Re: [PATCH 0/6] writeback: moving expire targets for background/kupdate works

Christoph Hellwig
2011-04-21T05:56:46Z

On Thu, Apr 21, 2011 at 01:50:31PM +0800, Wu Fengguang wrote:
> Hi Christoph,
>
> On Thu, Apr 21, 2011 at 12:34:50PM +0800, Christoph Hellwig wrote:
> > Hi Wu,
> >
> > if you're queueing up writeback changes can you look into splitting
> > inode_wb_list_lock as it was done in earlier versions of the inode
> > scalability patches? Especially if we don't get the I/O less
> > balance_dirty_pages in ASAP it'll at least allows us to scale the
> > busy waiting for the list manipulationes to one CPU per BDI.
>
> Do you mean to split inode_wb_list_lock into struct bdi_writeback?
> So as to improve at least the JBOD case now and hopefully benefit the
> 1-bdi case when switching to multiple bdi_writeback per bdi in future?
>
> I've not touched any locking code before, but it looks like some dumb
> code replacement. Let me try it :)

I can do the patch if you want, it would be useful to carry it in your
series to avoid conflicts, though.