On Wednesday, October 08, 2014 04:07:43 PM Michal Hocko wrote: > Hi Andrew, Rafael, > > this has been originally discussed here [1] but didn't lead anywhere AFAICS > so I would like to resurrect them. OK So any chance to CC linux-pm too next time? There are people on that list who may be interested as well and are not in the CC directly either. > The first and third patch are regression fixes and they are a stable > material IMO. The second patch is a simple cleanup. > > The 1st patch is fixing a regression introduced in 3.3 since when OOM > killer is not able to kill any frozen task and live lock as a result. > The fix gets us back to the 3.2. As it turned out during the discussion [2] > this was still not 100% sufficient and that's why we need the 3rd patch. > > I was thinking about the proper 1st vs. 3rd patch ordering because > the 1st patch basically opens a race window fixed by the later patch. > Original patch from Cong Wang has covered this by cgroup_freezing(current) > check in should_thaw_current(). But this approach still suffers from OOM > vs. PM freezer interaction (OOM killer would still live lock waiting for a > PM frozen task this time). > > So I think the most straight forward way is to address only OOM vs. > frozen task interaction in the first patch, mark it for stable 3.3+ and > leave the race to a separate follow up patch which is applicable to > stable 3.2+ (before a3201227f803 made it inefficient). > > Switching 1st and 3rd patches would make some sense as well but then > it might end up even more confusing because we would be fixing a > non-existent issue in upstream first... > > --- > [1] http://marc.info/?l=linux-kernel&m=140986986423092 > [2] http://marc.info/?l=linux-kernel&m=141074263721166 > I'm fine with the approach in general, but I need to stare at patch 3 for a little bit longer before I ACK it. Which may not happen really soon as I'll be rather busy on Thu/Fri and then I'll be traveling to the LPC/LCEU next week. -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- 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>