Re: Linux NFS and cached properties

["J. Bruce Fields" <bfields@fieldses.org>]

On Thu, Aug 02, 2012 at 10:04:05AM +1000, NeilBrown wrote:
> I never liked that fact that stopping the last thread did something extra.
> So when I added the ability to control the number of threads via sysfs I made

(You meant nfsd, not sysfs, right?  Or is there some interface I'm
overlooking?)

> sure that it *only* controlled the number of threads.  However I kept the
> legacy behaviour that sending SIGKILL to the nfsd threads would also unexport
> things.  Obviously I should have documented this better.
> 
> The more I think out it, the more I'd really like to go back to that.  It
> really is the *right* thing to do.
...
> > > 1/ iterate through all no-sleeping threads setting a flag an increasing a
> > > counter.
> > > 2/ when a thread completes current request, if test_and_clear the flag, it
> > > atomic_dec_and_test the counter and then wakes up some wait_queue_head.
> > > 3/ 'flush'ing thread waits on the waut_queue_head for the counter to be 0.
> > > 
> > > If you don't hate it I could possibly even provide some code.

By the way, are you still looking into one of those approaches?

--b.