From: Robin Holt <holt@sgi.com>
To: Nathan Fontenot <nfont@austin.ibm.com>
Cc: Greg KH <greg@kroah.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Robin Holt <holt@sgi.com>,
linuxppc-dev@lists.ozlabs.org,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Subject: Re: [PATCH 0/4] De-couple sysfs memory directories from memory sections
Date: Mon, 10 Jan 2011 13:11:22 -0600 [thread overview]
Message-ID: <20110110191122.GN2912@sgi.com> (raw)
In-Reply-To: <4D2B543A.3070609@austin.ibm.com>
> >> The root of this issue is in sysfs directory creation. Every time
> >> a directory is created a string compare is done against all sibling
> >> directories to ensure we do not create duplicates. The list of
> >> directory nodes in sysfs is kept as an unsorted list which results
> >> in this being an exponentially longer operation as the number of
> >> directories are created.
> >
> > Are you sure this is still an issue? I thought we solved this last
> > kernel or so with a simple patch?
>
> I'll go back and look at this again.
What I recall fixing is the symbolic linking from the node* to the
memory section. In that case, we cached the most recent mem section
and since they always were added sequentially, the cache saved a rescan.
Of course, I could be remembering something completely unrelated.
Robin
WARNING: multiple messages have this Message-ID (diff)
From: Robin Holt <holt@sgi.com>
To: Nathan Fontenot <nfont@austin.ibm.com>
Cc: Greg KH <greg@kroah.com>,
linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-mm@kvack.org,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Robin Holt <holt@sgi.com>
Subject: Re: [PATCH 0/4] De-couple sysfs memory directories from memory sections
Date: Mon, 10 Jan 2011 13:11:22 -0600 [thread overview]
Message-ID: <20110110191122.GN2912@sgi.com> (raw)
In-Reply-To: <4D2B543A.3070609@austin.ibm.com>
> >> The root of this issue is in sysfs directory creation. Every time
> >> a directory is created a string compare is done against all sibling
> >> directories to ensure we do not create duplicates. The list of
> >> directory nodes in sysfs is kept as an unsorted list which results
> >> in this being an exponentially longer operation as the number of
> >> directories are created.
> >
> > Are you sure this is still an issue? I thought we solved this last
> > kernel or so with a simple patch?
>
> I'll go back and look at this again.
What I recall fixing is the symbolic linking from the node* to the
memory section. In that case, we cached the most recent mem section
and since they always were added sequentially, the cache saved a rescan.
Of course, I could be remembering something completely unrelated.
Robin
WARNING: multiple messages have this Message-ID (diff)
From: Robin Holt <holt@sgi.com>
To: Nathan Fontenot <nfont@austin.ibm.com>
Cc: Greg KH <greg@kroah.com>,
linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-mm@kvack.org,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Robin Holt <holt@sgi.com>
Subject: Re: [PATCH 0/4] De-couple sysfs memory directories from memory sections
Date: Mon, 10 Jan 2011 13:11:22 -0600 [thread overview]
Message-ID: <20110110191122.GN2912@sgi.com> (raw)
In-Reply-To: <4D2B543A.3070609@austin.ibm.com>
> >> The root of this issue is in sysfs directory creation. Every time
> >> a directory is created a string compare is done against all sibling
> >> directories to ensure we do not create duplicates. The list of
> >> directory nodes in sysfs is kept as an unsorted list which results
> >> in this being an exponentially longer operation as the number of
> >> directories are created.
> >
> > Are you sure this is still an issue? I thought we solved this last
> > kernel or so with a simple patch?
>
> I'll go back and look at this again.
What I recall fixing is the symbolic linking from the node* to the
memory section. In that case, we cached the most recent mem section
and since they always were added sequentially, the cache saved a rescan.
Of course, I could be remembering something completely unrelated.
Robin
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next prev parent reply other threads:[~2011-01-10 19:21 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-10 18:08 [PATCH 0/4] De-couple sysfs memory directories from memory sections Nathan Fontenot
2011-01-10 18:08 ` Nathan Fontenot
2011-01-10 18:08 ` Nathan Fontenot
2011-01-10 18:11 ` [PATCH 1/4] allow memory blocks to span multiple " Nathan Fontenot
2011-01-10 18:11 ` Nathan Fontenot
2011-01-10 18:13 ` [PATCH 2/4] Update phys_index to [start|end]_section_nr Nathan Fontenot
2011-01-10 18:13 ` Nathan Fontenot
2011-01-10 18:14 ` [PATCH 3/4] Define memory_block_size_bytes for powerpc/pseries Nathan Fontenot
2011-01-10 18:14 ` Nathan Fontenot
2011-01-10 18:16 ` [PATCH 4/4] Define memory_block_size_bytes for x86_64 with CONFIG_X86_UV defined Nathan Fontenot
2011-01-10 18:16 ` Nathan Fontenot
2011-01-10 18:44 ` [PATCH 0/4] De-couple sysfs memory directories from memory sections Greg KH
2011-01-10 18:44 ` Greg KH
2011-01-10 18:44 ` Greg KH
2011-01-10 18:47 ` Nathan Fontenot
2011-01-10 18:47 ` Nathan Fontenot
2011-01-10 18:47 ` Nathan Fontenot
2011-01-10 19:11 ` Robin Holt [this message]
2011-01-10 19:11 ` Robin Holt
2011-01-10 19:11 ` Robin Holt
-- strict thread matches above, loose matches on Subject: below --
2011-01-20 16:36 Nathan Fontenot
2011-01-20 16:36 ` Nathan Fontenot
2011-01-20 16:45 ` Greg KH
2011-01-20 16:45 ` Greg KH
2011-01-20 16:51 ` Nathan Fontenot
2011-01-20 16:51 ` Nathan Fontenot
2011-01-20 17:25 ` Greg KH
2011-01-20 17:25 ` Greg KH
2011-01-20 17:09 ` Dave Hansen
2011-01-20 17:09 ` Dave Hansen
2011-01-20 17:09 ` Dave Hansen
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