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/+/3688516
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81047}
a537be463f