linux-kernel - Re: quicklists confuse meminfo

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.LFD.1.00.0803091407510.3099@apollo.tec.linutronix.de>
Date:	Sun, 9 Mar 2008 14:20:55 +0100 (CET)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Ingo Molnar <mingo@...e.hu>
cc:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Christoph Lameter <clameter@....com>,
	Bart Van Assche <bart.vanassche@...il.com>
Subject: Re: quicklists confuse meminfo

On Sun, 9 Mar 2008, Ingo Molnar wrote:
> * Ingo Molnar <mingo@...e.hu> wrote:
> 
> > > IMHO we need shrink pgtable cache mecanism.
> > 
> > ouch! Could you try the patch below? How large is the quicklist cache 
> > with this applied?
> 
> hm, Thomas pointed it out that this wont solve all the problems as 
> quicklists have a built-in "preserve me" throttle (which is rather 
> stupid).

There is also the imbalance across CPUs. I think I figured out what's
going there as well. The allocation happens on one CPU (via
page_alloc), but the tear down happens on the other CPU, which
accumulates the pages in the quicklist. So the quicklist of the busy
CPU is empty, while the one of the idle CPU goes up to the limit. When
I pin the loop to one CPU then the quicklists are stable.

Thanks,

	tglx
--
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/