Messages in this thread | | | Date | Wed, 30 May 2012 14:28:05 +0800 | From | Asias He <> | Subject | Re: [PATCH V3] block: Mitigate lock unbalance caused by lock switching |
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On 05/29/2012 09:45 PM, Tim Gardner wrote: > On 05/28/2012 07:39 PM, Asias He wrote: > > <snip> > >> @@ -440,6 +435,11 @@ void blk_cleanup_queue(struct request_queue *q) >> del_timer_sync(&q->backing_dev_info.laptop_mode_wb_timer); >> blk_sync_queue(q); >> >> + spin_lock_irq(lock); >> + if (q->queue_lock !=&q->__queue_lock) >> + q->queue_lock =&q->__queue_lock; >> + spin_unlock_irq(lock); >> + > > Isn't the 'if' clause superfluous ? You could just do the assignment, e.g., > > + spin_lock_irq(lock); > + q->queue_lock =&q->__queue_lock; > + spin_unlock_irq(lock);
Well, this saves a if clause but adds an unnecessary assignment if the lock is already internal lock.
-- Asias
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