• Michael Lippautz's avatar
    cppgc: Limit sweeping on allocation if possible · 25c6d74e
    Michael Lippautz authored
    Align slow path allocation with V8 in that:
    1. Try to refill from the free list.
    2. Perform limited sweeping of a space if necessary and retry the free
       list.
    3. Try to expand the space.
    4. Perform full sweeping of a space if necessary and retry the free
       list.
    5. Finish sweeping fully as we would anyways do a GC at this point.
    6. Retry the free list again
    7. Try expanding again as finishing sweeping may have freed up pages.
    
    Specifically, this adresses a performance problem where we would fully
    sweep the whole heap, possibly causing 100ms of jank on allocation. In
    such cases the new approach maintains performance and stays fast at the
    expense of using more memory.
    
    Allocations usually find memory in 1.-3. Steps 4.-7. are slow paths
    that are definitely expensive but prevent failing with OOM.
    
    Bug: v8:13294
    Change-Id: I56133fa4cbbc74f8abcdec49c7e10125c2dbc3e9
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3899260
    Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
    Reviewed-by: 's avatarOmer Katz <omerkatz@chromium.org>
    Reviewed-by: 's avatarAnton Bikineev <bikineev@chromium.org>
    Cr-Commit-Position: refs/heads/main@{#83268}
    25c6d74e
object-allocator.h 8.58 KB