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From John Rushford <jjrushf...@gmail.com>
Subject Re: Help with collapsed_connection plugin.
Date Thu, 22 Jun 2017 14:44:53 GMT
Leif,

The mutex is ref counted but the i look at the code  for TSContDestroy, I
see that the pointer to the mutex is only set to NULL,
INKContInternal::destroy().  I think that the plugins should call
TSMutexDestroy() also.  Is that correct?

On Thu, Jun 22, 2017 at 6:59 AM, Leif Hedstrom <zwoop@apache.org> wrote:

> Yes, this is the correct fix. In earlier versions, the core would create
> the mutex for you if it needed one, but this had some pretty expensive
> overhead. So now we just assert instead, so people can fix their plugins
> (and our plugins apparently).
>
> Fwiw, the mutex is needed when the continuation uses a specific set of
> APIs. This should be documented in the docs somewhere.
>
> Cheers,
>
> -- Leif
>
> > On Jun 21, 2017, at 8:18 PM, John Rushford <jjrushford@gmail.com> wrote:
> >
> >
> > Peter,
> >
> > I've found this with a couple of other plugins and fixed them by making
> exactly the change you you're asking about.  In testing i have not run into
> any issues with the plugins i have changed.
> >
> > John
> >
> >> On Jun 21, 2017, at 4:22 PM, Chou, Peter <pbchou@labs.att.com> wrote:
> >>
> >> Hi,
> >>
> >> I am taking a look at the collapsed_connection plugin. There appears to
> be an assertion failure crash incompatibility between this plugin and
> changes made in the 6.2.x branch. TS-4387 appears to require all
> continuations calling TSContSchedule() to have a mutex, but in the plugin
> no mutex is created in addMutexRetry() since TSContCreate() is called as
> TSContCreate(retryCacheUrlLock, NULL).
> >>
> >> Is it sufficient to change this call to TSContCreate(retryCacheUrlLock,
> TSMutexCreate())?
> >>
> >> Would this possibly cause side-effects such as mutex lock contention
> the plugin is not designed to deal with, and would the mutex need to be
> destroyed manually somewhere else in the code? I am still learning on this
> area of ATS...
> >>
> >> Thanks,
> >> Peter
>
>


-- 
John Rushford
jjrushford@gmail.com

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