Messages in this thread | | | Date | Sun, 28 Mar 2010 20:45:13 -0400 | From | Mathieu Desnoyers <> | Subject | Re: [patch 0/6] rcu head debugobjects |
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* Thomas Gleixner (tglx@linutronix.de) wrote: > B1;2005;0cOn Sat, 27 Mar 2010, Paul E. McKenney wrote: > > > > o Patch 4/6 looks good to me, and given that Thomas hasn't > > complained, I am guessing that he is OK with it. > > Looks sane at the first glance. Will go over it in detail tomorrow. > > > o Patch 6/6: Would it be possible to use the object_is_on_stack() > > function defined in include/linux/sched.h instead of passing > > in the flag on_stack to bdi_work_init()? It looks like > > fs/fs-writeback.c already includes include/linux/sched.h, so > > shouldn't be a problem from a #include-hell viewpoint. > > Well, I'm a bit wary about that. The reason is that we really want > the annotation of: > > init_on_stack(); > .... > destroy_on_stack(); > > instead of the confusing: > > init(); > .... > destroy_on_stack(); > > So having an automatism in the bdi_work_init() function will people > make forget to put the destroy_on_stack() annotation into it. > > The flag is horrible as well. How about this: > > /* helper function, do not use in code ! */ > __bdi_work_init(....., onstack) > { > .... > if (on_stack) { > work.state |= WS_ONSTACK; > init_rcu_head_on_stack(&work.rcu_head); > } else { > .... > } > > See, how this moves also the "work.state |= WS_ONSTACK;" line out of > the calling code. > > bdi_work_init(...) > { > __bdi_work_init(...., false); > } > > bdi_work_init_on_stack(...) > { > __bdi_work_init(...., true); > } > > > out of the code. > > To make it complete, please do not use the asymmetric: > > destroy_rcu_head_on_stack(&work.rcu_head); > > Create a helper function: > > bdi_destroy_work_on_stack(...) > { > destroy_rcu_head_on_stack(work->rcu_head); > } > > That makes it way more readable and we did that with the other on > stack initializers as well.
These changes are queued for v3. Thanks Thomas!
Mathieu
> > Thanks, > > tglx
-- Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.com
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