linux-kernel - Re: [PATCH 00/25] Cleanup and optimise the page allocator V5

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: <alpine.DEB.1.10.0903201203340.28571@qirst.com>
Date:	Fri, 20 Mar 2009 12:04:42 -0400 (EDT)
From:	Christoph Lameter <cl@...ux-foundation.org>
To:	Mel Gorman <mel@....ul.ie>
cc:	Linux Memory Management List <linux-mm@...ck.org>,
	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	Nick Piggin <npiggin@...e.de>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Lin Ming <ming.m.lin@...el.com>,
	Zhang Yanmin <yanmin_zhang@...ux.intel.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH 00/25] Cleanup and optimise the page allocator V5

On Fri, 20 Mar 2009, Mel Gorman wrote:

> hmm, I'm missing something in your reasoning. The contention I saw for
> zone->lru_lock
>
> &zone->lru_lock          37350 [<ffffffff8029d6fe>] ____pagevec_lru_add+0x9c/0x172
> &zone->lru_lock          55423 [<ffffffff8029d377>] release_pages+0x10a/0x21b
> &zone->lru_lock            402 [<ffffffff8029d9d9>] activate_page+0x4f/0x147
> &zone->lru_lock              6 [<ffffffff8029dbbd>] put_page+0x94/0x122
>
> So I just assumed it was LRU pages being taken off and freed that was
> causing the contention. Can SLUB affect that?

No. But it can affect the taking of the zone lock.

> Maybe you meant zone->lock and SLUB could tune buffers more to avoid
> that if that lock was hot. That is one alternative but the later patches
> proposed an alternative whereby high-order and compound pages could be
> stored on the PCP lists. Compound only really helps SLUB but high-order
> also helped stacks, signal handlers and the like so it seemed like a
> good idea one way or the other. Course, this meant a search of the PCP
> lists or increasing the size of the PCP structure - swings and
> roundabouts :/

Maybe include those as well? Its good stuff.
--
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/