Re: [PATCH] mm/zswap: reduce the size of the compression buffer to a single page

[Nhat Pham]

On Wed, Aug 20, 2025 at 11:15 AM Nhat Pham <nphamcs@xxxxxxxxx> wrote:
>
> Reduce the compression buffer size from 2 * PAGE_SIZE to only one page,
> as the compression output (in the success case) should not exceed the
> length of the input.
>
> In the past, Chengming tried to reduce the compression buffer size, but
> ran into issues with the LZO algorithm (see [2]). Herbert Xu reported
> that the issue has been fixed (see [3]). Now we should have the
> guarantee that compressors' output should not exceed one page in the
> success case, and the algorithm will just report failure otherwise.
>
> With this patch, we save one page per cpu (per compression algorithm).
>
> [1]: https://lore.kernel.org/linux-mm/20231213-zswap-dstmem-v4-1-f228b059dd89@xxxxxxxxxxxxx/
> [2]: https://lore.kernel.org/lkml/0000000000000b05cd060d6b5511@xxxxxxxxxx/
> [3]: https://lore.kernel.org/linux-mm/aKUmyl5gUFCdXGn-@xxxxxxxxxxxxxxxxxxx/
>
> Co-developed-by: Chengming Zhou <chengming.zhou@xxxxxxxxx>
> Signed-off-by: Chengming Zhou <chengming.zhou@xxxxxxxxx>

The syntax changes very slightly, but this is functionally the same
patch as Chengming's. So I'm keeping all of his credit - please let me
know if I miss any proper accreditations. :)