Messages in this thread | | | Date | Wed, 2 Dec 2015 13:00:46 +0100 | From | Michal Hocko <> | Subject | Re: [lkp] [mm, page_alloc] d0164adc89: -100.0% fsmark.app_overhead |
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On Wed 02-12-15 11:00:09, Mel Gorman wrote: > On Mon, Nov 30, 2015 at 10:14:24AM +0800, Huang, Ying wrote: > > > There is no reference to OOM possibility in the email that I can see. Can > > > you give examples of the OOM messages that shows the problem sites? It was > > > suspected that there may be some callers that were accidentally depending > > > on access to emergency reserves. If so, either they need to be fixed (if > > > the case is extremely rare) or a small reserve will have to be created > > > for callers that are not high priority but still cannot reclaim. > > > > > > Note that I'm travelling a lot over the next two weeks so I'll be slow to > > > respond but I will get to it. > > > > Here is the kernel log, the full dmesg is attached too. The OOM > > occurs during fsmark testing. > > > > Best Regards, > > Huang, Ying > > > > [ 31.453514] kworker/u4:0: page allocation failure: order:0, mode:0x2200000 > > [ 31.463570] CPU: 0 PID: 6 Comm: kworker/u4:0 Not tainted 4.3.0-08056-gd0164ad #1 > > [ 31.466115] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014 > > [ 31.477146] Workqueue: writeback wb_workfn (flush-253:0) > > [ 31.481450] 0000000000000000 ffff880035ac75e8 ffffffff8140a142 0000000002200000 > > [ 31.492582] ffff880035ac7670 ffffffff8117117b ffff880037586b28 ffff880000000040 > > [ 31.507631] ffff88003523b270 0000000000000040 ffff880035abc800 ffffffff00000000 > > This is an allocation failure and is not a triggering of the OOM killer so > the severity is reduced but it still looks like a bug in the driver. Looking > at the history and the discussion, it appears to me that __GFP_HIGH was > cleared from the allocation site by accident. I strongly suspect that Will > Deacon thought __GFP_HIGH was related to highmem instead of being related > to high priority. Will, can you review the following patch please? Ying, > can you test please?
I have posted basically the same patch http://lkml.kernel.org/r/1448980369-27130-1-git-send-email-mhocko@kernel.org
I didn't mention this allocation failure because I am not sure it is really related.
> ---8<--- > virtio: allow vring descriptor allocations to use high-priority reserves > > Commit b92b1b89a33c ("virtio: force vring descriptors to be allocated > from lowmem") prevented the inappropriate use of highmem pages but it > also masked out __GFP_HIGH. __GFP_HIGH is used for GFP_ATOMIC allocation > requests to grant access to a small emergency reserve. It's intended for > user by callers that have no alternative. > > Ying Huang reported the following page allocation failure warning after > commit d0164adc89f6 ("mm, page_alloc: distinguish between being unable to > sleep, unwilling to sleep and avoiding waking kswapd") > > kworker/u4:0: page allocation failure: order:0, mode:0x2200000 > CPU: 0 PID: 6 Comm: kworker/u4:0 Not tainted 4.3.0-08056-gd0164ad #1 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014 > Workqueue: writeback wb_workfn (flush-253:0) > 0000000000000000 ffff880035ac75e8 ffffffff8140a142 0000000002200000 > ffff880035ac7670 ffffffff8117117b ffff880037586b28 ffff880000000040 > ffff88003523b270 0000000000000040 ffff880035abc800 ffffffff00000000 > Call Trace: > [<ffffffff8140a142>] dump_stack+0x4b/0x69 > [<ffffffff8117117b>] warn_alloc_failed+0xdb/0x140 > [<ffffffff81174ec4>] __alloc_pages_nodemask+0x874/0xa60 > [<ffffffff811bcb62>] alloc_pages_current+0x92/0x120 > [<ffffffff811c73e4>] new_slab+0x3d4/0x480 > [<ffffffff811c7c36>] __slab_alloc+0x376/0x470 > [<ffffffff814e0ced>] ? alloc_indirect+0x1d/0x50 > [<ffffffff81338221>] ? xfs_submit_ioend_bio+0x31/0x40 > [<ffffffff814e0ced>] ? alloc_indirect+0x1d/0x50 > [<ffffffff811c8e8d>] __kmalloc+0x20d/0x260 > [<ffffffff814e0ced>] alloc_indirect+0x1d/0x50 > [<ffffffff814e0fec>] virtqueue_add_sgs+0x2cc/0x3a0 > [<ffffffff81573a30>] __virtblk_add_req+0xb0/0x1f0 > [<ffffffff8117a121>] ? pagevec_lookup_tag+0x21/0x30 > [<ffffffff813e5d72>] ? blk_rq_map_sg+0x1e2/0x4f0 > [<ffffffff81573c82>] virtio_queue_rq+0x112/0x280 > [<ffffffff813e9de7>] __blk_mq_run_hw_queue+0x1d7/0x370 > [<ffffffff813e9bef>] blk_mq_run_hw_queue+0x9f/0xc0 > [<ffffffff813eb10a>] blk_mq_insert_requests+0xfa/0x1a0 > [<ffffffff813ebdb3>] blk_mq_flush_plug_list+0x123/0x140 > [<ffffffff813e1777>] blk_flush_plug_list+0xa7/0x200 > [<ffffffff813e1c49>] blk_finish_plug+0x29/0x40 > [<ffffffff81215f85>] wb_writeback+0x185/0x2c0 > [<ffffffff812166a5>] wb_workfn+0xf5/0x390 > [<ffffffff81091297>] process_one_work+0x157/0x420 > [<ffffffff81091ef9>] worker_thread+0x69/0x4a0 > [<ffffffff81091e90>] ? rescuer_thread+0x380/0x380 > [<ffffffff8109746f>] kthread+0xef/0x110 > [<ffffffff81097380>] ? kthread_park+0x60/0x60 > [<ffffffff818bce8f>] ret_from_fork+0x3f/0x70 > [<ffffffff81097380>] ? kthread_park+0x60/0x60 > > Commit d0164adc89f6 ("mm, page_alloc: distinguish between being unable to > sleep, unwilling to sleep and avoiding waking kswapd") is stricter about > reserves. It distinguishes between callers that are high-priority with > access to emergency reserves and callers that simply do not want to sleep > and have recovery options. The reported allocation failure is truly atomic > with no recovery options that appears to have cleared __GFP_HIGH by mistake > for reasons that are unrelated to highmem. This patch restores the flag. > > Signed-off-by: Mel Gorman <mgorman@techsingularity.net> > --- > drivers/virtio/virtio_ring.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > index 096b857e7b75..f9e119e6df18 100644 > --- a/drivers/virtio/virtio_ring.c > +++ b/drivers/virtio/virtio_ring.c > @@ -107,9 +107,10 @@ static struct vring_desc *alloc_indirect(struct virtqueue *_vq, > /* > * We require lowmem mappings for the descriptors because > * otherwise virt_to_phys will give us bogus addresses in the > - * virtqueue. > + * virtqueue. Access to high-priority reserves is preserved > + * if originally requested by GFP_ATOMIC. > */ > - gfp &= ~(__GFP_HIGHMEM | __GFP_HIGH); > + gfp &= ~__GFP_HIGHMEM; > > desc = kmalloc(total_sg * sizeof(struct vring_desc), gfp); > if (!desc)
-- Michal Hocko SUSE Labs
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