linux-kernel - Re: [PATCH][RFC] slub: increasing order reduces memory usage of some key caches

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: <4880A613.1060002@linux-foundation.org>
Date:	Fri, 18 Jul 2008 09:17:55 -0500
From:	Christoph Lameter <cl@...ux-foundation.org>
To:	Richard Kennedy <richard@....demon.co.uk>
CC:	penberg@...helsinki.fi, mpm@...enic.com,
	linux-mm <linux-mm@...ck.org>,
	lkml <linux-kernel@...r.kernel.org>, Mel Gorman <mel@....ul.ie>
Subject: Re: [PATCH][RFC] slub: increasing order reduces memory usage	of	some
 key caches

Richard Kennedy wrote:

> Slabcache: dentry                Aliases:  0 Order :  0 Objects: 22553
> ** Reclaim accounting active
> 
> Sizes (bytes)     Slabs              Debug                Memory
> ------------------------------------------------------------------------
> Object :     208  Total  :    1188   Sanity Checks : Off  Total: 4866048
> SlabObj:     208  Full   :    1186   Redzoning     : Off  Used : 4691024
> SlabSiz:    4096  Partial:       0   Poisoning     : Off  Loss :  175024
> Loss   :       0  CpuSlab:       2   Tracking      : Off  Lalig:       0
> Align  :       8  Objects:      19   Tracing       : Off  Lpadd:  171072

So we are using 1188 pages before make

> and after a make kernel & a small delay

2399 pages after make

> on 2.6.26 + my patch

579 * 2 = 1158 (saved 30 pages even before doing anything) before make


> after the make

2025 *2 = 4050 pages which are much more than the 2399 with order 0.
So we are wasting a lot more space. You'd probably need to run slab defrag to get that memory back.

--
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/