From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with ESMTP id 96235900194 for ; Wed, 22 Jun 2011 20:14:30 -0400 (EDT) Received: by vws4 with SMTP id 4so1411358vws.14 for ; Wed, 22 Jun 2011 17:14:28 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20110622234450.GB20843@redhat.com> References: <201106212055.25400.nai.xia@gmail.com> <201106212132.39311.nai.xia@gmail.com> <20110622150350.GX20843@redhat.com> <20110622234450.GB20843@redhat.com> Date: Thu, 23 Jun 2011 08:14:28 +0800 Message-ID: Subject: Re: [PATCH] mmu_notifier, kvm: Introduce dirty bit tracking in spte and mmu notifier to help KSM dirty bit tracking From: Nai Xia Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Andrea Arcangeli Cc: Andrew Morton , Izik Eidus , Hugh Dickins , Chris Wright , Rik van Riel , linux-mm , Johannes Weiner , linux-kernel , kvm On Thu, Jun 23, 2011 at 7:44 AM, Andrea Arcangeli wrote: > On Thu, Jun 23, 2011 at 07:19:06AM +0800, Nai Xia wrote: >> OK, I'll have a try over other workarounds. >> I am not feeling good about need_pte_unmap myself. :-) > > The usual way is to check VM_HUGETLB in the caller and to call another > function that doesn't kmap. Casting pmd_t to pte_t isn't really nice > (but hey we're also doing that exceptionally in smaps_pte_range for > THP, but it safe there because we're casting the value of the pmd, not > the pointer to the pmd, so the kmap is done by the pte version of the > caller and not done by the pmd version of the caller). > > Is it done for migrate? Surely it's not for swapout ;). Thanks for the hint. :-) You know, another thing I am worried about is that I think I did make page_check_address() return a pmd version for skipping the tail subpages ... I did detecte a schedule in atomic if I kunmap() the returned value. :-( > >> Thanks for viewing! > > You're welcome! > > JFYI I'll be offline on vacation for a week, starting tomorrow, so if > I don't answer in the next few days that's the reason but I'll follow > the progress in a week. Have a nice vacation man! Enjoy the sunlight, we all have enough of code in rooms. ;-) Thanks, Nai > > Thanks! > Andrea > -- 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