From: Wu Fengguang <fengguang.wu@intel.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Jens Axboe <jens.axboe@oracle.com>, Jan Kara <jack@suse.cz>,
Theodore Tso <tytso@mit.edu>, Dave Chinner <david@fromorbit.com>,
Chris Mason <chris.mason@oracle.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 5/6] writeback: don't delay inodes redirtied by a fast dirtier
Date: Sun, 27 Sep 2009 10:02:34 +0800 [thread overview]
Message-ID: <20090927020233.GA10318@localhost> (raw)
In-Reply-To: <20090926194747.GA1593@infradead.org>
On Sun, Sep 27, 2009 at 03:47:47AM +0800, Christoph Hellwig wrote:
> On Wed, Sep 23, 2009 at 08:33:43PM +0800, Wu Fengguang wrote:
> > So let's distinguish between data redirty and metadata only redirty.
> > The first one is caused by a busy dirtier, while the latter one could
> > happen in XFS, NFS, etc. when they are doing delalloc or updating isize.
>
> Btw, I'm not sure the existing and preserved behaviour for that case
> is good. In the worst case the inode writeout gets delayed by another
> 30 seconds, doubling the window until a file is on disk if it was
> extended.
Yes, the preserved behaviour is not optimal for XFS, but safe.
We could try redirty_tail when there are no remaining
dirty pages, and only metadata dirtiness. Like this:
---
fs/fs-writeback.c | 20 +++++++-------------
1 file changed, 7 insertions(+), 13 deletions(-)
--- linux.orig/fs/fs-writeback.c 2009-09-27 09:52:15.000000000 +0800
+++ linux/fs/fs-writeback.c 2009-09-27 09:54:23.000000000 +0800
@@ -477,18 +477,7 @@ writeback_single_inode(struct inode *ino
spin_lock(&inode_lock);
inode->i_state &= ~I_SYNC;
if (!(inode->i_state & (I_FREEING | I_CLEAR))) {
- if ((inode->i_state & I_DIRTY_PAGES) && wbc->for_kupdate) {
- /*
- * More pages get dirtied by a fast dirtier.
- */
- goto select_queue;
- } else if (inode->i_state & I_DIRTY) {
- /*
- * At least XFS will redirty the inode during the
- * writeback (delalloc) and on io completion (isize).
- */
- redirty_tail(inode);
- } else if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
+ if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
/*
* We didn't write back all the pages. nfs_writepages()
* sometimes bales out without doing anything. Redirty
@@ -510,7 +499,6 @@ writeback_single_inode(struct inode *ino
* soon as the queue becomes uncongested.
*/
inode->i_state |= I_DIRTY_PAGES;
-select_queue:
if (wbc->nr_to_write <= 0) {
/*
* slice used up: queue for next turn
@@ -533,6 +521,12 @@ select_queue:
inode->i_state |= I_DIRTY_PAGES;
redirty_tail(inode);
}
+ } else if (inode->i_state & I_DIRTY) {
+ /*
+ * At least XFS will redirty the inode during the
+ * writeback (delalloc) and on io completion (isize).
+ */
+ redirty_tail(inode);
} else if (atomic_read(&inode->i_count)) {
/*
* The inode is clean, inuse
prev parent reply other threads:[~2009-09-27 2:02 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20090923123337.990689487@intel.com>
[not found] ` <20090923124027.456325340@intel.com>
2009-09-23 12:45 ` [PATCH 1/6] writeback: balance_dirty_pages() shall write more than dirtied pages Christoph Hellwig
2009-09-23 12:53 ` Wu Fengguang
2009-09-23 13:56 ` [PATCH 1/6 -v2] " Wu Fengguang
2009-09-23 13:58 ` Wu Fengguang
[not found] ` <20090923124027.589303074@intel.com>
2009-09-23 15:05 ` [PATCH 2/6] writeback: stop background writeback when below background threshold Jens Axboe
2009-09-24 1:24 ` Wu Fengguang
[not found] ` <20090923124028.060887241@intel.com>
2009-09-23 13:20 ` [PATCH 5/6] writeback: don't delay inodes redirtied by a fast dirtier Wu Fengguang
2009-09-23 13:23 ` Christoph Hellwig
2009-09-23 13:40 ` Wu Fengguang
2009-09-26 19:47 ` Christoph Hellwig
2009-09-27 2:02 ` Wu Fengguang [this message]
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