PDMCritSect.cpp@ 28112

Last change on this file since 28112 was 25748, checked in by vboxsync, 15 years ago
iprt/cdefs,*: Use RT_LOCK_STRICT and RT_LOCK_STRICT_ORDER for controlling deadlock detection and lock order validation. Currently both are disabled by default, but it's possible to add VBOX_WITH_STRICT_LOCKS=1 to LocalConfig.kmk to enable it all.
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1	/* $Id: PDMCritSect.cpp 25748 2010-01-12 10:27:27Z vboxsync $ */
2	/** @file
3	* PDM - Critical Sections, Ring-3.
4	*/
5
6	/*
7	* Copyright (C) 2006-2009 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	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
18	* Clara, CA 95054 USA or visit http://www.sun.com if you need
19	* additional information or have any questions.
20	*/
21
22
23	/*******************************************************************************
24	* Header Files *
25	*******************************************************************************/
26	#define LOG_GROUP LOG_GROUP_PDM//_CRITSECT
27	#include "PDMInternal.h"
28	#include <VBox/pdmcritsect.h>
29	#include <VBox/mm.h>
30	#include <VBox/vm.h>
31
32	#include <VBox/err.h>
33	#include <VBox/log.h>
34	#include <VBox/sup.h>
35	#include <iprt/asm.h>
36	#include <iprt/assert.h>
37	#include <iprt/lockvalidator.h>
38	#include <iprt/string.h>
39	#include <iprt/thread.h>
40
41
42	/*******************************************************************************
43	* Internal Functions *
44	*******************************************************************************/
45	static int pdmR3CritSectDeleteOne(PVM pVM, PPDMCRITSECTINT pCritSect, PPDMCRITSECTINT pPrev, bool fFinal);
46
47
48
49	/**
50	* Initializes the critical section subcomponent.
51	*
52	* @returns VBox status code.
53	* @param pVM The VM handle.
54	* @remark Not to be confused with PDMR3CritSectInit and pdmR3CritSectInitDevice which are
55	* for initializing a critical section.
56	*/
57	int pdmR3CritSectInit(PVM pVM)
58	{
59	STAM_REG(pVM, &pVM->pdm.s.StatQueuedCritSectLeaves, STAMTYPE_COUNTER, "/PDM/QueuedCritSectLeaves", STAMUNIT_OCCURENCES,
60	"Number of times a critical section leave requesed needed to be queued for ring-3 execution.");
61	return VINF_SUCCESS;
62	}
63
64
65	/**
66	* Relocates all the critical sections.
67	*
68	* @param pVM The VM handle.
69	*/
70	void pdmR3CritSectRelocate(PVM pVM)
71	{
72	RTCritSectEnter(&pVM->pdm.s.MiscCritSect);
73	for (PPDMCRITSECTINT pCur = pVM->pdm.s.pCritSects;
74	pCur;
75	pCur = pCur->pNext)
76	pCur->pVMRC = pVM->pVMRC;
77	RTCritSectLeave(&pVM->pdm.s.MiscCritSect);
78	}
79
80
81	/**
82	* Deletes all remaining critical sections.
83	*
84	* This is called at the end of the termination process.
85	*
86	* @returns VBox status.
87	* First error code, rest is lost.
88	* @param pVM The VM handle.
89	* @remark Don't confuse this with PDMR3CritSectDelete.
90	*/
91	VMMDECL(int) PDMR3CritSectTerm(PVM pVM)
92	{
93	int rc = VINF_SUCCESS;
94	RTCritSectEnter(&pVM->pdm.s.MiscCritSect);
95	while (pVM->pdm.s.pCritSects)
96	{
97	int rc2 = pdmR3CritSectDeleteOne(pVM, pVM->pdm.s.pCritSects, NULL, true /* final */);
98	AssertRC(rc2);
99	if (RT_FAILURE(rc2) && RT_SUCCESS(rc))
100	rc = rc2;
101	}
102	RTCritSectLeave(&pVM->pdm.s.MiscCritSect);
103	RTCritSectDelete(&pVM->pdm.s.MiscCritSect);
104	return rc;
105	}
106
107
108
109	/**
110	* Initalizes a critical section and inserts it into the list.
111	*
112	* @returns VBox status code.
113	* @param pVM The Vm handle.
114	* @param pCritSect The critical section.
115	* @param pvKey The owner key.
116	* @param RT_SRC_POS_DECL The source position.
117	* @param pszName The name of the critical section (for statistics).
118	* @param pszNameFmt Format string for namging the critical section. For
119	* statistics and lock validation.
120	* @param va Arguments for the format string.
121	*/
122	static int pdmR3CritSectInitOne(PVM pVM, PPDMCRITSECTINT pCritSect, void pvKey, RT_SRC_POS_DECL, const char pszNameFmt, va_list va)
123	{
124	VM_ASSERT_EMT(pVM);
125
126	/*
127	* Allocate the semaphore.
128	*/
129	AssertCompile(sizeof(SUPSEMEVENT) == sizeof(pCritSect->Core.EventSem));
130	int rc = SUPSemEventCreate(pVM->pSession, (PSUPSEMEVENT)&pCritSect->Core.EventSem);
131	if (RT_SUCCESS(rc))
132	{
133	/* Only format the name once. */
134	char pszName = RTStrAPrintf2V(pszNameFmt, va); /* @todo plug the "leak"... */
135	if (pszName)
136	{
137	#ifndef PDMCRITSECT_STRICT
138	pCritSect->Core.pValidatorRec = NULL;
139	#else
140	rc = RTLockValidatorRecExclCreate(&pCritSect->Core.pValidatorRec,
141	# ifdef RT_LOCK_STRICT_ORDER
142	RTLockValidatorClassForSrcPos(RT_SRC_POS_ARGS, "%s", pszName),
143	# else
144	NIL_RTLOCKVALCLASS,
145	# endif
146	RTLOCKVAL_SUB_CLASS_NONE,
147	pCritSect, true, "%s", pszName);
148	#endif
149	if (RT_SUCCESS(rc))
150	{
151	/*
152	* Initialize the structure (first bit is c&p from RTCritSectInitEx).
153	*/
154	pCritSect->Core.u32Magic = RTCRITSECT_MAGIC;
155	pCritSect->Core.fFlags = 0;
156	pCritSect->Core.cNestings = 0;
157	pCritSect->Core.cLockers = -1;
158	pCritSect->Core.NativeThreadOwner = NIL_RTNATIVETHREAD;
159	pCritSect->pVMR3 = pVM;
160	pCritSect->pVMR0 = pVM->pVMR0;
161	pCritSect->pVMRC = pVM->pVMRC;
162	pCritSect->pvKey = pvKey;
163	pCritSect->EventToSignal = NIL_RTSEMEVENT;
164	pCritSect->pNext = pVM->pdm.s.pCritSects;
165	pCritSect->pszName = pszName;
166	pVM->pdm.s.pCritSects = pCritSect;
167	STAMR3RegisterF(pVM, &pCritSect->StatContentionRZLock, STAMTYPE_COUNTER, STAMVISIBILITY_ALWAYS, STAMUNIT_OCCURENCES, NULL, "/PDM/CritSects/%s/ContentionRZLock", pCritSect->pszName);
168	STAMR3RegisterF(pVM, &pCritSect->StatContentionRZUnlock,STAMTYPE_COUNTER, STAMVISIBILITY_ALWAYS, STAMUNIT_OCCURENCES, NULL, "/PDM/CritSects/%s/ContentionRZUnlock", pCritSect->pszName);
169	STAMR3RegisterF(pVM, &pCritSect->StatContentionR3, STAMTYPE_COUNTER, STAMVISIBILITY_ALWAYS, STAMUNIT_OCCURENCES, NULL, "/PDM/CritSects/%s/ContentionR3", pCritSect->pszName);
170	#ifdef VBOX_WITH_STATISTICS
171	STAMR3RegisterF(pVM, &pCritSect->StatLocked, STAMTYPE_PROFILE_ADV, STAMVISIBILITY_ALWAYS, STAMUNIT_TICKS_PER_OCCURENCE, NULL, "/PDM/CritSects/%s/Locked", pCritSect->pszName);
172	#endif
173	return VINF_SUCCESS;
174	}
175
176	RTStrFree(pszName);
177	}
178	else
179	rc = VERR_NO_STR_MEMORY;
180	SUPSemEventClose(pVM->pSession, (SUPSEMEVENT)pCritSect->Core.EventSem);
181	}
182	return rc;
183	}
184
185
186	/**
187	* Initializes a PDM critical section for internal use.
188	*
189	* The PDM critical sections are derived from the IPRT critical sections, but
190	* works in GC as well.
191	*
192	* @returns VBox status code.
193	* @param pVM The VM handle.
194	* @param pDevIns Device instance.
195	* @param pCritSect Pointer to the critical section.
196	* @param RT_SRC_POS_DECL Use RT_SRC_POS.
197	* @param pszNameFmt Format string for namging the critical section. For
198	* statistics and lock validation.
199	* @param ... Arguments for the format string.
200	* @thread EMT(0)
201	*/
202	VMMR3DECL(int) PDMR3CritSectInit(PVM pVM, PPDMCRITSECT pCritSect, RT_SRC_POS_DECL, const char *pszNameFmt, ...)
203	{
204	#if HC_ARCH_BITS == 64 && GC_ARCH_BITS == 32
205	AssertCompile(sizeof(pCritSect->padding) >= sizeof(pCritSect->s));
206	#endif
207	Assert(RT_ALIGN_P(pCritSect, sizeof(uintptr_t)) == pCritSect);
208	va_list va;
209	va_start(va, pszNameFmt);
210	int rc = pdmR3CritSectInitOne(pVM, &pCritSect->s, pCritSect, RT_SRC_POS_ARGS, pszNameFmt, va);
211	va_end(va);
212	return rc;
213	}
214
215
216	/**
217	* Initializes a PDM critical section.
218	*
219	* The PDM critical sections are derived from the IPRT critical sections, but
220	* works in GC as well.
221	*
222	* @returns VBox status code.
223	* @param pVM The VM handle.
224	* @param pDevIns Device instance.
225	* @param pCritSect Pointer to the critical section.
226	* @param pszNameFmt Format string for namging the critical section. For
227	* statistics and lock validation.
228	* @param va Arguments for the format string.
229	*/
230	int pdmR3CritSectInitDevice(PVM pVM, PPDMDEVINS pDevIns, PPDMCRITSECT pCritSect, RT_SRC_POS_DECL,
231	const char *pszNameFmt, va_list va)
232	{
233	return pdmR3CritSectInitOne(pVM, &pCritSect->s, pDevIns, RT_SRC_POS_ARGS, pszNameFmt, va);
234	}
235
236
237	/**
238	* Deletes one critical section.
239	*
240	* @returns Return code from RTCritSectDelete.
241	*
242	* @param pVM The VM handle.
243	* @param pCritSect The critical section.
244	* @param pPrev The previous critical section in the list.
245	* @param fFinal Set if this is the final call and statistics shouldn't be deregistered.
246	*
247	* @remarks Caller must've entered the MiscCritSect.
248	*/
249	static int pdmR3CritSectDeleteOne(PVM pVM, PPDMCRITSECTINT pCritSect, PPDMCRITSECTINT pPrev, bool fFinal)
250	{
251	/*
252	* Assert free waiters and so on (c&p from RTCritSectDelete).
253	*/
254	Assert(pCritSect->Core.u32Magic == RTCRITSECT_MAGIC);
255	Assert(pCritSect->Core.cNestings == 0);
256	Assert(pCritSect->Core.cLockers == -1);
257	Assert(pCritSect->Core.NativeThreadOwner == NIL_RTNATIVETHREAD);
258	Assert(RTCritSectIsOwner(&pVM->pdm.s.MiscCritSect));
259
260	/*
261	* Unlink it.
262	*/
263	if (pPrev)
264	pPrev->pNext = pCritSect->pNext;
265	else
266	pVM->pdm.s.pCritSects = pCritSect->pNext;
267
268	/*
269	* Delete it (parts taken from RTCritSectDelete).
270	* In case someone is waiting we'll signal the semaphore cLockers + 1 times.
271	*/
272	ASMAtomicWriteU32(&pCritSect->Core.u32Magic, 0);
273	SUPSEMEVENT hEvent = (SUPSEMEVENT)pCritSect->Core.EventSem;
274	pCritSect->Core.EventSem = NIL_RTSEMEVENT;
275	while (pCritSect->Core.cLockers-- >= 0)
276	SUPSemEventSignal(pVM->pSession, hEvent);
277	ASMAtomicWriteS32(&pCritSect->Core.cLockers, -1);
278	int rc = SUPSemEventClose(pVM->pSession, hEvent);
279	AssertRC(rc);
280	RTLockValidatorRecExclDestroy(&pCritSect->Core.pValidatorRec);
281	pCritSect->pNext = NULL;
282	pCritSect->pvKey = NULL;
283	pCritSect->pVMR3 = NULL;
284	pCritSect->pVMR0 = NIL_RTR0PTR;
285	pCritSect->pVMRC = NIL_RTRCPTR;
286	RTStrFree((char *)pCritSect->pszName);
287	pCritSect->pszName = NULL;
288	if (!fFinal)
289	{
290	STAMR3Deregister(pVM, &pCritSect->StatContentionRZLock);
291	STAMR3Deregister(pVM, &pCritSect->StatContentionRZUnlock);
292	STAMR3Deregister(pVM, &pCritSect->StatContentionR3);
293	#ifdef VBOX_WITH_STATISTICS
294	STAMR3Deregister(pVM, &pCritSect->StatLocked);
295	#endif
296	}
297	return rc;
298	}
299
300
301	/**
302	* Deletes all critical sections with a give initializer key.
303	*
304	* @returns VBox status code.
305	* The entire list is processed on failure, so we'll only
306	* return the first error code. This shouldn't be a problem
307	* since errors really shouldn't happen here.
308	* @param pVM The VM handle.
309	* @param pvKey The initializer key.
310	*/
311	static int pdmR3CritSectDeleteByKey(PVM pVM, void *pvKey)
312	{
313	/*
314	* Iterate the list and match key.
315	*/
316	int rc = VINF_SUCCESS;
317	PPDMCRITSECTINT pPrev = NULL;
318	RTCritSectEnter(&pVM->pdm.s.MiscCritSect);
319	PPDMCRITSECTINT pCur = pVM->pdm.s.pCritSects;
320	while (pCur)
321	{
322	if (pCur->pvKey == pvKey)
323	{
324	int rc2 = pdmR3CritSectDeleteOne(pVM, pCur, pPrev, false /* not final */);
325	AssertRC(rc2);
326	if (RT_FAILURE(rc2) && RT_SUCCESS(rc))
327	rc = rc2;
328	}
329
330	/* next */
331	pPrev = pCur;
332	pCur = pCur->pNext;
333	}
334	RTCritSectLeave(&pVM->pdm.s.MiscCritSect);
335	return rc;
336	}
337
338
339	/**
340	* Deletes all undeleted critical sections initalized by a given device.
341	*
342	* @returns VBox status code.
343	* @param pVM The VM handle.
344	* @param pDevIns The device handle.
345	*/
346	int pdmR3CritSectDeleteDevice(PVM pVM, PPDMDEVINS pDevIns)
347	{
348	return pdmR3CritSectDeleteByKey(pVM, pDevIns);
349	}
350
351
352	/**
353	* Deletes the critical section.
354	*
355	* @returns VBox status code.
356	* @param pCritSect The PDM critical section to destroy.
357	*/
358	VMMR3DECL(int) PDMR3CritSectDelete(PPDMCRITSECT pCritSect)
359	{
360	if (!RTCritSectIsInitialized(&pCritSect->s.Core))
361	return VINF_SUCCESS;
362
363	/*
364	* Find and unlink it.
365	*/
366	PVM pVM = pCritSect->s.pVMR3;
367	AssertReleaseReturn(pVM, VERR_INTERNAL_ERROR);
368	PPDMCRITSECTINT pPrev = NULL;
369	RTCritSectEnter(&pVM->pdm.s.MiscCritSect);
370	PPDMCRITSECTINT pCur = pVM->pdm.s.pCritSects;
371	while (pCur)
372	{
373	if (pCur == &pCritSect->s)
374	{
375	int rc = pdmR3CritSectDeleteOne(pVM, pCur, pPrev, false /* not final */);
376	RTCritSectLeave(&pVM->pdm.s.MiscCritSect);
377	return rc;
378	}
379
380	/* next */
381	pPrev = pCur;
382	pCur = pCur->pNext;
383	}
384	RTCritSectLeave(&pVM->pdm.s.MiscCritSect);
385	AssertReleaseMsgFailed(("pCritSect=%p wasn't found!\n", pCritSect));
386	return VERR_INTERNAL_ERROR;
387	}
388
389
390	/**
391	* Gets the name of the critical section.
392	*
393	*
394	* @returns Pointer to the critical section name (read only) on success,
395	* NULL on failure (invalid critical section).
396	* @param pCritSect The critical section.
397	*/
398	VMMR3DECL(const char *) PDMR3CritSectName(PCPDMCRITSECT pCritSect)
399	{
400	AssertPtrReturn(pCritSect, NULL);
401	AssertReturn(pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC, NULL);
402	return pCritSect->s.pszName;
403	}
404
405
406	/**
407	* Yield the critical section if someone is waiting on it.
408	*
409	* When yielding, we'll leave the critical section and try to make sure the
410	* other waiting threads get a chance of entering before we reclaim it.
411	*
412	* @retval true if yielded.
413	* @retval false if not yielded.
414	* @param pCritSect The critical section.
415	*/
416	VMMR3DECL(bool) PDMR3CritSectYield(PPDMCRITSECT pCritSect)
417	{
418	AssertPtrReturn(pCritSect, false);
419	AssertReturn(pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC, false);
420	Assert(pCritSect->s.Core.NativeThreadOwner == RTThreadNativeSelf());
421
422	/* No recursion allowed here. */
423	int32_t const cNestings = pCritSect->s.Core.cNestings;
424	AssertReturn(cNestings == 1, false);
425
426	int32_t const cLockers = ASMAtomicReadS32(&pCritSect->s.Core.cLockers);
427	if (cLockers < cNestings)
428	return false;
429
430	#ifdef PDMCRITSECT_STRICT
431	RTLOCKVALSRCPOS const SrcPos = pCritSect->s.Core.pValidatorRec->SrcPos;
432	#endif
433	PDMCritSectLeave(pCritSect);
434
435	/*
436	* If we're lucky, then one of the waiters has entered the lock already.
437	* We spin a little bit in hope for this to happen so we can avoid the
438	* yield deatour.
439	*/
440	if (ASMAtomicUoReadS32(&pCritSect->s.Core.cNestings) == 0)
441	{
442	int cLoops = 20;
443	while ( cLoops > 0
444	&& ASMAtomicUoReadS32(&pCritSect->s.Core.cNestings) == 0
445	&& ASMAtomicUoReadS32(&pCritSect->s.Core.cLockers) >= 0)
446	{
447	ASMNopPause();
448	cLoops--;
449	}
450	if (cLoops == 0)
451	RTThreadYield();
452	}
453
454	#ifdef PDMCRITSECT_STRICT
455	int rc = PDMCritSectEnterDebug(pCritSect, VERR_INTERNAL_ERROR,
456	SrcPos.uId, SrcPos.pszFile, SrcPos.uLine, SrcPos.pszFunction);
457	#else
458	int rc = PDMCritSectEnter(pCritSect, VERR_INTERNAL_ERROR);
459	#endif
460	AssertLogRelRC(rc);
461	return true;
462	}
463
464
465	/**
466	* Schedule a event semaphore for signalling upon critsect exit.
467	*
468	* @returns VINF_SUCCESS on success.
469	* @returns VERR_TOO_MANY_SEMAPHORES if an event was already scheduled.
470	* @returns VERR_NOT_OWNER if we're not the critsect owner.
471	* @returns VERR_SEM_DESTROYED if RTCritSectDelete was called while waiting.
472	*
473	* @param pCritSect The critical section.
474	* @param EventToSignal The semapore that should be signalled.
475	*/
476	VMMR3DECL(int) PDMR3CritSectScheduleExitEvent(PPDMCRITSECT pCritSect, RTSEMEVENT EventToSignal)
477	{
478	Assert(EventToSignal != NIL_RTSEMEVENT);
479	if (RT_UNLIKELY(!RTCritSectIsOwner(&pCritSect->s.Core)))
480	return VERR_NOT_OWNER;
481	if (RT_LIKELY( pCritSect->s.EventToSignal == NIL_RTSEMEVENT
482	\|\| pCritSect->s.EventToSignal == EventToSignal))
483	{
484	pCritSect->s.EventToSignal = EventToSignal;
485	return VINF_SUCCESS;
486	}
487	return VERR_TOO_MANY_SEMAPHORES;
488	}
489
490
491	/**
492	* Counts the critical sections owned by the calling thread, optionally
493	* returning a comma separated list naming them.
494	*
495	* This is for diagnostic purposes only.
496	*
497	* @returns Lock count.
498	*
499	* @param pVM The VM handle.
500	* @param pszNames Where to return the critical section names.
501	* @param cbNames The size of the buffer.
502	*/
503	VMMR3DECL(uint32_t) PDMR3CritSectCountOwned(PVM pVM, char *pszNames, size_t cbNames)
504	{
505	/*
506	* Init the name buffer.
507	*/
508	size_t cchLeft = cbNames;
509	if (cchLeft)
510	{
511	cchLeft--;
512	pszNames[0] = pszNames[cchLeft] = '\0';
513	}
514
515	/*
516	* Iterate the critical sections.
517	*/
518	/* This is unsafe, but wtf. */
519	RTNATIVETHREAD const hNativeThread = RTThreadNativeSelf();
520	uint32_t cCritSects = 0;
521	for (PPDMCRITSECTINT pCur = pVM->pdm.s.pCritSects;
522	pCur;
523	pCur = pCur->pNext)
524	{
525	/* Same as RTCritSectIsOwner(). */
526	if (pCur->Core.NativeThreadOwner == hNativeThread)
527	{
528	cCritSects++;
529
530	/*
531	* Copy the name if there is space. Fun stuff.
532	*/
533	if (cchLeft)
534	{
535	/* try add comma. */
536	if (cCritSects != 1)
537	{
538	*pszNames++ = ',';
539	if (--cchLeft)
540	{
541	*pszNames++ = ' ';
542	cchLeft--;
543	}
544	}
545
546	/* try copy the name. */
547	if (cchLeft)
548	{
549	size_t const cchName = strlen(pCur->pszName);
550	if (cchName < cchLeft)
551	{
552	memcpy(pszNames, pCur->pszName, cchName);
553	pszNames += cchName;
554	cchLeft -= cchName;
555	}
556	else
557	{
558	if (cchLeft > 2)
559	{
560	memcpy(pszNames, pCur->pszName, cchLeft - 2);
561	pszNames += cchLeft - 2;
562	cchLeft = 2;
563	}
564	while (cchLeft-- > 0)
565	*pszNames++ = '+';
566	}
567	}
568	*pszNames = '\0';
569	}
570	}
571	}
572
573	return cCritSects;
574	}
575
576
577	/**
578	* Leave all critical sections the calling thread owns.
579	*
580	* @param pVM The VM handle.
581	*/
582	void PDMR3CritSectLeaveAll(PVM pVM)
583	{
584	RTNATIVETHREAD const hNativeSelf = RTThreadNativeSelf();
585
586	RTCritSectEnter(&pVM->pdm.s.MiscCritSect);
587	for (PPDMCRITSECTINT pCur = pVM->pdm.s.pCritSects;
588	pCur;
589	pCur = pCur->pNext)
590	{
591	while ( pCur->Core.NativeThreadOwner == hNativeSelf
592	&& pCur->Core.cNestings > 0)
593	PDMCritSectLeave((PPDMCRITSECT)pCur);
594	}
595	RTCritSectLeave(&pVM->pdm.s.MiscCritSect);
596	}
597

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source: vbox/trunk/src/VBox/VMM/PDMCritSect.cpp@ 28112

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