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/*
* Copyright (C) 2011 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 "os.h"
#include "Dalvik.h"
#include <sys/time.h>
#include <sys/resource.h>
#include <limits.h>
#include <errno.h>
#include <system/thread_defs.h>
#include <cutils/sched_policy.h>
/*
* Conversion map for "nice" values.
*
* We use Android thread priority constants to be consistent with the rest
* of the system. In some cases adjacent entries may overlap.
*/
static const int kNiceValues[10] = {
ANDROID_PRIORITY_LOWEST, /* 1 (MIN_PRIORITY) */
ANDROID_PRIORITY_BACKGROUND + 6,
ANDROID_PRIORITY_BACKGROUND + 3,
ANDROID_PRIORITY_BACKGROUND,
ANDROID_PRIORITY_NORMAL, /* 5 (NORM_PRIORITY) */
ANDROID_PRIORITY_NORMAL - 2,
ANDROID_PRIORITY_NORMAL - 4,
ANDROID_PRIORITY_URGENT_DISPLAY + 3,
ANDROID_PRIORITY_URGENT_DISPLAY + 2,
ANDROID_PRIORITY_URGENT_DISPLAY /* 10 (MAX_PRIORITY) */
};
void os_changeThreadPriority(Thread* thread, int newPriority)
{
if (newPriority < 1 || newPriority > 10) {
ALOGW("bad priority %d", newPriority);
newPriority = 5;
}
int newNice = kNiceValues[newPriority-1];
pid_t pid = thread->systemTid;
if (newNice >= ANDROID_PRIORITY_BACKGROUND) {
set_sched_policy(dvmGetSysThreadId(), SP_BACKGROUND);
} else if (getpriority(PRIO_PROCESS, pid) >= ANDROID_PRIORITY_BACKGROUND) {
set_sched_policy(dvmGetSysThreadId(), SP_FOREGROUND);
}
if (setpriority(PRIO_PROCESS, pid, newNice) != 0) {
std::string threadName(dvmGetThreadName(thread));
ALOGI("setPriority(%d) '%s' to prio=%d(n=%d) failed: %s",
pid, threadName.c_str(), newPriority, newNice, strerror(errno));
} else {
ALOGV("setPriority(%d) to prio=%d(n=%d)", pid, newPriority, newNice);
}
}
int os_getThreadPriorityFromSystem()
{
errno = 0;
int sysprio = getpriority(PRIO_PROCESS, 0);
if (sysprio == -1 && errno != 0) {
ALOGW("getpriority() failed: %s", strerror(errno));
return THREAD_NORM_PRIORITY;
}
int jprio = THREAD_MIN_PRIORITY;
for (int i = 0; i < NELEM(kNiceValues); i++) {
if (sysprio >= kNiceValues[i]) {
break;
}
jprio++;
}
if (jprio > THREAD_MAX_PRIORITY) {
jprio = THREAD_MAX_PRIORITY;
}
return jprio;
}
int os_raiseThreadPriority()
{
/* Get the priority (the "nice" value) of the current thread. The
* getpriority() call can legitimately return -1, so we have to
* explicitly test errno.
*/
errno = 0;
int oldThreadPriority = getpriority(PRIO_PROCESS, 0);
if (errno != 0) {
ALOGI("getpriority(self) failed: %s", strerror(errno));
} else if (oldThreadPriority > ANDROID_PRIORITY_NORMAL) {
/* Current value is numerically greater than "normal", which
* in backward UNIX terms means lower priority.
*/
if (oldThreadPriority >= ANDROID_PRIORITY_BACKGROUND) {
set_sched_policy(dvmGetSysThreadId(), SP_FOREGROUND);
}
if (setpriority(PRIO_PROCESS, 0, ANDROID_PRIORITY_NORMAL) != 0) {
ALOGI("Unable to elevate priority from %d to %d",
oldThreadPriority, ANDROID_PRIORITY_NORMAL);
} else {
/*
* The priority has been elevated. Return the old value
* so the caller can restore it later.
*/
ALOGV("Elevating priority from %d to %d",
oldThreadPriority, ANDROID_PRIORITY_NORMAL);
return oldThreadPriority;
}
}
return INT_MAX;
}
void os_lowerThreadPriority(int oldThreadPriority)
{
if (setpriority(PRIO_PROCESS, 0, oldThreadPriority) != 0) {
ALOGW("Unable to reset priority to %d: %s",
oldThreadPriority, strerror(errno));
} else {
ALOGV("Reset priority to %d", oldThreadPriority);
}
if (oldThreadPriority >= ANDROID_PRIORITY_BACKGROUND) {
set_sched_policy(dvmGetSysThreadId(), SP_BACKGROUND);
}
}
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