(12/19/11 3:31 PM), Dave Hansen wrote: > On 12/19/2011 11:24 AM, KOSAKI Motohiro wrote: >> (12/19/11 1:38 PM), Naoya Horiguchi wrote: >>> This flag shows that a given pages is a subpage of transparent hugepage. >>> It does not care about whether it is a head page or a tail page, because >>> it's clear from pfn of the target page which you should know when you read >>> /proc/kpageflags. >>> >>> Signed-off-by: Naoya Horiguchi<n-horiguchi@xxxxxxxxxxxxx> >> >> NAK. >> >> The detail of transparent hugepage are hidden by design. We hope it >> keep 'transparent'. >> Until any explain why we should expose KPF_THP, we don't agree it. > > Transparent shouldn't mean "undebuggable", though. :) > > Let's say you profiled a application and the data shows you're missing > the TLB a bunch, but you're also using THP. This might give you a shot > at figuring out which parts of your application are *TRULY* THP-backed > instead of just the areas you *think* are backed. > > I'm not sure there's another way to figure it out at the moment. A snapshot status of THP doesn't help your purpose. I think you need perf or similar profiling subsystem enhancement. Because of, if you've seen KPF_THP at once, It has no guarantee to keep hugepages until applications run. Opposite, If you only need rough statistics, the best way is to add some new stat to /sys/kernel/mm/transparent_hugepage. I don't think your usecase and current proposal are matched. -- 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>