On Thu, Oct 22, 2009 at 05:47:10PM +0300, Pekka Enberg wrote: > On Thu, Oct 22, 2009 at 5:22 PM, Mel Gorman <mel@xxxxxxxxx> wrote: > > Test 1: Verify your problem occurs on 2.6.32-rc5 if you can > > > > Test 2: Apply the following two patches and test again > > > > 1/5 page allocator: Always wake kswapd when restarting an allocation attempt after direct reclaim failed > > 2/5 page allocator: Do not allow interrupts to use ALLOC_HARDER > > These are pretty obvious bug fixes and should go to linux-next ASAP IMHO. > Agreed, but I wanted to pin down where exactly we stand with this problem before sending patches any direction for merging. > > Test 5: If things are still screwed, apply the following > > 5/5 Revert 373c0a7e, 8aa7e847: Fix congestion_wait() sync/async vs read/write confusion > > > > Frans Pop reports that the bulk of his problems go away when this > > patch is reverted on 2.6.31. There has been some confusion on why > > exactly this patch was wrong but apparently the conversion was not > > complete and further work was required. It's unknown if all the > > necessary work exists in 2.6.31-rc5 or not. If there are still > > allocation failures and applying this patch fixes the problem, > > there are still snags that need to be ironed out. > > As explained by Jens Axboe, this changes timing but is not the source > of the OOMs so the revert is bogus even if it "helps" on some > workloads. IIRC the person who reported the revert to help things did > report that the OOMs did not go away, they were simply harder to > trigger with the revert. > IIRC, there were mixed reports as to how much the revert helped. I'm hoping that patches 1+2 cover the bases hence why I asked them to be tested on their own. Patch 2 in particular might be responsible for watermarks being impacted enough to cause timing problems. I left reverting with patch 5 as a standalone test to see how much of a factor the timing changes introduced are if there are still allocation problems. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- To unsubscribe from this list: send the line "unsubscribe kernel-testers" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
