Exemple #1
0
void LockerImpl<IsForMMAPV1>::lockMMAPV1Flush() {
    if (!IsForMMAPV1)
        return;

    // The flush lock always has a reference count of 1, because it is dropped at the end of
    // each write unit of work in order to allow the flush thread to run. See the comments in
    // the header for information on how the MMAP V1 journaling system works.
    LockRequest* globalLockRequest = _requests.find(resourceIdGlobal).objAddr();
    if (globalLockRequest->recursiveCount == 1) {
        invariant(LOCK_OK == lock(resourceIdMMAPV1Flush, _getModeForMMAPV1FlushLock()));
    }

    dassert(getLockMode(resourceIdMMAPV1Flush) == _getModeForMMAPV1FlushLock());
}
Exemple #2
0
void LockerImpl<IsForMMAPV1>::restoreLockState(OperationContext* opCtx,
                                               const Locker::LockSnapshot& state) {
    // We shouldn't be saving and restoring lock state from inside a WriteUnitOfWork.
    invariant(!inAWriteUnitOfWork());
    invariant(_modeForTicket == MODE_NONE);

    std::vector<OneLock>::const_iterator it = state.locks.begin();
    // If we locked the PBWM, it must be locked before the resourceIdGlobal resource.
    if (it != state.locks.end() && it->resourceId == resourceIdParallelBatchWriterMode) {
        invariant(LOCK_OK == lock(opCtx, it->resourceId, it->mode));
        it++;
    }

    invariant(LOCK_OK == lockGlobal(opCtx, state.globalMode));
    for (; it != state.locks.end(); it++) {
        // This is a sanity check that lockGlobal restored the MMAP V1 flush lock in the
        // expected mode.
        if (IsForMMAPV1 && (it->resourceId == resourceIdMMAPV1Flush)) {
            invariant(it->mode == _getModeForMMAPV1FlushLock());
        } else {
            invariant(LOCK_OK == lock(it->resourceId, it->mode));
        }
    }
    invariant(_modeForTicket != MODE_NONE);
}
Exemple #3
0
void LockerImpl<IsForMMAPV1>::endWriteUnitOfWork() {
    invariant(_wuowNestingLevel > 0);

    if (--_wuowNestingLevel > 0) {
        // Don't do anything unless leaving outermost WUOW.
        return;
    }

    LockRequestsMap::Iterator it = _requests.begin();
    while (_numResourcesToUnlockAtEndUnitOfWork > 0) {
        if (it->unlockPending) {
            invariant(!it.finished());
            _numResourcesToUnlockAtEndUnitOfWork--;
        }
        while (it->unlockPending > 0) {
            // If a lock is converted, unlock() may be called multiple times on a resource within
            // the same WriteUnitOfWork. All such unlock() requests must thus be fulfilled here.
            it->unlockPending--;
            unlock(it.key());
        }
        it.next();
    }

    // For MMAP V1, we need to yield the flush lock so that the flush thread can run
    if (IsForMMAPV1) {
        invariant(unlock(resourceIdMMAPV1Flush));
        invariant(LOCK_OK == lock(resourceIdMMAPV1Flush, _getModeForMMAPV1FlushLock()));
    }
}
Exemple #4
0
LockResult LockerImpl<IsForMMAPV1>::lockBegin(OperationContext* opCtx,
                                              ResourceId resId,
                                              LockMode mode) {
    dassert(!getWaitingResource().isValid());

    LockRequest* request;
    bool isNew = true;

    LockRequestsMap::Iterator it = _requests.find(resId);
    if (!it) {
        scoped_spinlock scopedLock(_lock);
        LockRequestsMap::Iterator itNew = _requests.insert(resId);
        itNew->initNew(this, &_notify);

        request = itNew.objAddr();
    } else {
        request = it.objAddr();
        isNew = false;
    }

    // If unlockPending is nonzero, that means a LockRequest already exists for this resource but
    // is planned to be released at the end of this WUOW due to two-phase locking. Rather than
    // unlocking the existing request, we can reuse it if the existing mode matches the new mode.
    if (request->unlockPending && isModeCovered(mode, request->mode)) {
        request->unlockPending--;
        if (!request->unlockPending) {
            _numResourcesToUnlockAtEndUnitOfWork--;
        }
        return LOCK_OK;
    }

    // Making this call here will record lock re-acquisitions and conversions as well.
    globalStats.recordAcquisition(_id, resId, mode);
    _stats.recordAcquisition(resId, mode);

    // Give priority to the full modes for global, parallel batch writer mode,
    // and flush lock so we don't stall global operations such as shutdown or flush.
    const ResourceType resType = resId.getType();
    if (resType == RESOURCE_GLOBAL || (IsForMMAPV1 && resId == resourceIdMMAPV1Flush)) {
        if (mode == MODE_S || mode == MODE_X) {
            request->enqueueAtFront = true;
            request->compatibleFirst = true;
        }
    } else if (resType != RESOURCE_MUTEX) {
        // This is all sanity checks that the global and flush locks are always be acquired
        // before any other lock has been acquired and they must be in sync with the nesting.
        DEV {
            const LockRequestsMap::Iterator itGlobal = _requests.find(resourceIdGlobal);
            invariant(itGlobal->recursiveCount > 0);
            invariant(itGlobal->mode != MODE_NONE);

            // Check the MMAP V1 flush lock is held in the appropriate mode
            invariant(!IsForMMAPV1 ||
                      isLockHeldForMode(resourceIdMMAPV1Flush, _getModeForMMAPV1FlushLock()));
        };
    }
Exemple #5
0
LockResult LockerImpl<IsForMMAPV1>::lockBegin(ResourceId resId, LockMode mode) {
    dassert(!getWaitingResource().isValid());

    LockRequest* request;
    bool isNew = true;

    LockRequestsMap::Iterator it = _requests.find(resId);
    if (!it) {
        scoped_spinlock scopedLock(_lock);
        LockRequestsMap::Iterator itNew = _requests.insert(resId);
        itNew->initNew(this, &_notify);

        request = itNew.objAddr();
    } else {
        request = it.objAddr();
        isNew = false;
    }

    // Making this call here will record lock re-acquisitions and conversions as well.
    globalStats.recordAcquisition(_id, resId, mode);
    _stats.recordAcquisition(resId, mode);

    // Give priority to the full modes for global, parallel batch writer mode,
    // and flush lock so we don't stall global operations such as shutdown or flush.
    const ResourceType resType = resId.getType();
    if (resType == RESOURCE_GLOBAL || (IsForMMAPV1 && resId == resourceIdMMAPV1Flush)) {
        if (mode == MODE_S || mode == MODE_X) {
            request->enqueueAtFront = true;
            request->compatibleFirst = true;
        }
    } else if (resType != RESOURCE_MUTEX) {
        // This is all sanity checks that the global and flush locks are always be acquired
        // before any other lock has been acquired and they must be in sync with the nesting.
        DEV {
            const LockRequestsMap::Iterator itGlobal = _requests.find(resourceIdGlobal);
            invariant(itGlobal->recursiveCount > 0);
            invariant(itGlobal->mode != MODE_NONE);

            // Check the MMAP V1 flush lock is held in the appropriate mode
            invariant(!IsForMMAPV1 ||
                      isLockHeldForMode(resourceIdMMAPV1Flush, _getModeForMMAPV1FlushLock()));
        };
    }
Exemple #6
0
void LockerImpl<IsForMMAPV1>::endWriteUnitOfWork() {
    invariant(_wuowNestingLevel > 0);

    if (--_wuowNestingLevel > 0) {
        // Don't do anything unless leaving outermost WUOW.
        return;
    }

    while (!_resourcesToUnlockAtEndOfUnitOfWork.empty()) {
        unlock(_resourcesToUnlockAtEndOfUnitOfWork.front());
        _resourcesToUnlockAtEndOfUnitOfWork.pop();
    }

    // For MMAP V1, we need to yield the flush lock so that the flush thread can run
    if (IsForMMAPV1) {
        invariant(unlock(resourceIdMMAPV1Flush));
        invariant(LOCK_OK == lock(resourceIdMMAPV1Flush, _getModeForMMAPV1FlushLock()));
    }
}