On 2024/2/9 05:09, Andrew Morton wrote:
> 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
It's correct. Thanks!
The other patch that includes optimization and cleanup is updated based on
mm-unstable and just resend:
https://lore.kernel.org/all/20240209044112.3883835-1-chengming.zhou@xxxxxxxxx/
>
> --- 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
>
>
