[llvm-dev] Hitting kMaxNumChunks

Frederik Deweerdt via llvm-dev llvm-dev at lists.llvm.org
Wed Jan 24 12:10:56 PST 2018

On Wed, Jan 24, 2018 at 11:30 AM, Kostya Serebryany <kcc at google.com> wrote:
> +Aleksey, who has been dealing with the allocator recently.
> If you have a "((idx)) < ((kMaxNumChunks))" (0x40000, 0x40000)
> check failure, it means that you've allocated (and did not deallocate) 2^18
> large heap regions, each *at least* (2^17+1) bytes.
> This means, that you have live large heap chunks of 2^35 bytes (or more) in
> total, which is 32Gb.
> Does this sound correct?
Yes, it does. Our software typically allocates several hundred Gb, and
the size of the objects depend on the traffic. They would
realistically reach 2^17+1 bytes.

> If yes, yea, I guess we need to bump kMaxNumChunks
I'll increase the limit to 2^19 for our build, and I'll report the results here.


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