On Thu, Mar 03, 2016 at 07:55:15AM +0800, Ming Lei wrote: > > command indeed. Except for keeping the flags in sync, which sounds > > like a good іdea in general there is not reall need for this one. > > NO_SG_MERGE has been bypassed after bio splitting is introduced, > and looks it should have been removed. Partially at least. Anyway, let's start a discussion on blk-mq merge flags. First I really hate the way how any merges are opt-in. I'd be much happier with an opt-out to get the sane behavior by default. Every drivers set BLK_MQ_F_SHOULD_MERGE, and while only a few drivers set BLK_MQ_F_SG_MERGE I suspect all should as well. Especially as the SG merging is cheaper and more useful than the bio mergig in many cases. Jens, what are you fine with simply adding a BLK_MQ_F_NOMERGE as an inverse flag that disables both bio and sg merging (where we control it), and just default to doing them? > > > -- > Ming Lei ---end quoted text--- -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
