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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 A1221C55192 for ; Thu, 23 Apr 2020 10:40:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7F44220857 for ; Thu, 23 Apr 2020 10:40:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="fBDzYVCC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727121AbgDWKkF (ORCPT ); Thu, 23 Apr 2020 06:40:05 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:23127 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725863AbgDWKkE (ORCPT ); Thu, 23 Apr 2020 06:40:04 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1587638402; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=+r/PR2FbN4xLG8Nok2HJ4M/QJoOCF0Nk3Bss40sN0xs=; b=fBDzYVCCqW1GoVdwQp91lZNHO5HeSb4pWmnedQElmzSBpXNLACkopal9QJXMg2pm3UJ3L+ +XpkN+whgwN7VBTpJK1UvxiK45oP99p+B8qza+MQOhVUymFMokiZwcpFQjGqIFVo6cUp8p SeCWD8j9VoIYkfaBgy55TAtxYAumP9s= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-246-AkzxH94nMVKFKkFx37Ew_w-1; Thu, 23 Apr 2020 06:39:20 -0400 X-MC-Unique: AkzxH94nMVKFKkFx37Ew_w-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 07DD5835B41; Thu, 23 Apr 2020 10:39:17 +0000 (UTC) Received: from gondolin (ovpn-112-121.ams2.redhat.com [10.36.112.121]) by smtp.corp.redhat.com (Postfix) with ESMTP id 11C6260608; Thu, 23 Apr 2020 10:39:03 +0000 (UTC) Date: Thu, 23 Apr 2020 12:39:01 +0200 From: Cornelia Huck To: Tianjia Zhang Cc: Christian Borntraeger , pbonzini@redhat.com, tsbogend@alpha.franken.de, paulus@ozlabs.org, mpe@ellerman.id.au, benh@kernel.crashing.org, frankja@linux.ibm.com, david@redhat.com, heiko.carstens@de.ibm.com, gor@linux.ibm.com, sean.j.christopherson@intel.com, vkuznets@redhat.com, wanpengli@tencent.com, jmattson@google.com, joro@8bytes.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, maz@kernel.org, james.morse@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, christoffer.dall@arm.com, peterx@redhat.com, thuth@redhat.com, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-mips@vger.kernel.org, kvm-ppc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/7] KVM: s390: clean up redundant 'kvm_run' parameters Message-ID: <20200423123901.72a4c6a4.cohuck@redhat.com> In-Reply-To: <5e1e126d-f1b0-196c-594b-4289d0afb9a8@linux.alibaba.com> References: <20200422125810.34847-1-tianjia.zhang@linux.alibaba.com> <20200422125810.34847-2-tianjia.zhang@linux.alibaba.com> <20200422154543.2efba3dd.cohuck@redhat.com> <20200422180403.03f60b0c.cohuck@redhat.com> <5e1e126d-f1b0-196c-594b-4289d0afb9a8@linux.alibaba.com> Organization: Red Hat GmbH MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Thu, 23 Apr 2020 11:01:43 +0800 Tianjia Zhang wrote: > On 2020/4/23 0:04, Cornelia Huck wrote: > > On Wed, 22 Apr 2020 17:58:04 +0200 > > Christian Borntraeger wrote: > > > >> On 22.04.20 15:45, Cornelia Huck wrote: > >>> On Wed, 22 Apr 2020 20:58:04 +0800 > >>> Tianjia Zhang wrote: > >>> > >>>> In the current kvm version, 'kvm_run' has been included in the 'kvm_vcpu' > >>>> structure. Earlier than historical reasons, many kvm-related function > >>> > >>> s/Earlier than/For/ ? > >>> > >>>> parameters retain the 'kvm_run' and 'kvm_vcpu' parameters at the same time. > >>>> This patch does a unified cleanup of these remaining redundant parameters. > >>>> > >>>> Signed-off-by: Tianjia Zhang > >>>> --- > >>>> arch/s390/kvm/kvm-s390.c | 37 ++++++++++++++++++++++--------------- > >>>> 1 file changed, 22 insertions(+), 15 deletions(-) > >>>> > >>>> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c > >>>> index e335a7e5ead7..d7bb2e7a07ff 100644 > >>>> --- a/arch/s390/kvm/kvm-s390.c > >>>> +++ b/arch/s390/kvm/kvm-s390.c > >>>> @@ -4176,8 +4176,9 @@ static int __vcpu_run(struct kvm_vcpu *vcpu) > >>>> return rc; > >>>> } > >>>> > >>>> -static void sync_regs_fmt2(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) > >>>> +static void sync_regs_fmt2(struct kvm_vcpu *vcpu) > >>>> { > >>>> + struct kvm_run *kvm_run = vcpu->run; > >>>> struct runtime_instr_cb *riccb; > >>>> struct gs_cb *gscb; > >>>> > >>>> @@ -4235,7 +4236,7 @@ static void sync_regs_fmt2(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) > >>>> } > >>>> if (vcpu->arch.gs_enabled) { > >>>> current->thread.gs_cb = (struct gs_cb *) > >>>> - &vcpu->run->s.regs.gscb; > >>>> + &kvm_run->s.regs.gscb; > >>> > >>> Not sure if these changes (vcpu->run-> => kvm_run->) are really worth > >>> it. (It seems they amount to at least as much as the changes advertised > >>> in the patch description.) > >>> > >>> Other opinions? > >> > >> Agreed. It feels kind of random. Maybe just do the first line (move kvm_run from the > >> function parameter list into the variable declaration)? Not sure if this is better. > >> > > > > There's more in this patch that I cut... but I think just moving > > kvm_run from the parameter list would be much less disruptive. > > > > I think there are two kinds of code(`vcpu->run->` and `kvm_run->`), but > there will be more disruptive, not less. I just fail to see the benefit; sure, kvm_run-> is convenient, but the current code is just fine, and any rework should be balanced against the cost (e.g. cluttering git annotate).