On Mon, Aug 22, 2016 at 11:37:07AM +0200, Michal Hocko wrote: > [ups, fixing up Greg's email] > > On Mon 22-08-16 11:32:49, Michal Hocko wrote: > > Hi, > > there have been multiple reports [1][2][3][4][5] about pre-mature OOM > > killer invocations since 4.7 which contains oom detection rework. All of > > them were for order-2 (kernel stack) alloaction requests failing because > > of a high fragmentation and compaction failing to make any forward > > progress. While investigating this we have found out that the compaction > > just gives up too early. Vlastimil has been working on compaction > > improvement for quite some time and his series [6] is already sitting > > in mmotm tree. This already helps a lot because it drops some heuristics > > which are more aimed at lower latencies for high orders rather than > > reliability. Joonsoo has then identified further problem with too many > > blocks being marked as unmovable [7] and Vlastimil has prepared a patch > > on top of his series [8] which is also in the mmotm tree now. > > > > That being said, the regression is real and should be fixed for 4.7 > > stable users. [6][8] was reported to help and ooms are no longer > > reproducible. I know we are quite late (rc3) in 4.8 but I would vote > > for mergeing those patches and have them in 4.8. For 4.7 I would go > > with a partial revert of the detection rework for high order requests > > (see patch below). This patch is really trivial. If those compaction > > improvements are just too large for 4.8 then we can use the same patch > > as for 4.7 stable for now and revert it in 4.9 after compaction changes > > are merged. > > > > Thoughts? > > > > [1] http://lkml.kernel.org/r/20160731051121.GB307@x4 > > [2] http://lkml.kernel.org/r/201608120901.41463.a.miskiewicz@xxxxxxxxx > > [3] http://lkml.kernel.org/r/20160801192620.GD31957@xxxxxxxxxxxxxx > > [4] https://lists.opensuse.org/opensuse-kernel/2016-08/msg00021.html > > [5] https://bugzilla.opensuse.org/show_bug.cgi?id=994066 > > [6] http://lkml.kernel.org/r/20160810091226.6709-1-vbabka@xxxxxxx > > [7] http://lkml.kernel.org/r/20160816031222.GC16913@js1304-P5Q-DELUXE > > [8] http://lkml.kernel.org/r/f7a9ea9d-bb88-bfd6-e340-3a933559305a@xxxxxxx > > > > --- > > From 899b738538de41295839dca2090a774bdd17acd2 Mon Sep 17 00:00:00 2001 > > From: Michal Hocko <mhocko@xxxxxxxx> > > Date: Mon, 22 Aug 2016 10:52:06 +0200 > > Subject: [PATCH] mm, oom: prevent pre-mature OOM killer invocation for high > > order request > > > > There have been several reports about pre-mature OOM killer invocation > > in 4.7 kernel when order-2 allocation request (for the kernel stack) > > invoked OOM killer even during basic workloads (light IO or even kernel > > compile on some filesystems). In all reported cases the memory is > > fragmented and there are no order-2+ pages available. There is usually > > a large amount of slab memory (usually dentries/inodes) and further > > debugging has shown that there are way too many unmovable blocks which > > are skipped during the compaction. Multiple reporters have confirmed that > > the current linux-next which includes [1] and [2] helped and OOMs are > > not reproducible anymore. A simpler fix for the stable is to simply > > ignore the compaction feedback and retry as long as there is a reclaim > > progress for high order requests which we used to do before. We already > > do that for CONFING_COMPACTION=n so let's reuse the same code when > > compaction is enabled as well. > > > > [1] http://lkml.kernel.org/r/20160810091226.6709-1-vbabka@xxxxxxx > > [2] http://lkml.kernel.org/r/f7a9ea9d-bb88-bfd6-e340-3a933559305a@xxxxxxx > > > > Fixes: 0a0337e0d1d1 ("mm, oom: rework oom detection") > > Signed-off-by: Michal Hocko <mhocko@xxxxxxxx> > > --- > > mm/page_alloc.c | 50 ++------------------------------------------------ > > 1 file changed, 2 insertions(+), 48 deletions(-) So, if this goes into Linus's tree, can you let stable@xxxxxxxxxxxxxxx know about it so we can add it to the 4.7-stable tree? Otherwise there's not much I can do here now, right? thanks, greg k-h -- 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>