From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754280AbZDNHJg (ORCPT ); Tue, 14 Apr 2009 03:09:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753493AbZDNHJP (ORCPT ); Tue, 14 Apr 2009 03:09:15 -0400 Received: from one.firstfloor.org ([213.235.205.2]:44512 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752379AbZDNHJO (ORCPT ); Tue, 14 Apr 2009 03:09:14 -0400 Date: Tue, 14 Apr 2009 09:11:59 +0200 From: Andi Kleen To: KOSAKI Motohiro Cc: Wu Fengguang , Andrew Morton , Andi Kleen , LKML , "linux-mm@kvack.org" Subject: Re: [RFC][PATCH] proc: export more page flags in /proc/kpageflags Message-ID: <20090414071159.GV14687@one.firstfloor.org> References: <20090414133448.C645.A69D9226@jp.fujitsu.com> <20090414064132.GB5746@localhost> <20090414154606.C665.A69D9226@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090414154606.C665.A69D9226@jp.fujitsu.com> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 14, 2009 at 03:54:40PM +0900, KOSAKI Motohiro wrote: > Hi There are two use cases here: First what is useful for the administrator as a general abstraction. And what is useful for the kernel hacker for debugging. The kernel hacker wants everything even if it's subject to change, the administrator wants a higher level abstraction they can make sense of and that doesn't change too often. I think there's a case for both usages, but perhaps they should be separated (in a public and a internal interface perhaps?) My comments below are about abstractions for the first case. > > > On Tue, Apr 14, 2009 at 12:37:10PM +0800, KOSAKI Motohiro wrote: > > > > Export the following page flags in /proc/kpageflags, > > > > just in case they will be useful to someone: > > > > > > > > - PG_swapcache > > > > - PG_swapbacked > > > > - PG_mappedtodisk > > > > - PG_reserved PG_reserved should be exported as PG_KERNEL or somesuch. > > > > - PG_private > > > > - PG_private_2 > > > > - PG_owner_priv_1 > > > > > > > > - PG_head > > > > - PG_tail > > > > - PG_compound I would combine these three into a pseudo "large page" flag. > > > > > > > > - PG_unevictable > > > > - PG_mlocked > > > > > > > > - PG_poison PG_poison is also useful to export. But since it depends on my patchkit I will pull a patch for that into the HWPOISON series. > > > > - PG_unevictable > > > > - PG_mlocked > > this 9 flags shouldn't exported. > I can't imazine administrator use what purpose those flags. I think an abstraced "PG_pinned" or somesuch flag that combines page lock, unevictable, mlocked would be useful for the administrator. -Andi From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with ESMTP id 263AD5F0001 for ; Tue, 14 Apr 2009 03:09:08 -0400 (EDT) Date: Tue, 14 Apr 2009 09:11:59 +0200 From: Andi Kleen Subject: Re: [RFC][PATCH] proc: export more page flags in /proc/kpageflags Message-ID: <20090414071159.GV14687@one.firstfloor.org> References: <20090414133448.C645.A69D9226@jp.fujitsu.com> <20090414064132.GB5746@localhost> <20090414154606.C665.A69D9226@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090414154606.C665.A69D9226@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org To: KOSAKI Motohiro Cc: Wu Fengguang , Andrew Morton , Andi Kleen , LKML , "linux-mm@kvack.org" List-ID: On Tue, Apr 14, 2009 at 03:54:40PM +0900, KOSAKI Motohiro wrote: > Hi There are two use cases here: First what is useful for the administrator as a general abstraction. And what is useful for the kernel hacker for debugging. The kernel hacker wants everything even if it's subject to change, the administrator wants a higher level abstraction they can make sense of and that doesn't change too often. I think there's a case for both usages, but perhaps they should be separated (in a public and a internal interface perhaps?) My comments below are about abstractions for the first case. > > > On Tue, Apr 14, 2009 at 12:37:10PM +0800, KOSAKI Motohiro wrote: > > > > Export the following page flags in /proc/kpageflags, > > > > just in case they will be useful to someone: > > > > > > > > - PG_swapcache > > > > - PG_swapbacked > > > > - PG_mappedtodisk > > > > - PG_reserved PG_reserved should be exported as PG_KERNEL or somesuch. > > > > - PG_private > > > > - PG_private_2 > > > > - PG_owner_priv_1 > > > > > > > > - PG_head > > > > - PG_tail > > > > - PG_compound I would combine these three into a pseudo "large page" flag. > > > > > > > > - PG_unevictable > > > > - PG_mlocked > > > > > > > > - PG_poison PG_poison is also useful to export. But since it depends on my patchkit I will pull a patch for that into the HWPOISON series. > > > > - PG_unevictable > > > > - PG_mlocked > > this 9 flags shouldn't exported. > I can't imazine administrator use what purpose those flags. I think an abstraced "PG_pinned" or somesuch flag that combines page lock, unevictable, mlocked would be useful for the administrator. -Andi -- 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/ . Don't email: email@kvack.org