Re: RAID1 might_sleep() warning on 3.19-rc7

From: NeilBrown
Date: Tue Feb 17 2015 - 20:09:52 EST


On Fri, 13 Feb 2015 15:48:03 +0100 Peter Zijlstra <peterz@xxxxxxxxxxxxx>
wrote:

> On Fri, Feb 13, 2015 at 11:27:46AM +0100, Peter Zijlstra wrote:
>
> > > I've moved blk_flush_plug to the beginning of the function.
> >
> > > I wondered if it really make sense to call blk_flush_plug with nr_iowait
> > > elevated and delayacct_blkio active. blk_flush_plug() could call schedule()
> > > for non-"io" reasons and maybe that could upset stuff???
> >
> > Yeah, good question that. Lemme ponder that a bit.
>
> Yes, I thikn your version makes most sense as, you say, even regular
> schedule() call nested in my version would go towards blk delayacct --
> and I doubt that was the intent; even though the current kernel works
> that way.
>
> I'll move the now rudimentary io_schedule() into sched.h as an inline.

Thanks.

Are you OK with this going to -stable for 3.19?

NeilBrown

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