Messages in this thread | | | Subject | Re: [PATCH RFC tip/core/rcu 11/11] rcu: move TREE_RCU from softirq to kthread | From | Steven Rostedt <> | Date | Wed, 23 Feb 2011 14:35:10 -0500 |
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On Wed, 2011-02-23 at 20:23 +0100, Peter Zijlstra wrote: > On Wed, 2011-02-23 at 13:19 -0600, Christoph Lameter wrote: > > > this_cpu_inc is already percpu atomic. On x86 it is an instruction that > > cannot be interrupted nor preempted while in progress. > > On x86, yes, but is this true for all architectures? I guess the > fallback is implemented with local_irq_disable() which might be good > enough for some but not for NMI usage.
IIRC, those archs that can not do an atomic inc or cmpxchg have NMIs that are basically "The Sh*t hit the fan, bail". Where the NMIs are used only to dump out the state of the system and not something more advanced that can do things like profiling.
-- Steve
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