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 Feb 2012 09:14:32 -0600 (CST)
From:	Christoph Lameter <cl@...ux.com>
To:	Mel Gorman <mgorman@...e.de>
cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Linux-MM <linux-mm@...ck.org>,
	Linux-Netdev <netdev@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	David Miller <davem@...emloft.net>, Neil Brown <neilb@...e.de>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Pekka Enberg <penberg@...helsinki.fi>
Subject: Re: [PATCH 02/15] mm: sl[au]b: Add knowledge of PFMEMALLOC reserve
 pages

On Wed, 8 Feb 2012, Mel Gorman wrote:

> o struct kmem_cache_cpu could be left alone even though it's a small saving

Its multiplied by the number of caches and by the number of
processors.

> o struct slab also be left alone
> o struct array_cache could be left alone although I would point out that
>   it would make no difference in size as touched is changed to a bool to
>   fit pfmemalloc in

Both of these are performance critical structures in slab.

> o It would still be necessary to do the object pointer tricks in slab.c

These trick are not done for slub. It seems that they are not necessary?

> remain. However, the downside of requiring a page flag is very high. In
> the event we increase the number of page flags - great, I'll use one but
> right now I do not think the use of page flag is justified.

On 64 bit I think there is not much of an issue with another page flag.

Also consider that the slab allocators do not make full use of the other
page flags. We could overload one of the existing flags. I removed
slubs use of them last year. PG_active could be overloaded I think.

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Powered by blists - more mailing lists