Hello, This patchset introduces memory shrinker for the VirtIO-GPU DRM driver. During OOM, the shrinker will release BOs that are marked as "not needed" by userspace using the new madvise IOCTL. The userspace in this case is the Mesa VirGL driver, it will mark the cached BOs as "not needed", allowing kernel driver to release memory of the cached shmem BOs on lowmem situations, preventing OOM kills. This patchset includes couple fixes for problems of VirtIO-GPU driver that I found while was working on the shrinker, it also includes prerequisite DMA API usage improvement needed by the shrinker. The Mesa and IGT patches will be kept on hold until this kernel series will be approved and applied. This patchset was tested using Qemu and crosvm, including both cases of IOMMU off/on. Note that this patchset only enables initial shrinking of the guest memory, shrinking of the host memory is unsupported yet. Mesa: https://gitlab.freedesktop.org/digetx/mesa/-/commits/virgl-madvise IGT: https://gitlab.freedesktop.org/digetx/igt-gpu-tools/-/tree/virtio-madvise Changelog: v2: - Improved shrinker by using a more fine-grained locking to reduce contention during scan of objects and dropped locking from the 'counting' callback by tracking count of shrinkable pages. This was suggested by Rob Clark in the comment to v1. - Factored out common shrinker code into drm_gem_shmem_helper.c and switched Panfrost driver to use the new common memory shrinker. This was proposed by Thomas Zimmermann in his prototype series that he shared with us in the comment to v1. Note that I only compile-tested the Panfrost driver. - Shrinker now takes object_name_lock during scan to prevent racing with dma-buf exporting. - Shrinker now takes vmap_lock during scan to prevent racing with shmem vmap/unmap code. - Added "Correct doc-comment of drm_gem_shmem_get_sg_table()" patch, which I sent out previously as a standalone change, since the drm_gem_shmem_helper.c is now touched by this patchset anyways and it doesn't hurt to group all the patches together. Dmitry Osipenko (8): drm/virtio: Correct drm_gem_shmem_get_sg_table() error handling drm/virtio: Check whether transferred 2D BO is shmem drm/virtio: Unlock GEM reservations in error code path drm/virtio: Improve DMA API usage for shmem BOs drm/shmem-helper: Correct doc-comment of drm_gem_shmem_get_sg_table() drm/shmem-helper: Add generic memory shrinker drm/virtio: Support memory shrinking drm/panfrost: Switch to generic memory shrinker drivers/gpu/drm/drm_gem_shmem_helper.c | 196 ++++++++++++++++++++- drivers/gpu/drm/panfrost/Makefile | 1 - drivers/gpu/drm/panfrost/panfrost_device.h | 4 - drivers/gpu/drm/panfrost/panfrost_drv.c | 19 +- drivers/gpu/drm/panfrost/panfrost_gem.c | 27 +-- drivers/gpu/drm/panfrost/panfrost_gem.h | 9 - drivers/gpu/drm/panfrost/panfrost_job.c | 22 ++- drivers/gpu/drm/virtio/virtgpu_drv.c | 22 ++- drivers/gpu/drm/virtio/virtgpu_drv.h | 26 ++- drivers/gpu/drm/virtio/virtgpu_gem.c | 96 ++++++++++ drivers/gpu/drm/virtio/virtgpu_ioctl.c | 37 ++++ drivers/gpu/drm/virtio/virtgpu_kms.c | 17 +- drivers/gpu/drm/virtio/virtgpu_object.c | 78 ++++---- drivers/gpu/drm/virtio/virtgpu_plane.c | 17 +- drivers/gpu/drm/virtio/virtgpu_vq.c | 30 +++- include/drm/drm_device.h | 4 + include/drm/drm_gem.h | 11 ++ include/drm/drm_gem_shmem_helper.h | 25 +++ include/uapi/drm/virtgpu_drm.h | 14 ++ 19 files changed, 544 insertions(+), 111 deletions(-) -- 2.35.1
