On Wed, Nov 04, 2009 at 03:05:55AM +0100, Frans Pop wrote: > On Wednesday 04 November 2009, Mel Gorman wrote: > > > If you'd like me to test with the congestion_wait() revert on top of > > > this for comparison, please let me know. > > > > No, there is resistance to rolling back the congestion_wait() changes > > I've never promoted the revert as a solution. It just shows the cause of a > regression. > Yeah, I still haven't managed to figure out what exactly is wrong in there other than "something changed with timing" and writeback behaves differently. I still don't know the why of it because I haven't digged into that area in depth in the past and failed at reproducing this. "My desktop is fine" :/ > > from what I gather because they were introduced for sane reasons. The > > consequence is just that the reliability of high-order atomics are > > impacted because more processes are making forward progress where > > previously they would have waited until kswapd had done work. Your > > driver has already been fixed in this regard and maybe it's a case that > > the other atomic users simply have to be fixed to "not do that". > > The problem is that although my driver has been fixed so that it no longer > causes the SKB allocation errors, the also rather serious behavior change > where due to swapping my 3rd gitk takes up to twice as long to load with > desktop freezes of up 45 seconds or so is still there. > > Although that's somewhat separate from the issue that started this whole > investigation, I still feel that should be sorted out as well. > You're right. That behaviour sucks. > The congestion_wait() change, even if theoretically valid, introduced a > very real regression IMO. Such long desktop freezes during swapping should > be avoided; .30 and earlier simply behaved a whole lot better in the same > situation. > Agreed. I'll start from scratch again trying to reproduce what you're seeing locally. I'll try breaking my network card so that it's making high-order atomics and see where I get. Machines that were previously tied up are now free so I might have a better chance. -- 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
