lkml.org 
[lkml]   [2010]   [Apr]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: PROBLEM + POSS FIX: kernel stack overflow, xfs, many disks, heavy write load, 8k stack, x86-64
Dave Chinner wrote:

> So effectively the storage subsystem (NFS, filesystem, DM, MD,
> device drivers) have about 4K of stack to work in now. That seems to
> be a lot less than last time I looked at this, and we've been really
> careful not to increase XFS's stack usage for quite some time now.

OK. I should note that we have what appears to be a similar problem on a
2.6.28 distro kernel, so I'm not sure this is a very recent change. (We
see the lockups on that kernel, we haven't tried larger stacks + stack
instrumentation on the earlier kernel).

Do you know if there are any obvious knobs to twiddle to make these
codepaths less likely? The cluster is resilient against occasional
server death, but frequent death is more annoying.

We're currently running with sysctls:

net.ipv4.ip_nonlocal_bind=1
kernel.panic=300
vm.dirty_background_ratio=3
vm.min_free_kbytes=16384

I'm not sure what circumstances force the memory reclaim (and why it
doesn't come from discarding a cached page).

Is the problem is the DMA/DMA32 zone and we should try playing with
lowmem_reserve_ratio? Is there anything else we could do to keep dirty
pages out of the low zones?

Before trying THREAD_ORDER 2, we tried doubling the RAM in a couple of
boxes from 2GB to 4GB without any significant reduction in the problem.

Lastly - if we end up stuck with THREAD_ORDER 2, does anyone know what
symptoms to look out for to know if unable to allocate thread stacks due
to fragmentation?

> I'll have to have a bit of a think on this one - if you could
> provide further stack traces as they get deeper (esp. if they go
> past 8k) that would be really handy.

Two of the worst offenders below. We have plenty to send if you would
like more. Please let us know if you'd like us to try anything else or
would like other info.

Thanks very much for your thoughts, suggestions and work so far, it's
very much appreciated here.

regards,

jb

=== server16 ===

apache2 used greatest stack depth: 7208 bytes left

Depth Size Location (72 entries)
----- ---- --------
0) 8336 304 select_task_rq_fair+0x235/0xad0
1) 8032 96 try_to_wake_up+0x189/0x3f0
2) 7936 16 default_wake_function+0x12/0x20
3) 7920 32 autoremove_wake_function+0x16/0x40
4) 7888 64 __wake_up_common+0x5a/0x90
5) 7824 64 __wake_up+0x48/0x70
6) 7760 64 insert_work+0x9f/0xb0
7) 7696 48 __queue_work+0x36/0x50
8) 7648 16 queue_work_on+0x4d/0x60
9) 7632 16 queue_work+0x1f/0x30
10) 7616 16 queue_delayed_work+0x2d/0x40
11) 7600 32 ata_pio_queue_task+0x35/0x40
12) 7568 48 ata_sff_qc_issue+0x146/0x2f0
13) 7520 96 mv_qc_issue+0x12d/0x540 [sata_mv]
14) 7424 96 ata_qc_issue+0x1fe/0x320
15) 7328 64 ata_scsi_translate+0xae/0x1a0
16) 7264 64 ata_scsi_queuecmd+0xbf/0x2f0
17) 7200 48 scsi_dispatch_cmd+0x114/0x2b0
18) 7152 96 scsi_request_fn+0x419/0x590
19) 7056 32 __blk_run_queue+0x82/0x150
20) 7024 48 elv_insert+0x1aa/0x2d0
21) 6976 48 __elv_add_request+0x83/0xd0
22) 6928 96 __make_request+0x139/0x490
23) 6832 208 generic_make_request+0x3df/0x4d0
24) 6624 80 submit_bio+0x7c/0x100
25) 6544 96 _xfs_buf_ioapply+0x128/0x2c0 [xfs]
26) 6448 48 xfs_buf_iorequest+0x75/0xd0 [xfs]
27) 6400 32 xlog_bdstrat_cb+0x4d/0x60 [xfs]
28) 6368 80 xlog_sync+0x218/0x510 [xfs]
29) 6288 64 xlog_state_release_iclog+0xbb/0x100 [xfs]
30) 6224 160 xlog_state_sync+0x1ab/0x230 [xfs]
31) 6064 32 _xfs_log_force+0x5a/0x80 [xfs]
32) 6032 32 xfs_log_force+0x18/0x40 [xfs]
33) 6000 64 xfs_alloc_search_busy+0x14b/0x160 [xfs]
34) 5936 112 xfs_alloc_get_freelist+0x130/0x170 [xfs]
35) 5824 48 xfs_allocbt_alloc_block+0x33/0x70 [xfs]
36) 5776 208 xfs_btree_split+0xb3/0x6a0 [xfs]
37) 5568 96 xfs_btree_make_block_unfull+0x151/0x190 [xfs]
38) 5472 224 xfs_btree_insrec+0x39c/0x5b0 [xfs]
39) 5248 128 xfs_btree_insert+0x86/0x180 [xfs]
40) 5120 144 xfs_free_ag_extent+0x33b/0x7b0 [xfs]
41) 4976 224 xfs_alloc_fix_freelist+0x120/0x490 [xfs]
42) 4752 96 xfs_alloc_vextent+0x1f5/0x630 [xfs]
43) 4656 272 xfs_bmap_btalloc+0x497/0xa70 [xfs]
44) 4384 16 xfs_bmap_alloc+0x21/0x40 [xfs]
45) 4368 448 xfs_bmapi+0x85e/0x1200 [xfs]
46) 3920 256 xfs_iomap_write_allocate+0x248/0x3c0 [xfs]
47) 3664 208 xfs_iomap+0x3d8/0x410 [xfs]
48) 3456 32 xfs_map_blocks+0x2c/0x30 [xfs]
49) 3424 256 xfs_page_state_convert+0x443/0x730 [xfs]
50) 3168 64 xfs_vm_writepage+0xab/0x160 [xfs]
51) 3104 384 shrink_page_list+0x65e/0x840
52) 2720 528 shrink_zone+0x63f/0xe10
53) 2192 112 do_try_to_free_pages+0xc2/0x3c0
54) 2080 128 try_to_free_pages+0x77/0x80
55) 1952 240 __alloc_pages_nodemask+0x3e4/0x710
56) 1712 48 alloc_pages_current+0x8c/0xe0
57) 1664 32 __page_cache_alloc+0x67/0x70
58) 1632 144 __do_page_cache_readahead+0xd3/0x220
59) 1488 16 ra_submit+0x21/0x30
60) 1472 80 ondemand_readahead+0x11d/0x250
61) 1392 64 page_cache_async_readahead+0xa9/0xe0
62) 1328 592 __generic_file_splice_read+0x48a/0x530
63) 736 48 generic_file_splice_read+0x4f/0x90
64) 688 96 xfs_splice_read+0xf2/0x130 [xfs]
65) 592 32 xfs_file_splice_read+0x4b/0x50 [xfs]
66) 560 64 do_splice_to+0x77/0xb0
67) 496 112 splice_direct_to_actor+0xcc/0x1c0
68) 384 80 do_splice_direct+0x57/0x80
69) 304 96 do_sendfile+0x16c/0x1e0
70) 208 80 sys_sendfile64+0x8d/0xb0
71) 128 128 system_call_fastpath+0x16/0x1b
=== server9 ===

[223269.859411] apache2 used greatest stack depth: 7088 bytes left

Depth Size Location (62 entries)
----- ---- --------
0) 8528 32 down_trylock+0x1e/0x50
1) 8496 80 _xfs_buf_find+0x12f/0x290 [xfs]
2) 8416 64 xfs_buf_get+0x61/0x1c0 [xfs]
3) 8352 48 xfs_buf_read+0x2f/0x110 [xfs]
4) 8304 48 xfs_buf_readahead+0x61/0x90 [xfs]
5) 8256 48 xfs_btree_readahead_sblock+0xea/0xf0 [xfs]
6) 8208 16 xfs_btree_readahead+0x5f/0x90 [xfs]
7) 8192 112 xfs_btree_increment+0x2e/0x2b0 [xfs]
8) 8080 176 xfs_btree_rshift+0x2f2/0x530 [xfs]
9) 7904 272 xfs_btree_delrec+0x4a3/0x1020 [xfs]
10) 7632 64 xfs_btree_delete+0x40/0xd0 [xfs]
11) 7568 96 xfs_alloc_fixup_trees+0x7d/0x350 [xfs]
12) 7472 144 xfs_alloc_ag_vextent_near+0x916/0xb30 [xfs]
13) 7328 32 xfs_alloc_ag_vextent+0xe5/0x140 [xfs]
14) 7296 96 xfs_alloc_vextent+0x49f/0x630 [xfs]
15) 7200 160 xfs_bmbt_alloc_block+0xbe/0x1d0 [xfs]
16) 7040 208 xfs_btree_split+0xb3/0x6a0 [xfs]
17) 6832 96 xfs_btree_make_block_unfull+0x151/0x190 [xfs]
18) 6736 224 xfs_btree_insrec+0x39c/0x5b0 [xfs]
19) 6512 128 xfs_btree_insert+0x86/0x180 [xfs]
20) 6384 352 xfs_bmap_add_extent_delay_real+0x41e/0x1660 [xfs]
21) 6032 208 xfs_bmap_add_extent+0x41c/0x450 [xfs]
22) 5824 448 xfs_bmapi+0x982/0x1200 [xfs]
23) 5376 256 xfs_iomap_write_allocate+0x248/0x3c0 [xfs]
24) 5120 208 xfs_iomap+0x3d8/0x410 [xfs]
25) 4912 32 xfs_map_blocks+0x2c/0x30 [xfs]
26) 4880 256 xfs_page_state_convert+0x443/0x730 [xfs]
27) 4624 64 xfs_vm_writepage+0xab/0x160 [xfs]
28) 4560 384 shrink_page_list+0x65e/0x840
29) 4176 528 shrink_zone+0x63f/0xe10
30) 3648 112 do_try_to_free_pages+0xc2/0x3c0
31) 3536 128 try_to_free_pages+0x77/0x80
32) 3408 240 __alloc_pages_nodemask+0x3e4/0x710
33) 3168 48 alloc_pages_current+0x8c/0xe0
34) 3120 80 new_slab+0x247/0x300
35) 3040 96 __slab_alloc+0x137/0x490
36) 2944 64 kmem_cache_alloc+0x110/0x120
37) 2880 64 kmem_zone_alloc+0x9a/0xe0 [xfs]
38) 2816 32 kmem_zone_zalloc+0x1e/0x50 [xfs]
39) 2784 32 _xfs_trans_alloc+0x38/0x80 [xfs]
40) 2752 96 xfs_trans_alloc+0x9f/0xb0 [xfs]
41) 2656 256 xfs_iomap_write_allocate+0xf1/0x3c0 [xfs]
42) 2400 208 xfs_iomap+0x3d8/0x410 [xfs]
43) 2192 32 xfs_map_blocks+0x2c/0x30 [xfs]
44) 2160 256 xfs_page_state_convert+0x443/0x730 [xfs]
45) 1904 64 xfs_vm_writepage+0xab/0x160 [xfs]
46) 1840 32 __writepage+0x17/0x50
47) 1808 288 write_cache_pages+0x1f7/0x400
48) 1520 16 generic_writepages+0x24/0x30
49) 1504 48 xfs_vm_writepages+0x5c/0x80 [xfs]
50) 1456 16 do_writepages+0x21/0x40
51) 1440 64 writeback_single_inode+0xeb/0x3c0
52) 1376 128 writeback_inodes_wb+0x318/0x510
53) 1248 16 writeback_inodes_wbc+0x1e/0x20
54) 1232 224 balance_dirty_pages_ratelimited_nr+0x269/0x3a0
55) 1008 192 generic_file_buffered_write+0x19b/0x240
56) 816 288 xfs_write+0x837/0x920 [xfs]
57) 528 16 xfs_file_aio_write+0x5b/0x70 [xfs]
58) 512 272 do_sync_write+0xd1/0x120
59) 240 48 vfs_write+0xcb/0x1a0
60) 192 64 sys_write+0x55/0x90
61) 128 128 system_call_fastpath+0x16/0x1b
\
 
 \ /
  Last update: 2010-04-09 15:47    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site