Messages in this thread | | | Date | Thu, 26 Mar 2015 17:03:25 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH] lglock: Use spinlock_t instead of arch_spinlock_t |
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On Thu, Mar 26, 2015 at 04:02:08PM +0100, Daniel Wagner wrote: > @@ -67,9 +67,9 @@ void lg_global_lock(struct lglock *lg) > preempt_disable(); > lock_acquire_exclusive(&lg->lock_dep_map, 0, 0, NULL, _RET_IP_); > for_each_possible_cpu(i) { > - arch_spinlock_t *lock; > + spinlock_t *lock; > lock = per_cpu_ptr(lg->lock, i); > - arch_spin_lock(lock); > + spin_lock(lock); > } > }
Nope, that'll blow up in two separate places.
One: lockdep, it can only track a limited number of held locks, and it will further report a recursion warning on the 2nd cpu.
Second: preempt_count_add(), spin_lock() does preempt_disable(), with enough CPUs you'll overflow the preempt counter (255).
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