linux-kernel - Re: [PATCH 0/8] v2 De-Couple sysfs memory directories from memory sections

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Message-ID: <4CA21906.1080002@redhat.com>
Date:	Tue, 28 Sep 2010 18:34:14 +0200
From:	Avi Kivity <avi@...hat.com>
To:	Robin Holt <holt@....com>
CC:	Nathan Fontenot <nfont@...tin.ibm.com>,
	linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	linuxppc-dev@...abs.org, Greg KH <greg@...ah.com>,
	Dave Hansen <dave@...ux.vnet.ibm.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
Subject: Re: [PATCH 0/8] v2 De-Couple sysfs memory directories from memory
 sections

  On 09/28/2010 05:12 PM, Robin Holt wrote:
> >  Why not update sysfs directory creation to be fast, for example by
> >  using an rbtree instead of a linked list.  This fixes an
> >  implementation problem in the kernel instead of working around it
> >  and creating a new ABI.
>
> Because the old ABI creates 129,000+ entries inside
> /sys/devices/system/memory with their associated links from
> /sys/devices/system/node/node*/ back to those directory entries.
>
> Thankfully things like rpm, hald, and other miscellaneous commands scan
> that information.  On our 8 TB test machine, hald runs continuously
> following boot for nearly an hour mostly scanning useless information
> from /sys/

I see - so the problem wasn't just kernel internal; the ABI itself was 
unsuitable.  Too bad this wasn't considered at the time it was added.

(129k entries / 1 hour = 35 entries/sec; not very impressive)

-- 
error compiling committee.c: too many arguments to function

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