Re: [PATCH 1/2] mm: vmscan: restore high-cpu watermark safety in kswapd

[Vlastimil Babka]

On 4/16/25 15:45, Johannes Weiner wrote:
> Vlastimil points out that commit a211c6550efc ("mm: page_alloc:
> defrag_mode kswapd/kcompactd watermarks") switched kswapd from
> zone_watermark_ok_safe() to the standard, percpu-cached version of
> reading free pages, thus dropping the watermark safety precautions for
> systems with high CPU counts (e.g. >212 cpus on 64G). Restore them.
> 
> Since zone_watermark_ok_safe() is no longer the right interface, and
> this was the last caller of the function anyway, open-code the
> zone_page_state_snapshot() conditional and delete the function.
> 
> Reported-by: Vlastimil Babka <vbabka@xxxxxxx>
> Fixes: a211c6550efc ("mm: page_alloc: defrag_mode kswapd/kcompactd watermarks")
> Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>

Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx>