Re: [PATCH v2 1/3] mm/zswap: don't return LRU_SKIP if we have dropped lru lock

[Yosry Ahmed]

On Sun, Jan 28, 2024 at 01:28:49PM +0000, Chengming Zhou wrote:
> LRU_SKIP can only be returned if we don't ever dropped lru lock, or
> we need to return LRU_RETRY to restart from the head of lru list.
> 
> Otherwise, the iteration might continue from a cursor position that
> was freed while the locks were dropped.

Does this warrant a stable backport?

> 
> Actually we may need to introduce another LRU_STOP to really terminate
> the ongoing shrinking scan process, when we encounter a warm page
> already in the swap cache. The current list_lru implementation
> doesn't have this function to early break from __list_lru_walk_one.
> 
> Fixes: b5ba474f3f51 ("zswap: shrink zswap pool based on memory pressure")
> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
> Reviewed-by: Nhat Pham <nphamcs@xxxxxxxxx>
> Signed-off-by: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>

Acked-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx>