On Thu, 8 Feb 2024 02:32:54 +0000 chengming.zhou@xxxxxxxxx wrote:
> From: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
>
> We have to invalidate any duplicate entry even when !zswap_enabled
> since zswap can be disabled anytime. If the folio store success before,
> then got dirtied again but zswap disabled, we won't invalidate the old
> duplicate entry in the zswap_store(). So later lru writeback may
> overwrite the new data in swapfile.
>
> ...
>
> --- a/mm/zswap.c
> +++ b/mm/zswap.c
> @@ -1516,7 +1516,7 @@ bool zswap_store(struct folio *folio)
> if (folio_test_large(folio))
> return false;
>
> - if (!zswap_enabled || !tree)
> + if (!tree)
> return false;
>
> /*
> @@ -1531,6 +1531,10 @@ bool zswap_store(struct folio *folio)
> zswap_invalidate_entry(tree, dupentry);
> }
> spin_unlock(&tree->lock);
> +
> + if (!zswap_enabled)
> + return false;
> +
> objcg = get_obj_cgroup_from_folio(folio);
> if (objcg && !obj_cgroup_may_zswap(objcg)) {
> memcg = get_mem_cgroup_from_objcg(objcg);
OK, thanks.
I saw only one reject from mm-unstable patches. Your patch "mm/zswap:
make sure each swapfile always have zswap rb-tree" now does
--- a/mm/zswap.c~mm-zswap-make-sure-each-swapfile-always-have-zswap-rb-tree
+++ a/mm/zswap.c
@@ -1518,9 +1518,6 @@ bool zswap_store(struct folio *folio)
if (folio_test_large(folio))
return false;
- if (!tree)
- return false;
-
/*
* If this is a duplicate, it must be removed before attempting to store
* it, otherwise, if the store fails the old page won't be removed from
