On Mon, 30 Apr 2012, Minchan Kim wrote: > > What kind of consistency guarantees do you mean? The data sent to > > userspace is always a snapshot of the state and therefore can be stale > > by the time it reaches userspace. > > Consistency between component of snapshot. > let's assume following as > > 1. User expect some events's value would be minus when event he expect happen. > A : -3, B : -4, C : -5, D : -6 > 2. Logically, it's not possible to mix plus and minus values for the events. > A : -3, B : -4, C : -5, D : -6 ( O ) > A : -3, B : -4, C : 1, D : 2 ( X ) > > But in current implementation, some of those could be minus and some of those could be plus. > Which event could user believe? > At least, we need a _captured_ value when event triggered so that user can ignore other values. Sorry, I still don't quite understand the problem. The current implementation provides the same kind of snapshot consistency as reading from /proc/vmstat does (modulo the fact that we read them twice) for the values we support. Pekka -- 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>