[PATCH] talloc_free_for_exit() and targeted write protection for talloc destructor

[Andrew Bartlett]

On Tue, 2016-11-29 at 07:57 +0100, Volker Lendecke wrote:
> On Tue, Nov 29, 2016 at 07:13:53AM +1300, Andrew Bartlett wrote:
> > 
> > In a hope of getting more attention and being more transparent,
> > here is
> > the talloc changes I included in my previous patch set.
> > 
> > As background, I want to make our LDAP server multi-process, and
> > running a connect()/bind()/close() loop against the LDAP server
> > showed
> > a significant cost in talloc_free(ev) and talloc_autofree() just
> > before
> > exit.
> 
> Question -- why don't you directly call exit() without the
> talloc_free(ev)? Or even _exit()? We should be able to live with
> crashed processes. What destructors are you missing?

I assumed there would at least be messaging database entries to un-
register.  _exit() seemed a little extreme, but I agree it is an
option, and of course exit() calls handlers registered with atexit().  

Memory on the autofree context from that atexit() registered call was
around half the overhead in our examination of the flame graphs. 

Thanks,

Andrew Bartlett

-- 
Andrew Bartlett                       http://samba.org/~abartlet/
Authentication Developer, Samba Team  http://samba.org
Samba Developer, Catalyst IT          http://catalyst.net.nz/services/samba