Baloo

priority.cpp
1/*
2 This file is part of the KDE Project
3 SPDX-FileCopyrightText: 2008 Sebastian Trueg <trueg@kde.org>
4
5 Parts of this file are based on code from Strigi
6 SPDX-FileCopyrightText: 2006-2007 Jos van den Oever <jos@vandenoever.info>
7
8 SPDX-License-Identifier: LGPL-2.0-or-later
9*/
10
11#include "priority.h"
12
13#ifndef _GNU_SOURCE
14#define _GNU_SOURCE
15#endif
16
17#include <QDebug>
18
19#include <sys/time.h>
20#include <sys/resource.h>
21
22#include <unistd.h>
23#ifndef _WIN32
24#include <sys/syscall.h>
25#include <cerrno>
26
27#include <sched.h>
28#endif
29
30#ifdef SYS_ioprio_set
31namespace {
32#ifndef IOPRIO_CLASS_IDLE
33 enum {
34 IOPRIO_CLASS_NONE,
35 IOPRIO_CLASS_RT,
36 IOPRIO_CLASS_BE,
37 IOPRIO_CLASS_IDLE,
38 };
39#endif
40
41#ifndef IOPRIO_WHO_PROCESS
42 enum {
43 IOPRIO_WHO_PROCESS = 1,
44 IOPRIO_WHO_PGRP,
45 IOPRIO_WHO_USER,
46 };
47#endif
48
49#ifndef IOPRIO_CLASS_SHIFT
50 const int IOPRIO_CLASS_SHIFT = 13;
51#endif
52}
53#endif
54
55bool lowerIOPriority()
56{
57#ifdef SYS_ioprio_set
58 if ( syscall( SYS_ioprio_set, IOPRIO_WHO_PROCESS, 0, IOPRIO_CLASS_IDLE<<IOPRIO_CLASS_SHIFT ) < 0 ) {
59 qDebug( "cannot set io scheduling to idle (%s). Trying best effort.\n", strerror( errno ));
60 if ( syscall( SYS_ioprio_set, IOPRIO_WHO_PROCESS, 0, 7|IOPRIO_CLASS_BE<<IOPRIO_CLASS_SHIFT ) < 0 ) {
61 qDebug( "cannot set io scheduling to best effort.\n");
62 return false;
63 }
64 }
65 return true;
66#else
67 return false;
68#endif
69}
70
71bool lowerPriority()
72{
73#ifndef Q_OS_WIN
74 return !setpriority( PRIO_PROCESS, 0, 19 );
75#else
76 return false;
77#endif
78}
79
80bool lowerSchedulingPriority()
81{
82#ifdef SCHED_BATCH
83 struct sched_param param;
84 memset( &param, 0, sizeof(param) );
85 param.sched_priority = 0;
86 return !sched_setscheduler( 0, SCHED_BATCH, &param );
87#else
88 return false;
89#endif
90}
91
92bool setIdleSchedulingPriority()
93{
94#ifdef SCHED_IDLE
95 struct sched_param param;
96 memset( &param, 0, sizeof(param) );
97 param.sched_priority = 0;
98 return !sched_setscheduler( 0, SCHED_IDLE, &param );
99#else
100 return false;
101#endif
102}
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