On 9/3/18 4:26 PM, Logan Gunthorpe wrote: > > > On 01/09/18 02:28 AM, Christoph Hellwig wrote: >> On Thu, Aug 30, 2018 at 01:11:18PM -0600, Jens Axboe wrote: >>> I think this belongs in the caller - both the validity check, and >>> passing in NOMERGE for this type of request. I don't want to impose >>> this overhead on everything, for a pretty niche case. >> >> It is just a single branch, which will be predicted as not taken >> for non-P2P users. The benefit is that we get proper error checking >> by doing it in the block code. > > I personally agree with Christoph. But if there's consensus in the other > direction or this is a real blocker moving this forward, I can remove it > for the next version. It's a simple branch because the check isn't exhaustive. It just checks the first page. At that point you may as well just require the caller to flag the bio/rq as being P2P, and then do a check for P2P compatibility with the queue. -- Jens Axboe
