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Re: [PATCH 44/49] xfs: Reduce allocations during CIL insertion

To: Mark Tinguely <tinguely@xxxxxxx>
Subject: Re: [PATCH 44/49] xfs: Reduce allocations during CIL insertion
From: "Michael L. Semon" <mlsemon35@xxxxxxxxx>
Date: Fri, 26 Jul 2013 16:46:09 -0400
Cc: xfs@xxxxxxxxxxx
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On 07/24/2013 09:28 AM, Mark Tinguely wrote:
> On 07/23/13 16:44, Michael L. Semon wrote:
>> On 07/23/2013 05:15 PM, Mark Tinguely wrote:
>>> On 07/19/13 01:25, Dave Chinner wrote:
>>>> From: Dave Chinner<dchinner@xxxxxxxxxx>
>>>>
>>>> Now that we have the size of the object before the formatting pass
>>>> is called, we can allocation the log vector and it's buffer in a
>>>> single allocation rather than two separate allocations.
>>>>
>>>> Store the size of the allocated buffer in the log vector so that
>>>> we potentially avoid allocation for future modifications of the
>>>> object.
>>>>
>>>> While touching this code, remove the IOP_FORMAT definition.
>>
>>>> Signed-off-by: Dave Chinner<dchinner@xxxxxxxxxx>
>>>
>>> Looks good.
>>>
>>> Reviewed-by: Mark Tinguely<tinguely@xxxxxxx>
>>>
>>> _______________________________________________
>>> xfs mailing list
>>> xfs@xxxxxxxxxxx
>>> http://oss.sgi.com/mailman/listinfo/xfs
>>
>> I'd like to register a gentle "test this well" protest on this patch.
>> While trying to figure out the origin of an unrelated lockdep, I
>> tried to copy 3 kernel gits from one 2k non-CRC XFS filesystem to
>> another one.  With at least this patch used, the cp operatin stops,
>> leading to not-umountable, not-syncable filesystems.  It might be
>> while copying the 2nd git, or the 3rd git, while copying header files,
>> or while copying those large *.pack files, but it will happen
>> somewhere.
>>
>> A bisect of the issue ends on this patch, but its removal means that
>> 45_49 and 46_49 cannot be applied without good knowledge of the code
>> to be patched.
>>
>> This one's on me for not being able to get good information to Dave.
>> If I can find a way to get trace-cmd to pipe over ssh or something
>> like that, then maybe there's a chance to make a file that `trace-cmd
>> report` can read.  Previous attempts to save to different filesystems
>> or save over NFS and CIFS have all failed.  Will keep trying...
>>
>> For diagnosing this patch, is there an effective trace that is rather
>> small?  And would you need more than just the XFS events?
>>
>> Thanks!
>>
>> Michael
>>
> 
> Thanks for the heads up.
> 
> If you could please redo the test and get the stack traces with 
> /proc/sysrq-trigger and if you kernel works with crash, a core dump. For the 
> stack trace, I mostly want to know if it has several "xlog_grant_head_wait" 
> entries in it, because ...
> 
> ...I seemed to have triggered a couple log space reservation hangs with 
> fsstress one XFS partition and a mega-copy on another partition, but will 
> have to graft the new XFS tree onto a Linux 3.10 kernel to get crash (and one 
> of my sata controllers) to work again.
> 
> Thanks.
> 
> --Mark.

Well, I tried.  Here's a Google Drive link, and hopefully it works:

https://drive.google.com/folderview?id=0B41268QKoNjtckwzVTJqWnIydEE

The instructions in Documentation/kdump/kdump.txt were followed 
fairly well.  The dump was taken from /proc/vmcore and extracted 
like this:

$ cat /proc/vmcore | gzip -9vc > 4git-cp-kernel-dump-1.gz

You seem to have things well under control, so it all might not be 
needed, anyway.  It does mean that kernel core dumps will go more 
quickly next time.

BTW, there's a "crash" program referenced in kdump.txt, and it's been 
downloaded but not built yet.  Were you looking for output from the 
crash program?

Thanks!

Michael

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