Re: [PATCH 1/6] Extend completions to provide XFS object flush requirements

Matthew Wilcox
2008-06-26T11:41:57Z

On Thu, Jun 26, 2008 at 09:32:09PM +1000, Dave Chinner wrote:
> On Thu, Jun 26, 2008 at 05:26:12AM -0600, Matthew Wilcox wrote:
> > On Thu, Jun 26, 2008 at 02:41:12PM +1000, Dave Chinner wrote:
> > > XFS object flushing doesn't quite match existing completion semantics. It
> > > mixed exclusive access with completion. That is, we need to mark an object as
> > > being flushed before flushing it to disk, and then block any other attempt to
> > > flush it until the completion occurs.
> >
> > This sounds like mutex semantics. Why are the existing mutexes not
> > appropriate for your needs?
>
> Different threads doing wait and complete.

Then let's leave it as a semaphore. You can get rid of the sema_t if
you like, but I don't think that turning completions into semaphores is
a good idea (because it's confusing).

--
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