On Tue, Apr 01, 2014 at 02:31:31PM -0400, Rik van Riel wrote: > On 04/01/2014 12:21 PM, Linus Torvalds wrote: > > On Tue, Apr 1, 2014 at 9:11 AM, Rik van Riel <riel@xxxxxxxxxx> wrote: > >> > >> Memory pressure is not necessarily caused by the same process > >> whose accessed bit we just cleared. Memory pressure may not > >> even be caused by any process's virtual memory at all, but it > >> could be caused by the page cache. > > > > If we have that much memory pressure on the page cache without having > > any memory pressure on the actual VM space, then the swap-out activity > > will never be an issue anyway. > > > > IOW, I think all these scenarios are made-up. I'd much rather go for > > simpler implementation, and make things more complex only in the > > presence of numbers. Of which we have none. > > We've been bitten by the lack of a properly tracked accessed > bit before, but admittedly that was with the KVM code and EPT. > > I'll add my Acked-by: to Shaohua's original patch then, and > will keep my eyes open for any problems that may or may not > materialize... > > Shaohua? I'd agree to choose the simple implementation at current stage and check if there are problems really. Andrew, can you please pick up my orginal patch "x86: clearing access bit don't flush tlb" (with Rik's Ack)? Or I can resend it if you preferred. Thanks, Shaohua -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>