linux-kernel - Re: [PATCH v6 7/7] zsmalloc: use shrinker to trigger auto-compaction

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 8 Jul 2015 00:12:04 +0900
From:	Sergey Senozhatsky <sergey.senozhatsky@...il.com>
To:	Minchan Kim <minchan@...nel.org>
Cc:	Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
	Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org,
	Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
Subject: Re: [PATCH v6 7/7] zsmalloc: use shrinker to trigger auto-compaction

On (07/08/15 00:01), Minchan Kim wrote:
[..]
> > But why would we do this? Yes, it's kinda-sorta bad -- we were not
> > able to register zspool shrinker, so there will be no automatic
> > compaction... And that's it.
> > 
> > It does not affect zsmalloc/zram functionality by any means. Including
> > compaction itself -- user still has a way to compact zspool (manually).
> > And in some scenarios user will never even see automatic compaction in
> > action (assuming that there is a plenty of RAM available).
> > 
> > Can you explain your decision?
> 
> I don't think it would fail in *real practice*.
> Althout it might happen, what does zram could help in that cases?
> 

This argument depends on the current register_shrinker() implementation,
should some one add additional return branch there and it's done.

> If it were failed, it means there is already little memory on the system
> so zram could not be helpful for those environment.
> IOW, zram should be enabled earlier.
> 
> If you want it strongly, please reproduce such failing and prove that
> zram was helpful for the system.

No, thanks. I'll just remove it.

	-ss
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/