Messages in this thread | | | Subject | Re: [rfc] "fair" rw spinlocks | From | Peter Zijlstra <> | Date | Mon, 30 Nov 2009 22:27:09 +0100 |
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On Mon, 2009-11-30 at 22:12 +0100, Thomas Gleixner wrote:
> I think the conversion Linus proposed is pretty feasible. I went > through the read_lock sites and most of them are protecting function > calls which we already use under rcu_read_lock() in other places like > find_task* and thread or pid iterators. > > There are a few non obvious ones in signal.c and posix-cpu-timers.c > (what a surprise) but nothing looks too scary. > > If nobody beats me I'm going to let sed loose on the kernel, lift the > task_struct rcu free code from -rt and figure out what explodes.
Things like sched.c:tg_set_bandwidth() take the tasklist_lock in read-mode to exclude tasks being added concurrently to avoid sched_rt_can_attach() races with tg_has_rt_tasks().
Possibly the cgroup stuff has a smaller lock to use for this.
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