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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C6147C6FA86 for ; Mon, 19 Sep 2022 16:17:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229521AbiISQRO (ORCPT ); Mon, 19 Sep 2022 12:17:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44724 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229553AbiISQRL (ORCPT ); Mon, 19 Sep 2022 12:17:11 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EE5D529812 for ; Mon, 19 Sep 2022 09:17:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1663604229; 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: in-reply-to:in-reply-to:references:references; bh=Xn5fnqKtyryYA5w5sfE3wIiUTcmcdDi6qpfcSbkJ4Lw=; b=gvS/LdR0maZ69qRF+LRVo4hBcSsZrKehnRsKkVWPbxPgh8zoi3Xa8s4Nf6vkAkw6aFZecj 8nntOrwh46jfZKmUDMYdGKYCcWKumUUTP+ioXnSUXr+5XDNeWRPAYNZylQO9zZPeVu0MP0 jNhQBDFSQkW7w8DoH34QcU1C4k6z2Yg= Received: from mail-qt1-f198.google.com (mail-qt1-f198.google.com [209.85.160.198]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-500-MrQQsEa9Mei03og1DjfsmA-1; Mon, 19 Sep 2022 12:17:06 -0400 X-MC-Unique: MrQQsEa9Mei03og1DjfsmA-1 Received: by mail-qt1-f198.google.com with SMTP id ew15-20020a05622a514f00b0035cb76e35e5so12057074qtb.7 for ; Mon, 19 Sep 2022 09:17:06 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date; bh=Xn5fnqKtyryYA5w5sfE3wIiUTcmcdDi6qpfcSbkJ4Lw=; b=t69vqhpqNgzwD/AdxqN5Uk+sHaQc2lOOyKVd++d5wpsaGdC3s2nmQTk5dEoQjlgLZz vOH2yzgb0VEdyXmiNwSOjfWw+xXU9Jw685LNc77G0u5DMcuKGBW7SVfhl+F71hXcITPK mlfdHnYRKR9qEQzUVEUX0zaP1Xf0kFrmxfRkcZjCGpdyekoccex9gM3tJ1oZBNOg8P6F q8gB9MKt+p7nMF0TcFkTxE58pkgH7qKuWMVQL90wCFxkqkx7ksQv1aoSqT6f64a0VKvl 2qN4WduXNCGcGJP90b70/8BZ/QxsMUpxGckWqPpgpNZXIkJCez4bLFltpEZ5xkAuhf3l ygyw== X-Gm-Message-State: ACrzQf2lUifCkemgAl0AMsBHZ+hb3B0rvYUHJ/dYZ9PFXxU3Fliutyl2 OGU8sznvy8LvwCgdQBiFthmU/jNNdlWB+r8mDvJ3kEyhgjQFCcAEvnHAIJpMXOIbCeX7kQCz/5Z u/WbGReuO/mrnsYM4l+/x X-Received: by 2002:ac8:5e0a:0:b0:35c:e8d8:6c19 with SMTP id h10-20020ac85e0a000000b0035ce8d86c19mr5068672qtx.178.1663604225353; Mon, 19 Sep 2022 09:17:05 -0700 (PDT) X-Google-Smtp-Source: AMsMyM51+LmYDmB5JjErlr4hYbacMbbiBwggTg81wkAjJVlWGP8agHsUu4S5cY7WS6QJw0cvQ6qJIg== X-Received: by 2002:ac8:5e0a:0:b0:35c:e8d8:6c19 with SMTP id h10-20020ac85e0a000000b0035ce8d86c19mr5068640qtx.178.1663604225144; Mon, 19 Sep 2022 09:17:05 -0700 (PDT) Received: from xz-m1.local (bras-base-aurron9127w-grc-46-70-31-27-79.dsl.bell.ca. [70.31.27.79]) by smtp.gmail.com with ESMTPSA id bv12-20020a05622a0a0c00b0035cf2995ad8sm826570qtb.51.2022.09.19.09.17.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 19 Sep 2022 09:17:04 -0700 (PDT) Date: Mon, 19 Sep 2022 12:17:02 -0400 From: Peter Xu To: Gavin Shan Cc: Marc Zyngier , kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, linux-doc@vger.kernel.org, catalin.marinas@arm.com, linux-kselftest@vger.kernel.org, bgardon@google.com, shuah@kernel.org, corbet@lwn.net, drjones@redhat.com, will@kernel.org, zhenyzha@redhat.com, dmatlack@google.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, pbonzini@redhat.com, oliver.upton@linux.dev, shan.gavin@gmail.com Subject: Re: [PATCH v2 1/5] KVM: x86: Introduce KVM_REQ_RING_SOFT_FULL Message-ID: References: <20220916045135.154505-1-gshan@redhat.com> <20220916045135.154505-2-gshan@redhat.com> <87illlkqfu.wl-maz@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Mon, Sep 19, 2022 at 09:58:10AM +1000, Gavin Shan wrote: > I think Marc's explanation makes sense. It won't make difference in terms > of performance. We need to explicitly handle barrier when kvm_test_request() > is used. So I prefer to keep the code if Peter agrees. No strong opinion here. I keep thinking clear+set look awkward even if it's unlikely path to trigger (ring should be recycled when reaching here for any sane user app), but if it's already 2:1 then please go ahead. :) Thanks, -- Peter Xu