On Thu 15-09-16 10:41:18, Johannes Weiner wrote: > Hi Michal, > > On Thu, Sep 01, 2016 at 11:51:00AM +0200, Michal Hocko wrote: > > Hi, > > this is an early RFC to see whether the approach I've taken is acceptable. > > The series is on top of the current mmotm tree (2016-08-31-16-06). I didn't > > get to test it so it might be completely broken. > > > > The primary point of this series is to get rid of TIF_MEMDIE finally. > > Recent changes in the oom proper allows for that finally, I believe. Now > > that all the oom victims are reapable we are no longer depending on > > ALLOC_NO_WATERMARKS because the memory held by the victim is reclaimed > > asynchronously. A partial access to memory reserves should be sufficient > > just to guarantee that the oom victim is not starved due to other > > memory consumers. This also means that we do not have to pretend to be > > conservative and give access to memory reserves only to one thread from > > the process at the time. This is patch 1. > > > > Patch 2 is a simple cleanup which turns TIF_MEMDIE users to tsk_is_oom_victim > > which is process rather than thread centric. None of those callers really > > requires to be thread aware AFAICS. > > > > The tricky part then is exit_oom_victim vs. oom_killer_disable because > > TIF_MEMDIE acted as a token there so we had a way to count threads from > > the process. It didn't work 100% reliably and had it own issues but we > > have to replace it with something which doesn't rely on counting threads > > but rather find a moment when all threads have reached steady state in > > do_exit. This is what patch 3 does and I would really appreciate if Oleg > > could double check my thinking there. I am also CCing Al on that one > > because I am moving exit_io_context up in do_exit right before exit_notify. > > You're explaining the mechanical thing you are doing, but I'm having > trouble understanding why you want to get rid of TIF_MEMDIE. For one, > it's more code. And apparently, it's also more complicated than what > we have right now. > > Can you please explain in the cover letter what's broken/undesirable? Sure, I will extend the cover when submitting the series again. This RFC was mostly aimed at correctness so I focused more on technical details. Patch 1 should contain some reasoning. Do you find it sufficient or I should extend on top of that? Thanks! -- Michal Hocko 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/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>