Hi Christoph, On Fri, Aug 11, 2017 at 12:46:15PM +0200, Christoph Hellwig wrote: > On Wed, Aug 09, 2017 at 08:06:24PM -0700, Dan Williams wrote: > > I like it, but do you think we should switch to sbvec[<constant>] to > > preclude pathological cases where nr_pages is large? > > Yes, please.
Still, I don't understand how sbvec[nr_pages] with on-stack bio in do_mpage_readpage can help the performance. IIUC, do_mpage_readpage works with page-base. IOW, it passes just one page, not multiple pages so if we use on-stack bio, we just add *a page* via bio_add_page and submit the bio before the function returning. So, rather than sbvec[1], why de we need sbvec[nr_pages]? Please, let me open my eyes. :) Thanks.
