Re: threaded programs report bogus process size ?

[mlelstv%serpens.de@localhost (Michael van Elst)]

njoly%pasteur.fr@localhost (Nicolas Joly) writes:

>I just noticed that threaded processes may report increasing process
>size of their life ...

libpthread never frees the pthread data structure and associated
thread stack when a thread ends but puts it onto a private queue
("deadqueue") and reclaims it again when a new thread is created.

The reclaim can fail when a new thread is created shortly after
an old thread ended because of a race with the kernel. As a result
a new thread is allocated.

So _some_ leakage is allowed by design.

The problem is that the reclaim operation is only tried for the
thread that ended last (the top of the "deadqueue"). So in a
tight pthread_create/join loop the leaked threads just pile up.

To correct this the reclaim operation should loop over the queue
and try to reclaim any of the dead threads.

-- 
-- 
                                Michael van Elst
Internet: mlelstv%serpens.de@localhost
                                "A potential Snark may lurk in every tree."