Re: [BUG] fatal hang untarring 90GB file, possibly writeback related.

Mel Gorman
2011-05-11T09:16:20Z

On Wed, May 11, 2011 at 02:38:09AM +0530, Raghavendra D Prabhu wrote:
> * On Tue, May 10, 2011 at 10:29:57AM -0500, James Bottomley <James.Bottomley@HansenPartnership.com> wrote:
> >On Tue, 2011-05-10 at 15:35 +0100, Mel Gorman wrote:
> >>On Tue, May 10, 2011 at 09:01:04AM -0500, James Bottomley wrote:
> >>> On Tue, 2011-05-10 at 11:21 +0100, Mel Gorman wrote:
> >>> > I really would like to hear if the fix makes a big difference or
> >>> > if we need to consider forcing SLUB high-order allocations bailing
> >>> > at the first sign of trouble (e.g. by masking out __GFP_WAIT in
> >>> > allocate_slab). Even with the fix applied, kswapd might be waking up
> >>> > less but processes will still be getting stalled in direct compaction
> >>> > and direct reclaim so it would still be jittery.
>
> >>> "the fix" being this
>
> >>> https://lkml.org/lkml/2011/3/5/121
>
>
> >>Drop this for the moment. It was a long shot at best and there is little
> >>evidence the problem is in this area.
>
> >>I'm attaching two patches. The first is the NO_KSWAPD one to stop
> >>kswapd being woken up by SLUB using speculative high-orders. The second
> >>one is more drastic and prevents slub entering direct reclaim or
> >>compaction. It applies on top of patch 1. These are both untested and
> >>afraid are a bit rushed as well :(
> >
> >Preliminary results with both patches applied still show kswapd
> >periodically going up to 99% but it doesn't stay there, it comes back
> >down again (and, obviously, the system doesn't hang).
> >
> >This is sysrq-M from a couple of times when it went up there:
> >
> >[ 426.736958] SysRq : Show Memory
> >[ 426.736974] Mem-Info:
> >[ 426.736977] Node 0 DMA per-cpu:
> >[ 426.736983] CPU 0: hi: 0, btch: 1 usd: 0
> >[ 426.736986] CPU 1: hi: 0, btch: 1 usd: 0
> >[ 426.736989] CPU 2: hi: 0, btch: 1 usd: 0
> >[ 426.736993] CPU 3: hi: 0, btch: 1 usd: 0
> >[ 426.736996] Node 0 DMA32 per-cpu:
> >[ 426.737002] CPU 0: hi: 186, btch: 31 usd: 169
> >[ 426.737005] CPU 1: hi: 186, btch: 31 usd: 40
> >[ 426.737009] CPU 2: hi: 186, btch: 31 usd: 166
> >[ 426.737012] CPU 3: hi: 186, btch: 31 usd: 168
> >[ 426.737015] Node 0 Normal per-cpu:
> >[ 426.737020] CPU 0: hi: 0, btch: 1 usd: 0
> >[ 426.737024] CPU 1: hi: 0, btch: 1 usd: 0
> >[ 426.737027] CPU 2: hi: 0, btch: 1 usd: 0
> >[ 426.737030] CPU 3: hi: 0, btch: 1 usd: 0
> >[ 426.737036] active_anon:108658 inactive_anon:37031 isolated_anon:0
> >[ 426.737037] active_file:32006 inactive_file:41051 isolated_file:32
> >[ 426.737038] unevictable:8 dirty:41202 writeback:204 unstable:0
> >[ 426.737039] free:191520 slab_reclaimable:8490 slab_unreclaimable:27477
> >[ 426.737039] mapped:9176 shmem:26412 pagetables:5427 bounce:0
> >[ 426.737051] Node 0 DMA free:8140kB min:548kB low:684kB high:820kB active_anon:0kB inactive_anon:12kB active_file:240kB inactive_file:7280kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:15676kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:180kB slab_unreclaimable:16kB kernel_stack:0kB pagetables:0kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
> >[ 426.737064] lowmem_reserve[]: 0 1856 1862 1862
> >[ 426.737078] Node 0 DMA32 free:757892kB min:66820kB low:83524kB high:100228kB active_anon:434632kB inactive_anon:148112kB active_file:127784kB inactive_file:156924kB unevictable:32kB isolated(anon):0kB isolated(file):0kB present:1901408kB mlocked:32kB dirty:164808kB writeback:816kB mapped:36704kB shmem:105648kB slab_reclaimable:33676kB slab_unreclaimable:108372kB kernel_stack:2304kB pagetables:21708kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:160 all_unreclaimable? no
> >[ 426.737092] lowmem_reserve[]: 0 0 5 5
> >[ 426.737106] Node 0 Normal free:48kB min:212kB low:264kB high:316kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:6060kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:104kB slab_unreclaimable:1520kB kernel_stack:176kB pagetables:0kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? yes
> >[ 426.737119] lowmem_reserve[]: 0 0 0 0
> >[ 426.737132] Node 0 DMA: 3*4kB 2*8kB 1*16kB 1*32kB 2*64kB 2*128kB 2*256kB 2*512kB 2*1024kB 2*2048kB 0*4096kB = 8140kB
> >[ 426.737174] Node 0 DMA32: 945*4kB 585*8kB 6469*16kB 4871*32kB 3189*64kB 1338*128kB 228*256kB 58*512kB 24*1024kB 1*2048kB 0*4096kB = 757884kB
> >[ 426.737227] Node 0 Normal: 2*4kB 5*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 48kB
> >[ 426.737257] 99595 total pagecache pages
> >[ 426.737260] 0 pages in swap cache
> >[ 426.737263] Swap cache stats: add 0, delete 0, find 0/0
> >[ 426.737266] Free swap = 3768316kB
> >[ 426.737268] Total swap = 3768316kB
> >[ 426.744603] 525808 pages RAM
> >[ 426.744612] 57618 pages reserved
> >[ 426.744614] 141551 pages shared
> >[ 426.744617] 186065 pages non-shared
> >[ 472.301810] SysRq : Show Memory
> >[ 472.301826] Mem-Info:
> >[ 472.301829] Node 0 DMA per-cpu:
> >[ 472.301835] CPU 0: hi: 0, btch: 1 usd: 0
> >[ 472.301839] CPU 1: hi: 0, btch: 1 usd: 0
> >[ 472.301842] CPU 2: hi: 0, btch: 1 usd: 0
> >[ 472.301845] CPU 3: hi: 0, btch: 1 usd: 0
> >[ 472.301848] Node 0 DMA32 per-cpu:
> >[ 472.301854] CPU 0: hi: 186, btch: 31 usd: 184
> >[ 472.301857] CPU 1: hi: 186, btch: 31 usd: 46
> >[ 472.301860] CPU 2: hi: 186, btch: 31 usd: 158
> >[ 472.301863] CPU 3: hi: 186, btch: 31 usd: 163
> >[ 472.301866] Node 0 Normal per-cpu:
> >[ 472.301871] CPU 0: hi: 0, btch: 1 usd: 0
> >[ 472.301874] CPU 1: hi: 0, btch: 1 usd: 0
> >[ 472.301878] CPU 2: hi: 0, btch: 1 usd: 0
> >[ 472.301881] CPU 3: hi: 0, btch: 1 usd: 0
> >[ 472.301886] active_anon:107673 inactive_anon:37031 isolated_anon:0
> >[ 472.301887] active_file:31533 inactive_file:33323 isolated_file:32
> >[ 472.301888] unevictable:8 dirty:26256 writeback:6475 unstable:0
> >[ 472.301889] free:198742 slab_reclaimable:9347 slab_unreclaimable:28647
> >[ 472.301889] mapped:8307 shmem:26412 pagetables:5427 bounce:0
> >[ 472.301901] Node 0 DMA free:8140kB min:548kB low:684kB high:820kB active_anon:0kB inactive_anon:12kB active_file:240kB inactive_file:7280kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:15676kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:180kB slab_unreclaimable:16kB kernel_stack:0kB pagetables:0kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
> >[ 472.301915] lowmem_reserve[]: 0 1856 1862 1862
> >[ 472.301928] Node 0 DMA32 free:786780kB min:66820kB low:83524kB high:100228kB active_anon:430692kB inactive_anon:148112kB active_file:125892kB inactive_file:126012kB unevictable:32kB isolated(anon):0kB isolated(file):128kB present:1901408kB mlocked:32kB dirty:105024kB writeback:25900kB mapped:33228kB shmem:105648kB slab_reclaimable:37104kB slab_unreclaimable:113052kB kernel_stack:2288kB pagetables:21708kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:3196 all_unreclaimable? no
> >[ 472.301943] lowmem_reserve[]: 0 0 5 5
> >[ 472.301956] Node 0 Normal free:48kB min:212kB low:264kB high:316kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:6060kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:104kB slab_unreclaimable:1520kB kernel_stack:176kB pagetables:0kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? yes
> >[ 472.301968] lowmem_reserve[]: 0 0 0 0
> >[ 472.301982] Node 0 DMA: 3*4kB 2*8kB 1*16kB 1*32kB 2*64kB 2*128kB 2*256kB 2*512kB 2*1024kB 2*2048kB 0*4096kB = 8140kB
> >[ 472.302015] Node 0 DMA32: 6121*4kB 1912*8kB 5094*16kB 4920*32kB 3168*64kB 1381*128kB 262*256kB 68*512kB 24*1024kB 1*2048kB 0*4096kB = 786756kB
> >[ 472.302048] Node 0 Normal: 2*4kB 5*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 48kB
> >[ 472.302090] 91312 total pagecache pages
> >[ 472.302093] 0 pages in swap cache
> >[ 472.302096] Swap cache stats: add 0, delete 0, find 0/0
> >[ 472.302099] Free swap = 3768316kB
> >[ 472.302102] Total swap = 3768316kB
> >[ 472.309521] 525808 pages RAM
> >[ 472.309529] 57618 pages reserved
> >[ 472.309548] 142496 pages shared
> >[ 472.309551] 177182 pages non-shared
> >
> >I'll finish off this verification, and then re-run with the watch-highorder script running.
> >
> >James
> Hi,
>
> I saw similar lockups while doing a heavy copy routine (basically
> copying an entire partition). I don't think this may be related to
> ext4, since the source and destination filesystems were btrfs and
> xfs.
>

If you have SLUB configured, can you try again with the same two patches
I attached earlier in the thread please?

> <SNIP>
>
> The mv was basically frozen though after sometime it resumed. I also noticed that levels of dirty data were really high (=~ 1G) which I presumed may have caused this.
>

Is 1G higher than what /proc/sys/vm/dirty_ratio should allow?

--
Mel Gorman
SUSE Labs