linux-kernel - Re: [patch 2/2] slub: add min

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:	Mon, 23 Feb 2009 12:26:24 +0200
From:	Pekka Enberg <penberg@...helsinki.fi>
To:	David Rientjes <rientjes@...gle.com>
Cc:	Christoph Lameter <cl@...ux-foundation.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [patch 2/2] slub: add min_partial sysfs tunable

Hi David,

On Mon, 23 Feb 2009, Pekka Enberg wrote:
> > The patches look good but the description is bit lacking. Does this
> > actually fix up something? Why don't we fix the limit calculations
> > instead?
> > 
> > I'm a sucker for numbers so I'm easily fooled into merging patches with
> > statements of the form "this shaves off N bytes/kb/mb on XYZ systems".

On Mon, 2009-02-23 at 01:58 -0800, David Rientjes wrote:
> The memory savings from simply moving min_partial from struct 
> kmem_cache_node to struct kmem_cache is obviously not significant (unless 
> maybe you're from SGI or something), at the largest it's
> 
> 	# allocated caches * (MAX_NUMNODES - 1) * sizeof(unsigned long)
> 
> The true savings occurs when userspace reduces the number of partial slabs 
> that would otherwise be wasted, especially on machines with a large 
> number of nodes (ia64 with CONFIG_NODES_SHIFT at 10 for default?).  As 
> well as the kernel estimates ideal values for n->min_partial and ensures 
> it's within a sane range, userspace has no other input other than writing 
> to /sys/kernel/slab/cache/shrink.

Applied with the above explanation added to the changelog. Thanks!

			Pekka

--
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/