From: Al Viro <viro@ZenIV.linux.org.uk>
To: npiggin@suse.de
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
Dave Hansen <haveblue@us.ibm.com>
Subject: Re: [patch 04/27] fs: introduce mnt_clone_write
Date: Sat, 25 Apr 2009 04:35:03 +0100 [thread overview]
Message-ID: <20090425033503.GV8633@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20090425012209.513109971@suse.de>
On Sat, Apr 25, 2009 at 11:20:24AM +1000, npiggin@suse.de wrote:
> This patch speeds up lmbench lat_mmap test by about another 2% after the
> first patch.
>
> Before:
> avg = 462.286
> std = 5.46106
>
> After:
> avg = 453.12
> std = 9.58257
>
> (50 runs of each, stddev gives a reasonable confidence)
>
> It does this by introducing mnt_clone_write, which avoids some heavyweight
> operations of mnt_want_write if called on a vfsmount which we know already
> has a write count; and mnt_want_write_file, which can call mnt_clone_write
> if the file is open for write.
>
> After these two patches, mnt_want_write and mnt_drop_write go from 7% on
> the profile down to 1.3% (including mnt_clone_write).
NAK in this form; nested mnt_want_write() *CAN* fail (note the check for
superblock itself being r/o). Make you mnt_clone_write() returning int
and doing that superblock check, and I'm OK with it.
next prev parent reply other threads:[~2009-04-25 3:35 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-25 1:20 [patch 00/27] [rfc] vfs scalability patchset npiggin
2009-04-25 1:20 ` [patch 01/27] fs: cleanup files_lock npiggin
2009-04-25 3:20 ` Al Viro
2009-04-25 5:35 ` Eric W. Biederman
2009-04-26 6:12 ` Nick Piggin
2009-04-25 9:42 ` Alan Cox
2009-04-26 6:15 ` Nick Piggin
2009-04-25 1:20 ` [patch 02/27] fs: scale files_lock npiggin
2009-04-25 3:32 ` Al Viro
2009-04-25 1:20 ` [patch 03/27] fs: mnt_want_write speedup npiggin
2009-04-25 1:20 ` [patch 04/27] fs: introduce mnt_clone_write npiggin
2009-04-25 3:35 ` Al Viro [this message]
2009-04-25 1:20 ` [patch 05/27] fs: brlock vfsmount_lock npiggin
2009-04-25 3:50 ` Al Viro
2009-04-26 6:36 ` Nick Piggin
2009-04-25 1:20 ` [patch 06/27] fs: dcache fix LRU ordering npiggin
2009-04-25 1:20 ` [patch 07/27] fs: dcache scale hash npiggin
2009-04-25 1:20 ` [patch 08/27] fs: dcache scale lru npiggin
2009-04-25 1:20 ` [patch 09/27] fs: dcache scale nr_dentry npiggin
2009-04-25 1:20 ` [patch 10/27] fs: dcache scale dentry refcount npiggin
2009-04-25 1:20 ` [patch 11/27] fs: dcache scale d_unhashed npiggin
2009-04-25 1:20 ` [patch 12/27] fs: dcache scale subdirs npiggin
2009-04-25 1:20 ` [patch 13/27] fs: scale inode alias list npiggin
2009-04-25 1:20 ` [patch 14/27] fs: use RCU / seqlock logic for reverse and multi-step operaitons npiggin
2009-04-25 1:20 ` [patch 15/27] fs: dcache remove dcache_lock npiggin
2009-04-25 1:20 ` [patch 16/27] fs: dcache reduce dput locking npiggin
2009-04-25 1:20 ` [patch 17/27] fs: dcache per-bucket dcache hash locking npiggin
2009-04-25 1:20 ` [patch 18/27] fs: dcache reduce dcache_inode_lock npiggin
2009-04-25 1:20 ` [patch 19/27] fs: dcache per-inode inode alias locking npiggin
2009-04-25 1:20 ` [patch 20/27] fs: icache lock s_inodes list npiggin
2009-04-25 1:20 ` [patch 21/27] fs: icache lock inode hash npiggin
2009-04-25 1:20 ` [patch 22/27] fs: icache lock i_state npiggin
2009-04-25 1:20 ` [patch 23/27] fs: icache lock i_count npiggin
2009-04-25 1:20 ` [patch 24/27] fs: icache atomic inodes_stat npiggin
2009-04-25 1:20 ` [patch 25/27] fs: icache lock lru/writeback lists npiggin
2009-04-25 1:20 ` [patch 26/27] fs: icache protect inode state npiggin
2009-04-25 1:20 ` [patch 27/27] fs: icache remove inode_lock npiggin
2009-04-25 4:18 ` [patch 00/27] [rfc] vfs scalability patchset Al Viro
2009-04-25 5:02 ` Nick Piggin
2009-04-25 8:01 ` Christoph Hellwig
2009-04-25 8:06 ` Al Viro
2009-04-28 9:09 ` Christoph Hellwig
2009-04-28 9:48 ` Nick Piggin
2009-04-28 10:58 ` Peter Zijlstra
2009-04-28 11:32 ` Eric W. Biederman
2009-04-30 6:14 ` Nick Piggin
2009-04-25 19:08 ` Eric W. Biederman
2009-04-25 19:31 ` Al Viro
2009-04-25 20:29 ` Eric W. Biederman
2009-04-25 22:05 ` Theodore Tso
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