Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932334Ab1FVXTI (ORCPT ); Wed, 22 Jun 2011 19:19:08 -0400 Received: from mail-yx0-f174.google.com ([209.85.213.174]:44522 "EHLO mail-yx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755096Ab1FVXTH convert rfc822-to-8bit (ORCPT ); Wed, 22 Jun 2011 19:19:07 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=mWlfnRuKzUFd7KMWeweNODBvrFCXaBct5UlNi6nR7DkmfwBage4ztH5DTWfvHMdncJ 2dnsAg+2U39gCieE04jE9r2iOLq1hPe1oDRvt7aXhSfAC4ddrQoTBqLPY0hJO7fg0zmY T/CuZe7hVwnlJ8LDLya7bItrxOa/EGQGRsXW0= 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 To: Andrea Arcangeli Cc: Andrew Morton , Izik Eidus , Hugh Dickins , Chris Wright , Rik van Riel , linux-mm , Johannes Weiner , linux-kernel , kvm Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1831 Lines: 53 On Wed, Jun 22, 2011 at 11:03 PM, Andrea Arcangeli wrote: > 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) >> ? ? ? ? ? ? ? kvm_mmu_set_mask_ptes(0ull, 0ull, 0ull, 0ull, >> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? VMX_EPT_EXECUTABLE_MASK); >> ? ? ? ? ? ? ? kvm_enable_tdp(); >> + ? ? ? ? ? ? kvm_dirty_update = 0; >> ? ? ? } else >> ? ? ? ? ? ? ? kvm_disable_tdp(); >> > > Why not return !shadow_dirty_mask instead of adding a new var? > >> ?struct mmu_notifier_ops { >> + ? ? int (*dirty_update)(struct mmu_notifier *mn, >> + ? ? ? ? ? ? ? ? ? ? ? ? ?struct mm_struct *mm); >> + > > 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 from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/