From: Sergey Senozhatsky <senozhatsky@chromium.org>
To: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>,
Andrew Morton <akpm@linux-foundation.org>,
Nitin Gupta <ngupta@vflare.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCHv4 4/9] zram: Introduce recompress sysfs knob
Date: Sat, 5 Nov 2022 08:22:54 +0900 [thread overview]
Message-ID: <Y2Wezsw+FQU6KAlq@google.com> (raw)
In-Reply-To: <Y2VLf+W1xwBuu0G7@google.com>
On (22/11/04 10:27), Minchan Kim wrote:
> > objects that are in-compressible (in a way that saves us memory in
> > zsmalloc) by any of the ZRAM's algorithms.
> >
> > > read_block_state
> > > zram_algo_idx(zram, index) > 0 ? 'r' : '.');
> > >
> > > zram_read_from_zpool
> > > if (zram_algo_idx(zram, idx) != 0)
> > > idx = 1;
> >
> > As an idea, maybe we can store everything re-compression related
> > in a dedicated meta field? SKIP flag, algorithm ID, etc.
> >
> > We don't have too many bits left in ->flags on 32-bit systems. We
> > currently probably need at least 3 bits - one for RECOMP_SKIP and at
> > least 2 for algorithm ID. 2 bits for algorithm ID put us into situation
> > that we can have only 00, 01, 10, 11 as IDs, that is maximum 3 recompress
> > algorithms: 00 is the primary one and the rest are alternative ones.
> > Maximum 3 re-compression algorithms sounds like a reasonable max value to
> > me. Yeah, maybe we can use flags bits for it.
>
> If possbile, let's go with those three bits into flags since we could
> factor them out into dedicated field, anytime later since it's not ABI.
Ack.
next prev parent reply other threads:[~2022-11-04 23:23 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-18 4:55 [PATCHv4 0/9] zram: Support multiple compression streams Sergey Senozhatsky
2022-10-18 4:55 ` [PATCHv4 1/9] zram: Preparation for multi-zcomp support Sergey Senozhatsky
2022-11-02 20:13 ` Minchan Kim
2022-11-03 2:40 ` Sergey Senozhatsky
2022-10-18 4:55 ` [PATCHv4 2/9] zram: Add recompression algorithm sysfs knob Sergey Senozhatsky
2022-11-02 20:15 ` Minchan Kim
2022-11-03 3:05 ` Sergey Senozhatsky
2022-11-03 3:54 ` Sergey Senozhatsky
2022-11-03 17:10 ` Minchan Kim
2022-11-03 4:09 ` Sergey Senozhatsky
2022-11-03 5:36 ` Sergey Senozhatsky
2022-11-03 17:11 ` Minchan Kim
2022-11-03 16:34 ` Minchan Kim
2022-11-04 3:18 ` Sergey Senozhatsky
2022-11-04 4:53 ` Sergey Senozhatsky
2022-11-04 17:43 ` Minchan Kim
2022-11-04 23:41 ` Sergey Senozhatsky
2022-11-05 0:00 ` Sergey Senozhatsky
2022-11-07 19:08 ` Minchan Kim
2022-11-08 0:40 ` Sergey Senozhatsky
2022-11-05 0:01 ` Minchan Kim
2022-11-05 1:30 ` Sergey Senozhatsky
2022-11-04 16:34 ` Minchan Kim
2022-11-04 23:25 ` Sergey Senozhatsky
2022-11-04 23:40 ` Minchan Kim
2022-11-04 23:44 ` Sergey Senozhatsky
2022-11-05 0:02 ` Minchan Kim
2022-10-18 4:55 ` [PATCHv4 3/9] zram: Factor out WB and non-WB zram read functions Sergey Senozhatsky
2022-11-02 20:20 ` Minchan Kim
2022-11-03 2:43 ` Sergey Senozhatsky
2022-10-18 4:55 ` [PATCHv4 4/9] zram: Introduce recompress sysfs knob Sergey Senozhatsky
2022-11-02 21:06 ` Minchan Kim
2022-11-03 3:25 ` Sergey Senozhatsky
2022-11-03 6:03 ` Sergey Senozhatsky
2022-11-03 17:00 ` Minchan Kim
2022-11-04 3:48 ` Sergey Senozhatsky
2022-11-04 7:12 ` Sergey Senozhatsky
2022-11-04 17:53 ` Minchan Kim
2022-11-04 17:27 ` Minchan Kim
2022-11-04 23:22 ` Sergey Senozhatsky [this message]
2022-11-04 7:53 ` Sergey Senozhatsky
2022-11-04 8:08 ` Sergey Senozhatsky
2022-11-04 17:47 ` Minchan Kim
2022-10-18 4:55 ` [PATCHv4 5/9] documentation: Add recompression documentation Sergey Senozhatsky
2022-10-18 4:55 ` [PATCHv4 6/9] zram: Add recompression algorithm choice to Kconfig Sergey Senozhatsky
2022-10-18 4:55 ` [PATCHv4 7/9] zram: Add recompress flag to read_block_state() Sergey Senozhatsky
2022-10-18 4:55 ` [PATCHv4 8/9] zram: Clarify writeback_store() comment Sergey Senozhatsky
2022-10-18 4:55 ` [PATCHv4 9/9] zram: Use IS_ERR_VALUE() to check for zs_malloc() errors Sergey Senozhatsky
2022-11-02 20:07 ` [PATCHv4 0/9] zram: Support multiple compression streams Minchan Kim
2022-11-03 3:36 ` Sergey Senozhatsky
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