Re: [Regression] mm:slab/sheaves: severe performance regression in cross-CPU slab allocation

[Vlastimil Babka (SUSE)]

On 2/25/26 10:31, Ming Lei wrote:
> Hi Vlastimil,
> 
> On Wed, Feb 25, 2026 at 09:45:03AM +0100, Vlastimil Babka (SUSE) wrote:
>> On 2/24/26 21:27, Vlastimil Babka wrote:
>> > 
>> > It made sense to me not to refill sheaves when we can't reclaim, but I
>> > didn't anticipate this interaction with mempools. We could change them
>> > but there might be others using a similar pattern. Maybe it would be for
>> > the best to just drop that heuristic from __pcs_replace_empty_main()
>> > (but carefully as some deadlock avoidance depends on it, we might need
>> > to e.g. replace it with gfpflags_allow_spinning()). I'll send a patch
>> > tomorrow to test this theory, unless someone beats me to it (feel free to).
>> Could you try this then, please? Thanks!
> 
> Thanks for working on this issue!
> 
> Unfortunately the patch doesn't make a difference on IOPS in the perf test,
> follows the collected perf profile on linus tree(basically 7.0-rc1 with your patch):

what about this patch in addition to the previous one? Thanks.

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