void
MXUser_DownSemaphore(MXUserSemaphore *sema) // IN/OUT:
{
int err;
ASSERT(sema);
MXUserValidateHeader(&sema->header, MXUSER_TYPE_SEMA);
Atomic_Inc(&sema->activeUserCount);
MXUserAcquisitionTracking(&sema->header, TRUE); // rank checking
if (vmx86_stats) {
VmTimeType start = 0;
Bool tryDownSuccess = FALSE;
MXUserAcquireStats *acquireStats;
acquireStats = Atomic_ReadPtr(&sema->acquireStatsMem);
if (LIKELY(acquireStats != NULL)) {
start = Hostinfo_SystemTimerNS();
}
err = MXUserTryDown(&sema->nativeSemaphore, &tryDownSuccess);
if (LIKELY(err == 0)) {
if (!tryDownSuccess) {
err = MXUserDown(&sema->nativeSemaphore);
}
}
if (LIKELY((err == 0) && (acquireStats != NULL))) {
MXUserHisto *histo;
VmTimeType value = Hostinfo_SystemTimerNS() - start;
MXUserAcquisitionSample(&acquireStats->data, TRUE,
!tryDownSuccess, value);
histo = Atomic_ReadPtr(&acquireStats->histo);
if (UNLIKELY(histo != NULL)) {
MXUserHistoSample(histo, value, GetReturnAddress());
}
}
} else {
err = MXUserDown(&sema->nativeSemaphore);
}
if (UNLIKELY(err != 0)) {
MXUserDumpAndPanic(&sema->header, "%s: Internal error (%d)\n",
__FUNCTION__, err);
}
MXUserReleaseTracking(&sema->header);
Atomic_Dec(&sema->activeUserCount);
}
static int
MXUserTimedDown(NativeSemaphore *sema, // IN:
uint32 msecWait, // IN:
Bool *downOccurred) // OUT:
{
uint64 nsecWait;
VmTimeType before;
kern_return_t err;
ASSERT_ON_COMPILE(KERN_SUCCESS == 0);
/*
* Work in nanoseconds. Time the semaphore_timedwait operation in case
* it is interrupted (KERN_ABORT). If it is, determine how much time is
* necessary to fulfill the specified wait time and retry with a new
* and appropriate timeout.
*/
nsecWait = 1000000ULL * (uint64) msecWait;
before = Hostinfo_SystemTimerNS();
do {
VmTimeType after;
mach_timespec_t ts;
ts.tv_sec = nsecWait / MXUSER_A_BILLION;
ts.tv_nsec = nsecWait % MXUSER_A_BILLION;
err = semaphore_timedwait(*sema, ts);
after = Hostinfo_SystemTimerNS();
if (err == KERN_SUCCESS) {
*downOccurred = TRUE;
} else {
*downOccurred = FALSE;
if (err == KERN_OPERATION_TIMED_OUT) {
/* Really timed out; no down occurred, no error */
err = KERN_SUCCESS;
} else {
if (err == KERN_ABORTED) {
VmTimeType duration = after - before;
if (duration < nsecWait) {
nsecWait -= duration;
before = after;
} else {
err = KERN_SUCCESS; // "timed out" anyway... no error
}
}
}
}
} while (nsecWait && (err == KERN_ABORTED));
return err;
}
void
MXUser_ReleaseRecLock(MXUserRecLock *lock) // IN/OUT:
{
ASSERT(lock);
MXUserValidateHeader(&lock->header, MXUSER_TYPE_REC);
ASSERT(Atomic_Read(&lock->refCount) > 0);
if (UNLIKELY(lock->vmmLock != NULL)) {
ASSERT(MXUserMX_UnlockRec);
(*MXUserMX_UnlockRec)(lock->vmmLock);
} else {
if (vmx86_stats) {
MXUserHeldStats *heldStats = Atomic_ReadPtr(&lock->heldStatsMem);
if (LIKELY(heldStats != NULL)) {
if (MXRecLockCount(&lock->recursiveLock) == 1) {
MXUserHeldStats *heldStats;
heldStats = Atomic_ReadPtr(&lock->heldStatsMem);
if (UNLIKELY(heldStats != NULL)) {
VmTimeType value;
MXUserHisto *histo = Atomic_ReadPtr(&heldStats->histo);
value = Hostinfo_SystemTimerNS() - heldStats->holdStart;
MXUserBasicStatsSample(&heldStats->data, value);
if (UNLIKELY(histo != NULL)) {
MXUserHistoSample(histo, value, GetReturnAddress());
}
}
}
}
}
if (vmx86_debug) {
if (MXRecLockCount(&lock->recursiveLock) == 0) {
MXUserDumpAndPanic(&lock->header,
"%s: Release of an unacquired recursive lock\n",
__FUNCTION__);
}
if (!MXRecLockIsOwner(&lock->recursiveLock)) {
MXUserDumpAndPanic(&lock->header,
"%s: Non-owner release of an recursive lock\n",
__FUNCTION__);
}
}
MXUserReleaseTracking(&lock->header);
MXRecLockRelease(&lock->recursiveLock);
}
}
void
MXUser_AcquireRecLock(MXUserRecLock *lock) // IN/OUT:
{
ASSERT(lock);
MXUserValidateHeader(&lock->header, MXUSER_TYPE_REC);
ASSERT(Atomic_Read(&lock->refCount) > 0);
if (UNLIKELY(lock->vmmLock != NULL)) {
ASSERT(MXUserMX_LockRec);
(*MXUserMX_LockRec)(lock->vmmLock);
} else {
/* Rank checking is only done on the first acquisition */
MXUserAcquisitionTracking(&lock->header, TRUE);
if (vmx86_stats) {
VmTimeType value = 0;
MXUserAcquireStats *acquireStats;
acquireStats = Atomic_ReadPtr(&lock->acquireStatsMem);
MXRecLockAcquire(&lock->recursiveLock,
(acquireStats == NULL) ? NULL : &value);
if (LIKELY(acquireStats != NULL)) {
if (MXRecLockCount(&lock->recursiveLock) == 1) {
MXUserHeldStats *heldStats;
MXUserHisto *histo;
MXUserAcquisitionSample(&acquireStats->data, TRUE,
value > acquireStats->data.contentionDurationFloor,
value);
histo = Atomic_ReadPtr(&acquireStats->histo);
if (UNLIKELY(histo != NULL)) {
MXUserHistoSample(histo, value, GetReturnAddress());
}
heldStats = Atomic_ReadPtr(&lock->heldStatsMem);
if (UNLIKELY(heldStats != NULL)) {
heldStats->holdStart = Hostinfo_SystemTimerNS();
}
}
}
} else {
MXRecLockAcquire(&lock->recursiveLock,
NULL); // non-stats
}
}
}
void
MXUser_AcquireExclLock(MXUserExclLock *lock) // IN/OUT:
{
ASSERT(lock);
MXUserValidateHeader(&lock->header, MXUSER_TYPE_EXCL);
MXUserAcquisitionTracking(&lock->header, TRUE);
if (vmx86_stats) {
VmTimeType value = 0;
MXUserStats *stats = Atomic_ReadPtr(&lock->statsMem);
MXRecLockAcquire(&lock->recursiveLock, (stats == NULL) ? NULL : &value);
if (LIKELY(stats != NULL)) {
MXUserHisto *histo;
MXUserAcquisitionSample(&stats->acquisitionStats, TRUE, value != 0,
value);
histo = Atomic_ReadPtr(&stats->acquisitionHisto);
if (UNLIKELY(histo != NULL)) {
MXUserHistoSample(histo, value, GetReturnAddress());
}
stats->holdStart = Hostinfo_SystemTimerNS();
}
} else {
MXRecLockAcquire(&lock->recursiveLock,
NULL); // non-stats
}
if (vmx86_debug && (MXRecLockCount(&lock->recursiveLock) > 1)) {
MXUserDumpAndPanic(&lock->header,
"%s: Acquire on an acquired exclusive lock\n",
__FUNCTION__);
}
}
void
MXUser_ReleaseExclLock(MXUserExclLock *lock) // IN/OUT:
{
ASSERT(lock);
MXUserValidateHeader(&lock->header, MXUSER_TYPE_EXCL);
if (vmx86_stats) {
MXUserStats *stats = Atomic_ReadPtr(&lock->statsMem);
if (LIKELY(stats != NULL)) {
MXUserHisto *histo;
VmTimeType value = Hostinfo_SystemTimerNS() - stats->holdStart;
MXUserBasicStatsSample(&stats->heldStats, value);
histo = Atomic_ReadPtr(&stats->heldHisto);
if (UNLIKELY(histo != NULL)) {
MXUserHistoSample(histo, value, GetReturnAddress());
}
}
}
if (vmx86_debug && !MXRecLockIsOwner(&lock->recursiveLock)) {
int lockCount = MXRecLockCount(&lock->recursiveLock);
MXUserDumpAndPanic(&lock->header,
"%s: Non-owner release of an %s exclusive lock\n",
__FUNCTION__,
lockCount == 0 ? "unacquired" : "acquired");
}
MXUserReleaseTracking(&lock->header);
MXRecLockRelease(&lock->recursiveLock);
}
void
MXUser_ReleaseRWLock(MXUserRWLock *lock) // IN/OUT:
{
HolderContext *myContext;
ASSERT(lock);
MXUserValidateHeader(&lock->header, MXUSER_TYPE_RW);
myContext = MXUserGetHolderContext(lock);
if (vmx86_stats) {
MXUserStats *stats = Atomic_ReadPtr(&lock->statsMem);
if (LIKELY(stats != NULL)) {
MXUserHisto *histo;
VmTimeType duration = Hostinfo_SystemTimerNS() - myContext->holdStart;
/*
* The statistics are not always atomically safe so protect them
* when necessary
*/
if ((myContext->state == RW_LOCKED_FOR_READ) && lock->useNative) {
MXRecLockAcquire(&lock->recursiveLock,
NULL); // non-stats
}
MXUserBasicStatsSample(&stats->heldStats, duration);
histo = Atomic_ReadPtr(&stats->heldHisto);
if (UNLIKELY(histo != NULL)) {
MXUserHistoSample(histo, duration, GetReturnAddress());
}
if ((myContext->state == RW_LOCKED_FOR_READ) && lock->useNative) {
MXRecLockRelease(&lock->recursiveLock);
}
}
}
if (UNLIKELY(myContext->state == RW_UNLOCKED)) {
uint32 lockCount = Atomic_Read(&lock->holderCount);
MXUserDumpAndPanic(&lock->header,
"%s: Non-owner release of an %s read-write lock\n",
__FUNCTION__,
lockCount == 0 ? "unacquired" : "acquired");
}
MXUserReleaseTracking(&lock->header);
Atomic_Dec(&lock->holderCount);
if (LIKELY(lock->useNative)) {
int err = MXUserNativeRWRelease(&lock->nativeLock,
myContext->state == RW_LOCKED_FOR_READ);
if (UNLIKELY(err != 0)) {
MXUserDumpAndPanic(&lock->header, "%s: Internal error (%d)\n",
__FUNCTION__, err);
}
} else {
ASSERT(Atomic_Read(&lock->holderCount) == 0);
MXRecLockRelease(&lock->recursiveLock);
}
myContext->state = RW_UNLOCKED;
}
static INLINE void
MXUserAcquisition(MXUserRWLock *lock, // IN/OUT:
Bool forRead) // IN:
{
HolderContext *myContext;
ASSERT(lock);
MXUserValidateHeader(&lock->header, MXUSER_TYPE_RW);
MXUserAcquisitionTracking(&lock->header, TRUE);
myContext = MXUserGetHolderContext(lock);
if (UNLIKELY(myContext->state != RW_UNLOCKED)) {
MXUserDumpAndPanic(&lock->header,
"%s: AcquireFor%s after AcquireFor%s\n",
__FUNCTION__,
forRead ? "Read" : "Write",
(myContext->state == RW_LOCKED_FOR_READ) ? "Read" :
"Write");
}
if (vmx86_stats) {
VmTimeType value;
MXUserStats *stats = Atomic_ReadPtr(&lock->statsMem);
if (lock->useNative) {
int err = 0;
Bool contended;
VmTimeType begin = Hostinfo_SystemTimerNS();
contended = MXUserNativeRWAcquire(&lock->nativeLock, forRead, &err);
value = contended ? Hostinfo_SystemTimerNS() - begin : 0;
if (UNLIKELY(err != 0)) {
MXUserDumpAndPanic(&lock->header, "%s: Error %d: contended %d\n",
__FUNCTION__, err, contended);
}
} else {
value = 0;
MXRecLockAcquire(&lock->recursiveLock,
(stats == NULL) ? NULL : &value);
}
if (LIKELY(stats != NULL)) {
MXUserHisto *histo;
/*
* The statistics are not atomically safe so protect them when
* necessary.
*/
if (forRead && lock->useNative) {
MXRecLockAcquire(&lock->recursiveLock,
NULL); // non-stats
}
MXUserAcquisitionSample(&stats->acquisitionStats, TRUE, value != 0,
value);
histo = Atomic_ReadPtr(&stats->acquisitionHisto);
if (UNLIKELY(histo != NULL)) {
MXUserHistoSample(histo, value, GetReturnAddress());
}
if (forRead && lock->useNative) {
MXRecLockRelease(&lock->recursiveLock);
}
myContext->holdStart = Hostinfo_SystemTimerNS();
}
} else {
if (LIKELY(lock->useNative)) {
int err = 0;
MXUserNativeRWAcquire(&lock->nativeLock, forRead, &err);
if (UNLIKELY(err != 0)) {
MXUserDumpAndPanic(&lock->header, "%s: Error %d\n",
__FUNCTION__, err);
}
} else {
MXRecLockAcquire(&lock->recursiveLock,
NULL); // non-stats
}
}
if (!forRead || !lock->useNative) {
ASSERT(Atomic_Read(&lock->holderCount) == 0);
}
Atomic_Inc(&lock->holderCount);
myContext->state = forRead ? RW_LOCKED_FOR_READ : RW_LOCKED_FOR_WRITE;
}
