From 9c64e749cebd9c2d3d55261530a98bcccb83b950 Mon Sep 17 00:00:00 2001 From: Sebastian Ott Date: Tue, 23 Jan 2024 19:14:14 +0100 Subject: [PATCH 1/2] drm/virtio: Set segment size for virtio_gpu device Set the segment size of the virtio_gpu device to the value used by the drm helpers when allocating sg lists to fix the following complaint from DMA_API debug code: DMA-API: virtio-pci 0000:07:00.0: mapping sg segment longer than device claims to support [len=262144] [max=65536] Cc: stable@vger.kernel.org Tested-by: Zhenyu Zhang Acked-by: Vivek Kasireddy Signed-off-by: Sebastian Ott Signed-off-by: Dmitry Osipenko Link: https://patchwork.freedesktop.org/patch/msgid/7258a4cc-da16-5c34-a042-2a23ee396d56@redhat.com --- drivers/gpu/drm/virtio/virtgpu_drv.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.c b/drivers/gpu/drm/virtio/virtgpu_drv.c index f8e9abe647b9..9539aa28937f 100644 --- a/drivers/gpu/drm/virtio/virtgpu_drv.c +++ b/drivers/gpu/drm/virtio/virtgpu_drv.c @@ -94,6 +94,7 @@ static int virtio_gpu_probe(struct virtio_device *vdev) goto err_free; } + dma_set_max_seg_size(dev->dev, dma_max_mapping_size(dev->dev) ?: UINT_MAX); ret = virtio_gpu_init(vdev, dev); if (ret) goto err_free; From 1c1914d6e8c6edbf5b45047419ff51abdb1dce96 Mon Sep 17 00:00:00 2001 From: "T.J. Mercier" Date: Wed, 17 Jan 2024 18:11:40 +0000 Subject: [PATCH 2/2] dma-buf: heaps: Don't track CMA dma-buf pages under RssFile MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit DMA buffers allocated from the CMA dma-buf heap get counted under RssFile for processes that map them and trigger page faults. In addition to the incorrect accounting reported to userspace, reclaim behavior was influenced by the MM_FILEPAGES counter until linux 6.8, but this memory is not reclaimable. [1] Change the CMA dma-buf heap to set VM_PFNMAP on the VMA so MM does not poke at the memory managed by this dma-buf heap, and use vmf_insert_pfn to correct the RSS accounting. The system dma-buf heap does not suffer from this issue since remap_pfn_range is used during the mmap of the buffer, which also sets VM_PFNMAP on the VMA. [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/mm/vmscan.c?id=fb46e22a9e3863e08aef8815df9f17d0f4b9aede Fixes: b61614ec318a ("dma-buf: heaps: Add CMA heap to dmabuf heaps") Signed-off-by: T.J. Mercier Acked-by: Christian König Signed-off-by: Sumit Semwal Link: https://patchwork.freedesktop.org/patch/msgid/20240117181141.286383-1-tjmercier@google.com --- drivers/dma-buf/heaps/cma_heap.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/dma-buf/heaps/cma_heap.c b/drivers/dma-buf/heaps/cma_heap.c index ee899f8e6721..4a63567e93ba 100644 --- a/drivers/dma-buf/heaps/cma_heap.c +++ b/drivers/dma-buf/heaps/cma_heap.c @@ -168,10 +168,7 @@ static vm_fault_t cma_heap_vm_fault(struct vm_fault *vmf) if (vmf->pgoff > buffer->pagecount) return VM_FAULT_SIGBUS; - vmf->page = buffer->pages[vmf->pgoff]; - get_page(vmf->page); - - return 0; + return vmf_insert_pfn(vma, vmf->address, page_to_pfn(buffer->pages[vmf->pgoff])); } static const struct vm_operations_struct dma_heap_vm_ops = { @@ -185,6 +182,8 @@ static int cma_heap_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma) if ((vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0) return -EINVAL; + vm_flags_set(vma, VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP); + vma->vm_ops = &dma_heap_vm_ops; vma->vm_private_data = buffer;