On Tue 20-12-16 14:49:01, Michal Hocko wrote: > Hi, > This has been posted [1] initially to later be reduced to a single patch > [2]. Johannes then suggested [3] to split up the second patch and make > the access to memory reserves by __GF_NOFAIL requests which do not > invoke the oom killer a separate change. This is patch 3 now. > > Tetsuo has noticed [4] that recent changes have changed GFP_NOFAIL > semantic for costly order requests. I believe that the primary reason > why this happened is that our GFP_NOFAIL checks are too scattered > and it is really easy to forget about adding one. That's why I am > proposing patch 1 which consolidates all the nofail handling at a single > place. This should help to make this code better maintainable. > > Patch 2 on top is a further attempt to make GFP_NOFAIL semantic less > surprising. As things stand currently GFP_NOFAIL overrides the oom killer > prevention code which is both subtle and not really needed. The patch 2 > has more details about issues this might cause. We have also seen > a report where __GFP_NOFAIL|GFP_NOFS requests cause the oom killer which > is premature. > > Patch 3 is an attempt to reduce chances of GFP_NOFAIL requests being > preempted by other memory consumers by giving them access to memory > reserves. > > [1] http://lkml.kernel.org/r/20161123064925.9716-1-mhocko@xxxxxxxxxx > [2] http://lkml.kernel.org/r/20161214150706.27412-1-mhocko@xxxxxxxxxx > [3] http://lkml.kernel.org/r/20161216173151.GA23182@xxxxxxxxxxx > [4] http://lkml.kernel.org/r/1479387004-5998-1-git-send-email-penguin-kernel@xxxxxxxxxxxxxxxxxxx Friendly ping on this. -- 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>