Пример #1
0
    __declspec(noinline) void makeChunkWritable(size_t chunkno) { 
        scoped_lock lk(mapViewMutex);

        if( writable.get(chunkno) ) // double check lock
            return;

        // remap all maps in this chunk.  common case is a single map, but could have more than one with smallfiles or .ns files
        size_t chunkStart = chunkno * MemoryMappedFile::ChunkSize;
        size_t chunkNext = chunkStart + MemoryMappedFile::ChunkSize;

        scoped_lock lk2(privateViews._mutex());
        map<void*,DurableMappedFile*>::iterator i = privateViews.finditer_inlock((void*) (chunkNext-1));
        while( 1 ) {
            const pair<void*,DurableMappedFile*> x = *(--i);
            DurableMappedFile *mmf = x.second;
            if( mmf == 0 )
                break;

            size_t viewStart = (size_t) x.first;
            size_t viewEnd = (size_t) (viewStart + mmf->length());
            if( viewEnd <= chunkStart )
                break;

            size_t protectStart = max(viewStart, chunkStart);
            dassert(protectStart<chunkNext);

            size_t protectEnd = min(viewEnd, chunkNext);
            size_t protectSize = protectEnd - protectStart;
            dassert(protectSize>0&&protectSize<=MemoryMappedFile::ChunkSize);

            DWORD oldProtection;
            bool ok = VirtualProtect( reinterpret_cast<void*>( protectStart ),
                                      protectSize,
                                      PAGE_WRITECOPY,
                                      &oldProtection );
            if ( !ok ) {
                DWORD dosError = GetLastError();
                log() << "VirtualProtect for " << mmf->filename()
                        << " chunk " << chunkno
                        << " failed with " << errnoWithDescription( dosError )
                        << " (chunk size is " << protectSize
                        << ", address is " << hex << protectStart << dec << ")"
                        << " in mongo::makeChunkWritable, terminating"
                        << endl;
                fassertFailed( 16362 );
            }
        }

        writable.set(chunkno);
    }
Пример #2
0
 /** notification on unmapping so we can clear writable bits */
 void MemoryMappedFile::clearWritableBits(void *p) {
     for( unsigned i = ((size_t)p)/ChunkSize; i <= (((size_t)p)+len)/ChunkSize; i++ ) {
         writable.clear(i);
         verify( !writable.get(i) );
     }
 }
Пример #3
0
    __declspec(noinline) void makeChunkWritable(size_t chunkno) { 
        scoped_lock lk(mapViewMutex);

        if( writable.get(chunkno) ) // double check lock
            return;

        // remap all maps in this chunk.  common case is a single map, but could have more than one with smallfiles or .ns files
        size_t chunkStart = chunkno * MemoryMappedFile::ChunkSize;
        size_t chunkNext = chunkStart + MemoryMappedFile::ChunkSize;

        scoped_lock lk2(privateViews._mutex());
        map<void*,DurableMappedFile*>::iterator i = privateViews.finditer_inlock((void*) (chunkNext-1));
        while( 1 ) {
            const pair<void*,DurableMappedFile*> x = *(--i);
            DurableMappedFile *mmf = x.second;
            if( mmf == 0 )
                break;

            size_t viewStart = (size_t) x.first;
            size_t viewEnd = (size_t) (viewStart + mmf->length());
            if( viewEnd <= chunkStart )
                break;

            size_t protectStart = max(viewStart, chunkStart);
            dassert(protectStart<chunkNext);

            size_t protectEnd = min(viewEnd, chunkNext);
            size_t protectSize = protectEnd - protectStart;
            dassert(protectSize>0&&protectSize<=MemoryMappedFile::ChunkSize);

            DWORD oldProtection;
            bool ok = VirtualProtect( reinterpret_cast<void*>( protectStart ),
                                      protectSize,
                                      PAGE_WRITECOPY,
                                      &oldProtection );
            if ( !ok ) {
                DWORD dosError = GetLastError();

                if (dosError == ERROR_COMMITMENT_LIMIT) {
                    // System has run out of memory between physical RAM & page file, tell the user
                    BSONObjBuilder bb;

                    ProcessInfo p;
                    p.getExtraInfo(bb);

                    log() << "MongoDB has exhausted the system memory capacity.";
                    log() << "Current Memory Status: " << bb.obj().toString();
                }

                log() << "VirtualProtect for " << mmf->filename()
                        << " chunk " << chunkno
                        << " failed with " << errnoWithDescription( dosError )
                        << " (chunk size is " << protectSize
                        << ", address is " << hex << protectStart << dec << ")"
                        << " in mongo::makeChunkWritable, terminating"
                        << endl;
                fassertFailed( 16362 );
            }
        }

        writable.set(chunkno);
    }