On Tue, Jun 21, 2011 at 12:59:00PM +0100, P?draig Brady wrote: > On 21/06/11 12:34, Mel Gorman wrote: > > On Tue, Jun 21, 2011 at 11:47:35AM +0100, P?draig Brady wrote: > >> On 21/06/11 11:39, Mel Gorman wrote: > >>> On Tue, Jun 21, 2011 at 10:53:02AM +0100, P?draig Brady wrote: > >>>> I tried the 2 patches here to no avail: > >>>> http://marc.info/?l=linux-mm&m=130503811704830&w=2 > >>>> > >>>> I originally logged this at: > >>>> https://bugzilla.redhat.com/show_bug.cgi?id=712019 > >>>> > >>>> I can compile up and quickly test any suggestions. > >>>> > >>> > >>> I recently looked through what kswapd does and there are a number > >>> of problem areas. Unfortunately, I haven't gotten around to doing > >>> anything about it yet or running the test cases to see if they are > >>> really problems. In your case, the following is a strong possibility > >>> though. This should be applied on top of the two patches merged from > >>> that thread. > >>> > >>> This is not tested in any way, based on 3.0-rc3 > >> > >> This does not fix the issue here. > >> > > > > I made a silly mistake here. When you mentioned two patches applied, > > I assumed you meant two patches that were finally merged from that > > discussion thread instead of looking at your linked mail. Now that I > > have checked, I think you applied the SLUB patches while the patches > > I was thinking of are; > > > > [afc7e326: mm: vmscan: correct use of pgdat_balanced in sleeping_prematurely] > > [f06590bd: mm: vmscan: correctly check if reclaimer should schedule during shrink_slab] > > > > The first one in particular has been reported by another user to fix > > hangs related to copying large files. I'm assuming you are testing > > against the Fedora kernel. As these patches were merged for 3.0-rc1, can > > you check if applying just these two patches to your kernel helps? > > These patches are already present in my 2.6.38.8-32.fc15.x86_64 kernel :( > While doing a review of patches for unrelated reasons between 2.6.38 and 3.0-rc3, I noted a few patches related to high CPU usage that may not have made it to the Fedora kernel. * d527caf2 mm: compaction: prevent kswapd compacting memory to reduce CPU usage 8afdcece mm: vmscan: kswapd should not free an excessive number of pages when balancing small zones 602605a4 mm: compaction: minimise the time IRQs are disabled while isolating free pages b2eef8c0 mm: compaction: minimise the time IRQs are disabled while isolating pages for migration * 929bea7c vmscan: all_unreclaimable() use zone->all_unreclaimable as a name * afc7e326 mm: vmscan: correct use of pgdat_balanced in sleeping_prematurely * f06590bd mm: vmscan: correctly check if reclaimer should schedule during shrink_slab The ones marked * are already in 2.6.38.8 so presumably in the Fedora kernel as well but worth double checking. Of the remaining patches, patch 2 is the most relevant to your problem as it was explicitly targeted at reclaiming during copying large amounts of data. -- Mel Gorman SUSE Labs -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>