Re: [PATCH 3/6] mm/zswap: stop lru list shrinking when encounter warm region

[Yosry Ahmed <yosryahmed@google.com>]

On Thu, Feb 01, 2024 at 03:49:03PM +0000, Chengming Zhou wrote:
> When the shrinker encounter an existing folio in swap cache, it means
> we are shrinking into the warmer region. We should terminate shrinking
> if we're in the dynamic shrinker context.
> 
> This patch add LRU_STOP to support this, to avoid overshrinking.
> 
> Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>

LGTM with one comment below.

Reviewed-by: Yosry Ahmed <yosryahmed@google.com>

> ---
>  include/linux/list_lru.h | 1 +
>  mm/list_lru.c            | 3 +++
>  mm/zswap.c               | 4 +++-
>  3 files changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/include/linux/list_lru.h b/include/linux/list_lru.h
> index f2882a820690..5633e970144b 100644
> --- a/include/linux/list_lru.h
> +++ b/include/linux/list_lru.h
> @@ -24,6 +24,7 @@ enum lru_status {
>  	LRU_SKIP,		/* item cannot be locked, skip */
>  	LRU_RETRY,		/* item not freeable. May drop the lock
>  				   internally, but has to return locked. */
> +	LRU_STOP,		/* stop lru list walking */

nit: Should we add "May drop the lock internally, but has to return
locked" like LRU_RETRY and LRU_REMOVED_RETRY?

>  };
>  
>  struct list_lru_one {
[..]