From: Minchan Kim <minchan@kernel.org>
To: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Nitin Gupta <ngupta@vflare.org>,
Brian Geffon <bgeffon@google.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCHv2] zram: do not waste zram_table_entry flags bits
Date: Thu, 15 Sep 2022 16:36:36 +0000 [thread overview]
Message-ID: <YyNUlEGwooXzpF9Z@google.com> (raw)
In-Reply-To: <20220912152744.527438-1-senozhatsky@chromium.org>
On Tue, Sep 13, 2022 at 12:27:44AM +0900, Sergey Senozhatsky wrote:
> zram_table_entry::flags stores object size in the lower bits and
> zram pageflags in the upper bits. However, for some reason, we
> use 24 lower bits, while maximum zram object size is PAGE_SIZE,
> which requires PAGE_SHIFT bits (up to 16 on arm64). This wastes
> 24 - PAGE_SHIFT bits that we can use for additional zram pageflags
> instead.
>
> Also add a BUILD_BUG_ON() to alert us should we run out of bits
> in zram_table_entry::flags.
>
> Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Minchan Kim <minchan@kernel.org>
prev parent reply other threads:[~2022-09-15 16:36 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-12 15:27 [PATCHv2] zram: do not waste zram_table_entry flags bits Sergey Senozhatsky
2022-09-12 15:39 ` Brian Geffon
2022-09-13 1:54 ` Sergey Senozhatsky
2022-09-13 2:07 ` Brian Geffon
2022-09-13 2:10 ` Sergey Senozhatsky
2022-09-15 16:36 ` Minchan Kim [this message]
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