linux-kernel - Re: [PATCH] zram: add zstd to the supported algorithms list

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Date:   Fri, 25 Aug 2017 16:45:33 +0900
From:   Sergey Senozhatsky <sergey.senozhatsky@...il.com>
To:     Minchan Kim <minchan@...nel.org>
Cc:     Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        linux-kernel@...r.kernel.org, Nick Terrell <terrelln@...com>,
        Herbert Xu <herbert@...dor.apana.org.au>
Subject: Re: [PATCH] zram: add zstd to the supported algorithms list

On (08/25/17 14:36), Minchan Kim wrote:
[..]
> > hmmm... frankly, I don't think it would confuse anyone. the code is
> > there - compiled - anyway, and the module is visible in /proc/crypto
> > etc. if we will make it unavailable in zram then this can be confusing,
> > probably... if anyone ever pays any attention at all. my guess is that
> > people look what's in /sys/block/zram0/comp_algorithm just once, then
> > they set up a create-zram script/systemd unit file/etc. and forget
> > about it.
> 
> Although we don't show "deflate", zram still supports

right. I forgot about it :) [... and I have authored that code]

> Again, my point is that I want to show limited representative compression
> (high speed/low comp, low speed/high comp, mid/mid) algorithm via
> /sys/block/zram0/comp_algorithm rather than adding new entry whenever
> new algorithm is added on.

ok, will send out a patch set.



that may lead to a bigger/more general question:

- if zstd is so much better, then do we need deflate/inflate at all in
  the kernel? may be zstd can replace it?

what do you think, Nick?

	-ss