From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752170Ab0IOG2U (ORCPT ); Wed, 15 Sep 2010 02:28:20 -0400 Received: from cantor2.suse.de ([195.135.220.15]:42195 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750733Ab0IOG2T (ORCPT ); Wed, 15 Sep 2010 02:28:19 -0400 From: Nikanth Karthikesan Organization: suse.de To: KOSAKI Motohiro Subject: Re: [PATCH v2] After swapout/swapin private dirty mappings are reported clean in smaps Date: Wed, 15 Sep 2010 12:01:11 +0530 User-Agent: KMail/1.12.4 (Linux/2.6.31.12-0.2-default; KDE/4.3.5; x86_64; ; ) Cc: Richard Guenther , linux-mm@kvack.org, Andrew Morton , balbir@linux.vnet.ibm.com, Michael Matz , Matt Mackall , linux-kernel@vger.kernel.org References: <20100915134724.C9EE.A69D9226@jp.fujitsu.com> <201009151034.22497.knikanth@suse.de> <20100915141710.C9F7.A69D9226@jp.fujitsu.com> In-Reply-To: <20100915141710.C9F7.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201009151201.11359.knikanth@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday 15 September 2010 10:50:25 KOSAKI Motohiro wrote: > > On Wednesday 15 September 2010 10:18:11 KOSAKI Motohiro wrote: > > > > On Wednesday 15 September 2010 05:56:36 KOSAKI Motohiro wrote: > > > > > > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c > > > > > > index 439fc1f..06fc468 100644 > > > > > > --- a/fs/proc/task_mmu.c > > > > > > +++ b/fs/proc/task_mmu.c > > > > > > @@ -368,7 +368,11 @@ static int smaps_pte_range(pmd_t *pmd, > > > > > > unsigned long addr, unsigned long end, mss->shared_clean += > > > > > > PAGE_SIZE; mss->pss += (PAGE_SIZE << PSS_SHIFT) / mapcount; > > > > > > } else { > > > > > > - if (pte_dirty(ptent)) > > > > > > + /* > > > > > > + * File-backed pages, now anonymous are dirty > > > > > > + * with respect to the file. > > > > > > + */ > > > > > > + if (pte_dirty(ptent) || (vma->vm_file && PageAnon(page))) > > > > > > mss->private_dirty += PAGE_SIZE; > > > > > > else > > > > > > mss->private_clean += PAGE_SIZE; > > > > > > > > > > This is risky than v1. number of dirties are used a lot of > > > > > application. > > > > > > > > This is exactly to help those applications, as currently after > > > > swap-out and swap-in, the same pages are accounted as > > > > "Private_Clean:" instead of "Private_Dirty:". > > > > > > I don't think so. > > > > Actually this behaviour is observed. With a simple memhog, you can see > > pages which are "Private_Dirty:", become "Swap:" and then to > > "Private_Clean:". And that confused GDB. > > As I said, incorrect information is always no good solustion. We should > concern how to provide good and enough information, but not how to lie. > If currect gdb is crappy, it should fix. > How? Current smaps information without this patch provides incorrect information. Just because a private dirty page became part of swap cache, it shown as clean and backed by a file. If it is shown as clean and backed by swap then it is fine. Thanks Nikanth > > > incorrect infomation bring a lot of confusion rather than > > > its worth. > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with SMTP id 68B806B007B for ; Wed, 15 Sep 2010 02:28:20 -0400 (EDT) From: Nikanth Karthikesan Subject: Re: [PATCH v2] After swapout/swapin private dirty mappings are reported clean in smaps Date: Wed, 15 Sep 2010 12:01:11 +0530 References: <20100915134724.C9EE.A69D9226@jp.fujitsu.com> <201009151034.22497.knikanth@suse.de> <20100915141710.C9F7.A69D9226@jp.fujitsu.com> In-Reply-To: <20100915141710.C9F7.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201009151201.11359.knikanth@suse.de> Sender: owner-linux-mm@kvack.org To: KOSAKI Motohiro Cc: Richard Guenther , linux-mm@kvack.org, Andrew Morton , balbir@linux.vnet.ibm.com, Michael Matz , Matt Mackall , linux-kernel@vger.kernel.org List-ID: On Wednesday 15 September 2010 10:50:25 KOSAKI Motohiro wrote: > > On Wednesday 15 September 2010 10:18:11 KOSAKI Motohiro wrote: > > > > On Wednesday 15 September 2010 05:56:36 KOSAKI Motohiro wrote: > > > > > > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c > > > > > > index 439fc1f..06fc468 100644 > > > > > > --- a/fs/proc/task_mmu.c > > > > > > +++ b/fs/proc/task_mmu.c > > > > > > @@ -368,7 +368,11 @@ static int smaps_pte_range(pmd_t *pmd, > > > > > > unsigned long addr, unsigned long end, mss->shared_clean += > > > > > > PAGE_SIZE; mss->pss += (PAGE_SIZE << PSS_SHIFT) / mapcount; > > > > > > } else { > > > > > > - if (pte_dirty(ptent)) > > > > > > + /* > > > > > > + * File-backed pages, now anonymous are dirty > > > > > > + * with respect to the file. > > > > > > + */ > > > > > > + if (pte_dirty(ptent) || (vma->vm_file && PageAnon(page))) > > > > > > mss->private_dirty += PAGE_SIZE; > > > > > > else > > > > > > mss->private_clean += PAGE_SIZE; > > > > > > > > > > This is risky than v1. number of dirties are used a lot of > > > > > application. > > > > > > > > This is exactly to help those applications, as currently after > > > > swap-out and swap-in, the same pages are accounted as > > > > "Private_Clean:" instead of "Private_Dirty:". > > > > > > I don't think so. > > > > Actually this behaviour is observed. With a simple memhog, you can see > > pages which are "Private_Dirty:", become "Swap:" and then to > > "Private_Clean:". And that confused GDB. > > As I said, incorrect information is always no good solustion. We should > concern how to provide good and enough information, but not how to lie. > If currect gdb is crappy, it should fix. > How? Current smaps information without this patch provides incorrect information. Just because a private dirty page became part of swap cache, it shown as clean and backed by a file. If it is shown as clean and backed by swap then it is fine. Thanks Nikanth > > > incorrect infomation bring a lot of confusion rather than > > > its worth. > -- 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