On Wed, Oct 06, 2010 at 04:15:25AM +0800, Andrew Morton wrote: > > The patch titled > mm: retry page fault when blocking on disk transfer > has been added to the -mm tree. Its filename is > mm-retry-page-fault-when-blocking-on-disk-transfer.patch > > Before you just go and hit "reply", please: > a) Consider who else should be cc'ed > b) Prefer to cc a suitable mailing list as well > c) Ideally: find the original patch on the mailing list and do a > reply-to-all to that, adding suitable additional cc's > > *** Remember to use Documentation/SubmitChecklist when testing your code *** > > See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find > out what to do about this > > The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ > > ------------------------------------------------------ > Subject: mm: retry page fault when blocking on disk transfer > From: Michel Lespinasse <walken@xxxxxxxxxx> > > This change reduces mmap_sem hold times that are caused by waiting for > disk transfers when accessing file mapped VMAs. > > It introduces the VM_FAULT_ALLOW_RETRY flag, which indicates that the call > site wants mmap_sem to be released if blocking on a pending disk transfer. > In that case, filemap_fault() returns the VM_FAULT_RETRY status bit and > do_page_fault() will then re-acquire mmap_sem and retry the page fault. > > It is expected that the retry will hit the same page which will now be > cached, and thus it will complete with a low mmap_sem hold time. > > Signed-off-by: Michel Lespinasse <walken@xxxxxxxxxx> > Acked-by: Rik van Riel <riel@xxxxxxxxxx> Reviewed-by: Wu Fengguang <fengguang.wu@xxxxxxxxx> Also would like to see Ying Han's Signed-off-by :) Thanks, Fengguang -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
