Messages in this thread |  | | Date | Thu, 2 Feb 2012 12:19:12 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH] Avoid mask based num_possible_cpus and num_online_cpus -v5 |
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On Fri, 03 Feb 2012 06:33:02 +1030 Rusty Russell <rusty@rustcorp.com.au> wrote:
> On Wed, 1 Feb 2012 14:01:25 -0800, Andrew Morton <akpm@linux-foundation.org> wrote: > > > Though most of the callers of these two routines are init time (with few > > > exceptions of runtime calls), it is cleaner to use variables > > > and not go through this repeated mask based calculation. > > > > Looks good to me. > > But, I wonder who's asking num_possible_cpus(). It's not a very useful > thing to know, though some arch's "know" it's contiguous, so can cheat. > > Optimizing it seems particularly foolish.
We're fools for optimisations!
> We either audit and wean > everyone off who's using it incorrectly, or insist on contiguous CPU > numbers and drop the mask altogether.
drivers/block/nvme.c looks like it's assuming a contiguous map. Maybe also drivers/scsi/bnx2fc (wtf?). I didn't see anything else outside arch code.
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