Excessive xfs_inode allocations trigger OOM killer

[Michal Hocko]

[fixup linux-mm address]

On Wed 21-09-16 10:04:25, Michal Hocko wrote:
> On Wed 21-09-16 07:46:12, Dave Chinner wrote:
> > [cc Michal, linux-mm at kvack.org]
> > 
> > On Tue, Sep 20, 2016 at 10:56:31PM +0200, Florian Weimer wrote:
> [...]
> > > [51669.515086] make invoked oom-killer: gfp_mask=0x27000c0(GFP_KERNEL_ACCOUNT|__GFP_NOTRACK), order=2, oom_score_adj=0
> > > [51669.515092] CPU: 1 PID: 1202 Comm: make Tainted: G          I     4.7.1fw #1
> > > [51669.515093] Hardware name: System manufacturer System Product Name/P6X58D-E, BIOS 0701    05/10/2011
> > > [51669.515095]  0000000000000000 ffffffff812a7d39 0000000000000000 0000000000000000
> > > [51669.515098]  ffffffff8114e4da ffff880018707d98 0000000000000000 000000000066ca81
> > > [51669.515100]  ffffffff8170e88d ffffffff810fe69e ffff88033fc38728 0000000200000006
> > > [51669.515102] Call Trace:
> > > [51669.515108]  [<ffffffff812a7d39>] ? dump_stack+0x46/0x5d
> > > [51669.515113]  [<ffffffff8114e4da>] ? dump_header.isra.12+0x51/0x176
> > > [51669.515116]  [<ffffffff810fe69e>] ? oom_kill_process+0x32e/0x420
> > > [51669.515119]  [<ffffffff811003a0>] ? page_alloc_cpu_notify+0x40/0x40
> > > [51669.515120]  [<ffffffff810fdcdc>] ? find_lock_task_mm+0x2c/0x70
> > > [51669.515122]  [<ffffffff810fea6d>] ? out_of_memory+0x28d/0x2d0
> > > [51669.515125]  [<ffffffff81103137>] ? __alloc_pages_nodemask+0xb97/0xc90
> > > [51669.515128]  [<ffffffff81076d9c>] ? copy_process.part.54+0xec/0x17a0
> > > [51669.515131]  [<ffffffff81123318>] ? handle_mm_fault+0xaa8/0x1900
> > > [51669.515133]  [<ffffffff81078614>] ? _do_fork+0xd4/0x320
> > > [51669.515137]  [<ffffffff81084ecc>] ? __set_current_blocked+0x2c/0x40
> > > [51669.515140]  [<ffffffff810013ce>] ? do_syscall_64+0x3e/0x80
> > > [51669.515144]  [<ffffffff8151433c>] ? entry_SYSCALL64_slow_path+0x25/0x25
> > .....
> > > [51669.515194] DMA: 1*4kB (U) 1*8kB (U) 1*16kB (U) 0*32kB 2*64kB (U) 1*128kB (U) 1*256kB (U) 0*512kB 1*1024kB (U) 1*2048kB (M) 3*4096kB (M) = 15900kB
> > > [51669.515202] DMA32: 45619*4kB (UME) 73*8kB (UM) 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 183060kB
> > > [51669.515209] Normal: 39979*4kB (UE) 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 159916kB
> > .....
> > 
> > Alright, that's what I suspected. high order allocation for a new
> > kernel stack and memory is so fragmented that a contiguous
> > allocation fails. Really, this is a memory reclaim issue, not an XFS
> > issue.  There is lots of reclaimable memory available, but memory
> > reclaim is:
> > 
> > 	a) not trying hard enough to reclaim reclaimable memory; and
> > 	b) not waiting for memory compaction to rebuild contiguous
> > 	   memory regions for high order allocations.
> > 
> > Instead, it is declaring OOM and kicking the killer to free memory
> > held busy userspace.
> 
> Yes this was the case with 4.7 kernel. There is a workaround sitting in
> the linus tree 6b4e3181d7bd ("mm, oom: prevent premature OOM killer
> invocation for high order request") which should get to stable
> eventually. More approapriate fix is currently in the linux-next.
> 
> Testing the same workload with linux-next would be very helpful.
> 
> Thanks!
> 
> -- 
> Michal Hocko
> SUSE Labs

-- 
Michal Hocko
SUSE Labs