• Dominik Inführ's avatar
    [heap] Track unprotected chunks in LocalHeap · a537be46
    Dominik Inführ authored
    CodePageCollectionMemoryModificationScope now increases a per-thread
    counter and inserts unprotected code chunks into a thread-local set
    of chunks. This information is moved from Heap into LocalHeap.
    
    We can't use kMaxWriteUnprotectCounter on the unprotect counter on the
    MemoryChunk anymore, since e.g. for concurrent Sparkplug N threads might
    now allocate a code object on the same page and since
    CodePageCollectionMemoryModificationScope doesn't know about the
    other threads anymore, each thread has to increase that counter by 1.
    We DCHECK that nesting depth now in the scope's constructor instead.
    
    We still need to remove chunks from `unprotected_memory_chunks_` when
    freeing an executable MemoryChunk during GC. Fortunately we can still do
    this, since all threads are in a safepoint during GC and we can remove
    the chunk from each thread-local set without any synchronization.
    
    Bug: chromium:1330887
    Change-Id: Icefc61b8d8de113d8dcfb1cf64122d12dd9798c4
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3688516Reviewed-by: 's avatarMichael Lippautz <mlippautz@chromium.org>
    Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
    Reviewed-by: 's avatarIgor Sheludko <ishell@chromium.org>
    Cr-Commit-Position: refs/heads/main@{#81047}
    a537be46
safepoint.h 5.82 KB