Messages in this thread | | | Date | Wed, 30 May 2012 15:28:37 +0900 | Subject | Re: [PATCH V3] block: Mitigate lock unbalance caused by lock switching | From | Tejun Heo <> |
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Hello,
On Wed, May 30, 2012 at 3:28 PM, Asias He <asias@redhat.com> wrote: >> 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.
It's not hot path. Dirtying the cacheline there doesn't mean anything. I don't really care either way but making optimization argument is pretty silly here.
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