From: Andreas Dilger Subject: Re: [PATCH] ext2 statfs speed up Date: Thu, 5 Jul 2007 22:52:23 -0600 Message-ID: <20070706045223.GU5633@schatzie.adilger.int> References: <1183659089.19473.7.camel@dyn9047017100.beaverton.ibm.com> <20070705210651.GN5633@schatzie.adilger.int> <1183687737.19473.29.camel@dyn9047017100.beaverton.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andrew Morton , ext4 To: Badari Pulavarty Return-path: Received: from 74-0-229-162.T1.lbdsl.net ([74.0.229.162]:48705 "EHLO mail.clusterfs.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752359AbXGFEw1 (ORCPT ); Fri, 6 Jul 2007 00:52:27 -0400 Content-Disposition: inline In-Reply-To: <1183687737.19473.29.camel@dyn9047017100.beaverton.ibm.com> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Jul 05, 2007 19:08 -0700, Badari Pulavarty wrote: > On Thu, 2007-07-05 at 15:06 -0600, Andreas Dilger wrote: > > On Jul 05, 2007 11:11 -0700, Badari Pulavarty wrote: > > > @@ -1131,17 +1134,22 @@ static int ext2_statfs (struct dentry * > > > buf->f_bfree = ext2_count_free_blocks(sb); > > > + es->s_free_blocks_count = cpu_to_le32(buf->f_bfree); > > > buf->f_ffree = ext2_count_free_inodes(sb); > > > + es->s_free_inodes_count = cpu_to_le32(buf->f_ffree); > > > > Hmm, this is still sub-optimal. For ext3 and ext4 it just uses > > percpu_counter_sum() instead of the slow ext*_count_free_blocks(), which > > walks all of the groups. Not that this is a reason to hold this patch, > > because at least we are removing 1/2 of the overhead for ext2. > > I am wondering why we are not currently using percpu_counter_sum() > for ext2 ? I see that ext2 already has all the stuff it needs. > Can't I just do following ? Yes, that is exactly what I was asking above. > fs/ext2/super.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > Index: linux-2.6.22-rc7/fs/ext2/super.c > =================================================================== > --- linux-2.6.22-rc7.orig/fs/ext2/super.c 2007-07-05 12:35:15.000000000 -0700 > +++ linux-2.6.22-rc7/fs/ext2/super.c 2007-07-05 20:37:32.000000000 -0700 > @@ -1142,13 +1142,13 @@ static int ext2_statfs (struct dentry * > buf->f_type = EXT2_SUPER_MAGIC; > buf->f_bsize = sb->s_blocksize; > buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last; > - buf->f_bfree = ext2_count_free_blocks(sb); > + buf->f_bfree = percpu_counter_sum(&sbi->s_freeblocks_counter); > es->s_free_blocks_count = cpu_to_le32(buf->f_bfree); > buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count); > if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count)) > buf->f_bavail = 0; > buf->f_files = le32_to_cpu(es->s_inodes_count); > - buf->f_ffree = ext2_count_free_inodes(sb); > + buf->f_ffree = percpu_counter_sum(&sbi->s_freeinodes_counter); > es->s_free_inodes_count = cpu_to_le32(buf->f_ffree); > buf->f_namelen = EXT2_NAME_LEN; > fsid = le64_to_cpup((void *)es->s_uuid) ^ Cheers, Andreas -- Andreas Dilger Principal Software Engineer Cluster File Systems, Inc.