Re: [PATCH 07/45] writeback: dont redirty tail an inode with dirtypages

From: Jan Kara
Date: Fri Oct 09 2009 - 11:46:50 EST


On Wed 07-10-09 15:38:25, Wu Fengguang wrote:
> This avoids delaying writeback for an expired (XFS) inode with lots of
> dirty pages, but no active dirtier at the moment.
OK, looks good.
Acked-by: Jan Kara <jack@xxxxxxx>

Honza
>
> CC: Dave Chinner <david@xxxxxxxxxxxxx>
> CC: Christoph Hellwig <hch@xxxxxxxxxxxxx>
> Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
> ---
> fs/fs-writeback.c | 20 +++++++-------------
> 1 file changed, 7 insertions(+), 13 deletions(-)
>
> --- linux.orig/fs/fs-writeback.c 2009-10-06 23:37:57.000000000 +0800
> +++ linux/fs/fs-writeback.c 2009-10-06 23:38:28.000000000 +0800
> @@ -479,18 +479,7 @@ 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
> @@ -512,7 +501,6 @@ 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
> @@ -535,6 +523,12 @@ 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
>
>
--
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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