allocate() — netty Function Reference

Architecture documentation for the allocate() function in PoolChunk.java from the netty codebase.

Function java Buffer Telemetry calls 5 called by 1

Entity Profile

Buffer→ Telemetry→ allocate() — netty Function Reference

Dependency Diagram

graph TD
  dc4b66ae_8f51_844d_74c5_b56fbafe898a["allocate()"]
  271be16e_fb25_9fe6_0749_cf5dd80dd903["PoolChunk"]
  dc4b66ae_8f51_844d_74c5_b56fbafe898a -->|defined in| 271be16e_fb25_9fe6_0749_cf5dd80dd903
  de510c10_913b_9792_3aa7_159e623d5dd8["allocateSubpage()"]
  de510c10_913b_9792_3aa7_159e623d5dd8 -->|calls| dc4b66ae_8f51_844d_74c5_b56fbafe898a
  84c148a2_d160_9465_4de0_96875dcb9627["isSubpage()"]
  dc4b66ae_8f51_844d_74c5_b56fbafe898a -->|calls| 84c148a2_d160_9465_4de0_96875dcb9627
  0a6285e7_f5a0_2309_9441_672954c343b9["initBufWithSubpage()"]
  dc4b66ae_8f51_844d_74c5_b56fbafe898a -->|calls| 0a6285e7_f5a0_2309_9441_672954c343b9
  de510c10_913b_9792_3aa7_159e623d5dd8["allocateSubpage()"]
  dc4b66ae_8f51_844d_74c5_b56fbafe898a -->|calls| de510c10_913b_9792_3aa7_159e623d5dd8
  ff51bcad_2a8e_9ef1_b286_8e676953d24e["allocateRun()"]
  dc4b66ae_8f51_844d_74c5_b56fbafe898a -->|calls| ff51bcad_2a8e_9ef1_b286_8e676953d24e
  6dc0c69f_ef55_2ceb_be1e_ae840dbf3fed["initBuf()"]
  dc4b66ae_8f51_844d_74c5_b56fbafe898a -->|calls| 6dc0c69f_ef55_2ceb_be1e_ae840dbf3fed
  style dc4b66ae_8f51_844d_74c5_b56fbafe898a fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

buffer/src/main/java/io/netty/buffer/PoolChunk.java lines 325–368

    boolean allocate(PooledByteBuf<T> buf, int reqCapacity, int sizeIdx, PoolThreadCache cache) {
        final long handle;
        if (sizeIdx <= arena.sizeClass.smallMaxSizeIdx) {
            final PoolSubpage<T> nextSub;
            // small
            // Obtain the head of the PoolSubPage pool that is owned by the PoolArena and synchronize on it.
            // This is need as we may add it back and so alter the linked-list structure.
            PoolSubpage<T> head = arena.smallSubpagePools[sizeIdx];
            head.lock();
            try {
                nextSub = head.next;
                if (nextSub != head) {
                    assert nextSub.doNotDestroy && nextSub.elemSize == arena.sizeClass.sizeIdx2size(sizeIdx) :
                            "doNotDestroy=" + nextSub.doNotDestroy + ", elemSize=" + nextSub.elemSize + ", sizeIdx=" +
                                    sizeIdx;
                    handle = nextSub.allocate();
                    assert handle >= 0;
                    assert isSubpage(handle);
                    nextSub.chunk.initBufWithSubpage(buf, null, handle, reqCapacity, cache, false);
                    return true;
                }
                handle = allocateSubpage(sizeIdx, head);
                if (handle < 0) {
                    return false;
                }
                assert isSubpage(handle);
            } finally {
                head.unlock();
            }
        } else {
            // normal
            // runSize must be multiple of pageSize
            int runSize = arena.sizeClass.sizeIdx2size(sizeIdx);
            handle = allocateRun(runSize);
            if (handle < 0) {
                return false;
            }
            assert !isSubpage(handle);
        }

        ByteBuffer nioBuffer = cachedNioBuffers != null? cachedNioBuffers.pollLast() : null;
        initBuf(buf, nioBuffer, handle, reqCapacity, cache, false);
        return true;
    }