On Thu, 8 Feb 2024 02:32:54 +0000 chengming.zhou@linux.dev wrote:
From: Chengming Zhou zhouchengming@bytedance.com
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