Re: [PATCH 3/5] mm/zswap: refactor out __zswap_load()

[Chengming Zhou]

On 2023/12/14 08:52, Yosry Ahmed wrote:
> On Tue, Dec 12, 2023 at 8:18 PM Chengming Zhou
> <zhouchengming@xxxxxxxxxxxxx> wrote:
>>
>> The zswap_load() and zswap_writeback_entry() have the same part that
>> decompress the data from zswap_entry to page, so refactor out the
>> common part as __zswap_load(entry, page).
>>
>> Signed-off-by: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
>> Reviewed-by: Nhat Pham <nphamcs@xxxxxxxxx>
> 
> On a second look, there a few nits here.
> 
> First I think it makes more sense to move this refactoring ahead of
> reusing destmem. Right now, we add the destmem reuse to zswap_load()
> only, then we do the refactor and zswap_writeback_entry() gets it
> automatically, so there is a slight change coming to
> zswap_writeback_entry() hidden in the refactoring patch.
> 
> Let's refactor out __zswap_load() first, then reuse destmem in it.

I tried but found that putting the __zswap_load() first would introduce
another failure case in zswap_writeback_entry(), since the temporary
memory allocation may fail.

So instead, I also move the dstmem reusing in zswap_writeback_entry() to
the dstmem reusing patch. Then this patch becomes having only refactoring.

Thanks.