[PATCH v19 00/30] Add generic memory shrinker to VirtIO-GPU and Panfrost DRM drivers

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This series:

  1. Adds common drm-shmem memory shrinker
  2. Moves drm-shmem drivers to new SGT usage policy
  3. Enables shrinker for VirtIO-GPU driver
  4. Switches Panfrost driver to the common shrinker
  5. Fixes bugs and improves/refactors drm-shmem code

Mesa: https://gitlab.freedesktop.org/digetx/mesa/-/commits/virgl-madvise
IGT:  https://gitlab.freedesktop.org/digetx/igt-gpu-tools/-/commits/virtio-madvise


v19:- Addressed v18 review comments from Boris Brezillon:

      - Improved bisectablity of Panfrost and drm-shmem patches by
        fixing iterim warning splats related to shrinker changes.

      - Improved commit messages

      - Reworked Lima patch to avoid adding `put_pages` flag

      - Reworked Panfrost patch that switches driver to explicit
        get/put pages by moving drm_gem_shmem_put_pages() into
        gem_mapping_release() instead of gem_free_object().

      - Updated Panfrost patch that switches driver to generic shrinker
        with more comments and minor imporovemnts.

      - Added new Panfrost patch from Boris that fixes handling of
        a partially mapped heap BOs.

    - Added link to the related Mesa MR to the commit msg of the patch
      that adds new DRM_VIRTGPU_MADVISE ioctl, like was requested by
      Gurchetan Singh.

    - Added ackes/r-b from Boris Brezillon and Maxime Ripard

    - New patches in v19:

        drm/gem: Document locking rule of vmap and evict callbacks
        drm/panfrost: Fix the error path in panfrost_mmu_map_fault_addr()

    - Factored out couple code changes into these new separate patches:

        drm/shmem-helper: Avoid lockdep warning when pages are released
        drm/shmem-helper: Turn warnings about imported GEM into errors

v18:- Added new pathes that change sgt allocation policy. Previously once
      sgt was allocated, it exsited till GEM was freed. Now sgt is destroyed
      once pages are unpinned and drivers have to manage the pages' pinning
      refcounting by themselves using get/put() and pin/unpin() pages.
      This removes pages refcounting ambiguity from the drm-shmem core.

    - Dropped patch that changed drm_gem_shmem_vmap_locked() error handling,
      like was requested by Boris Brezillon.

    - Added new patches that make minor improvements:

        - Optimize unlocked get_pages_sgt()
        - Don't free refcounted GEM

    - Dropped t-b from the Panfrost shrinker patch that was given for older
      patch version since code changed with the new sgt allocation policy.

v17:- Dropped patches that added new drm-shmem sgt flags, fixing dma-buf UAF
      in drm-prime error code path and preventing invalid page_count when GEM
      is freed. Will revist them later on and then factor them out into a
      seprate patchset.

    - Dropped patches that replaced drm_gem_shmem_free() with
      drm_gem_object_put(), they not needed anymore after changing
      drm_gem_shmem_free() to not touch reservation lock.

    - Addressed review comments from Boris Brezillon:

        - Added new patch to clean up error unwinding in

        - Added new __drm_gem_shmem_put_pages() to let the callers
          to assert the held reservation lock themselves

        - Moved replacement of shmem->pages check with refcount_read()
          in drm_gem_shmem_free() to the shrinker addition patch

        - Improved commit message of the vmap_use_count patch

    - Added r-bs from Boris Brezillon that he gave to v16

v16:- Added more comments to the code for the new drm-shmem flags

    - Added r-bs from Boris Brezillon

    - Fixed typos and made impovements pointed out by Boris Brezillon

    - Replaced kref with refcount_t as was suggested by Boris Brezillon

    - Corrected placement of got_sgt flag in the Lima driver, also renamed
      flag to got_pages_sgt

    - Removed drm_gem_shmem_resv_assert_held() and made drm_gem_shmem_free()
      to free pages without a new func that doesn't touch resv lock, as was
      suggested by Boris Brezillon

    - Added pages_pin_count to drm_gem_shmem_print_info()

v15:- Moved drm-shmem reference counters to use kref that allows to
      optimize unlocked functions, like was suggested by Boris Brezillon.

    - Changed drm/gem/shmem function names to use _locked postfix and
      dropped the _unlocked, making the naming scheme consistent across
      DRM code, like was suggested by Boris Brezillon.

    - Added patch that fixes UAF in drm-shmem for drivers that import
      dma-buf and then release buffer in the import error code path.

    - Added patch that makes drm-shmem use new flag for SGT's get_pages()
      refcounting, preventing unbalanced refcounting when GEM is freed.

    - Fixed guest blob pinning in virtio-gpu driver that was missed
      previously in the shrinker patch.

    - Moved VC4 and virtio-gpu drivers to use drm_gem_put() in
      GEM-creation error code paths, which is now required by drm-shmem
      and was missed in a previous patch versions.

    - Virtio-GPU now attaches shmem pages to host on first use and not
      when BO is created. In older patch versions there was a potential
      race condition in the BO creation code path where both
      get_sgt()+object_attach() should've been made under same resv lock,
      otherwise pages could be evicted before attachment is invoked.

    - Virtio-GPU and drm-shmem shrinker patches are split into smaller

v14:- All the prerequisite reservation locking patches landed upstream,
      previously were a part of this series in v13 and older.


    - Added patches to improve locked/unlocked function names, like was
      suggested by Boris Brezillon for v13.

    - Made all exported drm-shmem symbols GPL, like was previously
      discussed with Thomas Zimmermann on this series.

    - Improved virtio-gpu shrinker patch. Now it won't detach purged BO
      when userspace closes GEM. Crosvm (and not qemu) checks res_id on
      CMD_CTX_DETACH_RESOURCE and prints noisy error message if ID is
      invalid, which wasn't noticed before.

v13:- Updated virtio-gpu shrinker patch to use drm_gem_shmem_object_pin()
      directly instead of drm_gem_pin() and dropped patch that exported
      drm_gem_pin() functions, like was requested by Thomas Zimmermann in

v12:- Fixed the "no previous prototype for function" warning reported by
      kernel build bot for v11.

    - Fixed the missing reservation lock reported by Intel CI for VGEM
      driver. Other drivers using drm-shmem were affected similarly to
      VGEM. The problem was in the dma-buf attachment code path that led
      to drm-shmem pinning function which assumed the held reservation lock
      by drm_gem_pin(). In the past that code path was causing trouble for
      i915 driver and we've changed the locking scheme for the attachment
      code path in the dma-buf core to let exporters to handle the locking
      themselves. After a closer investigation, I realized that my assumption
      about testing of dma-buf export code path using Panfrost driver was
      incorrect. Now I created additional local test to exrecise the Panfrost
      export path. I also reproduced the issue reported by the Intel CI for
      v10. It's all fixed now by making the drm_gem_shmem_pin() to take the
      resv lock by itself.

    - Patches are based on top of drm-tip, CC'd intel-gfx CI for testing.

v11:- Rebased on a recent linux-next. Added new patch as a result:

        drm/shmem-helper: Export drm_gem_shmem_get_pages_sgt_locked()

        It's needed by the virtio-gpu driver to swap-in/unevict shmem
        object, previously get_pages_sgt() didn't use locking.

    - Separated the "Add memory shrinker" patch into smaller parts to ease
      the reviewing, as was requested by Thomas Zimmermann:

        drm/shmem-helper: Factor out pages alloc/release from
        drm/shmem-helper: Add pages_pin_count field
        drm/shmem-helper: Switch drm_gem_shmem_vmap/vunmap to use pin/unpin
        drm/shmem-helper: Factor out unpinning part from drm_gem_shmem_purge()

    - Addessed the v10 review comments from Thomas Zimmermann: return errno
      instead of bool, sort code alphabetically, rename function and etc
      minor changes.

    - Added new patch to remove the "map->is_iomem" from drm-shmem, as
      was suggested by Thomas Zimmermann.

    - Added acks and r-b's that were given to v10.

v10:- Was partially applied to misc-fixes/next.


Boris Brezillon (1):
  drm/panfrost: Fix the error path in panfrost_mmu_map_fault_addr()

Dmitry Osipenko (29):
  drm/gem: Change locked/unlocked postfix of drm_gem_v/unmap() function
  drm/gem: Add _locked postfix to functions that have unlocked
  drm/gem: Document locking rule of vmap and evict callbacks
  drm/shmem-helper: Make all exported symbols GPL
  drm/shmem-helper: Refactor locked/unlocked functions
  drm/shmem-helper: Remove obsoleted is_iomem test
  drm/shmem-helper: Add and use pages_pin_count
  drm/shmem-helper: Use refcount_t for pages_use_count
  drm/shmem-helper: Add and use lockless drm_gem_shmem_get_pages()
  drm/shmem-helper: Switch drm_gem_shmem_vmap/vunmap to use pin/unpin
  drm/shmem-helper: Use refcount_t for vmap_use_count
  drm/shmem-helper: Prepare drm_gem_shmem_free() to shrinker addition
  drm/shmem-helper: Make drm_gem_shmem_get_pages() public
  drm/shmem-helper: Add drm_gem_shmem_put_pages()
  drm/shmem-helper: Avoid lockdep warning when pages are released
  drm/lima: Explicitly get and put drm-shmem pages
  drm/panfrost: Explicitly get and put drm-shmem pages
  drm/virtio: Explicitly get and put drm-shmem pages
  drm/v3d: Explicitly get and put drm-shmem pages
  drm/shmem-helper: Change sgt allocation policy
  drm/shmem-helper: Add common memory shrinker
  drm/shmem-helper: Export drm_gem_shmem_get_pages_sgt_locked()
  drm/shmem-helper: Optimize unlocked get_pages_sgt()
  drm/shmem-helper: Don't free refcounted GEM
  drm/shmem-helper: Turn warnings about imported GEM into errors
  drm/virtio: Pin display framebuffer BO
  drm/virtio: Attach shmem BOs dynamically
  drm/virtio: Support shmem shrinking
  drm/panfrost: Switch to generic memory shrinker

 drivers/gpu/drm/drm_client.c                  |   6 +-
 drivers/gpu/drm/drm_gem.c                     |  26 +-
 drivers/gpu/drm/drm_gem_framebuffer_helper.c  |   6 +-
 drivers/gpu/drm/drm_gem_shmem_helper.c        | 663 +++++++++++++++---
 drivers/gpu/drm/drm_internal.h                |   4 +-
 drivers/gpu/drm/drm_prime.c                   |   4 +-
 drivers/gpu/drm/lima/lima_gem.c               |  23 +-
 drivers/gpu/drm/lima/lima_sched.c             |   4 +-
 drivers/gpu/drm/panfrost/Makefile             |   1 -
 drivers/gpu/drm/panfrost/panfrost_device.h    |   4 -
 drivers/gpu/drm/panfrost/panfrost_drv.c       |  31 +-
 drivers/gpu/drm/panfrost/panfrost_dump.c      |   4 +-
 drivers/gpu/drm/panfrost/panfrost_gem.c       | 110 ++-
 drivers/gpu/drm/panfrost/panfrost_gem.h       |   9 -
 .../gpu/drm/panfrost/panfrost_gem_shrinker.c  | 127 ----
 drivers/gpu/drm/panfrost/panfrost_job.c       |  18 +-
 drivers/gpu/drm/panfrost/panfrost_mmu.c       |  39 +-
 drivers/gpu/drm/panfrost/panfrost_perfcnt.c   |   6 +-
 drivers/gpu/drm/v3d/v3d_bo.c                  |  11 +-
 drivers/gpu/drm/virtio/virtgpu_drv.h          |  22 +-
 drivers/gpu/drm/virtio/virtgpu_gem.c          |  85 +++
 drivers/gpu/drm/virtio/virtgpu_ioctl.c        |  57 +-
 drivers/gpu/drm/virtio/virtgpu_kms.c          |   8 +
 drivers/gpu/drm/virtio/virtgpu_object.c       | 143 +++-
 drivers/gpu/drm/virtio/virtgpu_plane.c        |  17 +-
 drivers/gpu/drm/virtio/virtgpu_submit.c       |  15 +-
 drivers/gpu/drm/virtio/virtgpu_vq.c           |  40 ++
 include/drm/drm_device.h                      |  10 +-
 include/drm/drm_gem.h                         |  15 +-
 include/drm/drm_gem_shmem_helper.h            | 117 +++-
 include/uapi/drm/virtgpu_drm.h                |  14 +
 31 files changed, 1216 insertions(+), 423 deletions(-)
 delete mode 100644 drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c


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