Re: [RFC][PATCH 1/7] Resource counters

Srivatsa Vaddagiri wrote:
On Tue, Mar 13, 2007 at 06:41:05PM +0300, Pavel Emelianov wrote:
right, but atomic ops have much less impact on most
architectures than locks :)
Right. But atomic_add_unless() is slower as it is
essentially a loop. See my previous letter in this sub-thread.

If I am not mistaken, you shouldn't loop in normal cases, which means
it boils down to a atomic_read() + atomic_cmpxch()



So does the lock - in a normal case (when it's not
heavily contented) it will boil down to atomic_dec_and_test().

Nevertheless, making charge like in this patchset
requires two atomic ops with atomic_xxx and only
one with spin_lock().
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