Messages in this thread | | | Date | Mon, 5 Aug 2019 22:58:13 +0800 | From | Boqun Feng <> | Subject | Re: [PATCH] locking/percpu_rwsem: Rewrite to not use rwsem |
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On Mon, Aug 05, 2019 at 10:43:18PM +0800, Boqun Feng wrote: > On Mon, Aug 05, 2019 at 04:02:41PM +0200, Peter Zijlstra wrote: > [...] > > > > static inline void percpu_up_read(struct percpu_rw_semaphore *sem) > > { > > + rwsem_release(&sem->dep_map, 1, _RET_IP_); > > + > > preempt_disable(); > > /* > > * Same as in percpu_down_read(). > > */ > > - if (likely(rcu_sync_is_idle(&sem->rss))) > > + if (likely(rcu_sync_is_idle(&sem->rss))) { > > __this_cpu_dec(*sem->read_count); > > - else > > - __percpu_up_read(sem); /* Unconditional memory barrier */ > > - preempt_enable(); > > + preempt_enable(); > > + return; > > + } > > > > - rwsem_release(&sem->rw_sem.dep_map, 1, _RET_IP_); > > Missing a preempt_enable() here? >
Ah.. you modified the semantics of __percpu_up_read() to imply a preempt_enable(), sorry for the noise...
Regards, Boqun
> Regards, > Boqun > > > + __percpu_up_read(sem); /* Unconditional memory barrier */ > > } > > > [...]
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