From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-98.freemail.mail.aliyun.com (out30-98.freemail.mail.aliyun.com [115.124.30.98]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D8C5E633EC; Thu, 7 Mar 2024 08:15:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.98 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709799346; cv=none; b=nxeuEbBOUtebeZTDOormmftUKT+wYsAwZ0HW12cfE7MSG1N15bU8rNMwnWE4EysUh4hvck9/1ph/KLtBg7DrWDG8Sp3YE8GAXvZJ7LiNUIguqHq7pDVRLbndUNuvlBuxMVNieRQiJnWEa4E8hVvEOa5Yw1IkVQC/tVGy1/lx7oU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709799346; c=relaxed/simple; bh=qn4XlrCB0/U0FkhSoivYtFw9BAhWHViJJmb7sOeaNCI=; h=Message-ID:Subject:Date:From:To:Cc:References:In-Reply-To: Content-Type; b=nLI54+ClbWpIk2ubPiVJHkunGQNFBLuRVcHprfXcXFra7hBfM2x8hio1mSLVlqaaMTHZU4TJZcYxRgiWN90u4p/WoVUT5n4e71Mo9meQ1BuH1MTshQiuTzcv3okom0A59P2A5Msb2BKwvsL/vGbLnw3hk8vfQNOqex7bz+Q5JDU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=O5eaitda; arc=none smtp.client-ip=115.124.30.98 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="O5eaitda" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1709799335; h=Message-ID:Subject:Date:From:To:Content-Type; bh=18OSYGa/SGkgZJEOI3rLdiQkYGsKgGpvPail2nzxpk8=; b=O5eaitdakZcCcTp3OC8XXthP+6TQBcnEoa8br0cX3GmDyNy9Zxr72fXvfhC6fd68lsPTxwmlxGEBBC4jm5eUWquJysSgCIlyuBHLJ80wK4bdLAxOcaiqlmYjx0JMbhWCwcHBuHRAPGB2LVEGpT0I9UpkmPbs7yZX6HJabxAURE0= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R121e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046051;MF=xuanzhuo@linux.alibaba.com;NM=1;PH=DS;RN=34;SR=0;TI=SMTPD_---0W2-19Np_1709799332; Received: from localhost(mailfrom:xuanzhuo@linux.alibaba.com fp:SMTPD_---0W2-19Np_1709799332) by smtp.aliyun-inc.com; Thu, 07 Mar 2024 16:15:33 +0800 Message-ID: <1709798771.2564156-2-xuanzhuo@linux.alibaba.com> Subject: Re: [PATCH vhost v3 00/19] virtio: drivers maintain dma info for premapped vq Date: Thu, 7 Mar 2024 16:06:11 +0800 From: Xuan Zhuo To: Jason Wang Cc: "Michael S. Tsirkin" , virtualization@lists.linux.dev, Richard Weinberger , Anton Ivanov , Johannes Berg , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Hans de Goede , =?utf-8?q?Ilpo_J=C3=A4rvinen?= , Vadim Pasternak , Bjorn Andersson , Mathieu Poirier , Cornelia Huck , Halil Pasic , Eric Farman , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , linux-um@lists.infradead.org, netdev@vger.kernel.org, platform-driver-x86@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, bpf@vger.kernel.org References: <20240229072044.77388-1-xuanzhuo@linux.alibaba.com> <20240229031755-mutt-send-email-mst@kernel.org> <1709197357.626784-1-xuanzhuo@linux.alibaba.com> <20240229043238-mutt-send-email-mst@kernel.org> <1709718889.4420547-1-xuanzhuo@linux.alibaba.com> In-Reply-To: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: On Thu, 7 Mar 2024 13:28:27 +0800, Jason Wang wrote: > On Wed, Mar 6, 2024 at 6:01=E2=80=AFPM Xuan Zhuo wrote: > > > > On Thu, 29 Feb 2024 04:34:20 -0500, "Michael S. Tsirkin" wrote: > > > On Thu, Feb 29, 2024 at 05:02:37PM +0800, Xuan Zhuo wrote: > > > > On Thu, 29 Feb 2024 03:21:14 -0500, "Michael S. Tsirkin" wrote: > > > > > On Thu, Feb 29, 2024 at 03:20:25PM +0800, Xuan Zhuo wrote: > > > > > > As discussed: > > > > > > http://lore.kernel.org/all/CACGkMEvq0No8QGC46U4mGsMtuD44fD_cfLc= PaVmJ3rHYqRZxYg@mail.gmail.com > > > > > > > > > > > > If the virtio is premapped mode, the driver should manage the d= ma info by self. > > > > > > So the virtio core should not store the dma info. > > > > > > So we can release the memory used to store the dma info. > > > > > > > > > > > > But if the desc_extra has not dma info, we face a new question, > > > > > > it is hard to get the dma info of the desc with indirect flag. > > > > > > For split mode, that is easy from desc, but for the packed mode, > > > > > > it is hard to get the dma info from the desc. And for hardening > > > > > > the dma unmap is saft, we should store the dma info of indirect > > > > > > descs. > > > > > > > > > > > > So I introduce the "structure the indirect desc table" to > > > > > > allocate space to store dma info with the desc table. > > > > > > > > > > > > On the other side, we mix the descs with indirect flag > > > > > > with other descs together to share the unmap api. That > > > > > > is complex. I found if we we distinguish the descs with > > > > > > VRING_DESC_F_INDIRECT before unmap, thing will be clearer. > > > > > > > > > > > > Because of the dma array is allocated in the find_vqs(), > > > > > > so I introduce a new parameter to find_vqs(). > > > > > > > > > > > > Note: > > > > > > this is on the top of > > > > > > [PATCH vhost v1] virtio: packed: fix unmap leak for ind= irect desc table > > > > > > http://lore.kernel.org/all/20240223071833.26095-1-xuanz= huo@linux.alibaba.com > > > > > > > > > > > > Please review. > > > > > > > > > > > > Thanks > > > > > > > > > > > > v3: > > > > > > 1. fix the conflict with the vp_modern_create_avq(). > > > > > > > > > > Okay but are you going to address huge memory waste all this is c= ausing for > > > > > - people who never do zero copy > > > > > - systems where dma unmap is a nop > > > > > > > > > > ? > > > > > > > > > > You should address all comments when you post a new version, not = just > > > > > what was expedient, or alternatively tag patch as RFC and explain > > > > > in commit log that you plan to do it later. > > > > > > > > > > > > Do you miss this one? > > > > http://lore.kernel.org/all/1708997579.5613105-1-xuanzhuo@linux.alib= aba.com > > > > > > > > > I did. The answer is that no, you don't get to regress memory usage > > > for lots of people then fix it up. > > > So the patchset is big, I guess it will take a couple of cycles to > > > merge gradually. > > > > Hi @Michael > > > > So, how about this patch set? > > > > I do not think they (dma maintainers) will agree the API dma_can_skip_u= nmap(). > > > > If you think sq wastes too much memory using pre-mapped dma mode, how a= bout > > we only enable it when xsk is bond? > > > > Could you give me some advice? > > I think we have some discussion, one possible solution is: > > when pre mapping is enabled, virtio core won't store dma metadatas. > > Then it makes virtio-net align with other NIC. YES. This patch set works as this. But the virtio-net must allocate too much memory to store dma and len. num =3D queue size * 19 Michael thinks that waste too much memory. http://lore.kernel.org/all/20240225032330-mutt-send-email-mst@kernel.org So we try this: http://lore.kernel.org/all/20240301071918.64631-1-xuanzhuo@linux.alibaba.c= om But I think that is difficult to be accepted by the DMA maintainers. So I have two advices: 1. virtio-net sq works without indirect. - that more like other NIC - the num of the memory to store the dma info is queue_size 2. The default mode of virtio-net sq is no-premapped - we just switch the mode when binding xsk Thanks. > > Thanks > > > > > Thanks. > > > > > > > > > > > I asked you. But I didnot recv your answer. > > > > > > > > Thanks. > > > > > > > > > > > > > > > > > > > v2: > > > > > > 1. change the dma item of virtio-net, every item have MAX_S= KB_FRAGS + 2 > > > > > > addr + len pairs. > > > > > > 2. introduce virtnet_sq_free_stats for __free_old_xmit > > > > > > > > > > > > v1: > > > > > > 1. rename transport_vq_config to vq_transport_config > > > > > > 2. virtio-net set dma meta number to (ring-size + 1)(MAX_SK= B_FRGAS +2) > > > > > > 3. introduce virtqueue_dma_map_sg_attrs > > > > > > 4. separate vring_create_virtqueue to an independent commit > > > > > > > > > > > > > > > > > > > > > > > > Xuan Zhuo (19): > > > > > > virtio_ring: introduce vring_need_unmap_buffer > > > > > > virtio_ring: packed: remove double check of the unmap ops > > > > > > virtio_ring: packed: structure the indirect desc table > > > > > > virtio_ring: split: remove double check of the unmap ops > > > > > > virtio_ring: split: structure the indirect desc table > > > > > > virtio_ring: no store dma info when unmap is not needed > > > > > > virtio: find_vqs: pass struct instead of multi parameters > > > > > > virtio: vring_create_virtqueue: pass struct instead of multi > > > > > > parameters > > > > > > virtio: vring_new_virtqueue(): pass struct instead of multi p= arameters > > > > > > virtio_ring: simplify the parameters of the funcs related to > > > > > > vring_create/new_virtqueue() > > > > > > virtio: find_vqs: add new parameter premapped > > > > > > virtio_ring: export premapped to driver by struct virtqueue > > > > > > virtio_net: set premapped mode by find_vqs() > > > > > > virtio_ring: remove api of setting vq premapped > > > > > > virtio_ring: introduce dma map api for page > > > > > > virtio_ring: introduce virtqueue_dma_map_sg_attrs > > > > > > virtio_net: unify the code for recycling the xmit ptr > > > > > > virtio_net: rename free_old_xmit_skbs to free_old_xmit > > > > > > virtio_net: sq support premapped mode > > > > > > > > > > > > arch/um/drivers/virtio_uml.c | 31 +- > > > > > > drivers/net/virtio_net.c | 283 ++++++--- > > > > > > drivers/platform/mellanox/mlxbf-tmfifo.c | 24 +- > > > > > > drivers/remoteproc/remoteproc_virtio.c | 31 +- > > > > > > drivers/s390/virtio/virtio_ccw.c | 33 +- > > > > > > drivers/virtio/virtio_mmio.c | 30 +- > > > > > > drivers/virtio/virtio_pci_common.c | 59 +- > > > > > > drivers/virtio/virtio_pci_common.h | 9 +- > > > > > > drivers/virtio/virtio_pci_legacy.c | 16 +- > > > > > > drivers/virtio/virtio_pci_modern.c | 38 +- > > > > > > drivers/virtio/virtio_ring.c | 698 ++++++++++++---= -------- > > > > > > drivers/virtio/virtio_vdpa.c | 45 +- > > > > > > include/linux/virtio.h | 13 +- > > > > > > include/linux/virtio_config.h | 48 +- > > > > > > include/linux/virtio_ring.h | 82 +-- > > > > > > tools/virtio/virtio_test.c | 4 +- > > > > > > tools/virtio/vringh_test.c | 28 +- > > > > > > 17 files changed, 847 insertions(+), 625 deletions(-) > > > > > > > > > > > > -- > > > > > > 2.32.0.3.g01195cf9f > > > > > > > > > > >