sched-linux.cpp@ 8170

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1	/* $Id: sched-linux.cpp 8170 2008-04-18 17:52:25Z vboxsync $ */
2	/** @file
3	* Incredibly Portable Runtime - Scheduling, POSIX.
4	*/
5
6	/*
7	* Copyright (C) 2006-2007 Sun Microsystems, Inc.
8	*
9	* This file is part of VirtualBox Open Source Edition (OSE), as
10	* available from http://www.virtualbox.org. This file is free software;
11	* you can redistribute it and/or modify it under the terms of the GNU
12	* General Public License (GPL) as published by the Free Software
13	* Foundation, in version 2 as it comes in the "COPYING" file of the
14	* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15	* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16	*
17	* The contents of this file may alternatively be used under the terms
18	* of the Common Development and Distribution License Version 1.0
19	* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
20	* VirtualBox OSE distribution, in which case the provisions of the
21	* CDDL are applicable instead of those of the GPL.
22	*
23	* You may elect to license modified versions of this file under the
24	* terms and conditions of either the GPL or the CDDL or both.
25	*
26	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
27	* Clara, CA 95054 USA or visit http://www.sun.com if you need
28	* additional information or have any questions.
29	*/
30
31	/*
32	* !WARNING!
33	*
34	* When talking about lowering and raising priority, we do NOT refere to
35	* the common direction priority values takes on unix systems (lower means
36	* higher). So, when we raise the priority of a linux thread the nice
37	* value will decrease, and when we lower the priority the nice value
38	* will increase. Confusing, right?
39	*
40	* !WARNING!
41	*/
42
43
44
45	/** @def THREAD_LOGGING
46	* Be very careful with enabling this, it may cause deadlocks when combined
47	* with the 'thread' logging prefix.
48	*/
49	#ifdef __DOXYGEN__
50	# define THREAD_LOGGING
51	#endif
52
53
54	/*******************************************************************************
55	* Header Files *
56	*******************************************************************************/
57	#define LOG_GROUP RTLOGGROUP_THREAD
58	#include <errno.h>
59	#include <pthread.h>
60	#include <sched.h>
61	#include <unistd.h>
62	#include <sys/resource.h>
63
64	#include <iprt/thread.h>
65	#include <iprt/process.h>
66	#include <iprt/semaphore.h>
67	#include <iprt/string.h>
68	#include <iprt/assert.h>
69	#include <iprt/log.h>
70	#include <iprt/err.h>
71	#include "internal/sched.h"
72	#include "internal/thread.h"
73
74
75	/*******************************************************************************
76	* Structures and Typedefs *
77	*******************************************************************************/
78
79	/** Array scheduler attributes corresponding to each of the thread types.
80	* @internal */
81	typedef struct PROCPRIORITYTYPE
82	{
83	/** For sanity include the array index. */
84	RTTHREADTYPE enmType;
85	/** The thread priority or nice delta - depends on which priority type. */
86	int iPriority;
87	} PROCPRIORITYTYPE;
88
89
90	/**
91	* Configuration of one priority.
92	* @internal
93	*/
94	typedef struct
95	{
96	/** The priority. */
97	RTPROCPRIORITY enmPriority;
98	/** The name of this priority. */
99	const char *pszName;
100	/** The process nice value. */
101	int iNice;
102	/** The delta applied to the iPriority value. */
103	int iDelta;
104	/** Array scheduler attributes corresponding to each of the thread types. */
105	const PROCPRIORITYTYPE *paTypes;
106	} PROCPRIORITY;
107
108
109	/**
110	* Saved priority settings
111	* @internal
112	*/
113	typedef struct
114	{
115	/** Process priority. */
116	int iPriority;
117	/** Process level. */
118	struct sched_param SchedParam;
119	/** Process level. */
120	int iPolicy;
121	/** pthread level. */
122	struct sched_param PthreadSchedParam;
123	/** pthread level. */
124	int iPthreadPolicy;
125	} SAVEDPRIORITY, *PSAVEDPRIORITY;
126
127
128	/*******************************************************************************
129	* Global Variables *
130	*******************************************************************************/
131	/**
132	* Deltas for a process in which we are not restricted
133	* to only be lowering the priority.
134	*/
135	static const PROCPRIORITYTYPE g_aTypesLinuxFree[RTTHREADTYPE_END] =
136	{
137	{ RTTHREADTYPE_INVALID, -999999999 },
138	{ RTTHREADTYPE_INFREQUENT_POLLER, +3 },
139	{ RTTHREADTYPE_MAIN_HEAVY_WORKER, +2 },
140	{ RTTHREADTYPE_EMULATION, +1 },
141	{ RTTHREADTYPE_DEFAULT, 0 },
142	{ RTTHREADTYPE_GUI, 0 },
143	{ RTTHREADTYPE_MAIN_WORKER, 0 },
144	{ RTTHREADTYPE_VRDP_IO, -1 },
145	{ RTTHREADTYPE_DEBUGGER, -1 },
146	{ RTTHREADTYPE_MSG_PUMP, -2 },
147	{ RTTHREADTYPE_IO, -3 },
148	{ RTTHREADTYPE_TIMER, -4 }
149	};
150
151	/**
152	* Deltas for a process in which we are restricted and can only lower the priority.
153	*/
154	static const PROCPRIORITYTYPE g_aTypesLinuxRestricted[RTTHREADTYPE_END] =
155	{
156	{ RTTHREADTYPE_INVALID, -999999999 },
157	{ RTTHREADTYPE_INFREQUENT_POLLER, +3 },
158	{ RTTHREADTYPE_MAIN_HEAVY_WORKER, +2 },
159	{ RTTHREADTYPE_EMULATION, +1 },
160	{ RTTHREADTYPE_DEFAULT, 0 },
161	{ RTTHREADTYPE_GUI, 0 },
162	{ RTTHREADTYPE_MAIN_WORKER, 0 },
163	{ RTTHREADTYPE_VRDP_IO, 0 },
164	{ RTTHREADTYPE_DEBUGGER, 0 },
165	{ RTTHREADTYPE_MSG_PUMP, 0 },
166	{ RTTHREADTYPE_IO, 0 },
167	{ RTTHREADTYPE_TIMER, 0 }
168	};
169
170	/**
171	* All threads have the same priority.
172	*
173	* This is typically choosen when we find that we can't raise the priority
174	* to the process default of a thread created by a low priority thread.
175	*/
176	static const PROCPRIORITYTYPE g_aTypesLinuxFlat[RTTHREADTYPE_END] =
177	{
178	{ RTTHREADTYPE_INVALID, -999999999 },
179	{ RTTHREADTYPE_INFREQUENT_POLLER, 0 },
180	{ RTTHREADTYPE_MAIN_HEAVY_WORKER, 0 },
181	{ RTTHREADTYPE_EMULATION, 0 },
182	{ RTTHREADTYPE_DEFAULT, 0 },
183	{ RTTHREADTYPE_GUI, 0 },
184	{ RTTHREADTYPE_MAIN_WORKER, 0 },
185	{ RTTHREADTYPE_VRDP_IO, 0 },
186	{ RTTHREADTYPE_DEBUGGER, 0 },
187	{ RTTHREADTYPE_MSG_PUMP, 0 },
188	{ RTTHREADTYPE_IO, 0 },
189	{ RTTHREADTYPE_TIMER, 0 }
190	};
191
192	/**
193	* Process and thread level priority, full access at thread level.
194	*/
195	static const PROCPRIORITY g_aUnixConfigs[] =
196	{
197	{ RTPROCPRIORITY_FLAT, "Flat", 0, 0, g_aTypesLinuxFlat },
198	{ RTPROCPRIORITY_LOW, "Low", 9, 9, g_aTypesLinuxFree },
199	{ RTPROCPRIORITY_LOW, "Low", 9, 9, g_aTypesLinuxFlat },
200	{ RTPROCPRIORITY_LOW, "Low", 15, 15, g_aTypesLinuxFree },
201	{ RTPROCPRIORITY_LOW, "Low", 15, 15, g_aTypesLinuxFlat },
202	{ RTPROCPRIORITY_LOW, "Low", 17, 17, g_aTypesLinuxFree },
203	{ RTPROCPRIORITY_LOW, "Low", 17, 17, g_aTypesLinuxFlat },
204	{ RTPROCPRIORITY_LOW, "Low", 19, 19, g_aTypesLinuxFlat },
205	{ RTPROCPRIORITY_LOW, "Low", 9, 9, g_aTypesLinuxRestricted },
206	{ RTPROCPRIORITY_LOW, "Low", 15, 15, g_aTypesLinuxRestricted },
207	{ RTPROCPRIORITY_LOW, "Low", 17, 17, g_aTypesLinuxRestricted },
208	{ RTPROCPRIORITY_NORMAL, "Normal", 0, 0, g_aTypesLinuxFree },
209	{ RTPROCPRIORITY_NORMAL, "Normal", 0, 0, g_aTypesLinuxRestricted },
210	{ RTPROCPRIORITY_NORMAL, "Normal", 0, 0, g_aTypesLinuxFlat },
211	{ RTPROCPRIORITY_HIGH, "High", -9, -9, g_aTypesLinuxFree },
212	{ RTPROCPRIORITY_HIGH, "High", -7, -7, g_aTypesLinuxFree },
213	{ RTPROCPRIORITY_HIGH, "High", -5, -5, g_aTypesLinuxFree },
214	{ RTPROCPRIORITY_HIGH, "High", -3, -3, g_aTypesLinuxFree },
215	{ RTPROCPRIORITY_HIGH, "High", -1, -1, g_aTypesLinuxFree },
216	{ RTPROCPRIORITY_HIGH, "High", -9, -9, g_aTypesLinuxRestricted },
217	{ RTPROCPRIORITY_HIGH, "High", -7, -7, g_aTypesLinuxRestricted },
218	{ RTPROCPRIORITY_HIGH, "High", -5, -5, g_aTypesLinuxRestricted },
219	{ RTPROCPRIORITY_HIGH, "High", -3, -3, g_aTypesLinuxRestricted },
220	{ RTPROCPRIORITY_HIGH, "High", -1, -1, g_aTypesLinuxRestricted },
221	{ RTPROCPRIORITY_HIGH, "High", -9, -9, g_aTypesLinuxFlat },
222	{ RTPROCPRIORITY_HIGH, "High", -7, -7, g_aTypesLinuxFlat },
223	{ RTPROCPRIORITY_HIGH, "High", -5, -5, g_aTypesLinuxFlat },
224	{ RTPROCPRIORITY_HIGH, "High", -3, -3, g_aTypesLinuxFlat },
225	{ RTPROCPRIORITY_HIGH, "High", -1, -1, g_aTypesLinuxFlat }
226	};
227
228	/**
229	* The dynamic default priority configuration.
230	*
231	* This will be recalulated at runtime depending on what the
232	* system allow us to do and what the current priority is.
233	*/
234	static PROCPRIORITY g_aDefaultPriority =
235	{
236	RTPROCPRIORITY_LOW, "Default", 0, 0, g_aTypesLinuxRestricted
237	};
238
239	/** Pointer to the current priority configuration. */
240	static const PROCPRIORITY *g_pProcessPriority = &g_aDefaultPriority;
241
242	/** Set if we can raise the priority of a thread beyond the default.
243	*
244	* It might mean we have the CAP_SYS_NICE capability or that the
245	* process's RLIMIT_NICE is higher than the priority of the thread
246	* calculating the defaults.
247	*/
248	static bool g_fCanRaisePriority = false;
249
250	/** Set if we can restore the priority after having temporarily lowered or raised it. */
251	static bool g_fCanRestorePriority = false;
252
253	/** Set if we can NOT raise the priority to the process default in a thread
254	* created by a thread running below the process default.
255	*/
256	static bool g_fScrewedUpMaxPriorityLimitInheritance = true;
257
258	/** The highest priority we can set. */
259	static int g_iMaxPriority = 0;
260
261	/** The lower priority we can set. */
262	static int g_iMinPriority = 19;
263
264	/** Set when we've successfully determined the capabilities of the process and kernel. */
265	static bool g_fInitialized = false;
266
267
268
269	/*******************************************************************************
270	* Internal Functions *
271	*******************************************************************************/
272
273
274	/**
275	* Saves all the scheduling attributes we can think of.
276	*/
277	static void rtSchedNativeSave(PSAVEDPRIORITY pSave)
278	{
279	memset(pSave, 0xff, sizeof(*pSave));
280
281	errno = 0;
282	pSave->iPriority = getpriority(PRIO_PROCESS, 0 /* current process */);
283	Assert(errno == 0);
284
285	errno = 0;
286	sched_getparam(0 /* current process */, &pSave->SchedParam);
287	Assert(errno == 0);
288
289	errno = 0;
290	pSave->iPolicy = sched_getscheduler(0 /* current process */);
291	Assert(errno == 0);
292
293	int rc = pthread_getschedparam(pthread_self(), &pSave->iPthreadPolicy, &pSave->PthreadSchedParam);
294	Assert(rc == 0); NOREF(rc);
295	}
296
297
298	/**
299	* Restores scheduling attributes.
300	* Most of this won't work right, but anyway...
301	*/
302	static void rtSchedNativeRestore(PSAVEDPRIORITY pSave)
303	{
304	setpriority(PRIO_PROCESS, 0, pSave->iPriority);
305	sched_setscheduler(0, pSave->iPolicy, &pSave->SchedParam);
306	sched_setparam(0, &pSave->SchedParam);
307	pthread_setschedparam(pthread_self(), pSave->iPthreadPolicy, &pSave->PthreadSchedParam);
308	}
309
310
311	/**
312	* Starts a worker thread and wait for it to complete.
313	* We cannot use RTThreadCreate since we're already owner of the RW lock.
314	*/
315	static int rtSchedRunThread(void (pfnThread)(void pvArg), void pvArg)
316	{
317	/*
318	* Setup thread attributes.
319	*/
320	pthread_attr_t ThreadAttr;
321	int rc = pthread_attr_init(&ThreadAttr);
322	if (!rc)
323	{
324	rc = pthread_attr_setdetachstate(&ThreadAttr, PTHREAD_CREATE_JOINABLE);
325	if (!rc)
326	{
327	rc = pthread_attr_setstacksize(&ThreadAttr, 128*1024);
328	if (!rc)
329	{
330	/*
331	* Create the thread.
332	*/
333	pthread_t Thread;
334	rc = pthread_create(&Thread, &ThreadAttr, pfnThread, pvArg);
335	if (!rc)
336	{
337	/*
338	* Wait for the thread to finish.
339	*/
340	void pvRet = (void )-1;
341	do
342	{
343	rc = pthread_join(Thread, &pvRet);
344	} while (errno == EINTR);
345	if (rc)
346	return RTErrConvertFromErrno(rc);
347	return (int)(uintptr_t)pvRet;
348	}
349	}
350	}
351	pthread_attr_destroy(&ThreadAttr);
352	}
353	return RTErrConvertFromErrno(rc);
354	}
355
356
357	static void rtSchedDumpPriority(void)
358	{
359	#ifdef THREAD_LOGGING
360	Log(("Priority: g_fCanRaisePriority=%RTbool g_fCanRestorePriority=%RTbool g_fScrewedUpMaxPriorityLimitInheritance=%RTbool\n",
361	g_fCanRaisePriority, g_fCanRestorePriority, g_fScrewedUpMaxPriorityLimitInheritance));
362	Log(("Priority: g_iMaxPriority=%d g_iMinPriority=%d\n", g_iMaxPriority, g_iMinPriority));
363	Log(("Priority: enmPriority=%d \"%s\" iNice=%d iDelta=%d\n",
364	g_pProcessPriority->enmPriority,
365	g_pProcessPriority->pszName,
366	g_pProcessPriority->iNice,
367	g_pProcessPriority->iDelta));
368	Log(("Priority: %2d INFREQUENT_POLLER = %d\n", RTTHREADTYPE_INFREQUENT_POLLER, g_pProcessPriority->paTypes[RTTHREADTYPE_INFREQUENT_POLLER].iPriority));
369	Log(("Priority: %2d MAIN_HEAVY_WORKER = %d\n", RTTHREADTYPE_MAIN_HEAVY_WORKER, g_pProcessPriority->paTypes[RTTHREADTYPE_MAIN_HEAVY_WORKER].iPriority));
370	Log(("Priority: %2d EMULATION = %d\n", RTTHREADTYPE_EMULATION , g_pProcessPriority->paTypes[RTTHREADTYPE_EMULATION ].iPriority));
371	Log(("Priority: %2d DEFAULT = %d\n", RTTHREADTYPE_DEFAULT , g_pProcessPriority->paTypes[RTTHREADTYPE_DEFAULT ].iPriority));
372	Log(("Priority: %2d GUI = %d\n", RTTHREADTYPE_GUI , g_pProcessPriority->paTypes[RTTHREADTYPE_GUI ].iPriority));
373	Log(("Priority: %2d MAIN_WORKER = %d\n", RTTHREADTYPE_MAIN_WORKER , g_pProcessPriority->paTypes[RTTHREADTYPE_MAIN_WORKER ].iPriority));
374	Log(("Priority: %2d VRDP_IO = %d\n", RTTHREADTYPE_VRDP_IO , g_pProcessPriority->paTypes[RTTHREADTYPE_VRDP_IO ].iPriority));
375	Log(("Priority: %2d DEBUGGER = %d\n", RTTHREADTYPE_DEBUGGER , g_pProcessPriority->paTypes[RTTHREADTYPE_DEBUGGER ].iPriority));
376	Log(("Priority: %2d MSG_PUMP = %d\n", RTTHREADTYPE_MSG_PUMP , g_pProcessPriority->paTypes[RTTHREADTYPE_MSG_PUMP ].iPriority));
377	Log(("Priority: %2d IO = %d\n", RTTHREADTYPE_IO , g_pProcessPriority->paTypes[RTTHREADTYPE_IO ].iPriority));
378	Log(("Priority: %2d TIMER = %d\n", RTTHREADTYPE_TIMER , g_pProcessPriority->paTypes[RTTHREADTYPE_TIMER ].iPriority));
379	#endif
380	}
381
382
383	/**
384	* This just checks if it can raise the priority after having been
385	* created by a thread with a low priority.
386	*
387	* @returns zero on success, non-zero on failure.
388	* @param pvUser The priority of the parent before it was lowered (cast to int).
389	*/
390	static void rtSchedNativeSubProberThread(void pvUser)
391	{
392	int iPriority = getpriority(PRIO_PROCESS, 0);
393	Assert(iPriority == g_iMinPriority);
394
395	if (setpriority(PRIO_PROCESS, 0, iPriority + 1))
396	return (void *)-1;
397	if (setpriority(PRIO_PROCESS, 0, (int)(intptr_t)pvUser))
398	return (void *)-1;
399	return (void *)0;
400	}
401
402
403	/**
404	* The prober thread.
405	* We don't want to mess with the priority of the calling thread.
406	*
407	* @remark This is pretty presumptive stuff, but if it works on Linux and
408	* FreeBSD it does what I want.
409	*/
410	static void rtSchedNativeProberThread(void pvUser)
411	{
412	SAVEDPRIORITY SavedPriority;
413	rtSchedNativeSave(&SavedPriority);
414
415	/*
416	* Check if we can get higher priority (typically only root can do this).
417	* (Won't work right if our priority is -19 to start with, but what the heck.)
418	*
419	* We assume that the priority range is -19 to 19. Should probably find the right
420	* define for this.
421	*/
422	int iStart = getpriority(PRIO_PROCESS, 0);
423	int i = iStart;
424	while (i-- > -20)
425	if (setpriority(PRIO_PROCESS, 0, i))
426	break;
427	g_iMaxPriority = getpriority(PRIO_PROCESS, 0);
428	g_fCanRaisePriority = g_iMaxPriority < iStart;
429	g_fCanRestorePriority = setpriority(PRIO_PROCESS, 0, iStart) == 0;
430
431	/*
432	* Check if we temporarily lower the thread priority.
433	* Again, we assume we're not at the extreme end of the priority scale.
434	*/
435	iStart = getpriority(PRIO_PROCESS, 0);
436	i = iStart;
437	while (i++ < 19)
438	if (setpriority(PRIO_PROCESS, 0, i))
439	break;
440	g_iMinPriority = getpriority(PRIO_PROCESS, 0);
441	if ( setpriority(PRIO_PROCESS, 0, iStart)
442	\|\| getpriority(PRIO_PROCESS, 0) != iStart)
443	g_fCanRestorePriority = false;
444	if (g_iMinPriority == g_iMaxPriority)
445	g_fCanRestorePriority = g_fCanRaisePriority = false;
446
447	/*
448	* Check what happens to child threads when the parent lowers the
449	* priority when it's being created.
450	*/
451	iStart = getpriority(PRIO_PROCESS, 0);
452	g_fScrewedUpMaxPriorityLimitInheritance = true;
453	if ( g_fCanRestorePriority
454	&& !setpriority(PRIO_PROCESS, 0, g_iMinPriority)
455	&& iStart != g_iMinPriority)
456	{
457	if (rtSchedRunThread(rtSchedNativeSubProberThread, (void *)iStart) == 0)
458	g_fScrewedUpMaxPriorityLimitInheritance = false;
459	}
460
461	/* done */
462	rtSchedNativeRestore(&SavedPriority);
463	return (void *)VINF_SUCCESS;
464	}
465
466
467	/**
468	* Calculate the scheduling properties for all the threads in the default
469	* process priority, assuming the current thread have the type enmType.
470	*
471	* @returns iprt status code.
472	* @param enmType The thread type to be assumed for the current thread.
473	*/
474	int rtSchedNativeCalcDefaultPriority(RTTHREADTYPE enmType)
475	{
476	Assert(enmType > RTTHREADTYPE_INVALID && enmType < RTTHREADTYPE_END);
477
478	/*
479	* First figure out what's we're allowed to do in this process.
480	*/
481	if (!g_fInitialized)
482	{
483	int iPriority = getpriority(PRIO_PROCESS, 0);
484	#ifdef RLIMIT_RTPRIO
485	/** @todo */
486	#endif
487	int rc = rtSchedRunThread(rtSchedNativeProberThread, NULL);
488	if (RT_FAILURE(rc))
489	return rc;
490	Assert(getpriority(PRIO_PROCESS, 0) == iPriority); NOREF(iPriority);
491	g_fInitialized = true;
492	}
493
494	/*
495	* Select the right priority type table and update the default
496	* process priority structure.
497	*/
498	if (g_fCanRaisePriority && g_fCanRestorePriority && !g_fScrewedUpMaxPriorityLimitInheritance)
499	g_aDefaultPriority.paTypes = &g_aTypesLinuxFree[0];
500	else if (!g_fCanRaisePriority && g_fCanRestorePriority && !g_fScrewedUpMaxPriorityLimitInheritance)
501	g_aDefaultPriority.paTypes = &g_aTypesLinuxRestricted[0];
502	else
503	g_aDefaultPriority.paTypes = &g_aTypesLinuxFlat[0];
504	Assert(enmType == g_aDefaultPriority.paTypes[enmType].enmType);
505
506	int iPriority = getpriority(PRIO_PROCESS, 0 /* current process */);
507	g_aDefaultPriority.iNice = iPriority - g_aDefaultPriority.paTypes[enmType].iPriority;
508	g_aDefaultPriority.iDelta = g_aDefaultPriority.iNice;
509
510	rtSchedDumpPriority();
511	return VINF_SUCCESS;
512	}
513
514
515	/**
516	* The process priority validator thread.
517	* (We don't want to mess with the priority of the calling thread.)
518	*/
519	static void rtSchedNativeValidatorThread(void pvUser)
520	{
521	const PROCPRIORITY pCfg = (const PROCPRIORITY )pvUser;
522	SAVEDPRIORITY SavedPriority;
523	rtSchedNativeSave(&SavedPriority);
524
525	/*
526	* Try out the priorities from the top and down.
527	*/
528	int rc = VINF_SUCCESS;
529	int i = RTTHREADTYPE_END;
530	while (--i > RTTHREADTYPE_INVALID)
531	{
532	int iPriority = pCfg->paTypes[i].iPriority + pCfg->iDelta;
533	if (setpriority(PRIO_PROCESS, 0, iPriority))
534	{
535	rc = RTErrConvertFromErrno(errno);
536	break;
537	}
538	}
539
540	/* done */
541	rtSchedNativeRestore(&SavedPriority);
542	return (void *)rc;
543	}
544
545
546	/**
547	* Validates and sets the process priority.
548	*
549	* This will check that all rtThreadNativeSetPriority() will success for all the
550	* thread types when applied to the current thread.
551	*
552	* @returns iprt status code.
553	* @param enmPriority The priority to validate and set.
554	*/
555	int rtProcNativeSetPriority(RTPROCPRIORITY enmPriority)
556	{
557	Assert(enmPriority > RTPROCPRIORITY_INVALID && enmPriority < RTPROCPRIORITY_LAST);
558
559	int rc = VINF_SUCCESS;
560	if (enmPriority == RTPROCPRIORITY_DEFAULT)
561	g_pProcessPriority = &g_aDefaultPriority;
562	else
563	{
564	/*
565	* Find a configuration which matches and can be applied.
566	*/
567	rc = VERR_FILE_NOT_FOUND;
568	for (unsigned i = 0; i < ELEMENTS(g_aUnixConfigs); i++)
569	{
570	if (g_aUnixConfigs[i].enmPriority == enmPriority)
571	{
572	int iPriority = getpriority(PRIO_PROCESS, 0);
573	int rc3 = rtSchedRunThread(rtSchedNativeValidatorThread, (void *)&g_aUnixConfigs[i]);
574	Assert(getpriority(PRIO_PROCESS, 0) == iPriority); NOREF(iPriority);
575	if (RT_SUCCESS(rc3))
576	{
577	g_pProcessPriority = &g_aUnixConfigs[i];
578	rc = VINF_SUCCESS;
579	break;
580	}
581	if (rc == VERR_FILE_NOT_FOUND)
582	rc = rc3;
583	}
584	}
585	}
586
587	#ifdef THREAD_LOGGING
588	LogFlow(("rtProcNativeSetPriority: returns %Vrc enmPriority=%d\n", rc, enmPriority));
589	rtSchedDumpPriority();
590	#endif
591	return rc;
592	}
593
594
595	/**
596	* Sets the priority of the thread according to the thread type
597	* and current process priority.
598	*
599	* The RTTHREADINT::enmType member has not yet been updated and will be updated by
600	* the caller on a successful return.
601	*
602	* @returns iprt status code.
603	* @param pThread The thread in question.
604	* @param enmType The thread type.
605	*/
606	int rtThreadNativeSetPriority(PRTTHREADINT pThread, RTTHREADTYPE enmType)
607	{
608	/* sanity */
609	Assert(enmType > RTTHREADTYPE_INVALID && enmType < RTTHREADTYPE_END);
610	Assert(enmType == g_pProcessPriority->paTypes[enmType].enmType);
611	Assert((pthread_t)pThread->Core.Key == pthread_self());
612
613	/*
614	* Calculate the thread priority and apply it.
615	*/
616	int rc = VINF_SUCCESS;
617	int iPriority = g_pProcessPriority->paTypes[enmType].iPriority + g_pProcessPriority->iDelta;
618	if (!setpriority(PRIO_PROCESS, 0, iPriority))
619	{
620	AssertMsg(iPriority == getpriority(PRIO_PROCESS, 0), ("iPriority=%d getpriority()=%d\n", iPriority, getpriority(PRIO_PROCESS, 0)));
621	#ifdef THREAD_LOGGING
622	Log(("rtThreadNativeSetPriority: Thread=%p enmType=%d iPriority=%d pid=%d\n", pThread->Core.Key, enmType, iPriority, getpid()));
623	#endif
624	}
625	else
626	{
627	rc = RTErrConvertFromErrno(errno);
628	AssertMsgFailed(("setpriority(,, %d) -> errno=%d rc=%Vrc\n", iPriority, errno, rc));
629	rc = VINF_SUCCESS; //non-fatal for now.
630	}
631
632	return rc;
633	}
634

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source: vbox/trunk/src/VBox/Runtime/r3/linux/sched-linux.cpp@ 8170

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