Re: [PATCH v4 0/5] mm: batch TLB flushing for dirty folios in vmscan

[Andrew Morton]

On Mon, 25 May 2026 22:57:16 +0800 Zhang Peng <zippermonkey@xxxxxxxxxx> wrote:

> This series introduces batch TLB flushing optimization for dirty folios
> during memory reclaim, aiming to reduce IPI overhead on multi-core systems.

So often we see such good results from batching things.

> ...
> 
> Testing
> -------
> The benchmark script uses stress-ng to compare TLB shootdown behavior before and
> after this patch. It constrains a stress-ng workload via memcg to force reclaim
> through shrink_folio_list(), reporting TLB shootdowns and IPIs.
> 
> Core benchmark command: stress-ng --vm 16 --vm-bytes 2G --vm-keep --timeout 60
> 
> ==========================================================================
>                  batch_dirty_tlb_flush Benchmark Results
> ==========================================================================
>   Kernel: 7.0.0-rc1+   CPUs: 16
>   MemTotal: 31834M   SwapTotal: 8191M
>   memcg limit: 512M   alloc: 2G   workers: 16   duration: 60s
> --------------------------------------------------------------------------
> Metric                 Before        After             Delta (abs / %)
> --------------------------------------------------------------------------
> bogo ops/s             28238.63      35833.97          +7595.34 (+26.9%)
> TLB shootdowns         55428953      17621697          -37807256 (-68.2%)
> Function call IPIs     34073695      14498768          -19574927 (-57.4%)
> pgscan_anon (pages)    52856224      60252894          7396670 (+14.0%)
> pgsteal_anon (pages)   29004962      34054753          5049791 (+17.4%)
> --------------------------------------------------------------------------

Nice.

AI review asked a few things:
	https://sashiko.dev/#/patchset/20260525-batch-tlb-flush-v4-0-83789d6abc00@xxxxxxxxxx

Thanks.  I'll take no action at this time - there's no review yet and we're at
-rc5.