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 56377C433F5 for ; Mon, 28 Mar 2022 10:58:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240441AbiC1LAJ (ORCPT ); Mon, 28 Mar 2022 07:00:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33060 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240430AbiC1LAF (ORCPT ); Mon, 28 Mar 2022 07:00:05 -0400 Received: from out199-15.us.a.mail.aliyun.com (out199-15.us.a.mail.aliyun.com [47.90.199.15]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 58EF11C103 for ; Mon, 28 Mar 2022 03:58:24 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R251e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04394;MF=xianting.tian@linux.alibaba.com;NM=1;PH=DS;RN=6;SR=0;TI=SMTPD_---0V8SAF7z_1648465100; Received: from localhost(mailfrom:xianting.tian@linux.alibaba.com fp:SMTPD_---0V8SAF7z_1648465100) by smtp.aliyun-inc.com(127.0.0.1); Mon, 28 Mar 2022 18:58:20 +0800 From: Xianting Tian To: mst@redhat.com, jasowang@redhat.com, sgarzare@redhat.com Cc: virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Xianting Tian Subject: [PATCH 2/2] virtio_ring: add unlikely annotation for free descs check Date: Mon, 28 Mar 2022 18:58:17 +0800 Message-Id: <20220328105817.1028065-2-xianting.tian@linux.alibaba.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20220328105817.1028065-1-xianting.tian@linux.alibaba.com> References: <20220328105817.1028065-1-xianting.tian@linux.alibaba.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The 'if (vq->vq.num_free < descs_used)' check will almost always be false. Signed-off-by: Xianting Tian --- drivers/virtio/virtio_ring.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index d597fc0874ec..ab6d5f0cb579 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -525,7 +525,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, descs_used = total_sg; } - if (vq->vq.num_free < descs_used) { + if (unlikely(vq->vq.num_free < descs_used)) { pr_debug("Can't add buf len %i - avail = %i\n", descs_used, vq->vq.num_free); /* FIXME: for historical reasons, we force a notify here if -- 2.17.1