[PATCH] D69675: [scudo][standalone] Fix Secondary bug w/ freelist

[Matt Morehouse via Phabricator via llvm-commits]

morehouse accepted this revision.
morehouse added inline comments.
This revision is now accepted and ready to land.


================
Comment at: compiler-rt/lib/scudo/standalone/secondary.h:141
+      if (ZeroContents)
+        memset(Ptr, 0, H.BlockEnd - reinterpret_cast<uptr>(Ptr));
+      return Ptr;
----------------
cryptoad wrote:
> morehouse wrote:
> > We currently release unconditionally in `deallocate`.  Does this zero-out the memory?
> > 
> > If so, we might only need to zero the first page here, not the whole allocation.
> You are correct, we could technically `memset` only the portion before the first page boundary.
> As you also said it's the current as I want to move the release to abide by `release_to_os_interval_ms`
> This would mean that eventually it could not have been released prior to reallocation.
> At this point I'd rather not take a shortcut because I feel it's going to come back to me later on.
Sounds good as long as the memset doesn't negate the perf improvemnt from using a free list.


Repository:
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  https://reviews.llvm.org/D69675/new/

https://reviews.llvm.org/D69675