Messages in this thread | | | Date | Sun, 6 Nov 2005 13:49:45 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH] Fixes for RCU handling of task_struct |
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Ingo Molnar <mingo@elte.hu> wrote: > > ... > > RCU signal handling: send signals RCU-read-locked instead of > tasklist_lock read-locked. This is a scalability improvement on SMP and > a preemption-latency improvement under PREEMPT_RCU. > > Signed-off-by: Paul E. McKenney <paulmck@us.ibm.com> > Signed-off-by: Ingo Molnar <mingo@elte.hu> > > ... > +static inline int get_task_struct_rcu(struct task_struct *t) > +{ > + int oldusage; > + > + do { > + oldusage = atomic_read(&t->usage); > + if (oldusage == 0) { > + return 0; > + } > + } while (cmpxchg(&t->usage.counter, > + oldusage, oldusage + 1) != oldusage); > + return 1; > +}
arm (at least) does not implement cmpxchg.
I think Nick is working on patches which implement cmpxchg on all architectures? - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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