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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 76930C31E44 for ; Fri, 14 Jun 2019 07:53:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4F5A62133D for ; Fri, 14 Jun 2019 07:53:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725951AbfFNHxP (ORCPT ); Fri, 14 Jun 2019 03:53:15 -0400 Received: from mail-wr1-f66.google.com ([209.85.221.66]:46702 "EHLO mail-wr1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725823AbfFNHxP (ORCPT ); Fri, 14 Jun 2019 03:53:15 -0400 Received: by mail-wr1-f66.google.com with SMTP id n4so1396887wrw.13 for ; Fri, 14 Jun 2019 00:53:14 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:in-reply-to:references:date :message-id:mime-version; bh=8fphykZty4ByRRDrabr8kIG4WtC4MdL+z6VNpErB0g0=; b=L5lLIam1ghURF6u6OZfab5ejwS2awhioLN3r2VNGezBtDs4StnHYaZprrE9PNqmWYR 4MTlXVD9EMQL6QL4MQsFtBaWhFPtfhDHBYVDSLUDdM6nkt4wMQ29NpgZftw6WH5rwjGi thkbjNLTIavhK7J+Xo2B8Ley82OdZ/gAEYM6rrEJ/KXOXatLX2Jf7jgL6OS2dMK6OHIW dTwR/V7HGqYoN/eho4PWmW4IQ7VEJtjZ/iGrJU0IVeDbhyOkS2Zz2sd2tzX5RAZQ7hbB Y65wdajXdbDDrWa/sHEO/hOB2f4ipsMVURODeahtnm5ruVzXroYtuAwJprTOjkGs+lfm rbpA== X-Gm-Message-State: APjAAAUHFcRqQpaShNFsKniPbUVQ6UXfeW8yM7khytuq8SGpVPY3aXRW n9AIYqXuMIt1jl+WtmpS4zoG1g== X-Google-Smtp-Source: APXvYqwudq3lF4n8Rq0cC6F8jfIcXcCrwvwQ7V8kVVjpQeinklynWmw5QYHdkRp6uBhckMxPdXxU9g== X-Received: by 2002:adf:e9c6:: with SMTP id l6mr4390021wrn.216.1560498793342; Fri, 14 Jun 2019 00:53:13 -0700 (PDT) Received: from vitty.brq.redhat.com (nat-pool-brq-t.redhat.com. [213.175.37.10]) by smtp.gmail.com with ESMTPSA id n10sm2013838wrw.83.2019.06.14.00.53.12 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Fri, 14 Jun 2019 00:53:12 -0700 (PDT) From: Vitaly Kuznetsov To: Michael Kelley , "m.maya.nakamura" Cc: "x86\@kernel.org" , "linux-hyperv\@vger.kernel.org" , "linux-kernel\@vger.kernel.org" , KY Srinivasan , Haiyang Zhang , Stephen Hemminger , "sashal\@kernel.org" Subject: RE: [PATCH v2 4/5] HID: hv: Remove dependencies on PAGE_SIZE for ring buffer In-Reply-To: References: <0e9385a241dc7c26445eb7e104d08e2e2c5d30de.1559807514.git.m.maya.nakamura@gmail.com> <87h88vdr36.fsf@vitty.brq.redhat.com> Date: Fri, 14 Jun 2019 09:53:11 +0200 Message-ID: <87ftoc7gd4.fsf@vitty.brq.redhat.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-hyperv-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org Michael Kelley writes: > From: Vitaly Kuznetsov Sent: Wednesday, June 12, 2019 3:40 AM >> Maya Nakamura writes: >> >> > Define the ring buffer size as a constant expression because it should >> > not depend on the guest page size. >> > >> > Signed-off-by: Maya Nakamura >> > --- >> > drivers/hid/hid-hyperv.c | 4 ++-- >> > 1 file changed, 2 insertions(+), 2 deletions(-) >> > >> > diff --git a/drivers/hid/hid-hyperv.c b/drivers/hid/hid-hyperv.c >> > index d3311d714d35..e8b154fa38e2 100644 >> > --- a/drivers/hid/hid-hyperv.c >> > +++ b/drivers/hid/hid-hyperv.c >> > @@ -112,8 +112,8 @@ struct synthhid_input_report { >> > >> > #pragma pack(pop) >> > >> > -#define INPUTVSC_SEND_RING_BUFFER_SIZE (10*PAGE_SIZE) >> > -#define INPUTVSC_RECV_RING_BUFFER_SIZE (10*PAGE_SIZE) >> > +#define INPUTVSC_SEND_RING_BUFFER_SIZE (40 * 1024) >> > +#define INPUTVSC_RECV_RING_BUFFER_SIZE (40 * 1024) >> > >> >> My understanding is that this size is pretty arbitrary and as I see you >> use it for hyperv-keyboard.c as well. It may make sense to have a >> define, something like HYPERV_STD_RINGBUFFER_SIZE. > > Yes, the size is pretty arbitrary because it hasn't been important enough > from a memory consumption or performance standpoint to run experiments > to see if a smaller value could be used. That said, I would not want to > link these two devices (keyboard and mouse) by using a shared ring buffer > size definition. Logically, the ring buffer sizes are independent of each other, > and using a common #define implies that they are somehow linked. Ok, makes sense, let's keep them separate. -- Vitaly