From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx146.postini.com [74.125.245.146]) by kanga.kvack.org (Postfix) with SMTP id E9DD36B0037 for ; Thu, 1 Aug 2013 02:28:18 -0400 (EDT) Received: by mail-la0-f53.google.com with SMTP id el20so1141511lab.12 for ; Wed, 31 Jul 2013 23:28:17 -0700 (PDT) Date: Thu, 1 Aug 2013 10:28:14 +0400 From: Cyrill Gorcunov Subject: Re: [patch 1/2] [PATCH] mm: Save soft-dirty bits on swapped pages Message-ID: <20130801062814.GB1764@moon> References: <20130730204154.407090410@gmail.com> <20130730204654.844299768@gmail.com> <20130801005132.GB19540@bbox> <20130801055303.GA1764@moon> <20130801061632.GE19540@bbox> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130801061632.GE19540@bbox> Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, luto@amacapital.net, xemul@parallels.com, akpm@linux-foundation.org, mpm@selenic.com, xiaoguangrong@linux.vnet.ibm.com, mtosatti@redhat.com, kosaki.motohiro@gmail.com, sfr@canb.auug.org.au, peterz@infradead.org, aneesh.kumar@linux.vnet.ibm.com On Thu, Aug 01, 2013 at 03:16:32PM +0900, Minchan Kim wrote: > > I don't get it. Could you correct me with below example? > > Process A context > try_to_unmap > swp_pte = swp_entry_to_pte /* change generic swp into arch swap */ > swp_pte = pte_swp_mksoft_dirty(swp_pte); > set_pte_at(, swp_pte); > > Process A context > .. > mincore_pte_range pte_t pte = *ptep; <-- local copy of the pte value, in memory it remains the same with swap softdirty bit set > pte_to_swp_entry > pte = pte_swp_clear_soft_dirty <=== 1) > change arch swp with generic swp > mincore_page > > Process B want to know dirty state of the page > .. > pagemap_read > pte_to_pagemap_entry > is_swap_pte > if (pte_swap_soft_dirty(pte)) <=== but failed by 1) > > So, Process B can't get the dirty status from process A's the page. -- 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