From: Fengguang Wu <fengguang.wu@gmail.com>
To: Theodore Tso <tytso@mit.edu>,
Suparna Bhattacharya <suparna@in.ibm.com>,
Andrew Morton <akpm@osdl.org>, Willy Tarreau <w@1wt.eu>,
Linus Torvalds <torvalds@osdl.org>,
"H. Peter Anvin" <hpa@zytor.com>,
git@vger.kernel.org, nigel@nigel.suspend2.net,
"J.H." <warthog9@kernel.org>,
Randy Dunlap <randy.dunlap@oracle.com>,
Pavel Machek <pavel@ucw.cz>,
kernel list <linux-kernel@vger.kernel.org>,
webmaster@kernel.org,
"linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>
Subject: Re: How git affects kernel.org performance
Date: Tue, 9 Jan 2007 15:59:46 +0800 [thread overview]
Message-ID: <368329554.17014@ustc.edu.cn> (raw)
Message-ID: <20070109075945.GA8799@mail.ustc.edu.cn> (raw)
In-Reply-To: <20070108125819.GA32756@thunk.org>
On Mon, Jan 08, 2007 at 07:58:19AM -0500, Theodore Tso wrote:
> On Mon, Jan 08, 2007 at 08:35:55AM +0530, Suparna Bhattacharya wrote:
> > > Yeah, slowly-growing directories will get splattered all over the disk.
> > >
> > > Possible short-term fixes would be to just allocate up to (say) eight
> > > blocks when we grow a directory by one block. Or teach the
> > > directory-growth code to use ext3 reservations.
> > >
> > > Longer-term people are talking about things like on-disk rerservations.
> > > But I expect directories are being forgotten about in all of that.
> >
> > By on-disk reservations, do you mean persistent file preallocation ? (that
> > is explicit preallocation of blocks to a given file) If so, you are
> > right, we haven't really given any thought to the possibility of directories
> > needing that feature.
>
> The fastest and probably most important thing to add is some readahead
> smarts to directories --- both to the htree and non-htree cases. If
Here's is a quick hack to practice the directory readahead idea.
Comments are welcome, it's a freshman's work :)
Regards,
Wu
---
fs/ext3/dir.c | 22 ++++++++++++++++++++++
fs/ext3/inode.c | 2 +-
2 files changed, 23 insertions(+), 1 deletion(-)
--- linux.orig/fs/ext3/dir.c
+++ linux/fs/ext3/dir.c
@@ -94,6 +94,25 @@ int ext3_check_dir_entry (const char * f
return error_msg == NULL ? 1 : 0;
}
+int ext3_get_block(struct inode *inode, sector_t iblock,
+ struct buffer_head *bh_result, int create);
+
+static void ext3_dir_readahead(struct file * filp)
+{
+ struct inode *inode = filp->f_path.dentry->d_inode;
+ struct address_space *mapping = inode->i_sb->s_bdev->bd_inode->i_mapping;
+ unsigned long sector;
+ unsigned long blk;
+ pgoff_t offset;
+
+ for (blk = 0; blk < inode->i_blocks; blk++) {
+ sector = blk << (inode->i_blkbits - 9);
+ sector = generic_block_bmap(inode->i_mapping, sector, ext3_get_block);
+ offset = sector >> (PAGE_CACHE_SHIFT - 9);
+ do_page_cache_readahead(mapping, filp, offset, 1);
+ }
+}
+
static int ext3_readdir(struct file * filp,
void * dirent, filldir_t filldir)
{
@@ -108,6 +127,9 @@ static int ext3_readdir(struct file * fi
sb = inode->i_sb;
+ if (!filp->f_pos)
+ ext3_dir_readahead(filp);
+
#ifdef CONFIG_EXT3_INDEX
if (EXT3_HAS_COMPAT_FEATURE(inode->i_sb,
EXT3_FEATURE_COMPAT_DIR_INDEX) &&
--- linux.orig/fs/ext3/inode.c
+++ linux/fs/ext3/inode.c
@@ -945,7 +945,7 @@ out:
#define DIO_CREDITS (EXT3_RESERVE_TRANS_BLOCKS + 32)
-static int ext3_get_block(struct inode *inode, sector_t iblock,
+int ext3_get_block(struct inode *inode, sector_t iblock,
struct buffer_head *bh_result, int create)
{
handle_t *handle = journal_current_handle();
next prev parent reply other threads:[~2007-01-09 7:59 UTC|newest]
Thread overview: 110+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-12-14 22:37 kernel.org lies about latest -mm kernel Pavel Machek
2006-12-14 23:01 ` Randy Dunlap
2006-12-14 23:38 ` Sergio Monteiro Basto
2006-12-16 17:44 ` [KORG] " Randy Dunlap
2006-12-16 17:57 ` Andrew Morton
2006-12-16 18:02 ` Randy Dunlap
2006-12-16 19:30 ` J.H.
2006-12-16 20:30 ` Russell King
2006-12-26 16:47 ` H. Peter Anvin
2006-12-16 21:21 ` Nigel Cunningham
2006-12-26 16:49 ` H. Peter Anvin
2007-01-07 3:35 ` Nigel Cunningham
2007-01-07 4:10 ` Jeff Garzik
2007-01-07 4:47 ` Nigel Cunningham
2007-01-07 4:22 ` Jeff Garzik
2007-01-07 4:29 ` Linus Torvalds
2007-01-07 20:11 ` Greg KH
2007-01-07 21:30 ` H. Peter Anvin
2007-01-07 5:17 ` H. Peter Anvin
2007-01-07 5:24 ` How git affects kernel.org performance H. Peter Anvin
2007-01-07 5:39 ` Linus Torvalds
2007-01-07 8:55 ` Willy Tarreau
2007-01-07 8:58 ` H. Peter Anvin
2007-01-07 9:03 ` Willy Tarreau
2007-01-07 10:28 ` Christoph Hellwig
2007-01-07 10:52 ` Willy Tarreau
2007-01-07 18:17 ` Linus Torvalds
2007-01-07 19:13 ` Linus Torvalds
[not found] ` <9e4733910701071126r7931042eldfb73060792f4f41@mail.gmail.com>
2007-01-07 19:35 ` Linus Torvalds
2007-01-07 10:50 ` Jan Engelhardt
2007-01-07 18:49 ` Randy Dunlap
2007-01-07 19:07 ` Jan Engelhardt
2007-01-07 19:28 ` Randy Dunlap
2007-01-07 19:37 ` Linus Torvalds
2007-01-07 9:15 ` Andrew Morton
2007-01-07 9:38 ` Rene Herman
2007-01-08 3:05 ` Suparna Bhattacharya
2007-01-08 12:58 ` Theodore Tso
2007-01-08 13:41 ` Johannes Stezenbach
2007-01-08 13:56 ` Theodore Tso
2007-01-08 13:59 ` Pavel Machek
2007-01-08 14:17 ` Theodore Tso
2007-01-08 13:43 ` Jeff Garzik
2007-01-09 1:09 ` Paul Jackson
2007-01-09 2:18 ` Jeremy Higdon
[not found] ` <20070109075945.GA8799@mail.ustc.edu.cn>
2007-01-09 7:59 ` Fengguang Wu [this message]
2007-01-09 16:23 ` Linus Torvalds
[not found] ` <20070110015739.GA26978@mail.ustc.edu.cn>
2007-01-10 1:57 ` Fengguang Wu
2007-01-10 3:20 ` Nigel Cunningham
[not found] ` <20070110140730.GA986@mail.ustc.edu.cn>
2007-01-10 14:07 ` Fengguang Wu
2007-01-12 10:54 ` Nigel Cunningham
2007-01-07 14:57 ` Robert Fitzsimons
2007-01-07 19:12 ` J.H.
2007-01-08 1:51 ` Jakub Narebski
2007-01-07 15:06 ` Krzysztof Halasa
2007-01-07 20:31 ` Shawn O. Pearce
2007-01-08 14:46 ` Nicolas Pitre
2007-01-09 4:29 ` [KORG] Re: kernel.org lies about latest -mm kernel Nigel Cunningham
2007-01-09 5:09 ` Adrian Bunk
2007-01-09 5:51 ` Nigel Cunningham
2006-12-17 12:32 ` Pavel Machek
2006-12-17 13:13 ` Jeff Garzik
2006-12-17 18:23 ` Randy Dunlap
2006-12-17 22:37 ` Matti Aarnio
2006-12-18 0:42 ` J.H.
2006-12-19 6:46 ` Willy Tarreau
2006-12-19 7:39 ` J.H.
2006-12-19 13:32 ` Willy Tarreau
2006-12-19 14:36 ` Dave Jones
2006-12-19 14:38 ` Willy Tarreau
2006-12-26 16:14 ` H. Peter Anvin
2007-01-08 20:10 ` Jean Delvare
2006-12-19 6:34 ` Willy Tarreau
2006-12-19 6:52 ` J.H.
2007-01-06 18:33 ` Randy Dunlap
2007-01-06 19:18 ` H. Peter Anvin
2007-01-06 19:35 ` Willy Tarreau
2007-01-06 19:37 ` Nicholas Miell
2007-01-06 20:13 ` Andrew Morton
2007-01-06 20:18 ` H. Peter Anvin
2007-03-19 19:27 ` [PATCH] sysctl: vfs_cache_divisor Randy Dunlap
2007-03-19 20:36 ` Andrew Morton
2007-03-19 20:42 ` Randy Dunlap
2007-03-20 4:22 ` H. Peter Anvin
2007-03-21 23:01 ` Randy Dunlap
2007-03-21 23:11 ` Andrew Morton
2007-03-23 0:07 ` Kyle Moffett
2007-03-23 20:36 ` Randy Dunlap
2007-03-23 20:59 ` H. Peter Anvin
2007-03-24 0:45 ` Kyle Moffett
2007-03-24 1:17 ` Kyle Moffett
2007-03-20 19:53 ` Ingo Oeser
2007-01-06 23:50 ` [KORG] Re: kernel.org lies about latest -mm kernel H. Peter Anvin
2007-01-06 20:13 ` Jeff Garzik
2007-01-06 20:17 ` Andrew Morton
2007-01-06 20:20 ` H. Peter Anvin
2007-01-06 20:36 ` Andrew Morton
2007-01-06 19:21 ` J.H.
2007-01-07 19:52 ` Randy Dunlap
2007-01-07 23:56 ` H. Peter Anvin
2006-12-26 17:02 ` H. Peter Anvin
2007-01-08 19:31 ` Jean Delvare
2007-01-08 19:37 ` Willy Tarreau
2007-01-08 22:05 ` Jean Delvare
2006-12-19 15:37 ` Tim Schmielau
2007-01-08 21:20 ` Jean Delvare
2007-01-08 21:33 ` J.H.
2007-01-09 7:01 ` Jean Delvare
2007-01-09 7:25 ` J.H.
2007-01-09 13:36 ` Jean Delvare
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