[mythtv-users] oom-killer on the loose.

Richard Thomas rich at dicksonlife.com
Mon Jan 12 22:28:07 UTC 2009


I'm a relatively new user of Myth, having it running for a week or two 
now. I'm having an issue where every 2-3 days, the system will hang. 
Looking through the logs, oom-killer has sprung into actions and started 
killing things off. I'm not sure how to track down what is causing the 
issue. Many processes are killed off by oom-killer so it doesn't appear 
to be one specific process. I'm running 2GB physical and 2GB swap which 
I would think would be plenty (Though I'm not against assigning more if 
appropriate).

I'm using the latest version of Knoppmyth, on and AMD 2-core Brisbane CPU.

Just now, I managed to catch the system after oom-killer had sprung into 
action but before the system was wiped out. Everything looked ok in free 
and top and memory was not tight. I rebooted as I am at work, away from 
home and have no way to reboot once it hangs.

 From the logs, it looks like it may be related to being on the 
half/whole hour. No program was recording at the time, nor had one just 
finished recording (The Myth commercial thing has been mentioned as 
using a lot of memory in another thread). Myth was in the menus and not 
showing live TV.

I have a fair bit of Linux experience and am pretty technically 
competent. I'm willing to put some effort in to fixing this but have not 
really had any run-ins with oom-killer before so would appreciate any 
pointers. Technical details follow:

Swap is on and correctly configured:

             total       used       free     shared    buffers     cached
Mem:       1942812     599208    1343604          0      36352     165260
-/+ buffers/cache:     397596    1545216
Swap:      1959920          0    1959920

Here is the first occurence of oom-killer today

Jan 12 14:32:39 mythtv kernel: cx88[0] dvb invoked oom-killer: 
gfp_mask=0xd0, order=0, oomkilladj=0
Jan 12 14:32:41 mythtv kernel:  [<c0165740>] out_of_memory+0x190/0x1d0
Jan 12 14:32:41 mythtv kernel:  [<c0167300>] __alloc_pages+0x310/0x330
Jan 12 14:32:41 mythtv kernel:  [<c017747b>] __vmalloc_area_node+0xcb/0x150
Jan 12 14:32:41 mythtv kernel:  [<c01775bf>] __vmalloc+0xf/0x20
Jan 12 14:32:41 mythtv kernel:  [<f9282c32>] 
videobuf_dma_init_kernel+0x42/0xc0 [videobuf_dma_sg]
Jan 12 14:32:41 mythtv kernel:  [<c013247e>] del_timer_sync+0xe/0x20
Jan 12 14:32:41 mythtv kernel:  [<f92830cf>] 
__videobuf_iolock+0xdf/0x110 [videobuf_dma_sg]
Jan 12 14:32:41 mythtv kernel:  [<c01320a0>] process_timeout+0x0/0x10
Jan 12 14:32:41 mythtv kernel:  [<f9282ff0>] __videobuf_iolock+0x0/0x110 
[videobuf_dma_sg]
Jan 12 14:32:41 mythtv kernel:  [<f927c767>] videobuf_iolock+0x47/0x90 
[videobuf_core]
Jan 12 14:32:41 mythtv kernel:  [<f92d6d23>] 
cx8802_buf_prepare+0xb3/0x110 [cx8802]
Jan 12 14:32:41 mythtv kernel:  [<fa3b9176>] dvb_buf_prepare+0x16/0x20 
[cx88_dvb]
Jan 12 14:32:41 mythtv kernel:  [<f927cdf2>] 
__videobuf_read_start+0xb2/0x140 [videobuf_core]
Jan 12 14:32:41 mythtv kernel:  [<f927cfa8>] 
videobuf_read_start+0x18/0x30 [videobuf_core]
Jan 12 14:32:41 mythtv kernel:  [<f937c3a6>] 
videobuf_dvb_thread+0x36/0x180 [videobuf_dvb]
Jan 12 14:32:41 mythtv mysqld_safe[14822]: Number of processes running 
now: 0
Jan 12 14:32:41 mythtv kernel:  [<f937c370>] 
videobuf_dvb_thread+0x0/0x180 [videobuf_dvb]
Jan 12 14:32:41 mythtv kernel:  [<c013cc42>] kthread+0x42/0x70
Jan 12 14:32:41 mythtv kernel:  [<c013cc00>] kthread+0x0/0x70
Jan 12 14:32:41 mythtv kernel:  [<c0105617>] kernel_thread_helper+0x7/0x10
Jan 12 14:32:41 mythtv kernel:  =======================
Jan 12 14:32:41 mythtv kernel: Mem-info:
Jan 12 14:32:41 mythtv kernel: DMA per-cpu:
Jan 12 14:32:41 mythtv kernel: CPU    0: Hot: hi:    0, btch:   1 usd:   
0   Cold: hi:    0, btch:   1 usd:   0
Jan 12 14:32:41 mythtv kernel: CPU    1: Hot: hi:    0, btch:   1 usd:   
0   Cold: hi:    0, btch:   1 usd:   0
Jan 12 14:32:41 mythtv kernel: Normal per-cpu:
Jan 12 14:32:41 mythtv kernel: CPU    0: Hot: hi:  186, btch:  31 usd:  
29   Cold: hi:   62, btch:  15 usd:  51
Jan 12 14:32:41 mythtv kernel: CPU    1: Hot: hi:  186, btch:  31 usd: 
182   Cold: hi:   62, btch:  15 usd:  56
Jan 12 14:32:41 mythtv kernel: HighMem per-cpu:
Jan 12 14:32:41 mythtv kernel: CPU    0: Hot: hi:  186, btch:  31 usd:  
18   Cold: hi:   62, btch:  15 usd:   3
Jan 12 14:32:41 mythtv kernel: CPU    1: Hot: hi:  186, btch:  31 usd: 
133   Cold: hi:   62, btch:  15 usd:   5
Jan 12 14:32:41 mythtv kernel: Active:159201 inactive:2098 dirty:0 
writeback:0 unstable:0
Jan 12 14:32:41 mythtv kernel:  free:97570 slab:199517 mapped:15120 
pagetables:504 bounce:0
Jan 12 14:32:41 mythtv kernel: DMA free:3544kB min:68kB low:84kB 
high:100kB lots:136kB active:0kB inactive:24kB present:16
256kB pages_scanned:41 all_unreclaimable? yes
Jan 12 14:32:41 mythtv kernel: lowmem_reserve[]: 0 873 1888 1888
Jan 12 14:32:41 mythtv kernel: Normal free:3692kB min:3744kB low:4680kB 
high:5616kB lots:7488kB active:24kB inactive:144kB
 present:894080kB pages_scanned:262 all_unreclaimable? yes
Jan 12 14:32:41 mythtv kernel: lowmem_reserve[]: 0 0 8126 8126
Jan 12 14:32:41 mythtv kernel: HighMem free:383044kB min:512kB 
low:1600kB high:2692kB lots:4872kB active:636780kB inactive
:8224kB present:1040196kB pages_scanned:0 all_unreclaimable? no
Jan 12 14:32:41 mythtv kernel: lowmem_reserve[]: 0 0 0 0
Jan 12 14:32:41 mythtv kernel: DMA: 0*4kB 1*8kB 1*16kB 0*32kB 1*64kB 
1*128kB 1*256kB 0*512kB 1*1024kB 1*2048kB 0*4096kB =
3544kB
Jan 12 14:32:41 mythtv kernel: Normal: 0*4kB 0*8kB 1*16kB 1*32kB 0*64kB 
0*128kB 0*256kB 1*512kB 1*1024kB 1*2048kB 0*4096kB
 = 3632kB
Jan 12 14:32:41 mythtv kernel: HighMem: 4478*4kB 15574*8kB 8561*16kB 
2524*32kB 322*64kB 15*128kB 1*256kB 0*512kB 0*1024kB
0*2048kB 0*4096kB = 383032kB
Jan 12 14:32:41 mythtv kernel: Swap cache: add 12524, delete 11569, find 
409/542, race 0+0
Jan 12 14:32:41 mythtv kernel: Free swap  = 1913972kB
Jan 12 14:32:41 mythtv kernel: Total swap = 1959920kB
Jan 12 14:32:41 mythtv kernel: Free swap:       1913972kB
Jan 12 14:32:41 mythtv kernel: 491472 pages of RAM
Jan 12 14:32:41 mythtv kernel: 262096 pages of HIGHMEM
Jan 12 14:32:41 mythtv kernel: 25230 reserved pages
Jan 12 14:32:41 mythtv kernel: 44678 pages shared
Jan 12 14:32:41 mythtv kernel: 955 pages swap cached
Jan 12 14:32:41 mythtv kernel: 0 pages dirty
Jan 12 14:32:41 mythtv kernel: 0 pages writeback
Jan 12 14:32:41 mythtv kernel: 15120 pages mapped
Jan 12 14:32:41 mythtv kernel: 199517 pages slab
Jan 12 14:32:41 mythtv kernel: 504 pages pagetables
Jan 12 14:32:41 mythtv kernel: Out of memory: kill process 4439 
(fluxbox) score 229748 or a child
Jan 12 14:32:41 mythtv kernel: Killed process 4466 (ssh-agent)

Note that there appears to be plenty of free swap. Not sure what to make 
of that.

There are quite a few of those. Here are what I think might be important 
parts:

Jan 12 14:32:39 mythtv kernel: cx88[0] dvb invoked oom-killer: 
gfp_mask=0xd0, order=0, oomkilladj=0
Jan 12 14:32:41 mythtv kernel: Killed process 4466 (ssh-agent)
Jan 12 14:32:41 mythtv kernel: cx88[0] dvb invoked oom-killer: 
gfp_mask=0xd0, order=0, oomkilladj=0
Jan 12 14:32:41 mythtv kernel: Killed process 4476 (xscreensaver)
Jan 12 14:32:41 mythtv kernel: cx88[0] dvb invoked oom-killer: 
gfp_mask=0xd0, order=0, oomkilladj=0
Jan 12 14:32:41 mythtv kernel: Killed process 4477 (mythfrontend)
Jan 12 14:32:41 mythtv kernel: cx88[0] dvb invoked oom-killer: 
gfp_mask=0xd0, order=0, oomkilladj=0
Jan 12 14:32:41 mythtv kernel: Killed process 14813 (mythbackend)
Jan 12 14:32:41 mythtv kernel: cx88[0] dvb invoked oom-killer: 
gfp_mask=0xd0, order=0, oomkilladj=0
Jan 12 14:32:41 mythtv kernel: Killed process 3920 (mysqld)
Jan 12 14:39:50 mythtv kernel: rt73 invoked oom-killer: gfp_mask=0xd0, 
order=0, oomkilladj=-17
Jan 12 14:39:51 mythtv kernel: Killed process 14826 (mysqld)
Jan 12 14:39:51 mythtv kernel: rt73 invoked oom-killer: gfp_mask=0xd0, 
order=0, oomkilladj=-17
Jan 12 14:39:51 mythtv kernel: Killed process 4818 (mtd)

As I say, any pointers much appreciated and if there's any other info it 
would help to dig out, I'd be happy to provide it.

Thanks

Rich


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