Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:18 as permitted sender) client-ip=2620:137:e000::1:18;
MIME-Version: 1.0
References: <20220308131725.60607-1-dmitry.osipenko@collabora.com>
In-Reply-To: <20220308131725.60607-1-dmitry.osipenko@collabora.com>
From:   Rob Clark <robdclark@gmail.com>
Date:   Tue, 8 Mar 2022 08:29:32 -0800
Message-ID: <CAF6AEGt=aVJ9nR+Wv+bJEFZrn-cNOSNXG1TaJr=Cx-FTgutwKA@mail.gmail.com>
Subject: Re: [PATCH v1 0/5] Add memory shrinker to VirtIO-GPU DRM driver
To:     Dmitry Osipenko <dmitry.osipenko@collabora.com>
Cc:     David Airlie <airlied@linux.ie>, Gerd Hoffmann <kraxel@redhat.com>,
        Gurchetan Singh <gurchetansingh@chromium.org>,
        Chia-I Wu <olvaffe@gmail.com>, Daniel Vetter <daniel@ffwll.ch>,
        Daniel Almeida <daniel.almeida@collabora.com>,
        Gert Wollny <gert.wollny@collabora.com>,
        Tomeu Vizoso <tomeu.vizoso@collabora.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        "open list:VIRTIO GPU DRIVER" 
        <virtualization@lists.linux-foundation.org>,
        Gustavo Padovan <gustavo.padovan@collabora.com>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        Dmitry Osipenko <digetx@gmail.com>,
        Rob Clark <robdclark@chromium.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Tue, Mar 8, 2022 at 5:17 AM Dmitry Osipenko
<dmitry.osipenko@collabora.com> wrote:
>
> 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.

Will host memory pressure already trigger shrinker in guest?  This is
something I'm quite interested in for "virtgpu native contexts" (ie.
native guest driver with new context type sitting on top of virtgpu),
since that isn't using host storage

BR,
-R

> This patchset includes couple fixes for problems 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.
>
> Mesa: https://gitlab.freedesktop.org/digetx/mesa/-/commits/virgl-madvise
> IGT:  https://gitlab.freedesktop.org/digetx/igt-gpu-tools/-/tree/virtio-madvise
>
> Dmitry Osipenko (5):
>   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/virtio: Add memory shrinker
>
>  drivers/gpu/drm/virtio/Makefile               |   3 +-
>  drivers/gpu/drm/virtio/virtgpu_drv.c          |  22 +++-
>  drivers/gpu/drm/virtio/virtgpu_drv.h          |  31 ++++-
>  drivers/gpu/drm/virtio/virtgpu_gem.c          |  84 ++++++++++++
>  drivers/gpu/drm/virtio/virtgpu_gem_shrinker.c | 124 ++++++++++++++++++
>  drivers/gpu/drm/virtio/virtgpu_ioctl.c        |  37 ++++++
>  drivers/gpu/drm/virtio/virtgpu_kms.c          |  17 ++-
>  drivers/gpu/drm/virtio/virtgpu_object.c       |  63 +++------
>  drivers/gpu/drm/virtio/virtgpu_plane.c        |  17 ++-
>  drivers/gpu/drm/virtio/virtgpu_vq.c           |  30 +++--
>  include/uapi/drm/virtgpu_drm.h                |  14 ++
>  11 files changed, 373 insertions(+), 69 deletions(-)
>  create mode 100644 drivers/gpu/drm/virtio/virtgpu_gem_shrinker.c
>
> --
> 2.35.1
>