On Wed, Mar 27, 2024 at 3:16 PM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote: > > On Tue, 26 Mar 2024 14:35:21 +0800, Jason Wang <jasowang@xxxxxxxxxx> wrote: > > On Mon, Mar 25, 2024 at 4:54 PM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote: > > > > > > As discussed: > > > > > > http://lore.kernel.org/all/CACGkMEvq0No8QGC46U4mGsMtuD44fD_cfLcPaVmJ3rHYqRZxYg@xxxxxxxxxxxxxx > > > > > > If the virtio is premapped mode, the driver should manage the dma info by self. > > > So the virtio core should not store the dma info. We can release the memory used > > > to store the dma info. > > > > > > For virtio-net xmit queue, if the virtio-net maintains the dma info, > > > the virtio-net must allocate too much memory(19 * queue_size for per-queue), so > > > we do not plan to make the virtio-net to maintain the dma info by default. The > > > virtio-net xmit queue only maintain the dma info when premapped mode is enable > > > (such as AF_XDP is enable). > > > > > > So this patch set try to do: > > > > > > 1. make the virtio core to do not store the dma info when driver can do that > > > - 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 hardening > > > the dma unmap is safe, we should store the dma info of indirect > > > descs when the virtio core does not store the bufer dma info. > > > > > > The follow patches to this: > > > * virtio_ring: packed: structure the indirect desc table > > > * virtio_ring: split: structure the indirect desc table > > > > > > - On the other side, in the umap handle, we mix the indirect descs with > > > other descs. That make things too complex. I found if we we distinguish > > > the descs with VRING_DESC_F_INDIRECT before unmap, thing will be clearer. > > > > > > The follow patches do this. > > > * virtio_ring: packed: remove double check of the unmap ops > > > * virtio_ring: split: structure the indirect desc table > > > > > > 2. make the virtio core to enable premapped mode by find_vqs() params > > > - Because the find_vqs() will try to allocate memory for the dma info. > > > If we set the premapped mode after find_vqs() and release the > > > dma info, that is odd. > > > > > > > > > Please review. > > > > > > Thanks > > > > This doesn't apply cleany on vhost.git linux-next branch. > > > > Which tree is this based on? > > > Sorry. That is on the top of "[PATCH vhost v5 0/6] refactor the params of > find_vqs()". > > Lore-URL: http://lore.kernel.org/all/20240325090419.33677-1-xuanzhuo@xxxxxxxxxxxxxxxxx > > Thanks. I've tried that but it doesn't work: % git am ~/Downloads/\[PATCH\ vhost\ v5\ 01_10\]\ virtio_ring_\ introduce\ vring_need_unmap_buffer.eml Applying: virtio_ring: introduce vring_need_unmap_buffer error: patch failed: drivers/virtio/virtio_ring.c:2080 error: drivers/virtio/virtio_ring.c: patch does not apply Patch failed at 0001 virtio_ring: introduce vring_need_unmap_buffer hint: Use 'git am --show-current-patch=diff' to see the failed patch When you have resolved this problem, run "git am --continue". If you prefer to skip this patch, run "git am --skip" instead. To restore the original branch and stop patching, run "git am --abort". I'm using vhost.git linux-next branch, HEAD is commit 56e71885b0349241c07631a7b979b61e81afab6a Author: Maxime Coquelin <maxime.coquelin@xxxxxxxxxx> Date: Tue Jan 9 12:10:24 2024 +0100 vduse: Temporarily fail if control queue feature requested Thanks > > > > > Thanks > > >
