Messages in this thread | | | From | Jeff Moyer <> | Subject | Re: [RFC][PATCH] add blockconsole | Date | Wed, 25 Apr 2012 11:52:28 -0400 |
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Jörn Engel <joern@logfs.org> writes:
> On Wed, 25 April 2012 09:42:39 -0400, Jeff Moyer wrote: >> >> Neat idea, but I'm curious to know how it works when the system panics >> and you no longer can schedule the writeback thread. What are the >> limitations you've seen in practice? > > If the writeback thread doesn't get scheduled, you lose that > information. Formerly I did the submit_bio directly, but lockdep > reminded me that I shouldn't do so from interrupt context. Bummer.
Well, submit_bio can sleep, obviously. Perhaps you could explore registering a panic notifier, and then flush the logs from there? Unfortunately, there is always the possibility that some required locks will be taken, but it might get you a little bit further. Or, you could explore the route that the diskdump or lkcd folks took, implementing their own polling mode drivers.
Cheers, Jeff -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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