Re: [PATCH mm-unstable v2 00/10] mm/kvm: locklessly clear the accessed bit

From: Paolo Bonzini
Date: Fri Jun 09 2023 - 05:18:31 EST


On 5/27/23 01:44, Yu Zhao wrote:
TLDR
====
This patchset adds a fast path to clear the accessed bit without
taking kvm->mmu_lock. It can significantly improve the performance of
guests when the host is under heavy memory pressure.

ChromeOS has been using a similar approach [1] since mid 2021 and it
was proven successful on tens of millions devices.

This v2 addressed previous requests [2] on refactoring code, removing
inaccurate/redundant texts, etc.

[1]https://crrev.com/c/2987928
[2]https://lore.kernel.org/r/20230217041230.2417228-1-yuzhao@xxxxxxxxxx/

From the KVM point of view the patches look good (though I wouldn't mind if Nicholas took a look at the ppc part). Jason's comment on the MMU notifier side are promising as well. Can you send v3 with Oliver's comments addressed?

Thanks,

Paolo