On Monday 04 June 2012 21:31:25 KOSAKI Motohiro wrote: > (6/4/12 4:23 AM), Bartlomiej Zolnierkiewicz wrote: > > On Friday 01 June 2012 22:31:01 KOSAKI Motohiro wrote: > >> (6/1/12 12:54 PM), Bartlomiej Zolnierkiewicz wrote: > >>> From: Bartlomiej Zolnierkiewicz<b.zolnierkie@xxxxxxxxxxx> > >>> Subject: [PATCH] proc: add /proc/kpageorder interface > >>> > >>> This makes page order information available to the user-space. > >> > >> No usecase new feature always should be NAKed. > > > > It is used to get page orders for Buddy pages and help to monitor > > free/used pages. Sample usage will be posted for inclusion to > > Pagemap Demo tools (http://selenic.com/repo/pagemap/). > > > > The similar situation is with /proc/kpagetype.. > > NAK then. > > First, your explanation didn't describe any usecase. "There is a similar feature" > is NOT a usecase. > > Second, /proc/kpagetype is one of mistaken feature. It was not designed deeply. > We have no reason to follow the mistake. Well, my usecase for /proc/kpagetype is to monitor/debug pageblock changes (i.e. to verify CMA and compaction operations). It is not perfect since interface gives us only a snapshot of pageblocks state at some random time. However it is a straightforward method and requires only minimal changes to the existing code. Maybe there is a better way to do this which would give a more accurate data and capture every state change (maybe a one involving tracing?) but I don't know about it. Do you know such better way to do it? > Third, pagemap demo doesn't describe YOUR feature's usefull at all. pagemap demo doesn't include my patches for /proc/kpage[order,type] yet so it is not surprising at all (it doesn't even work with current kernels without my other patches).. ;) > Fourth, pagemap demo is NOT useful at all. It's just toy. Practically, kpagetype > is only used from pagetype tool. I don't quite follow it, what pagetype tool are you referring to (kpagetype is a new interface)? Best regards, -- Bartlomiej Zolnierkiewicz Samsung Poland R&D Center -- 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>