From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <391777D4.86460218@sgi.com> Date: Mon, 08 May 2000 19:28:36 -0700 From: Rajagopal Ananthanarayanan MIME-Version: 1.0 Subject: Re: [DATAPOINT] pre7-6 will not swap References: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: "Quintela Carreira Juan J." Cc: Linus Torvalds , Andrea Arcangeli , Benjamin Redelings I , linux-mm@kvack.org List-ID: "Quintela Carreira Juan J." wrote: > > >>>>> "linus" == Linus Torvalds writes: > > linus> in vmscan.c, and that seems to be quite well-behaved too (but if somebody > linus> has the energy to test the two different versions, I'd absolutely love to > linus> hear results..) > > Hi Linus, > I have tested two versions of the patch (against vanilla > pre7-6), the first was to remove the test altogether (I think this is > from Rajagopal): > > --- pre7-6/mm/vmscan.c Fri May 5 23:58:56 2000 > +++ testing/mm/vmscan.c Mon May 8 23:30:52 2000 > @@ -114,8 +114,9 @@ > * Don't do any of the expensive stuff if > * we're not really interested in this zone. > */ > - if (!page->zone->zone_wake_kswapd) > +/* if (!page->zone->zone_wake_kswapd) > goto out_unlock; > +*/ > I'm having the same experience too. The one thing that makes stuff better is not to look at the zone at all in try_to_swap_out (as Juan points out above). I'm trying to also see if we can do better in shrink_mmap(). Although my gprof statistics say that we can end-up spending 91% of the time skipping pages, I'm not able to comeup with anything simple to make shrink_mmap behave better ... except one change which makes swapping a lot less and shrink_mmap a lot more agressive: don't skip pages based on zone's high water mark if we are trying hard to free pages (my heuristic was to stop skipping pages if priority in shrink_mmap was 3; YMMV). I'm not entirely convinced that this is the right thing to do. In all, I do think that try_to_swap_out shouldn't skip pages based on zones. We have now evidence from 3 different "workloads" in this direction --- my own dbench test, Juan's test above & Benjamin's "gaming" workload. -------------------------------------------------------------------------- Rajagopal Ananthanarayanan ("ananth") Member Technical Staff, SGI. -------------------------------------------------------------------------- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux.eu.org/Linux-MM/