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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 F38BEC43382 for ; Tue, 25 Sep 2018 11:42:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A08FC208D9 for ; Tue, 25 Sep 2018 11:42:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A08FC208D9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728397AbeIYRta (ORCPT ); Tue, 25 Sep 2018 13:49:30 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36898 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727159AbeIYRta (ORCPT ); Tue, 25 Sep 2018 13:49:30 -0400 Received: from smtp.corp.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.26]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A5B2A83F46; Tue, 25 Sep 2018 11:42:21 +0000 (UTC) Received: from vitty.brq.redhat.com.redhat.com (unknown [10.43.2.217]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A036B3001930; Tue, 25 Sep 2018 11:42:19 +0000 (UTC) From: Vitaly Kuznetsov To: Roman Kagan , Paolo Bonzini Cc: kvm@vger.kernel.org, Radim =?utf-8?B?S3LEjW3DocWZ?= , "K. Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger , "Michael Kelley \(EOSG\)" , Wanpeng Li , linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 RESEND 3/5] KVM: x86: hyperv: use get_vcpu_by_vpidx() in kvm_hv_flush_tlb() In-Reply-To: <20180925101040.GA2336@rkaganb.sw.ru> References: <20180822101832.31763-1-vkuznets@redhat.com> <20180822101832.31763-4-vkuznets@redhat.com> <8da03d2a-5405-f363-f081-e4bc46b106e3@redhat.com> <87r2hs7cco.fsf@vitty.brq.redhat.com> <87zhw62797.fsf@vitty.brq.redhat.com> <74055c3b-be66-4ce6-e727-a155f18a0ba1@redhat.com> <20180925085752.GA5391@rkaganb.sw.ru> <20180925101040.GA2336@rkaganb.sw.ru> Date: Tue, 25 Sep 2018 13:42:18 +0200 Message-ID: <871s9hreg5.fsf@vitty.brq.redhat.com> MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.84 on 10.5.11.26 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Tue, 25 Sep 2018 11:42:21 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Roman Kagan writes: > On Tue, Sep 25, 2018 at 11:29:57AM +0200, Paolo Bonzini wrote: >> On 25/09/2018 10:57, Roman Kagan wrote: >> > If we can assume that in all relevant cases vp_index coincides with the >> > cpu index (which I think we can) then Vitaly's approach is the most >> > efficient. >> > >> > If, on the opposite, we want to optimize for random mapping between >> > vp_index and cpu index, then it's probably better instead to iterate >> > over vcpus and test if their vp_index belongs to the requested mask. >> >> Yes, that would work too. Perhaps we can do both? You can have a >> kvm->num_mismatched_vp_indexes count to choose between the two. > > Makes sense to me. Thanks guys, I'll try to draft something up for v6. -- Vitaly