linux-kernel - Re: [PATCH v1] zram: add size class equals check into recompression

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Message-Id: <20221024135909.e351a2dde4eea521f359a04b@linux-foundation.org>
Date:   Mon, 24 Oct 2022 13:59:09 -0700
From:   Andrew Morton <akpm@...ux-foundation.org>
To:     Alexey Romanov <avromanov@...rdevices.ru>
Cc:     <minchan@...nel.org>, <senozhatsky@...omium.org>,
        <ngupta@...are.org>, <linux-mm@...ck.org>,
        <linux-kernel@...r.kernel.org>, <kernel@...rdevices.ru>
Subject: Re: [PATCH v1] zram: add size class equals check into recompression

On Mon, 24 Oct 2022 15:09:42 +0300 Alexey Romanov <avromanov@...rdevices.ru> wrote:

> It makes no sense for us to recompress the object if it will
> be in the same size class. We anyway don't get any memory gain.
> But, at the same time, we get a CPU time overhead when inserting
> this object into zspage and decompressing it afterwards.
> 

Dumb question: is it ever possible for compression to result in an
increase in size?

> +	    class_size_next == class_size_prev ||

IOW, could this be >=?