On Tue, Oct 5, 2010 at 10:38 AM, Rik van Riel <riel@xxxxxxxxxx> wrote: > On 10/05/2010 03:53 AM, Michel Lespinasse wrote: >> >> 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> > > Looks like it should be relatively easy to do something > similar in do_swap_page also. Good idea. We don't make use of swap too much, which is probably why we didn't have that in our kernel, but it seems like a good idea just for uniformity. I'll add this in a follow-on patch. -- Michel "Walken" Lespinasse A program is never fully debugged until the last user dies. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>