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 E8BB3C28D13 for ; Thu, 25 Aug 2022 07:11:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237678AbiHYHLv (ORCPT ); Thu, 25 Aug 2022 03:11:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48128 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237865AbiHYHL0 (ORCPT ); Thu, 25 Aug 2022 03:11:26 -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 BCF907393D for ; Thu, 25 Aug 2022 00:11:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1661411475; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=8hstYML2crFW9jfle1ivYRn1yE7n1hXLc4hnxMa+ms8=; b=XjLkglLfHZ5x8nYFwbWBstCfcMCtaMrjvI1exvLqQW1u8sUTKHnnSsxF88BznNp13mIjHZ zS6IgIVrdWx2tyfeQWudmNnrO+uX4Irj40OUM0ZDJJLeS25qNseh+Rfo/8CFGo/SYX/UCe Xpa8DzlUd/dxB8xis4qBVITWwOrfbiM= Received: from mail-pl1-f197.google.com (mail-pl1-f197.google.com [209.85.214.197]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-270-2meiecJKMRWJfa-kZevgCA-1; Thu, 25 Aug 2022 03:11:14 -0400 X-MC-Unique: 2meiecJKMRWJfa-kZevgCA-1 Received: by mail-pl1-f197.google.com with SMTP id s8-20020a170902ea0800b00172e456031eso7364594plg.3 for ; Thu, 25 Aug 2022 00:11:14 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc; bh=8hstYML2crFW9jfle1ivYRn1yE7n1hXLc4hnxMa+ms8=; b=QcDMK80/IENtGLKVORNaxWXsmXwdPIArl+YMYHX0bA0aZeNyJIkfOzAuNsVX9/xzq6 XUn3LhUfSxwXhdxtGBQqCnzUo/7CZ+eVO3lz/6GZnHQPjCmPk0QwfCWRLIY5c7FwbOA7 sGLK8sxeC748WE8udKj5qUZ3DR8wRj/Wpi6QeUTkCUCCDL2becyJffr/crbayrq2WXLc ZDZfZveyjZSNx+QdWis2sUanxet5xIu0HMKe543+F0zs2JmsknCW3f/Y+3qpALxjDLcp 7V9eUJkWwCU4H/KbSeEj0KrgA5R0/qv+/rstBjIsbZIZe0lL4GXRXj1P+zmAqCWwiZc7 ubYw== X-Gm-Message-State: ACgBeo1wzVZ/hOBAQ6qBrtKA51ESRs1z0Wz0krpKQMVENTyW2ZlSWzF1 810A0pdnT3efs3hlKkylZcccZEbwiwo9NvC6+QfGI4429Q9h749HCST9znlykyR4aejTBYZjLI2 V9CZ/y9Gtx+dbuoZh X-Received: by 2002:a17:90b:388a:b0:1fb:7dea:c31e with SMTP id mu10-20020a17090b388a00b001fb7deac31emr3196540pjb.162.1661411473477; Thu, 25 Aug 2022 00:11:13 -0700 (PDT) X-Google-Smtp-Source: AA6agR5CeHBniCJJchbK95vuG0eHIrILIUeqOvLvVnn+uoxSbeGyNwzgMkrqzzDmQjcA7tg+85ezFw== X-Received: by 2002:a17:90b:388a:b0:1fb:7dea:c31e with SMTP id mu10-20020a17090b388a00b001fb7deac31emr3196513pjb.162.1661411473242; Thu, 25 Aug 2022 00:11:13 -0700 (PDT) Received: from [10.72.12.107] ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id h20-20020aa796d4000000b0053671a241a5sm9059808pfq.191.2022.08.25.00.11.08 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 25 Aug 2022 00:11:12 -0700 (PDT) Message-ID: Date: Thu, 25 Aug 2022 15:11:02 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.13.0 Subject: Re: [RFC v2 5/7] virtio: unmask F_NEXT flag in desc_extra Content-Language: en-US To: Guo Zhi , eperezma@redhat.com, sgarzare@redhat.com, mst@redhat.com Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org References: <20220817135718.2553-1-qtxuning1999@sjtu.edu.cn> <20220817135718.2553-6-qtxuning1999@sjtu.edu.cn> From: Jason Wang In-Reply-To: <20220817135718.2553-6-qtxuning1999@sjtu.edu.cn> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 在 2022/8/17 21:57, Guo Zhi 写道: > We didn't unmask F_NEXT flag in desc_extra in the end of a chain, > unmask it so that we can access desc_extra to get next information. > > Signed-off-by: Guo Zhi I post a similar patch in the past. Please share the perf numbers (e.g pps via pktgen). Thanks > --- > drivers/virtio/virtio_ring.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > index a5ec724c01d8..1c1b3fa376a2 100644 > --- a/drivers/virtio/virtio_ring.c > +++ b/drivers/virtio/virtio_ring.c > @@ -567,7 +567,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > } > /* Last one doesn't continue. */ > desc[prev].flags &= cpu_to_virtio16(_vq->vdev, ~VRING_DESC_F_NEXT); > - if (!indirect && vq->use_dma_api) > + if (!indirect) > vq->split.desc_extra[prev & (vq->split.vring.num - 1)].flags &= > ~VRING_DESC_F_NEXT; > > @@ -584,6 +584,8 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > total_sg * sizeof(struct vring_desc), > VRING_DESC_F_INDIRECT, > false); > + vq->split.desc_extra[head & (vq->split.vring.num - 1)].flags &= > + ~VRING_DESC_F_NEXT; > } > > /* We're using some buffers from the free list. */ > @@ -693,7 +695,7 @@ static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head, > /* Put back on free list: unmap first-level descriptors and find end */ > i = head; > > - while (vq->split.vring.desc[i].flags & nextflag) { > + while (vq->split.desc_extra[i].flags & nextflag) { > vring_unmap_one_split(vq, i); > i = vq->split.desc_extra[i].next; > vq->vq.num_free++;