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/*
* Copyright (C) 2014-2016 Max Kellermann <max.kellermann@gmail.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "Util.hxx"
#include "system/Error.hxx"
#ifdef __linux__
#include <sched.h>
#include <sys/syscall.h>
#include <unistd.h>
#elif defined(_WIN32)
#include <windows.h>
#endif
#ifdef __linux__
#ifndef ANDROID
static int
linux_ioprio_set(int which, int who, int ioprio) noexcept
{
return syscall(__NR_ioprio_set, which, who, ioprio);
}
static void
ioprio_set_idle() noexcept
{
static constexpr int _IOPRIO_WHO_PROCESS = 1;
static constexpr int _IOPRIO_CLASS_IDLE = 3;
static constexpr int _IOPRIO_CLASS_SHIFT = 13;
static constexpr int _IOPRIO_IDLE =
(_IOPRIO_CLASS_IDLE << _IOPRIO_CLASS_SHIFT) | 7;
linux_ioprio_set(_IOPRIO_WHO_PROCESS, 0, _IOPRIO_IDLE);
}
#endif /* !ANDROID */
/**
* Wrapper for the "sched_setscheduler" system call. We don't use the
* one from the C library because Musl has an intentionally broken
* implementation.
*/
static int
linux_sched_setscheduler(pid_t pid, int sched,
const struct sched_param *param) noexcept
{
return syscall(__NR_sched_setscheduler, pid, sched, param);
}
#endif
void
SetThreadIdlePriority() noexcept
{
#ifdef __linux__
#ifdef SCHED_IDLE
static struct sched_param sched_param;
linux_sched_setscheduler(0, SCHED_IDLE, &sched_param);
#endif
#ifndef ANDROID
/* this system call is forbidden via seccomp on Android 8 and
leads to crash (SIGSYS) */
ioprio_set_idle();
#endif
#elif defined(_WIN32)
SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_IDLE);
#endif
};
void
SetThreadRealtime()
{
#ifdef __linux__
struct sched_param sched_param;
sched_param.sched_priority = 50;
int policy = SCHED_FIFO;
#ifdef SCHED_RESET_ON_FORK
policy |= SCHED_RESET_ON_FORK;
#endif
if (linux_sched_setscheduler(0, policy, &sched_param) < 0)
throw MakeErrno("sched_setscheduler failed");
#endif // __linux__
};
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