On Tue, 21 Feb 2012, KAMEZAWA Hiroyuki wrote: > > No perforamce impact by replacing spin_lock_irq()/spin_unlock_irq() to > spin_lock_irqsave() and spin_unlock_irqrestore() ? None that I noticed - but that is not at all a reassuring answer! It worries me a little. I think it would make more or less difference on different architectures, and I forget where x86 stands there - one of the more or the less affected? Worth branches down inside page_relock_lruvec()? It's also unfortunate to be "losing" the information of where _irq is needed and where _irqsave (but not much gets lost with git). It's something that can be fixed - and I think Konstantin's version already keeps the variants: I just didn't want to get confused by them, while focussing on the locking details. Hugh -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>