On Thu, 19 Dec 2013 15:41:34 +0100 Michal Hocko <mhocko@xxxxxxx> wrote: > On Wed 18-12-13 22:09:12, David Rientjes wrote: > > On Wed, 18 Dec 2013, Michal Hocko wrote: > > > > > > For memory isolation, we'd only want to bypass memcg charges when > > > > absolutely necessary and it seems like TIF_MEMDIE is the only case where > > > > that's required. We don't give processes with pending SIGKILLs or those > > > > in the exit() path access to memory reserves in the page allocator without > > > > first determining that reclaim can't make any progress for the same reason > > > > and then we only do so by setting TIF_MEMDIE when calling the oom killer. > > > > > > While I do understand arguments about isolation I would also like to be > > > practical here. How many charges are we talking about? Dozen pages? Much > > > more? > > > > The PF_EXITING bypass is indeed much less concerning than the > > fatal_signal_pending() bypass. I just spent a happy half hour reliving this thread and ended up deciding I agreed with everyone! I appears that many more emails are needed so I think I'll drop http://ozlabs.org/~akpm/mmots/broken-out/mm-memcg-avoid-oom-notification-when-current-needs-access-to-memory-reserves.patch for now. The claim that mm-memcg-avoid-oom-notification-when-current-needs-access-to-memory-reserves.patch will impact existing userspace seems a bit dubious to me. > OK, so can we at least agree on the patch posted here: > https://lkml.org/lkml/2013/12/12/129. This is a real bug and definitely > worth fixing. Yes, can we please get Eric's bug fixed? I don't believe that Eric has tested either https://lkml.org/lkml/2013/12/12/129 or http://ozlabs.org/~akpm/mmots/broken-out/mm-memcg-avoid-oom-notification-when-current-needs-access-to-memory-reserves.patch. Is he the only person who can reproduce this? -- 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>