / 10;
		}

		rc = write(fd, ptr, end - ptr);
		if (rc < 0) {
		/*
		* If the thread is in the process of exiting,
		* don't flag an error
		*/
		if (errno == ESRCH) {
		rc = 0;
		} else {
		SLOGV("android_set_rt_ioprio failed to write '%s' (%s); fd=%d\n",
		ptr, strerror(errno), fd);
		}
		}

		close(fd);
		return rc;
		}

		#else
		int android_set_ioprio(int pid __android_unused, IoSchedClass clazz __android_unused, int ioprio __android_unused) {
		return 0;
		}

		int android_get_ioprio(int pid __android_unused, IoSchedClass clazz, int ioprio) {
		*clazz = IoSchedClass_NONE;
		*ioprio = 0;
		#endif
		return 0;
		}

		int android_set_rt_ioprio(int tid __android_unused, int rt __android_unused)
		{
		return 0;
		}
		#endif