On Mon, Jul 26, 2010 at 08:56:35PM +0800, Wu Fengguang wrote:
> > > @@ -232,8 +232,15 @@ static void move_expired_inodes(struct l
> > > while (!list_empty(delaying_queue)) {
> > > inode = list_entry(delaying_queue->prev, struct inode, i_list);
> > > if (expire_interval &&
> > > - inode_dirtied_after(inode, older_than_this))
> > > - break;
> > > + inode_dirtied_after(inode, older_than_this)) {
> > > + if (wbc->for_background &&
> > > + list_empty(dispatch_queue) && list_empty(&tmp)) {
> > > + expire_interval >>= 1;
> > > + older_than_this = jiffies - expire_interval;
> > > + continue;
> > > + } else
> > > + break;
> > > + }
> >
> > This needs a comment.
> >
> > I think what it is saying is that if background flush is active but no
> > inodes are old enough, consider newer inodes. This is on the assumption
> > that page reclaim has encountered dirty pages and the dirty inodes are
> > still too young.
>
> Yes this should be commented. How about this one?
>
> @@ -232,8 +232,20 @@ static void move_expired_inodes(struct l
> while (!list_empty(delaying_queue)) {
> inode = list_entry(delaying_queue->prev, struct inode, i_list);
> if (expire_interval &&
> - inode_dirtied_after(inode, older_than_this))
> + inode_dirtied_after(inode, older_than_this)) {
> + /*
> + * background writeback will start with expired inodes,
> + * and then fresh inodes. This order helps reducing
> + * the number of dirty pages reaching the end of LRU
> + * lists and cause trouble to the page reclaim.
> + */
s/reducing/reduce/
Otherwise, it's enough detail to know what is going on. Thanks
Thanks
> + if (wbc->for_background &&
> + list_empty(dispatch_queue) && list_empty(&tmp)) {
> + expire_interval = 0;
> + continue;
> + }
> break;
> + }
> if (sb && sb != inode->i_sb)
> do_sb_sort = 1;
> sb = inode->i_sb;
>
--
Mel Gorman
Part-time Phd Student Linux Technology Center
University of Limerick IBM Dublin Software Lab
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