From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with ESMTP id D91C56B003D for ; Sun, 10 May 2009 01:33:15 -0400 (EDT) Date: Sat, 9 May 2009 22:26:12 -0700 From: Andrew Morton Subject: Re: [PATCH 4/8] proc: export more page flags in /proc/kpageflags Message-Id: <20090509222612.887b96e3.akpm@linux-foundation.org> In-Reply-To: <20090509104409.GB16138@elte.hu> References: <20090508105320.316173813@intel.com> <20090508111031.020574236@intel.com> <20090508114742.GB17129@elte.hu> <20090508132452.bafa287a.akpm@linux-foundation.org> <20090509104409.GB16138@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Ingo Molnar Cc: fengguang.wu@intel.com, fweisbec@gmail.com, rostedt@goodmis.org, a.p.zijlstra@chello.nl, lizf@cn.fujitsu.com, linux-kernel@vger.kernel.org, kosaki.motohiro@jp.fujitsu.com, andi@firstfloor.org, mpm@selenic.com, adobriyan@gmail.com, linux-mm@kvack.org List-ID: On Sat, 9 May 2009 12:44:09 +0200 Ingo Molnar wrote: > And because it was so crappy to be in /proc we are now also > treating it as a hard ABI, not as a debugfs interface - for that > single app that is using it. We'd probably make better progress here were someone to explain what pagemap actually is. pagemap is a userspace interface via which application developers (including embedded) can analyse, understand and optimise their use of memory. It is not debugging feature at all, let alone a kernel debugging feature. For this reason it is not appropriate that its interfaces be presented in debugfs. Furthermore the main control file for pagemap is in /proc//pagemap. pagemap _cannot_ be put in debugfs because debugfs doesn't maintain the per-process subdirectories in which to place it. /proc// is exactly the place where the pagemap file should appear. Yes, we could place pagemap's two auxiliary files into debugfs but it would be rather stupid to split the feature's control files across two pseudo filesystems, one of which may not even exist. Plus pagemap is not a kernel debugging feature. -- 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