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References: <20221128191616.1261026-1-nphamcs@gmail.com> <20230103045730.2ctv3n2ckzzmdzdx@snowball.t-8ch.de>
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From:   Nhat Pham <nphamcs@gmail.com>
Date:   Fri, 6 Jan 2023 12:32:04 -0800
Message-ID: <CAKEwX=MPxEsCJ8V8vNvMgXJ66Pq7qxnOX6S1sf97dc-oqaJfWQ@mail.gmail.com>
Subject: Re: [PATCH v7 0/6] Implement writeback for zsmalloc
To:     =?UTF-8?Q?Thomas_Wei=C3=9Fschuh?= <thomas@t-8ch.de>
Cc:     akpm@linux-foundation.org, hannes@cmpxchg.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, minchan@kernel.org,
        ngupta@vflare.org, senozhatsky@chromium.org, sjenning@redhat.com,
        ddstreet@ieee.org, vitaly.wool@konsulko.com, linux@weissschuh.net
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On Mon, Jan 2, 2023 at 8:57 PM Thomas Wei=C3=9Fschuh <thomas@t-8ch.de> wrot=
e:
>
> Hi,
>
> On Mon, Nov 28, 2022 at 11:16:09AM -0800, Nhat Pham wrote:
> > Unlike other zswap's allocators such as zbud or z3fold, zsmalloc
> > currently lacks the writeback mechanism. This means that when the zswap
> > pool is full, it will simply reject further allocations, and the pages
> > will be written directly to swap.
> >
> > This series of patches implements writeback for zsmalloc. When the zswa=
p
> > pool becomes full, zsmalloc will attempt to evict all the compressed
> > objects in the least-recently used zspages.
>
> Then this part of Documentation/admin-guide/mm/zswap.rst should probably
> also be updated at some point:
>
>     However, zsmalloc does not implement compressed page eviction, so
>     once zswap fills it cannot evict the oldest page, it can only reject
>     new pages.
>
> Thomas

Thanks for pointing this out, Thomas! I'll send a patch to update this.