From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_MUTT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 09940C28CC0 for ; Mon, 27 May 2019 12:32:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D659E20859 for ; Mon, 27 May 2019 12:32:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="c4TDFTpH" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727320AbfE0Mc6 (ORCPT ); Mon, 27 May 2019 08:32:58 -0400 Received: from merlin.infradead.org ([205.233.59.134]:39992 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726106AbfE0Mc5 (ORCPT ); Mon, 27 May 2019 08:32:57 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=Bb4riJdUbAvU2dFDq22LE6R9qG/UUI43/Y/+y4V6Qvs=; b=c4TDFTpHK0CYd1vWu7R1zqW+/ 2vf2CkvycdZ1TOZgh6586+6hBSUOonS4izJJJLlU/laLZdtRg9vo/tFqP67DP/DrVq5GNeyOXkp8N ExSQgN5WmAiXgiz9FXGhkb7sqDhbv1+1n9qPgIj2TuqbkRY8ULdb/xs9kniGA0ESzx0t8DJo/mrAl uLK3C6fLgcCbWbFpO9EhXKZtWIcTmu+x6Co60LQwrkDHUOi8//21mfSvFniFvyuP82yQFaVkGwBIf aK/OeehLVOOzYZiUm+0l62ODKjdgrXRftiZCRVCOymL15JzQ7yEwGoiNpC9TkUxMutHPzfpYZgiur Nuu3rPt0w==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1hVEnP-0003D7-9F; Mon, 27 May 2019 12:32:07 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 10A95202BF3E2; Mon, 27 May 2019 14:32:06 +0200 (CEST) Date: Mon, 27 May 2019 14:32:06 +0200 From: Peter Zijlstra To: Paolo Bonzini Cc: Juergen Gross , Nadav Amit , Ingo Molnar , Andy Lutomirski , Borislav Petkov , linux-kernel@vger.kernel.org, "K. Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger , Sasha Levin , Thomas Gleixner , x86@kernel.org, Dave Hansen , Boris Ostrovsky , linux-hyperv@vger.kernel.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, xen-devel@lists.xenproject.org Subject: Re: [RFC PATCH 5/6] x86/mm/tlb: Flush remote and local TLBs concurrently Message-ID: <20190527123206.GC2623@hirez.programming.kicks-ass.net> References: <20190525082203.6531-1-namit@vmware.com> <20190525082203.6531-6-namit@vmware.com> <08b21fb5-2226-7924-30e3-31e4adcfc0a3@suse.com> <20190527094710.GU2623@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 27, 2019 at 12:21:59PM +0200, Paolo Bonzini wrote: > On 27/05/19 11:47, Peter Zijlstra wrote: > > --- a/arch/x86/kernel/kvm.c > > +++ b/arch/x86/kernel/kvm.c > > @@ -580,7 +580,7 @@ static void __init kvm_apf_trap_init(voi > > > > static DEFINE_PER_CPU(cpumask_var_t, __pv_tlb_mask); > > > > -static void kvm_flush_tlb_others(const struct cpumask *cpumask, > > +static void kvm_flush_tlb_multi(const struct cpumask *cpumask, > > const struct flush_tlb_info *info) > > { > > u8 state; > > @@ -594,6 +594,9 @@ static void kvm_flush_tlb_others(const s > > * queue flush_on_enter for pre-empted vCPUs > > */ > > for_each_cpu(cpu, flushmask) { > > + if (cpu == smp_processor_id()) > > + continue; > > + > > Even this would be just an optimization; the vCPU you're running on > cannot be preempted. You can just change others to multi. Yeah, I know, but it felt weird so I added the explicit skip. No strong feelings though.