From: Benjamin LaHaise <bcrl@lhnet.ca>
To: Tejun Heo <tj@kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
Greg Kroah-Hartman <gregkh@suse.de>,
Kay Sievers <kay.sievers@vrfy.org>,
linux-kernel@vger.kernel.org,
Cornelia Huck <cornelia.huck@de.ibm.com>,
linux-fsdevel@vger.kernel.org,
Eric Dumazet <eric.dumazet@gmail.com>,
Serge Hallyn <serue@us.ibm.com>,
"Eric W. Biederman" <ebiederm@aristanetworks.com>
Subject: Re: [PATCH 3/7] sysfs: Keep an nlink count on sysfs directories.
Date: Mon, 11 Jan 2010 19:53:08 -0500 [thread overview]
Message-ID: <20100112005308.GL5524@kvack.org> (raw)
In-Reply-To: <4B4BC683.7060508@kernel.org>
On Tue, Jan 12, 2010 at 09:46:59AM +0900, Tejun Heo wrote:
> Hello,
>
> On 01/12/2010 05:21 AM, Eric W. Biederman wrote:
> > On large directories sysfs_count_nlinks can be a significant
> > bottleneck, so keep a count in sysfs_dirent.
>
> I was about to suggest changing s_flags to ushort too. Hmmm... adding
> a new field to sysfs_dirent somewhat worries me but this doesn't add
> to the size of the structure. How significant bottlenect are we
> talking about?
100,000 entries in a sysfs directory is a requirement for network devices.
> > If we exceed the maximum number of directory entries we can store
> > return nlink of 1. An nlink of 1 matches what reiserfs does in this
> > case, and it let's find and similar utlities know that we have a the
> > directory nlink can not be used for optimization purposes.
>
> Hmmm... what's the limit on reiserfs? Is it 64k too?
64k is too small. 10 gig interfaces can currently service 50-100k users,
each of which requires their own network device.
-ben
next prev parent reply other threads:[~2010-01-12 1:15 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-11 20:16 [PATCH 0/7] General sysfs enhancements Eric W. Biederman
2010-01-11 20:21 ` [PATCH 1/7] sysfs: Serialize updates to the vfs inode Eric W. Biederman
2010-01-12 5:41 ` Serge E. Hallyn
2010-01-11 20:21 ` [PATCH 2/7] sysfs: Pack sysfs_dirent more tightly Eric W. Biederman
2010-01-12 0:41 ` Tejun Heo
2010-01-11 20:21 ` [PATCH 3/7] sysfs: Keep an nlink count on sysfs directories Eric W. Biederman
2010-01-12 0:46 ` Tejun Heo
2010-01-12 0:53 ` Benjamin LaHaise [this message]
2010-01-12 1:06 ` Eric W. Biederman
2010-01-12 1:12 ` Benjamin LaHaise
2010-01-12 1:23 ` Eric W. Biederman
2010-01-12 6:22 ` Tejun Heo
2010-01-12 15:49 ` Valdis.Kletnieks
2010-01-12 1:02 ` Eric W. Biederman
2010-01-12 5:56 ` Serge E. Hallyn
2010-01-12 8:30 ` Eric W. Biederman
2010-01-12 12:41 ` Cornelia Huck
2010-01-12 15:34 ` Eric W. Biederman
2010-01-11 20:21 ` [PATCH 4/7] sysfs: Implement sysfs_rename_link Eric W. Biederman
2010-01-12 6:24 ` Tejun Heo
2010-01-12 17:30 ` Serge E. Hallyn
2010-01-11 20:21 ` [PATCH 5/7] driver core: Use sysfs_rename_link in device_rename Eric W. Biederman
2010-01-12 6:25 ` Tejun Heo
2010-01-12 17:34 ` Serge E. Hallyn
2010-01-11 20:21 ` [PATCH 6/7] sysfs: Pass super_block to sysfs_get_inode Eric W. Biederman
2010-01-12 17:43 ` Serge E. Hallyn
2010-01-11 20:21 ` [PATCH 7/7] sysfs: Kill unused sysfs_sb variable Eric W. Biederman
2010-01-12 17:43 ` Serge E. Hallyn
2010-01-15 21:37 ` [PATCH 0/7] General sysfs enhancements Greg KH
2010-02-13 3:20 ` [PATCH 0/6] " Eric W. Biederman
2010-02-13 3:22 ` [PATCH 1/6] sysfs: Serialize updates to the vfs inode Eric W. Biederman
2010-02-13 3:22 ` [PATCH 2/6] sysfs: Pack sysfs_dirent more tightly Eric W. Biederman
2010-02-13 3:22 ` [PATCH 3/6] sysfs: Implement sysfs_rename_link Eric W. Biederman
2010-02-13 3:22 ` [PATCH 4/6] driver core: Use sysfs_rename_link in device_rename Eric W. Biederman
2010-02-13 3:22 ` [PATCH 5/6] sysfs: Pass super_block to sysfs_get_inode Eric W. Biederman
2010-02-13 3:22 ` [PATCH 6/6] sysfs: Kill unused sysfs_sb variable Eric W. Biederman
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