Re: [PATCH 3/4]percpu_counter: fix code for 32bit systems

From: Tejun Heo
Date: Tue Apr 12 2011 - 15:03:16 EST


On Tue, Apr 12, 2011 at 04:04:04PM +0800, Shaohua Li wrote:
> static inline s64 percpu_counter_read(struct percpu_counter *fbc)
> {
> +#if BITS_PER_LONG == 32
> + s64 count;
> + spin_lock(&fbc->lock);
> + count = fbc->count;
> + spin_unlock(&fbc->lock);
> + return count;
> +#else
> return fbc->count;
> +#endif

I don't know. Is there any problem caused by this? The interface is
known to be unreliable and already being used in speculative manner.
I think it's more beneficial to avoid using locks on fast read path.

Thanks.

--
tejun
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