From: Alex Bligh <alex@alex.org.uk>
To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Alex Bligh <alex@alex.org.uk>,
Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
Ian Campbell <Ian.Campbell@citrix.com>,
Jan Beulich <JBeulich@suse.com>,
Xen Devel <xen-devel@lists.xen.org>
Subject: Re: Fatal crash on xen4.2 HVM + qemu-xen dm + NFS
Date: Wed, 06 Mar 2013 11:50:48 +0000 [thread overview]
Message-ID: <262CC5014C323700E12B5A63@nimrod.local> (raw)
In-Reply-To: <C997FAB0FF8E85982A18EC3A@nimrod.local>
Konrad,
--On 22 February 2013 19:53:22 +0000 Alex Bligh <alex@alex.org.uk> wrote:
>> You should be able to test this rather easy by (in your guest)
>> mounting an ext3 or ext4 with barrier support and then looking at
>> the blktrace/blkparse to make sure that the sync commands are indeed
>> hitting the platter.
>
> OK, I will do that.
>
> I take it that it will sufficient to show:
> a) blktrace on the guest performing FUA/FLUSH operations; and
> b) blktrace on the host performing FUA/FLUSH operations
> in each case where there is an ext4 FS with barrier support turned
> on.
Results are positive.
We used the -y flag on sparsecopy
https://github.com/abligh/sparsecopy
to generate frequent barrier operations on a write to a file. This does
an fdatasync() after a configurable number of bytes. This was run in a VM
with /dev/xvda mapped to a qcow file on a Constellation ES.2 SATA drive
in the host on /dev/sdb (with no other traffic on /dev/sdb).
This is with O_DIRECT switched off.
The sound of the disk is a bit of give-away this is working, but for those
that like blktrace / blkparse output. The WBS indicates a barrier write.
I think this indicates barriers are getting through. Correct?
--
Alex Bligh
Extract from output of guest VM
202,0 0 1 0.000000000 0 D WS 1066249 + 8 [swapper/0]
202,0 0 2 0.009730334 0 C WS 1066249 + 8 [0]
202,0 0 3 0.009737210 0 C WS 1066249 [0]
202,0 0 4 0.015065483 0 C WS 2013633 + 32 [0]
202,0 0 5 0.016021243 0 C WS 1066257 + 40 [0]
202,0 0 6 0.016149561 217 A WBS 1066297 + 8 <- (202,1)
1050232
202,0 0 7 0.016154194 217 Q WBS 1066297 + 8 [(null)]
202,0 0 8 0.016158208 217 G WBS 1066297 + 8 [(null)]
202,0 0 9 0.016162792 217 I WBS 1066297 + 8 [(null)]
202,0 0 10 0.034824799 0 D WS 1066297 + 8 [swapper/0]
202,0 0 11 0.041799906 0 C WS 1066297 + 8 [0]
202,0 0 12 0.041807562 0 C WS 1066297 [0]
202,0 1 1 0.014174798 3601 A WS 2013633 + 32 <- (202,1)
1997568
Extract from output of host VM
8,17 1 0 0.205626177 0 m N cfq1542S / complete
rqnoidle 1
8,17 1 0 0.205630473 0 m N cfq1542S / set_slice=30
8,17 1 0 0.205637109 0 m N cfq1542S / arm_idle: 2
group_idle: 0
8,17 1 0 0.205638061 0 m N cfq schedule dispatch
8,16 1 72 0.205742935 1542 A WBS 1950869136 + 8 <- (8,17)
1950867088
8,17 1 73 0.205746817 1542 Q WS 1950869136 + 8
[jbd2/sdb1-8]
8,17 1 74 0.205754223 1542 G WS 1950869136 + 8
[jbd2/sdb1-8]
8,17 1 75 0.205758076 1542 I WS 1950869136 + 8
[jbd2/sdb1-8]
8,17 1 0 0.205760996 0 m N cfq1542S / insert_request
8,17 1 0 0.205766871 0 m N cfq1542S / dispatch_insert
8,17 1 0 0.205770429 0 m N cfq1542S / dispatched a
request
8,17 1 0 0.205772193 0 m N cfq1542S / activate rq,
drv=1
8,17 1 76 0.205772854 1542 D WS 1950869136 + 8
[jbd2/sdb1-8]
8,17 1 0 0.210488008 0 m N cfq idle timer fired
next prev parent reply other threads:[~2013-03-06 11:50 UTC|newest]
Thread overview: 91+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-14 14:54 Fatal crash on xen4.2 HVM + qemu-xen dm + NFS Alex Bligh
2012-12-17 10:10 ` Jan Beulich
2012-12-17 17:09 ` Alex Bligh
2013-01-16 10:56 ` Alex Bligh
2013-01-16 14:34 ` Stefano Stabellini
2013-01-16 15:06 ` Alex Bligh
2013-01-16 16:00 ` Alex Bligh
2013-01-16 16:27 ` Stefano Stabellini
2013-01-16 17:13 ` Alex Bligh
2013-01-16 17:33 ` Stefano Stabellini
2013-01-16 17:39 ` Stefano Stabellini
2013-01-16 18:14 ` Alex Bligh
2013-01-16 18:49 ` Stefano Stabellini
2013-01-16 19:00 ` Stefano Stabellini
2013-01-17 7:58 ` Alex Bligh
2013-01-16 18:12 ` Alex Bligh
2013-01-21 15:15 ` Alex Bligh
2013-01-21 15:23 ` Ian Campbell
2013-01-21 15:35 ` Alex Bligh
2013-01-21 15:50 ` Ian Campbell
2013-01-21 16:33 ` Alex Bligh
2013-01-21 16:51 ` Ian Campbell
2013-01-21 17:06 ` Alex Bligh
2013-01-21 17:29 ` Ian Campbell
2013-01-21 17:31 ` Alex Bligh
2013-01-21 17:32 ` Ian Campbell
2013-01-21 18:14 ` Alex Bligh
2013-01-22 10:05 ` Ian Campbell
2013-01-22 13:02 ` Alex Bligh
2013-01-22 13:13 ` Ian Campbell
2013-01-21 20:37 ` Alex Bligh
2013-01-22 10:07 ` Ian Campbell
2013-01-22 13:01 ` Alex Bligh
2013-01-22 13:14 ` Ian Campbell
2013-01-22 13:18 ` Alex Bligh
2013-01-22 10:13 ` Ian Campbell
2013-01-22 12:59 ` Alex Bligh
2013-01-22 15:46 ` Stefano Stabellini
2013-01-22 15:42 ` Stefano Stabellini
2013-01-22 16:09 ` Stefano Stabellini
2013-01-22 20:31 ` Alex Bligh
2013-01-23 11:52 ` Stefano Stabellini
2013-01-23 15:19 ` Alex Bligh
2013-01-23 16:29 ` Stefano Stabellini
2013-01-25 11:28 ` Alex Bligh
2013-02-05 15:40 ` Alex Bligh
2013-02-22 17:28 ` Alex Bligh
2013-02-22 17:41 ` Konrad Rzeszutek Wilk
2013-02-22 18:00 ` Stefano Stabellini
2013-02-22 19:53 ` Alex Bligh
2013-03-06 11:50 ` Alex Bligh [this message]
2013-03-07 1:01 ` Konrad Rzeszutek Wilk
2013-03-07 4:15 ` Stefano Stabellini
2013-03-07 10:47 ` [PATCH] QEMU(upstream): Disable xen's use of O_DIRECT by default as it results in crashes Alex Bligh
2013-03-08 3:18 ` Stefano Stabellini
2013-03-08 9:25 ` [PATCHv2] " Alex Bligh
2013-03-08 9:26 ` [PATCH] " Alex Bligh
2013-03-08 10:17 ` George Dunlap
2013-03-08 10:27 ` Alex Bligh
2013-03-08 10:35 ` George Dunlap
2013-03-08 10:50 ` Alex Bligh
2013-03-08 11:18 ` George Dunlap
2013-03-08 11:40 ` [PATCHv3] " Alex Bligh
2013-03-08 12:54 ` George Dunlap
2013-03-11 14:02 ` Alex Bligh
2013-03-11 14:42 ` George Dunlap
2013-03-11 17:48 ` Konrad Rzeszutek Wilk
2013-03-11 17:55 ` Ian Jackson
2013-03-14 17:06 ` Alex Bligh
2013-03-14 18:26 ` Ian Jackson
2013-03-12 12:08 ` Ian Campbell
2013-03-14 18:37 ` Stefano Stabellini
2013-03-14 19:30 ` Ian Jackson
2013-03-14 19:56 ` Alex Bligh
2013-03-15 9:28 ` Ian Campbell
2013-03-15 10:43 ` Stefano Stabellini
2013-03-15 11:21 ` Ian Jackson
2013-03-15 11:28 ` Stefano Stabellini
2013-03-15 11:37 ` Ian Jackson
2013-03-15 11:43 ` Stefano Stabellini
2013-03-15 12:43 ` Alex Bligh
2013-03-15 12:50 ` Ian Campbell
2013-03-15 18:31 ` Ian Jackson
2013-03-18 10:29 ` Alex Bligh
2013-03-18 11:47 ` Stefano Stabellini
2013-03-18 12:21 ` Alex Bligh
2013-03-08 11:41 ` [PATCH] " Alex Bligh
2013-03-08 10:28 ` George Dunlap
2013-03-08 10:45 ` Alex Bligh
2013-03-07 10:51 ` Fatal crash on xen4.2 HVM + qemu-xen dm + NFS Alex Bligh
2013-03-07 8:16 ` Alex Bligh
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