/srv/irclogs.ubuntu.com/2015/01/06/#ubuntu-kernel.txt

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backjlackHello!15:50
backjlackAre there any known issues with btrfs on 3.13 on trusty?15:50
backjlackI've received a report from someone who's seeing memory allocation failures on a system with 24 GB of RAM with dpkg and related operations.15:51
backjlackhttp://pastebin.com/raw.php?i=GXaj1iHp15:51
backjlackBasically, they're not actually running apps which require a lot of memory, but they seem to be running into some kind of problem.15:52
ckingbackjlack, are there any special mount options being used?15:59
ckingi've seen issues with 3.13 btrfs on large memory systems with compression being used16:00
backjlackcking: I'll provide /proc/mounts as soon as I get it, shouldn't take long.16:00
backjlacksysctl config: http://pastebin.com/raw.php?i=3Guv4KaQ16:02
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backjlackcking: http://pastebin.com/raw.php?i=zNr62crU That's /proc/mounts from that system.16:04
backjlackPlease let me know if there's anything else you'd need or if you happen to have any recommendations.16:05
ckingbackjlack, those mount options don't look like the one's I've seen issues with16:07
backjlackYeah, I know what you mean. I've had issues with compression on an older 3.10.16:11
ckingbackjlack, it does seem that there are a lot of slabs being used for inodes, I make it ~4.65GB16:13
ckingbut still, that's still not all of memory16:13
backjlackThere's btrfs as well.16:14
ckingbackjlack, what's the kernel reporting in dmesg?16:14
backjlack3.13.0-4316:15
ckingbackjlack, I mean, is the kernel reporting any out of memory failures in the kernel log?16:15
ckingbackjlack, it does seem heavily loaded on memory, the conntrack messages possibly indicate lots of open connections etc..16:16
backjlackThis were logs I've received from the same system before the upgrade to 3.13.0-43: http://pastebin.com/raw.php?i=rSpQU9dk16:16
backjlackhttp://pastebin.com/raw.php?i=rSpQU9dk16:18
backjlackhttp://pastebin.com/raw.php?i=X8pggEsp16:22
ckingbackjlack, I believe there used to be vm.zone_reclaim_mode sysctl that could be set 1 to force cached memory to be reclaimed16:23
ckingnot checked on that lately, but it's worth a punt16:24
backjlackcking: Thanks! I've passed that on.16:25
backjlackAlso, btrfs seems to have some kind of problem.16:25
ckingbackjlack, in what way?16:26
cking(mind you, btrfs is experimental, so it does not surprise me)16:26
backjlackhttp://pastebin.com/raw.php?i=X8pggEsp16:26
backjlackThere's a btrfs related stack trace in there.16:27
ckingbackjlack, i also suggest that vm.min_free_kbytes = 242000 is enabled (or see what it is currently set at), this may help16:28
backjlackFrom what I've been told, these errors were still being encountered, even when that was enabled.16:29
ckingbackjlack, it would be interesting to see how the slabinfo changes in time to see if there is any leaking or it perhaps is just running low on memory because you are running a memory intensive system config16:34
backjlackcking: It's not my system, it's from a user. However, I'm interested in making sure the trusty kernel is stable and doesn't have problems.16:34
backjlackIt's being used by a lot of people and making sure it doesn't have such problems would be great.16:35
backjlackWhat would you need? Periodic snapshots of slabinfo?16:35
ckingbackjlack, periodic snapshots of slabinfo would be useful, eg. every minute or every 5 mins16:35
ckingas it stands, btrfs being used in production environments when it is "experimental" is a tad worrysome16:36
backjlackIt's a dev environment, but this is important.16:38
backjlackSuch usage catches bugs which are rather difficult to catch with automated fs testing.16:38
ckingsure, I agree, I think a bug should be opened, and we can work through this16:38
backjlackI've requested snapshotting for slabinfo and will open an issue after I get the slabinfo snapshots over a period of 24 hours.16:39
ckingbackjlack, well, I'm working on a thorough thrashing of btrfs and I will be backporting fixes once I've identified the kitten killer issues16:39
backjlackThere are issues even in newer kernels, like 3.14, 3.15 and so on.16:39
cking3.19-rc2?16:39
backjlackI've got stacktraces, but couldn't reproduce so far.16:39
backjlackI haven't tried that myself or in any dev environment yet. Reproducing the issues is rather difficult.16:40
backjlackGetting a hard btrfs crash which takes down the whole system or just crashes btrfs reproduced can be very difficult.16:41
ckingbackjlack, not with my tests, I crash it daily ;-)16:41
backjlackIs there a repository for these tests?16:41
ckingbackjlack, xfs tests, generic and xfs specific ones16:42
ckingI mean "btrfs specific ones"16:42
backjlackAh, I see. Ok, I'll try those as well.16:43
ckingand I'm testing against a wide mix of mount options, I've been hammering test configs for ~3+ weeks non-stop and I'm building a matrix of failure points16:43
ckingthen I start identifying fixes and backporting them16:43
ckingI'm on the case16:44
jsalisbury##16:50
jsalisbury## Kernel team meeting in 10 minutes in #ubuntu-meeting16:50
jsalisbury##16:50
bjfapw, LP: #1400289   ...  can you verify ?16:54
ubot5Launchpad bug 1400289 in linux (Ubuntu Vivid) "Hyper-V: drivers:scsi:storvsc: Fix a bug in handling ring buffer failures that may result in I/O freeze" [High,Fix committed] https://launchpad.net/bugs/140028916:55
bjfdannf, LP: #1381084  ...  can you verify?16:57
ubot5Launchpad bug 1381084 in linux (Ubuntu Trusty) "xgene-enet: add 10GbE support" [Medium,Fix committed] https://launchpad.net/bugs/138108416:57
apwbjf, ack16:57
dannfcmagina: ^ can you verify LP: #1381084 for bjf?16:59
ubot5Launchpad bug 1381084 in linux (Ubuntu Trusty) "xgene-enet: add 10GbE support" [Medium,Fix committed] https://launchpad.net/bugs/138108416:59
bjfarges, there are two for you: LP: #1396235  and  LP: #140115016:59
ubot5Launchpad bug 1396235 in linux (Ubuntu Utopic) "Ubuntu - unable to use XMON debugger (running ppc64le on PowerVM)" [Medium,Fix committed] https://launchpad.net/bugs/139623516:59
ubot5Launchpad bug 1401150 in linux (Ubuntu Utopic) "Endianness issue in the VPHN topology update code" [Medium,Fix committed] https://launchpad.net/bugs/140115016:59
argesbjf: was just looking at those : )16:59
bjfarges, would you be able to verify those if i let you have modoc for a bit?16:59
jsalisbury##17:00
jsalisbury## Meeting starting now17:00
jsalisbury##17:00
cmaginadannf, bjf: sure17:00
argesbjf: i'd be able to verify 1396235, but 1401150 is a perf fix i could only verify it doens't break things17:00
bjfarges, ok, i'll see about freeing up modoc for a bit ... lets shoot for tomorrow if that's ok17:01
argesbjf: works for me17:01
apwbjf, utlemming is on the case17:03
bjfcool17:04
bjfsforshee, you think we can mark LP: #1275879 as verified?17:07
ubot5Launchpad bug 1275879 in linux (Ubuntu Vivid) "Kernel panic " [High,Fix committed] https://launchpad.net/bugs/127587917:07
sforsheebjf: looking17:08
sforsheebjf: I think so, we'll be getting that commit via upstream stable either way17:09
=== jsalisbury changed the topic of #ubuntu-kernel to: Home: https://wiki.ubuntu.com/Kernel/ || Ubuntu Kernel Team Meeting - Tues January 13th, 2015 - 17:00 UTC || If you have a question just ask, and do wait around for an answer! If the question is should I file a bug for something, likely you can assume yes.
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