oxmc
125 lines
3.7 KiB
C++
125 lines
3.7 KiB
C++
// *****************************************************************************
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// * This file is part of the FreeFileSync project. It is distributed under *
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// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0 *
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// * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
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// *****************************************************************************
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#include "process_priority.h"
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#include <sys/resource.h> //setpriority
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using namespace zen;
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namespace
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{
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#if 0
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//https://linux.die.net/man/2/getpriority
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//CPU priority from highest to lowest range: [-NZERO, NZERO -1] usually: [-20, 19]
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enum //with values from CentOS 7
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{
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CPU_PRIO_VERYHIGH = -NZERO,
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CPU_PRIO_HIGH = -5,
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CPU_PRIO_NORMAL = 0,
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CPU_PRIO_LOW = 5,
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CPU_PRIO_VERYLOW = NZERO - 1,
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};
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int getCpuPriority() //throw SysError
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{
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errno = 0;
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const int prio = getpriority(PRIO_PROCESS, 0 /* = the calling process */);
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if (prio == -1 && errno != 0) //"can legitimately return the value -1"
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THROW_LAST_SYS_ERROR("getpriority");
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return prio;
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}
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//lowering is allowed, but increasing CPU prio requires admin rights >:(
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void setCpuPriority(int prio) //throw SysError
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{
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if (setpriority(PRIO_PROCESS, 0 /* = the calling process */, prio) != 0)
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THROW_LAST_SYS_ERROR("setpriority(" + numberTo<std::string>(prio) + ')');
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}
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#endif
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//---------------------------------------------------------------------------------------------------
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//- required functions ioprio_get/ioprio_set are not part of glibc: https://linux.die.net/man/2/ioprio_set
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//- and probably never will: https://sourceware.org/bugzilla/show_bug.cgi?id=4464
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//https://github.com/torvalds/linux/blob/master/include/uapi/linux/ioprio.h
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#define IOPRIO_CLASS_SHIFT 13
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#define IOPRIO_PRIO_VALUE(prioclass, priolevel) \
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(((prioclass) << IOPRIO_CLASS_SHIFT) | (priolevel))
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#define IOPRIO_NORM 4
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enum
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{
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IOPRIO_WHO_PROCESS = 1,
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IOPRIO_WHO_PGRP,
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IOPRIO_WHO_USER,
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};
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enum
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{
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IOPRIO_CLASS_NONE = 0,
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IOPRIO_CLASS_RT = 1,
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IOPRIO_CLASS_BE = 2,
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IOPRIO_CLASS_IDLE = 3,
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};
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int getIoPriority() //throw SysError
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{
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const int rv = ::syscall(SYS_ioprio_get, IOPRIO_WHO_PROCESS, ::getpid());
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if (rv == -1)
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THROW_LAST_SYS_ERROR("ioprio_get");
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//fix Linux kernel fuck up: bogus system default value
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if (rv == IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, IOPRIO_NORM))
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return IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, IOPRIO_NORM);
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return rv;
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}
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void setIoPriority(int ioPrio) //throw SysError
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{
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if (::syscall(SYS_ioprio_set, IOPRIO_WHO_PROCESS, ::getpid(), ioPrio) != 0)
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THROW_LAST_SYS_ERROR("ioprio_set(0x" + printNumber<std::string>("%x", static_cast<unsigned int>(ioPrio)) + ')');
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}
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}
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struct SetProcessPriority::Impl
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{
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std::optional<int> oldIoPrio;
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};
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SetProcessPriority::SetProcessPriority(ProcessPriority prio) : //throw FileError
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pimpl_(new Impl)
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{
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if (prio == ProcessPriority::background)
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try
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{
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pimpl_->oldIoPrio = getIoPriority(); //throw SysError
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setIoPriority(IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 6 /*0 (highest) to 7 (lowest)*/)); //throw SysError
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//maybe even IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0) ? nope: "only served when no one else is using the disk"
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}
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catch (const SysError& e) { throw FileError(_("Cannot change process I/O priorities."), e.toString()); }
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}
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SetProcessPriority::~SetProcessPriority()
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{
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if (pimpl_->oldIoPrio)
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try
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{
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setIoPriority(*pimpl_->oldIoPrio); //throw SysError
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}
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catch (const SysError& e) { logExtraError(_("Cannot change process I/O priorities.") + L"\n\n" + e.toString()); }
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}
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