VirtualBox

source: vbox/trunk/src/VBox/VMM/PDMCritSect.cpp@ 22309

Last change on this file since 22309 was 20753, checked in by vboxsync, 15 years ago

VMM: Added PDMR3CritSectLeaveAll for bulk unlocking during guru meditation.
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1/* $Id: PDMCritSect.cpp 20753 2009-06-21 23:11:24Z 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/string.h>
38#include <iprt/thread.h>
39
40
41/*******************************************************************************
42* Internal Functions *
43*******************************************************************************/
44static int pdmR3CritSectDeleteOne(PVM pVM, PPDMCRITSECTINT pCritSect, PPDMCRITSECTINT pPrev, bool fFinal);
45
46
47
48/**
49 * Initializes the critical section subcomponent.
50 *
51 * @returns VBox status code.
52 * @param pVM The VM handle.
53 * @remark Not to be confused with PDMR3CritSectInit and pdmR3CritSectInitDevice which are
54 * for initializing a critical section.
55 */
56int pdmR3CritSectInit(PVM pVM)
57{
58 STAM_REG(pVM, &pVM->pdm.s.StatQueuedCritSectLeaves, STAMTYPE_COUNTER, "/PDM/QueuedCritSectLeaves", STAMUNIT_OCCURENCES,
59 "Number of times a critical section leave requesed needed to be queued for ring-3 execution.");
60 return VINF_SUCCESS;
61}
62
63
64/**
65 * Relocates all the critical sections.
66 *
67 * @param pVM The VM handle.
68 */
69void pdmR3CritSectRelocate(PVM pVM)
70{
71 RTCritSectEnter(&pVM->pdm.s.MiscCritSect);
72 for (PPDMCRITSECTINT pCur = pVM->pdm.s.pCritSects;
73 pCur;
74 pCur = pCur->pNext)
75 pCur->pVMRC = pVM->pVMRC;
76 RTCritSectLeave(&pVM->pdm.s.MiscCritSect);
77}
78
79
80/**
81 * Deletes all remaining critical sections.
82 *
83 * This is called at the end of the termination process.
84 *
85 * @returns VBox status.
86 * First error code, rest is lost.
87 * @param pVM The VM handle.
88 * @remark Don't confuse this with PDMR3CritSectDelete.
89 */
90VMMDECL(int) PDMR3CritSectTerm(PVM pVM)
91{
92 int rc = VINF_SUCCESS;
93 RTCritSectEnter(&pVM->pdm.s.MiscCritSect);
94 while (pVM->pdm.s.pCritSects)
95 {
96 int rc2 = pdmR3CritSectDeleteOne(pVM, pVM->pdm.s.pCritSects, NULL, true /* final */);
97 AssertRC(rc2);
98 if (RT_FAILURE(rc2) && RT_SUCCESS(rc))
99 rc = rc2;
100 }
101 RTCritSectLeave(&pVM->pdm.s.MiscCritSect);
102 RTCritSectDelete(&pVM->pdm.s.MiscCritSect);
103 return rc;
104}
105
106
107
108/**
109 * Initalizes a critical section and inserts it into the list.
110 *
111 * @returns VBox status code.
112 * @param pVM The Vm handle.
113 * @param pCritSect The critical section.
114 * @param pvKey The owner key.
115 * @param pszName The name of the critical section (for statistics).
116 */
117static int pdmR3CritSectInitOne(PVM pVM, PPDMCRITSECTINT pCritSect, void *pvKey, const char *pszName)
118{
119 VM_ASSERT_EMT(pVM);
120
121 /*
122 * Allocate the semaphore.
123 */
124 AssertCompile(sizeof(SUPSEMEVENT) == sizeof(pCritSect->Core.EventSem));
125 int rc = SUPSemEventCreate(pVM->pSession, (PSUPSEMEVENT)&pCritSect->Core.EventSem);
126 if (RT_SUCCESS(rc))
127 {
128 /*
129 * Initialize the structure (first bit is c&p from RTCritSectInitEx).
130 */
131 pCritSect->Core.u32Magic = RTCRITSECT_MAGIC;
132 pCritSect->Core.fFlags = 0;
133 pCritSect->Core.cNestings = 0;
134 pCritSect->Core.cLockers = -1;
135 pCritSect->Core.NativeThreadOwner = NIL_RTNATIVETHREAD;
136 pCritSect->Core.Strict.ThreadOwner = NIL_RTTHREAD;
137 pCritSect->Core.Strict.pszEnterFile = NULL;
138 pCritSect->Core.Strict.u32EnterLine = 0;
139 pCritSect->Core.Strict.uEnterId = 0;
140 pCritSect->pVMR3 = pVM;
141 pCritSect->pVMR0 = pVM->pVMR0;
142 pCritSect->pVMRC = pVM->pVMRC;
143 pCritSect->pvKey = pvKey;
144 pCritSect->EventToSignal = NIL_RTSEMEVENT;
145 pCritSect->pNext = pVM->pdm.s.pCritSects;
146 pCritSect->pszName = RTStrDup(pszName);
147 pVM->pdm.s.pCritSects = pCritSect;
148 STAMR3RegisterF(pVM, &pCritSect->StatContentionRZLock, STAMTYPE_COUNTER, STAMVISIBILITY_ALWAYS, STAMUNIT_OCCURENCES, NULL, "/PDM/CritSects/%s/ContentionRZLock", pszName);
149 STAMR3RegisterF(pVM, &pCritSect->StatContentionRZUnlock,STAMTYPE_COUNTER, STAMVISIBILITY_ALWAYS, STAMUNIT_OCCURENCES, NULL, "/PDM/CritSects/%s/ContentionRZUnlock", pszName);
150 STAMR3RegisterF(pVM, &pCritSect->StatContentionR3, STAMTYPE_COUNTER, STAMVISIBILITY_ALWAYS, STAMUNIT_OCCURENCES, NULL, "/PDM/CritSects/%s/ContentionR3", pszName);
151#ifdef VBOX_WITH_STATISTICS
152 STAMR3RegisterF(pVM, &pCritSect->StatLocked, STAMTYPE_PROFILE_ADV, STAMVISIBILITY_ALWAYS, STAMUNIT_TICKS_PER_OCCURENCE, NULL, "/PDM/CritSects/%s/Locked", pszName);
153#endif
154 }
155 return rc;
156}
157
158
159/**
160 * Initializes a PDM critical section for internal use.
161 *
162 * The PDM critical sections are derived from the IPRT critical sections, but
163 * works in GC as well.
164 *
165 * @returns VBox status code.
166 * @param pVM The VM handle.
167 * @param pDevIns Device instance.
168 * @param pCritSect Pointer to the critical section.
169 * @param pszName The name of the critical section (for statistics).
170 * @thread EMT(0)
171 */
172VMMR3DECL(int) PDMR3CritSectInit(PVM pVM, PPDMCRITSECT pCritSect, const char *pszName)
173{
174#if HC_ARCH_BITS == 64 && GC_ARCH_BITS == 32
175 AssertCompile(sizeof(pCritSect->padding) >= sizeof(pCritSect->s));
176#endif
177 Assert(RT_ALIGN_P(pCritSect, sizeof(uintptr_t)) == pCritSect);
178 return pdmR3CritSectInitOne(pVM, &pCritSect->s, pCritSect, pszName);
179}
180
181
182/**
183 * Initializes a PDM critical section.
184 *
185 * The PDM critical sections are derived from the IPRT critical sections, but
186 * works in GC as well.
187 *
188 * @returns VBox status code.
189 * @param pVM The VM handle.
190 * @param pDevIns Device instance.
191 * @param pCritSect Pointer to the critical section.
192 * @param pszName The name of the critical section (for statistics).
193 */
194int pdmR3CritSectInitDevice(PVM pVM, PPDMDEVINS pDevIns, PPDMCRITSECT pCritSect, const char *pszName)
195{
196 return pdmR3CritSectInitOne(pVM, &pCritSect->s, pDevIns, pszName);
197}
198
199
200/**
201 * Deletes one critical section.
202 *
203 * @returns Return code from RTCritSectDelete.
204 *
205 * @param pVM The VM handle.
206 * @param pCritSect The critical section.
207 * @param pPrev The previous critical section in the list.
208 * @param fFinal Set if this is the final call and statistics shouldn't be deregistered.
209 *
210 * @remarks Caller must've entered the MiscCritSect.
211 */
212static int pdmR3CritSectDeleteOne(PVM pVM, PPDMCRITSECTINT pCritSect, PPDMCRITSECTINT pPrev, bool fFinal)
213{
214 /*
215 * Assert free waiters and so on (c&p from RTCritSectDelete).
216 */
217 Assert(pCritSect->Core.u32Magic == RTCRITSECT_MAGIC);
218 Assert(pCritSect->Core.cNestings == 0);
219 Assert(pCritSect->Core.cLockers == -1);
220 Assert(pCritSect->Core.NativeThreadOwner == NIL_RTNATIVETHREAD);
221 Assert(RTCritSectIsOwner(&pVM->pdm.s.MiscCritSect));
222
223 /*
224 * Unlink it.
225 */
226 if (pPrev)
227 pPrev->pNext = pCritSect->pNext;
228 else
229 pVM->pdm.s.pCritSects = pCritSect->pNext;
230
231 /*
232 * Delete it (parts taken from RTCritSectDelete).
233 * In case someone is waiting we'll signal the semaphore cLockers + 1 times.
234 */
235 ASMAtomicWriteU32(&pCritSect->Core.u32Magic, 0);
236 SUPSEMEVENT hEvent = (SUPSEMEVENT)pCritSect->Core.EventSem;
237 pCritSect->Core.EventSem = NIL_RTSEMEVENT;
238 while (pCritSect->Core.cLockers-- >= 0)
239 SUPSemEventSignal(pVM->pSession, hEvent);
240 ASMAtomicWriteS32(&pCritSect->Core.cLockers, -1);
241 int rc = SUPSemEventClose(pVM->pSession, hEvent);
242 AssertRC(rc);
243 pCritSect->pNext = NULL;
244 pCritSect->pvKey = NULL;
245 pCritSect->pVMR3 = NULL;
246 pCritSect->pVMR0 = NIL_RTR0PTR;
247 pCritSect->pVMRC = NIL_RTRCPTR;
248 RTStrFree((char *)pCritSect->pszName);
249 pCritSect->pszName = NULL;
250 if (!fFinal)
251 {
252 STAMR3Deregister(pVM, &pCritSect->StatContentionRZLock);
253 STAMR3Deregister(pVM, &pCritSect->StatContentionRZUnlock);
254 STAMR3Deregister(pVM, &pCritSect->StatContentionR3);
255#ifdef VBOX_WITH_STATISTICS
256 STAMR3Deregister(pVM, &pCritSect->StatLocked);
257#endif
258 }
259 return rc;
260}
261
262
263/**
264 * Deletes all critical sections with a give initializer key.
265 *
266 * @returns VBox status code.
267 * The entire list is processed on failure, so we'll only
268 * return the first error code. This shouldn't be a problem
269 * since errors really shouldn't happen here.
270 * @param pVM The VM handle.
271 * @param pvKey The initializer key.
272 */
273static int pdmR3CritSectDeleteByKey(PVM pVM, void *pvKey)
274{
275 /*
276 * Iterate the list and match key.
277 */
278 int rc = VINF_SUCCESS;
279 PPDMCRITSECTINT pPrev = NULL;
280 RTCritSectEnter(&pVM->pdm.s.MiscCritSect);
281 PPDMCRITSECTINT pCur = pVM->pdm.s.pCritSects;
282 while (pCur)
283 {
284 if (pCur->pvKey == pvKey)
285 {
286 int rc2 = pdmR3CritSectDeleteOne(pVM, pCur, pPrev, false /* not final */);
287 AssertRC(rc2);
288 if (RT_FAILURE(rc2) && RT_SUCCESS(rc))
289 rc = rc2;
290 }
291
292 /* next */
293 pPrev = pCur;
294 pCur = pCur->pNext;
295 }
296 RTCritSectLeave(&pVM->pdm.s.MiscCritSect);
297 return rc;
298}
299
300
301/**
302 * Deletes all undeleted critical sections initalized by a given device.
303 *
304 * @returns VBox status code.
305 * @param pVM The VM handle.
306 * @param pDevIns The device handle.
307 */
308int pdmR3CritSectDeleteDevice(PVM pVM, PPDMDEVINS pDevIns)
309{
310 return pdmR3CritSectDeleteByKey(pVM, pDevIns);
311}
312
313
314/**
315 * Deletes the critical section.
316 *
317 * @returns VBox status code.
318 * @param pCritSect The PDM critical section to destroy.
319 */
320VMMR3DECL(int) PDMR3CritSectDelete(PPDMCRITSECT pCritSect)
321{
322 if (!RTCritSectIsInitialized(&pCritSect->s.Core))
323 return VINF_SUCCESS;
324
325 /*
326 * Find and unlink it.
327 */
328 PVM pVM = pCritSect->s.pVMR3;
329 AssertReleaseReturn(pVM, VERR_INTERNAL_ERROR);
330 PPDMCRITSECTINT pPrev = NULL;
331 RTCritSectEnter(&pVM->pdm.s.MiscCritSect);
332 PPDMCRITSECTINT pCur = pVM->pdm.s.pCritSects;
333 while (pCur)
334 {
335 if (pCur == &pCritSect->s)
336 {
337 int rc = pdmR3CritSectDeleteOne(pVM, pCur, pPrev, false /* not final */);
338 RTCritSectLeave(&pVM->pdm.s.MiscCritSect);
339 return rc;
340 }
341
342 /* next */
343 pPrev = pCur;
344 pCur = pCur->pNext;
345 }
346 RTCritSectLeave(&pVM->pdm.s.MiscCritSect);
347 AssertReleaseMsgFailed(("pCritSect=%p wasn't found!\n", pCritSect));
348 return VERR_INTERNAL_ERROR;
349}
350
351
352/**
353 * Gets the name of the critical section.
354 *
355 *
356 * @returns Pointer to the critical section name (read only) on success,
357 * NULL on failure (invalid critical section).
358 * @param pCritSect The critical section.
359 */
360VMMR3DECL(const char *) PDMR3CritSectName(PCPDMCRITSECT pCritSect)
361{
362 AssertPtrReturn(pCritSect, NULL);
363 AssertReturn(pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC, NULL);
364 return pCritSect->s.pszName;
365}
366
367
368/**
369 * Schedule a event semaphore for signalling upon critsect exit.
370 *
371 * @returns VINF_SUCCESS on success.
372 * @returns VERR_TOO_MANY_SEMAPHORES if an event was already scheduled.
373 * @returns VERR_NOT_OWNER if we're not the critsect owner.
374 * @returns VERR_SEM_DESTROYED if RTCritSectDelete was called while waiting.
375 *
376 * @param pCritSect The critical section.
377 * @param EventToSignal The semapore that should be signalled.
378 */
379VMMR3DECL(int) PDMR3CritSectScheduleExitEvent(PPDMCRITSECT pCritSect, RTSEMEVENT EventToSignal)
380{
381 Assert(EventToSignal != NIL_RTSEMEVENT);
382 if (RT_UNLIKELY(!RTCritSectIsOwner(&pCritSect->s.Core)))
383 return VERR_NOT_OWNER;
384 if (RT_LIKELY( pCritSect->s.EventToSignal == NIL_RTSEMEVENT
385 || pCritSect->s.EventToSignal == EventToSignal))
386 {
387 pCritSect->s.EventToSignal = EventToSignal;
388 return VINF_SUCCESS;
389 }
390 return VERR_TOO_MANY_SEMAPHORES;
391}
392
393
394/**
395 * Counts the critical sections owned by the calling thread, optionally
396 * returning a comma separated list naming them.
397 *
398 * This is for diagnostic purposes only.
399 *
400 * @returns Lock count.
401 *
402 * @param pVM The VM handle.
403 * @param pszNames Where to return the critical section names.
404 * @param cbNames The size of the buffer.
405 */
406VMMR3DECL(uint32_t) PDMR3CritSectCountOwned(PVM pVM, char *pszNames, size_t cbNames)
407{
408 /*
409 * Init the name buffer.
410 */
411 size_t cchLeft = cbNames;
412 if (cchLeft)
413 {
414 cchLeft--;
415 pszNames[0] = pszNames[cchLeft] = '\0';
416 }
417
418 /*
419 * Iterate the critical sections.
420 */
421 /* This is unsafe, but wtf. */
422 RTNATIVETHREAD const hNativeThread = RTThreadNativeSelf();
423 uint32_t cCritSects = 0;
424 for (PPDMCRITSECTINT pCur = pVM->pdm.s.pCritSects;
425 pCur;
426 pCur = pCur->pNext)
427 {
428 /* Same as RTCritSectIsOwner(). */
429 if (pCur->Core.NativeThreadOwner == hNativeThread)
430 {
431 cCritSects++;
432
433 /*
434 * Copy the name if there is space. Fun stuff.
435 */
436 if (cchLeft)
437 {
438 /* try add comma. */
439 if (cCritSects != 1)
440 {
441 *pszNames++ = ',';
442 if (--cchLeft)
443 {
444 *pszNames++ = ' ';
445 cchLeft--;
446 }
447 }
448
449 /* try copy the name. */
450 if (cchLeft)
451 {
452 size_t const cchName = strlen(pCur->pszName);
453 if (cchName < cchLeft)
454 {
455 memcpy(pszNames, pCur->pszName, cchName);
456 pszNames += cchName;
457 cchLeft -= cchName;
458 }
459 else
460 {
461 if (cchLeft > 2)
462 {
463 memcpy(pszNames, pCur->pszName, cchLeft - 2);
464 pszNames += cchLeft - 2;
465 cchLeft = 2;
466 }
467 while (cchLeft-- > 0)
468 *pszNames++ = '+';
469 }
470 }
471 *pszNames = '\0';
472 }
473 }
474 }
475
476 return cCritSects;
477}
478
479
480/**
481 * Leave all critical sections the calling thread owns.
482 *
483 * @param pVM The VM handle.
484 */
485void PDMR3CritSectLeaveAll(PVM pVM)
486{
487 RTNATIVETHREAD const hNativeSelf = RTThreadNativeSelf();
488
489 RTCritSectEnter(&pVM->pdm.s.MiscCritSect);
490 for (PPDMCRITSECTINT pCur = pVM->pdm.s.pCritSects;
491 pCur;
492 pCur = pCur->pNext)
493 {
494 while ( pCur->Core.NativeThreadOwner == hNativeSelf
495 && pCur->Core.cNestings > 0)
496 PDMCritSectLeave((PPDMCRITSECT)pCur);
497 }
498 RTCritSectLeave(&pVM->pdm.s.MiscCritSect);
499}
500
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