linux-kernel - Re: [PATCH] Docs/admin-guide/mm/zswap: remove zsmalloc's lack of writeback warning

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Date:   Fri, 6 Jan 2023 14:03:40 -0800
From:   Nhat Pham <nphamcs@...il.com>
To:     corbet@....net
Cc:     hannes@...xchg.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org,
        kernel-team@...a.com, akpm@...ux-foundation.org,
        linux@...ssschuh.net
Subject: Re: [PATCH] Docs/admin-guide/mm/zswap: remove zsmalloc's lack of
 writeback warning

On Fri, Jan 6, 2023 at 2:00 PM Nhat Pham <nphamcs@...il.com> wrote:
>
> Writeback has been implemented for zsmalloc, so this warning no longer
> holds.
>
> Suggested-by: Thomas Weißschuh <linux@...ssschuh.net>
> Signed-off-by: Nhat Pham <nphamcs@...il.com>
> ---
>  Documentation/admin-guide/mm/zswap.rst | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/Documentation/admin-guide/mm/zswap.rst b/Documentation/admin-guide/mm/zswap.rst
> index f67de481c7f6..6dd74a18268b 100644
> --- a/Documentation/admin-guide/mm/zswap.rst
> +++ b/Documentation/admin-guide/mm/zswap.rst
> @@ -70,9 +70,7 @@ e.g. ``zswap.zpool=zbud``. It can also be changed at runtime using the sysfs
>  The zbud type zpool allocates exactly 1 page to store 2 compressed pages, which
>  means the compression ratio will always be 2:1 or worse (because of half-full
>  zbud pages).  The zsmalloc type zpool has a more complex compressed page
> -storage method, and it can achieve greater storage densities.  However,
> -zsmalloc does not implement compressed page eviction, so once zswap fills it
> -cannot evict the oldest page, it can only reject new pages.
> +storage method, and it can achieve greater storage densities.
>
>  When a swap page is passed from frontswap to zswap, zswap maintains a mapping
>  of the swap entry, a combination of the swap type and swap offset, to the zpool
> --
> 2.30.2
>

Link to the patch series:
https://lkml.org/lkml/2022/11/28/1140

And the suggestion:
https://lkml.org/lkml/2023/1/2/823