From: Dave Hansen <dave@linux.vnet.ibm.com>
To: Nitin Gupta <ngupta@vflare.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>,
Minchan Kim <minchan.kim@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Greg KH <greg@kroah.com>,
Linux Driver Project <devel@linuxdriverproject.org>,
linux-mm <linux-mm@kvack.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: OOM panics with zram
Date: Thu, 09 Sep 2010 10:24:41 -0700 [thread overview]
Message-ID: <1284053081.7586.7910.camel@nimitz> (raw)
In-Reply-To: <1281374816-904-1-git-send-email-ngupta@vflare.org>
Hi Nitin,
I've been playing with using zram (from -staging) to back some qemu
guest memory directly. Basically mmap()'ing the device in instead of
using anonymous memory. The old code with the backing swap devices
seemed to work pretty well, but I'm running into a problem with the new
code.
I have plenty of swap on the system, and I'd been running with compcache
nicely for a while. But, I went to go tar up (and gzip) a pretty large
directory in my qemu guest. It panic'd the qemu host system:
[703826.003126] Kernel panic - not syncing: Out of memory and no killable processes...
[703826.003127]
[703826.012350] Pid: 25508, comm: cat Not tainted 2.6.36-rc3-00114-g9b9913d #29
[703826.019385] Call Trace:
[703826.021928] [<ffffffff8104032a>] panic+0xba/0x1e0
[703826.026801] [<ffffffff810bb4a1>] ? next_online_pgdat+0x21/0x50
[703826.032799] [<ffffffff810a7713>] ? find_lock_task_mm+0x23/0x60
[703826.038795] [<ffffffff810a79ab>] ? dump_header+0x19b/0x1b0
[703826.044446] [<ffffffff810a8157>] out_of_memory+0x297/0x2d0
[703826.050098] [<ffffffff810abbaf>] __alloc_pages_nodemask+0x72f/0x740
[703826.056528] [<ffffffff81110d4e>] ? __set_page_dirty+0x6e/0xc0
[703826.062438] [<ffffffff810da477>] alloc_pages_current+0x87/0xd0
[703826.068438] [<ffffffff810a533b>] __page_cache_alloc+0xb/0x10
[703826.074263] [<ffffffff810ae2ff>] __do_page_cache_readahead+0xdf/0x220
[703826.080865] [<ffffffff810ae45c>] ra_submit+0x1c/0x20
[703826.085998] [<ffffffff810ae5f8>] ondemand_readahead+0xa8/0x1d0
[703826.091994] [<ffffffff810ae797>] page_cache_async_readahead+0x77/0xc0
[703826.098595] [<ffffffff810a6489>] generic_file_aio_read+0x259/0x6d0
[703826.104941] [<ffffffff810eac21>] do_sync_read+0xd1/0x110
[703826.110418] [<ffffffff810eb3f6>] vfs_read+0xc6/0x170
[703826.115547] [<ffffffff810eb860>] sys_read+0x50/0x90
[703826.120591] [<ffffffff81002c2b>] system_call_fastpath+0x16/0x1b
I have the feeling that the compcache device all of a sudden lost its
efficiency. It can't do much about having non-compressible data stuck
in it, of course.
But, it used to be able to write things out to backing storage. It
tries to return I/O errors when it runs out of space, but my system
didn't get that far. It panic'd before it got the chance.
This seems like an issue that will probably crop up when we use zram as
a swap device too. A panic seems like pretty undesirable behavior when
you've simply changed the kind of data being used. Have you run into
this at all?
-- Dave
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next prev parent reply other threads:[~2010-09-09 17:24 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-09 17:26 [PATCH 00/10] zram: various improvements and cleanups Nitin Gupta
2010-08-09 17:26 ` [PATCH 01/10] Replace ioctls with sysfs interface Nitin Gupta
2010-08-09 18:34 ` Pekka Enberg
2010-08-10 3:06 ` Nitin Gupta
2010-08-31 23:06 ` Dave Hansen
2010-08-09 17:26 ` [PATCH 02/10] Remove need for explicit device initialization Nitin Gupta
2010-08-09 18:36 ` Pekka Enberg
2010-08-10 3:38 ` Nitin Gupta
2010-08-09 17:26 ` [PATCH 03/10] Use percpu stats Nitin Gupta
2010-08-09 18:44 ` Pekka Enberg
2010-08-10 4:34 ` Andrew Morton
2010-08-11 16:39 ` Nitin Gupta
2010-08-11 17:18 ` Andrew Morton
2010-08-30 16:20 ` Christoph Lameter
2010-08-31 20:31 ` Nitin Gupta
2010-08-31 21:28 ` Eric Dumazet
2010-08-31 21:35 ` Christoph Lameter
2010-08-31 21:41 ` Eric Dumazet
2010-09-01 20:05 ` Christoph Lameter
2010-09-01 20:38 ` Eric Dumazet
2010-09-02 0:34 ` Christoph Lameter
2010-08-31 5:36 ` Anton Blanchard
2010-09-01 3:41 ` Anton Blanchard
2010-09-01 3:51 ` Anton Blanchard
2010-09-17 20:59 ` Andrew Morton
2010-08-09 17:26 ` [PATCH 04/10] Use percpu buffers Nitin Gupta
2010-08-09 18:57 ` Pekka Enberg
2010-08-10 4:47 ` Nitin Gupta
2010-08-10 5:05 ` Pekka Enberg
2010-08-10 5:32 ` Nitin Gupta
2010-08-10 7:36 ` Pekka Enberg
2010-08-09 17:26 ` [PATCH 05/10] Reduce per table entry overhead by 4 bytes Nitin Gupta
2010-08-09 18:59 ` Pekka Enberg
2010-08-10 4:55 ` Nitin Gupta
2010-08-09 17:26 ` [PATCH 06/10] Block discard support Nitin Gupta
2010-08-09 19:03 ` Pekka Enberg
2010-08-10 2:23 ` Jens Axboe
2010-08-10 4:54 ` Nitin Gupta
2010-08-10 15:54 ` Jens Axboe
2010-08-09 17:26 ` [PATCH 07/10] Increase compressed page size threshold Nitin Gupta
2010-08-09 18:32 ` Pekka Enberg
2010-08-09 17:26 ` [PATCH 08/10] Some cleanups Nitin Gupta
2010-08-09 19:02 ` Pekka Enberg
2010-08-09 17:26 ` [PATCH 09/10] Update zram documentation Nitin Gupta
2010-08-09 17:26 ` [PATCH 10/10] Document sysfs entries Nitin Gupta
2010-08-09 19:02 ` Pekka Enberg
2010-08-31 22:37 ` [PATCH 00/10] zram: various improvements and cleanups Greg KH
2010-09-01 3:32 ` Anton Blanchard
2010-09-09 17:24 ` Dave Hansen [this message]
2010-09-09 19:07 ` [patch -rc] oom: always return a badness score of non-zero for eligible tasks David Rientjes
2010-09-09 19:48 ` Dave Hansen
2010-09-09 21:00 ` David Rientjes
2010-09-09 21:10 ` Dave Hansen
2010-09-09 21:40 ` David Rientjes
2010-10-03 18:41 ` OOM panics with zram Nitin Gupta
2010-10-03 19:27 ` Dave Hansen
2010-10-03 19:40 ` Nitin Gupta
2010-10-04 11:08 ` Ed Tomlinson
2010-10-05 23:43 ` Greg KH
2010-10-06 2:29 ` Nitin Gupta
2010-10-06 2:36 ` Greg KH
2010-10-06 4:30 ` Nitin Gupta
2010-10-06 7:38 ` Pekka Enberg
2010-10-06 14:03 ` Greg KH
2010-10-06 14:16 ` Pekka Enberg
2010-10-06 14:53 ` Nitin Gupta
2010-10-06 14:02 ` Greg KH
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