On Wed, 7 Nov 2012, Oleg Nesterov wrote:
> On 11/07, Mikulas Patocka wrote: > > > > It looks sensible. > > > > Here I'm sending an improvement of the patch - I changed it so that there > > are not two-level nested functions for the fast path and so that both > > percpu_down_read and percpu_up_read use the same piece of code (to reduce > > cache footprint). > > IOW, the only change is that you eliminate "static update_fast_ctr()" > and fold it into down/up_read which takes the additional argument. > > Honestly, personally I do not think this is better, but I won't argue. > I agree with everything but I guess we need the ack from Paul. If you look at generated assembly (for x86-64), the footprint of my patch is 78 bytes shared for both percpu_down_read and percpu_up_read. The footprint of your patch is 62 bytes for update_fast_ctr, 46 bytes for percpu_down_read and 20 bytes for percpu_up_read. Mikulas -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
