linux-kernel - Re: [PATCH][RFC] evict streaming IO cache first

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]

Message-Id: <20080715134848.cf2204b9.akpm@linux-foundation.org>
Date:	Tue, 15 Jul 2008 13:48:48 -0700
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	Rik van Riel <riel@...hat.com>
Cc:	linux-kernel@...r.kernel.org, Lee.Schermerhorn@...com,
	kosaki.motohiro@...fujitsu.com
Subject: Re: [PATCH][RFC] evict streaming IO cache first

On Tue, 15 Jul 2008 16:09:48 -0400
Rik van Riel <riel@...hat.com> wrote:

> This patch still needs some testing under various workloads
> on different hardware - the approach should work but the
> threshold may need tweaking.
> 

More than "some"!

> 
> When there is a lot of streaming IO going on, we do not want
> to scan or evict pages from the working set.  The old VM used
> to skip any mapped page, but still evict indirect blocks and
> other data that is useful to cache.

I'd be surprised if indirect blocks are getting kicked - they tend to
be awfully sticky due to frequent touch_buffer()s or equivalent.

inode blocks tend to be pretty sticky too - this is affected a lot by
whether or not atime updates are enabled.

directory blocks might be less sticky, but that might be what we want
to happen.

> This patch adds logic to skip scanning the anon lists and
> the active file list if most of the file pages are on the
> inactive file list (where streaming IO pages live), while
> at the lowest scanning priority.
> 
> If the system is not doing a lot of streaming IO, eg. the
> system is running a database workload, then more often used
> file pages will be on the active file list and this logic
> is automatically disabled.
> 
--
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/