Messages in this thread | | | Date | Fri, 15 Apr 2011 00:22:55 -0400 | From | Christoph Hellwig <> | Subject | Re: 2.6.39 Block layer regression was [Bug] Boot hangs with 2.6.39-rc[123]] |
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On Thu, Apr 14, 2011 at 08:25:33PM -0700, Linus Torvalds wrote: > What's the thinking there? It looks very confused to me.
It is. I sent a patch a couple of days ago to fix it.
> Now, clearly RAID seems to be involved in the problem? The main thing > with that would be that the execution of the requests would tend to > generate new requests, that go back on the plug queue. Yes? And the > loop in flush_plug_list() means that they all should get flushed out, > I assume. But something clearly isn't working, and it does seem to be > about the RAID kind of setup. So either they didn't get put on the > plug queue, or the task got a new plug (which _wasn't_ flushed). > > Because we're clearly waiting for some request that hasn't completed. > Where in the plug queues would it be hiding?
There's a thread where Neil explains what the problem with MD is - it needs a callback on unplug time to generate e.g. the write intent bitmap or as large as possible writes for RAID5. Jens and Neil have been looking into it.
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