예제 #1
0
        /// <summary>
        /// Called to return a block to the pool. Once Return has been called the memory no longer belongs to the caller, and
        /// Very Bad Things will happen if the memory is read of modified subsequently. If a caller fails to call Return and the
        /// block tracking object is garbage collected, the block tracking object's finalizer will automatically re-create and return
        /// a new tracking object into the pool. This will only happen if there is a bug in the server, however it is necessary to avoid
        /// leaving "dead zones" in the slab due to lost block tracking objects.
        /// </summary>
        /// <param name="block">The block to return. It must have been acquired by calling Lease on the same memory pool instance.</param>
        internal void Return(MemoryPoolBlock block)
        {
#if BLOCK_LEASE_TRACKING
            Debug.Assert(block.Pool == this, "Returned block was not leased from this pool");
            Debug.Assert(block.IsLeased, $"Block being returned to pool twice: {block.Leaser}{Environment.NewLine}");
            block.IsLeased = false;
#endif

            if (!_isDisposed)
            {
                _blocks.Enqueue(block);
            }
            else
            {
                GC.SuppressFinalize(block);
            }
        }
예제 #2
0
        /// <summary>
        /// Internal method called when a block is requested and the pool is empty. It allocates one additional slab, creates all of the
        /// block tracking objects, and adds them all to the pool.
        /// </summary>
        private MemoryPoolBlock AllocateSlab()
        {
            var slab = MemoryPoolSlab.Create(_slabLength);

            _slabs.Push(slab);

            var basePtr = slab.NativePointer;
            // Page align the blocks
            var offset = (int)((((ulong)basePtr + (uint)_blockSize - 1) & ~((uint)_blockSize - 1)) - (ulong)basePtr);

            // Ensure page aligned
            Debug.Assert(((ulong)basePtr + (uint)offset) % _blockSize == 0);

            var blockCount = (_slabLength - offset) / _blockSize;

            Interlocked.Add(ref _totalAllocatedBlocks, blockCount);

            MemoryPoolBlock block = null;

            for (int i = 0; i < blockCount; i++)
            {
                block = new MemoryPoolBlock(this, slab, offset, _blockSize);

                if (i != blockCount - 1) // last block
                {
#if BLOCK_LEASE_TRACKING
                    block.IsLeased = true;
#endif
                    Return(block);
                }

                offset += _blockSize;
            }

            return(block);
        }