On Tue, Sep 08, 2015 at 01:34:20PM -0400, Tejun Heo wrote: > Hmmm... grep tells me that dm and md actually are branching on whether > the underlying device supports FUA. This is tricky. I didn't even > mean flush_flags to be used directly by upper layers. For rotational > devices, doing multiple FUAs compared multiple writes followed by > REQ_FLUSH is probably a lot worse - the head gets moved multiple times > likely skipping over data which can be written out while traversing > and it's not like stalling write pipeline and draining write queue has > much impact on hard drives. Well, that's what we'd need to do for the raid cache as well, given the resulst that Shaohua sees. Unless you have a good idea for another way to handle the issue we'll need to support both behaviors there. -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
