From patchwork Fri Jan 4 07:11:53 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Wang, Wei W" X-Patchwork-Id: 10748095 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 308BA14DE for ; Fri, 4 Jan 2019 07:47:10 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 19E9127F10 for ; Fri, 4 Jan 2019 07:47:10 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0957827F54; Fri, 4 Jan 2019 07:47:10 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A9C7327F10 for ; Fri, 4 Jan 2019 07:47:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726663AbfADHrC (ORCPT ); Fri, 4 Jan 2019 02:47:02 -0500 Received: from mga17.intel.com ([192.55.52.151]:41240 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726650AbfADHq7 (ORCPT ); Fri, 4 Jan 2019 02:46:59 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 03 Jan 2019 23:46:59 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,437,1539673200"; d="scan'208";a="103850441" Received: from devel-ww.sh.intel.com ([10.239.48.119]) by orsmga007.jf.intel.com with ESMTP; 03 Jan 2019 23:46:57 -0800 From: Wei Wang To: virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, mst@redhat.com, cohuck@redhat.com, pasic@linux.ibm.com, borntraeger@de.ibm.com Cc: pbonzini@redhat.com, dgilbert@redhat.com, wei.w.wang@intel.com Subject: [PATCH v2 2/2] virtio-balloon: improve update_balloon_size_func Date: Fri, 4 Jan 2019 15:11:53 +0800 Message-Id: <1546585913-34804-3-git-send-email-wei.w.wang@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1546585913-34804-1-git-send-email-wei.w.wang@intel.com> References: <1546585913-34804-1-git-send-email-wei.w.wang@intel.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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 --- 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 35ee762..af1e6d9 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -453,9 +453,12 @@ 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);