Re: Linux 2.6.29

From: Jens Axboe
Date: Thu Mar 26 2009 - 15:05:18 EST


On Thu, Mar 26 2009, Hugh Dickins wrote:
> On Thu, 26 Mar 2009, Jens Axboe wrote:
> > On Thu, Mar 26 2009, Hugh Dickins wrote:
> > >
> > > So, directing a barrier (WRITE_BARRIER or DISCARD_BARRIER) to a range
> > > of sectors in one partition interposes a barrier into the queue of I/O
> > > across (all partitions of) that whole device.
> >
> > Correct
> >
> > > I think that's not how filesystems really want barriers to behave,
> > > and might tend to discourage us from using barriers more freely.
> > > But I have zero appreciation of whether it's a significant issue
> > > worth non-trivial change - just wanted to get it out into the open.
> >
> > Per-partition definitely makes sense. The problem is that we do sorting
> > on a per-device basis right now. But it's a good point, I'll try and
> > take a look at how much work it would be to make it per-partition
> > instead. It wont be trivial :-)
>
> Thanks, that would be interesting.
> Trivial bores you anyway, doesn't it?

You're a good motivator, Hugh!

--
Jens Axboe

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