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 A1DB5900194 for ; Wed, 22 Jun 2011 19:19:08 -0400 (EDT) Received: by yxn22 with SMTP id 22so691691yxn.14 for ; Wed, 22 Jun 2011 16:19:06 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20110622150350.GX20843@redhat.com> References: <201106212055.25400.nai.xia@gmail.com> <201106212132.39311.nai.xia@gmail.com> <20110622150350.GX20843@redhat.com> Date: Thu, 23 Jun 2011 07:19:06 +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 Content-Transfer-Encoding: quoted-printable 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 Wed, Jun 22, 2011 at 11:03 PM, Andrea Arcangeli wr= ote: > On Tue, Jun 21, 2011 at 09:32:39PM +0800, Nai Xia wrote: >> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c >> index d48ec60..b407a69 100644 >> --- a/arch/x86/kvm/vmx.c >> +++ b/arch/x86/kvm/vmx.c >> @@ -4674,6 +4674,7 @@ static int __init vmx_init(void) >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 kvm_mmu_set_mask_ptes(0ull, 0ull, 0ull, 0ull= , >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 VMX_EPT_EXEC= UTABLE_MASK); >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 kvm_enable_tdp(); >> + =A0 =A0 =A0 =A0 =A0 =A0 kvm_dirty_update =3D 0; >> =A0 =A0 =A0 } else >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 kvm_disable_tdp(); >> > > Why not return !shadow_dirty_mask instead of adding a new var? > >> =A0struct mmu_notifier_ops { >> + =A0 =A0 int (*dirty_update)(struct mmu_notifier *mn, >> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0struct mm_struct *m= m); >> + > > Needs some docu. > > I think dirty_update isn't self explanatory name. I think > "has_test_and_clear_dirty" would be better. > > If we don't flush the smp tlb don't we risk that we'll insert pages in > the unstable tree that are volatile just because the dirty bit didn't > get set again on the spte? > > The first patch I guess it's a sign of hugetlbfs going a little over > the edge in trying to mix with the core VM... Passing that parameter > &need_pte_unmap all over the place not so nice, maybe it'd be possible > to fix within hugetlbfs to use a different method to walk the hugetlb > vmas. I'd prefer that if possible. OK, I'll have a try over other workarounds. I am not feeling good about need_pte_unmap myself. :-) Thanks for viewing! -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