From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx129.postini.com [74.125.245.129]) by kanga.kvack.org (Postfix) with SMTP id 86B6D6B004D for ; Mon, 19 Dec 2011 15:32:37 -0500 (EST) Received: from /spool/local by e9.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 19 Dec 2011 15:32:36 -0500 Received: from d01av01.pok.ibm.com (d01av01.pok.ibm.com [9.56.224.215]) by d01relay05.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id pBJKWYLG211502 for ; Mon, 19 Dec 2011 15:32:34 -0500 Received: from d01av01.pok.ibm.com (loopback [127.0.0.1]) by d01av01.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id pBJKWWE0006829 for ; Mon, 19 Dec 2011 15:32:32 -0500 Message-ID: <4EEF9F3E.9000107@linux.vnet.ibm.com> Date: Mon, 19 Dec 2011 12:31:58 -0800 From: Dave Hansen MIME-Version: 1.0 Subject: Re: [RFC][PATCH 2/3] pagemap: export KPF_THP References: <1324319919-31720-1-git-send-email-n-horiguchi@ah.jp.nec.com> <1324319919-31720-3-git-send-email-n-horiguchi@ah.jp.nec.com> <4EEF8F85.9010408@gmail.com> In-Reply-To: <4EEF8F85.9010408@gmail.com> Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: KOSAKI Motohiro Cc: Naoya Horiguchi , linux-mm@kvack.org, Andi Kleen , Wu Fengguang , Andrea Arcangeli , KOSAKI Motohiro , KAMEZAWA Hiroyuki , linux-kernel@vger.kernel.org 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 > > 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. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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: email@kvack.org