[PATCH] talloc with threads tutorial and tests

[Jeremy Allison]

On Mon, Mar 16, 2015 at 12:46:58PM -0700, Jeremy Allison wrote:
> On Mon, Mar 16, 2015 at 03:36:11PM -0400, Simo wrote:
> > On Mon, 2015-03-16 at 12:28 -0700, Jeremy Allison wrote:
> > > So one of the things that came up at the Vault
> > > conference in conversations with Jeff was the
> > > real lack of a guide on how to use talloc in
> > > pthreaded code.
> > > 
> > > Here is an attempt to fix that, plus a test
> > > case added to smbtorture local.talloc to ensure
> > > talloc works correctly in a threaded environment.
> > > 
> > > Please review and comment/push !
> > > 
> > > Thanks,
> > > 
> > > 	Jeremy.
> > 
> > +10!
> > 
> > Very nice to see this.
> > 
> > Aside:
> > Jeremy would you like a method of passing a context that avoids shared
> > variables and mutexes and uses instead a pipe for synchronization ?
> > I think it's be neat and simpler to use, perhaps even more performant as
> > you do not get many threads contending on a single variable, but with
> > the downside of requiring a pipe between main thread and each sub
> > thread.
> 
> Maybe as a second example. I really want to keep a simple,
> threads-only solution as the first example so people don't
> have to think about all the issues you get with pipes
> (sync/async send, signal handling, partial writes etc.
> etc. etc.).
> 
> I'm sure it would perform better, but this is about
> correctness initially, not performance.

Also, I'm eventually planning to tie this in with
a tevent+threads tutorial, showing how to have each
thread run a seprate event loop, and then synchronise
talloced memory passing between them when they need
to communicate. That's a perfect place to use the
sync-pipe example as it ties into the thread-local
tevent code.

Cheers,

	Jeremy.