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=-13.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT 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 E2340C43387 for ; Tue, 8 Jan 2019 07:10:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AEB812173C for ; Tue, 8 Jan 2019 07:10:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1546931452; bh=V2RAIktucXxrjj2gVr//OEPy9ScEKe+O6AWpSIqc0tw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=W1yBOu8XKv+AskYeQF6ME9aAvIUNuwHRLNRsXs6ILuGYUnCYd8DhTgVOLQgGQvRnK nbSthyXrAYeVt4Tt9nDvNcMg0WuGJYNGMhxq1I/Bh2wta+CGelCv68hCtItduLNoEl JKm0/rW3S5O5CNHlbihrXC9bntem2TbH6U4C/PgY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727673AbfAHHKt (ORCPT ); Tue, 8 Jan 2019 02:10:49 -0500 Received: from mail.kernel.org ([198.145.29.99]:39306 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727383AbfAHHKq (ORCPT ); Tue, 8 Jan 2019 02:10:46 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CDDD32087F; Tue, 8 Jan 2019 07:10:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1546931445; bh=V2RAIktucXxrjj2gVr//OEPy9ScEKe+O6AWpSIqc0tw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=qHSs555pZrvSlbs1RQiR9XsnYEK9AuL0vcymC2/ZGSYhl8lnW510y9tnbzfyegnLj aU9WIbNB2R53iuWLSTKkXJT+LEgoA3l+lzPnUzx/oPJKcNaFzBnOI8J0hnEf9Hq+Gz f4kfJILIPR+6TikxatWrXEp9vBiNhBXpdjm6wV3I= Date: Tue, 8 Jan 2019 08:10:43 +0100 From: Greg KH To: Wei Wang Cc: virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, mst@redhat.com, cohuck@redhat.com, borntraeger@de.ibm.com, pbonzini@redhat.com, dgilbert@redhat.com, pasic@linux.ibm.com Subject: Re: [PATCH v4 2/3] virtio-balloon: improve update_balloon_size_func Message-ID: <20190108071043.GB32048@kroah.com> References: <1546923005-40517-1-git-send-email-wei.w.wang@intel.com> <1546923005-40517-3-git-send-email-wei.w.wang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1546923005-40517-3-git-send-email-wei.w.wang@intel.com> User-Agent: Mutt/1.11.1 (2018-12-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 08, 2019 at 12:50:04PM +0800, Wei Wang wrote: > There is no need to update the balloon actual register when there is no > ballooning request. This patch avoids update_balloon_size when diff is 0. > > Signed-off-by: Wei Wang > Reviewed-by: Cornelia Huck > Reviewed-by: Halil Pasic > Tested-by: Christian Borntraeger > --- > drivers/virtio/virtio_balloon.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c > index 45d32f5..d48c12c 100644 > --- a/drivers/virtio/virtio_balloon.c > +++ b/drivers/virtio/virtio_balloon.c > @@ -457,9 +457,12 @@ static void update_balloon_size_func(struct work_struct *work) > update_balloon_size_work); > diff = towards_target(vb); > > + if (!diff) > + return; > + > if (diff > 0) > diff -= fill_balloon(vb, diff); > - else if (diff < 0) > + else > diff += leak_balloon(vb, -diff); > update_balloon_size(vb); > > -- > 2.7.4 > This is not the correct way to submit patches for inclusion in the stable kernel tree. Please read: https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html for how to do this properly.