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Removed cpusets/schedboost build time dependency.

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These two Soong product_variables were usually controlled by
ENABLE_CPUSETS and ENABLE_SCHEDBOOST in BoardConfig.mk. This change
turns the build time variables into runtime decision by checking if
a special file, "tasks", can be found under the mount points,
/dev/cpuset and /dev/stune, for cpusets and schedboost, respectively.

That special file only exists when the corresponding Linux kernel
configurations, CONFIG_CPUSETS and CONFIG_SCHEDTUNE, are set.

Bug: 34726944

Test: Tested on Sailfish with following configurations
          neither cpuset nor schedtune enabled in the kernel
          cpuset enabled, but schedtune disabled in the kernel
          both cpuset and schedtune enabled in the kernel

Change-Id: I6695b8b32b2fecb4fd995018418bbe2edc5d590f
This commit is contained in:
Isaac Chen 2017-02-16 11:47:33 +08:00
parent dce4b65fe0
commit 795267d4c7
3 changed files with 124 additions and 72 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

10
libcutils/Android.bp
View file

@ -60,7 +60,7 @@ cc_library {
"native_handle.c",
"open_memstream.c",
"record_stream.c",
"sched_policy.c",
"sched_policy.cpp",
"sockets.cpp",
"strdup16to8.c",
"strdup8to16.c",
@ -141,14 +141,6 @@ cc_library {
header_libs: ["libcutils_headers"],
export_header_lib_headers: ["libcutils_headers"],
product_variables: {
cpusets: {
cflags: ["-DUSE_CPUSETS"],
},
schedboost: {
cflags: ["-DUSE_SCHEDBOOST"],
},
},
cflags: [
"-Werror",
"-Wall",

17
libcutils/include/cutils/sched_policy.h
View file

@ -17,10 +17,27 @@
#ifndef __CUTILS_SCHED_POLICY_H
#define __CUTILS_SCHED_POLICY_H
#include <stdbool.h>
#ifdef __cplusplus
extern "C" {
#endif
/*
* Check if Linux kernel enables CPUSETS feature.
*
* Return value: 1 if Linux kernel CONFIG_CPUSETS=y; 0 otherwise.
*/
extern bool cpusets_enabled();
/*
* Check if Linux kernel enables SCHEDTUNE feature (only available in Android
* common kernel or Linaro LSK, not in mainline Linux as of v4.9)
*
* Return value: 1 if Linux kernel CONFIG_SCHEDTUNE=y; 0 otherwise.
*/
extern bool schedboost_enabled();
/* Keep in sync with THREAD_GROUP_* in frameworks/base/core/java/android/os/Process.java */
typedef enum {
SP_DEFAULT = -1,

169
libcutils/sched_policy.c → libcutils/sched_policy.cpp
View file

@ -58,13 +58,11 @@ static int __sys_supports_timerslack = -1;
static int bg_cgroup_fd = -1;
static int fg_cgroup_fd = -1;
#ifdef USE_CPUSETS
// File descriptors open to /dev/cpuset/../tasks, setup by initialize, or -1 on error
static int system_bg_cpuset_fd = -1;
static int bg_cpuset_fd = -1;
static int fg_cpuset_fd = -1;
static int ta_cpuset_fd = -1; // special cpuset for top app
#endif
// File descriptors open to /dev/stune/../tasks, setup by initialize, or -1 on error
static int bg_schedboost_fd = -1;
@ -106,8 +104,53 @@ static int add_tid_to_cgroup(int tid, int fd)
return 0;
}
static void __initialize(void) {
char* filename;
/*
If CONFIG_CPUSETS for Linux kernel is set, "tasks" can be found under
/dev/cpuset mounted in init.rc; otherwise, that file does not exist
even though the directory, /dev/cpuset, is still created (by init.rc).
A couple of other candidates (under cpuset mount directory):
notify_on_release
release_agent
Yet another way to decide if cpuset is enabled is to parse
/proc/self/status and search for lines begin with "Mems_allowed".
If CONFIG_PROC_PID_CPUSET is set, the existence "/proc/self/cpuset" can
be used to decide if CONFIG_CPUSETS is set, so we don't have a dependency
on where init.rc mounts cpuset. That's why we'd better require this
configuration be set if CONFIG_CPUSETS is set.
With runtime check using the following function, build time
variables like ENABLE_CPUSETS (used in Android.mk) or cpusets (used
in Android.bp) are not needed.
*/
bool cpusets_enabled() {
static bool enabled = (access("/dev/cpuset/tasks", F_OK) == 0);
return enabled;
}
/*
Similar to CONFIG_CPUSETS above, but with a different configuration
CONFIG_SCHEDTUNE that's in Android common Linux kernel and Linaro
Stable Kernel (LSK), but not in mainline Linux as of v4.9.
With runtime check using the following function, build time
variables like ENABLE_SCHEDBOOST (used in Android.mk) or schedboost
(used in Android.bp) are not needed.
*/
bool schedboost_enabled() {
static bool enabled = (access("/dev/stune/tasks", F_OK) == 0);
return enabled;
}
static void __initialize() {
const char* filename;
if (!access("/dev/cpuctl/tasks", W_OK)) {
__sys_supports_schedgroups = 1;
@ -126,28 +169,28 @@ static void __initialize(void) {
__sys_supports_schedgroups = 0;
}
#ifdef USE_CPUSETS
if (!access("/dev/cpuset/tasks", W_OK)) {
if (cpusets_enabled()) {
if (!access("/dev/cpuset/tasks", W_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);
filename = "/dev/cpuset/system-background/tasks";
system_bg_cpuset_fd = open(filename, O_WRONLY | O_CLOEXEC);
filename = "/dev/cpuset/top-app/tasks";
ta_cpuset_fd = open(filename, O_WRONLY | O_CLOEXEC);
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);
filename = "/dev/cpuset/system-background/tasks";
system_bg_cpuset_fd = open(filename, O_WRONLY | O_CLOEXEC);
filename = "/dev/cpuset/top-app/tasks";
ta_cpuset_fd = open(filename, O_WRONLY | O_CLOEXEC);
#ifdef USE_SCHEDBOOST
filename = "/dev/stune/top-app/tasks";
ta_schedboost_fd = open(filename, O_WRONLY | O_CLOEXEC);
filename = "/dev/stune/foreground/tasks";
fg_schedboost_fd = open(filename, O_WRONLY | O_CLOEXEC);
filename = "/dev/stune/background/tasks";
bg_schedboost_fd = open(filename, O_WRONLY | O_CLOEXEC);
#endif
if (schedboost_enabled()) {
filename = "/dev/stune/top-app/tasks";
ta_schedboost_fd = open(filename, O_WRONLY | O_CLOEXEC);
filename = "/dev/stune/foreground/tasks";
fg_schedboost_fd = open(filename, O_WRONLY | O_CLOEXEC);
filename = "/dev/stune/background/tasks";
bg_schedboost_fd = open(filename, O_WRONLY | O_CLOEXEC);
}
}
}
#endif
char buf[64];
snprintf(buf, sizeof(buf), "/proc/%d/timerslack_ns", getpid());
@ -235,33 +278,34 @@ int get_sched_policy(int tid, SchedPolicy *policy)
if (__sys_supports_schedgroups) {
char grpBuf[32];
#ifdef USE_CPUSETS
if (getCGroupSubsys(tid, "cpuset", grpBuf, sizeof(grpBuf)) < 0)
return -1;
if (grpBuf[0] == '\0') {
*policy = SP_FOREGROUND;
} else if (!strcmp(grpBuf, "foreground")) {
*policy = SP_FOREGROUND;
} else if (!strcmp(grpBuf, "background")) {
*policy = SP_BACKGROUND;
} else if (!strcmp(grpBuf, "top-app")) {
*policy = SP_TOP_APP;
if (cpusets_enabled()) {
if (getCGroupSubsys(tid, "cpuset", grpBuf, sizeof(grpBuf)) < 0)
return -1;
if (grpBuf[0] == '\0') {
*policy = SP_FOREGROUND;
} else if (!strcmp(grpBuf, "foreground")) {
*policy = SP_FOREGROUND;
} else if (!strcmp(grpBuf, "background")) {
*policy = SP_BACKGROUND;
} else if (!strcmp(grpBuf, "top-app")) {
*policy = SP_TOP_APP;
} else {
errno = ERANGE;
return -1;
}
} else {
errno = ERANGE;
return -1;
if (getCGroupSubsys(tid, "cpu", grpBuf, sizeof(grpBuf)) < 0)
return -1;
if (grpBuf[0] == '\0') {
*policy = SP_FOREGROUND;
} else if (!strcmp(grpBuf, "bg_non_interactive")) {
*policy = SP_BACKGROUND;
} else {
errno = ERANGE;
return -1;
}
}
#else
if (getCGroupSubsys(tid, "cpu", grpBuf, sizeof(grpBuf)) < 0)
return -1;
if (grpBuf[0] == '\0') {
*policy = SP_FOREGROUND;
} else if (!strcmp(grpBuf, "bg_non_interactive")) {
*policy = SP_BACKGROUND;
} else {
errno = ERANGE;
return -1;
}
#endif
} else {
int rc = sched_getscheduler(tid);
if (rc < 0)
@ -281,9 +325,10 @@ int get_sched_policy(int tid, SchedPolicy *policy)
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 (!cpusets_enabled()) {
return set_sched_policy(tid, policy);
}
if (tid == 0) {
tid = gettid();
}
@ -320,15 +365,14 @@ int set_cpuset_policy(int tid, SchedPolicy policy)
return -errno;
}
#ifdef USE_SCHEDBOOST
if (boost_fd > 0 && add_tid_to_cgroup(tid, boost_fd) != 0) {
if (errno != ESRCH && errno != ENOENT)
return -errno;
if (schedboost_enabled()) {
if (boost_fd > 0 && add_tid_to_cgroup(tid, boost_fd) != 0) {
if (errno != ESRCH && errno != ENOENT)
return -errno;
}
}
#endif
return 0;
#endif
}
static void set_timerslack_ns(int tid, unsigned long long slack) {
@ -420,18 +464,17 @@ int set_sched_policy(int tid, SchedPolicy policy)
break;
}
if (add_tid_to_cgroup(tid, fd) != 0) {
if (errno != ESRCH && errno != ENOENT)
return -errno;
}
#ifdef USE_SCHEDBOOST
if (boost_fd > 0 && add_tid_to_cgroup(tid, boost_fd) != 0) {
if (errno != ESRCH && errno != ENOENT)
return -errno;
if (schedboost_enabled()) {
if (boost_fd > 0 && add_tid_to_cgroup(tid, boost_fd) != 0) {
if (errno != ESRCH && errno != ENOENT)
return -errno;
}
}
#endif
} else {
struct sched_param param;