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Date:   Thu, 8 Jun 2023 12:02:30 -0400
From:   Johannes Weiner <hannes@cmpxchg.org>
To:     Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc:     vitaly.wool@konsulko.com, minchan@kernel.org,
        senozhatsky@chromium.org, yosryahmed@google.com,
        linux-mm@kvack.org, ddstreet@ieee.org, sjenning@redhat.com,
        nphamcs@gmail.com, akpm@linux-foundation.org,
        linux-kernel@vger.kernel.org, kernel-team@meta.com
Subject: Re: [RFC PATCH v2 2/7] mm: zswap: remove page reclaim logic from zbud
Message-ID: <20230608160230.GB352940@cmpxchg.org>
References: <20230606145611.704392-1-cerasuolodomenico@gmail.com>
 <20230606145611.704392-3-cerasuolodomenico@gmail.com>
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In-Reply-To: <20230606145611.704392-3-cerasuolodomenico@gmail.com>
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Hi Domenico,

On Tue, Jun 06, 2023 at 04:56:06PM +0200, Domenico Cerasuolo wrote:
> With the recent enhancement to zswap enabling direct page writeback, the
> need for the shrink code in zbud has become obsolete. As a result, this
> commit removes the page reclaim logic from zbud entirely.
> 
> Signed-off-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com>

I find the changelog a bit difficult to understand. How about:

Switch zbud to the new generic zswap LRU and remove its custom
implementation.

> @@ -585,7 +425,7 @@ static struct zpool_driver zbud_zpool_driver = {
>  	.destroy =	zbud_zpool_destroy,
>  	.malloc =	zbud_zpool_malloc,
>  	.free =		zbud_zpool_free,
> -	.shrink =	zbud_zpool_shrink,
> +	.shrink =	NULL,
>  	.map =		zbud_zpool_map,
>  	.unmap =	zbud_zpool_unmap,
>  	.total_size =	zbud_zpool_total_size,

Like Minchan pointed out in the zsmalloc patch, you can just remove
the line as the member is NULL by default.

With that, please add:

Acked-by: Johannes Weiner <hannes@cmpxchg.org>