On Fri, 5 Dec 2025 19:22:21 +0100 Loïc Molinari <[email protected]> wrote:
> This series aims to reduce the page tables overhead of DRM drivers for > builds with CONFIG_TRANSPARENT_HUGEPAGE enabled and either the sysfs > knob '/sys/kernel/mm/transparent_hugepage/shmem_enabled' appropriately > set or drivers using a dedicated huge tmpfs mount point. > > It starts by checking whether a faulty address in the page fault > handler is part of a huge page in order to attempt a PMD sized PFN > insertion into the VMA. It then introduces a dedicated > get_unmapped_area file operation on the DRM file descriptor for GEM > objects to get the best virtual address alignment for the underlying > shmem buffers. > > The remaining commits propose shmem helpers to create and release huge > tmpfs mount points and adapt the i915 and V3D drivers. The helpers are > then used to optionally enable Transparent Hugepage for Panfrost and > Panthor. > > For Panthor on a Rock 5B, this series makes the first memcpy() to an > entire BO object mapped in userspace about twice as fast with > Transparent Hugepage enabled. > > Implementing a fault-around handler using the arm64 contiguous page > hint (contptes) could also greatly help reduce page tables overhead > for small pages by mapping several contiguous pages around a faulty > address at once. This will be proposed in another patch series. > > Loïc Molinari (10): > drm/shmem-helper: Simplify page offset calculation in fault handler > drm/shmem-helper: Map huge pages in fault handler > drm/gem: Introduce drm_gem_get_unmapped_area() fop > drm/gem: Add huge tmpfs mountpoint helpers > drm/i915: Use huge tmpfs mountpoint helpers > drm/v3d: Use huge tmpfs mountpoint helpers > drm/gem: Get rid of *_with_mnt helpers > drm/panthor: Introduce huge tmpfs mountpoint option > drm/panfrost: Introduce huge tmpfs mountpoint option > Documentation/gpu/drm-mm: Add THP paragraph to GEM mapping section Queued to drm-misc-next. > > Documentation/gpu/drm-mm.rst | 29 ++- > drivers/gpu/drm/drm_gem.c | 202 +++++++++++++----- > drivers/gpu/drm/drm_gem_shmem_helper.c | 77 +++---- > drivers/gpu/drm/i915/Makefile | 3 +- > .../gpu/drm/i915/gem/i915_gem_object_types.h | 9 +- > drivers/gpu/drm/i915/gem/i915_gem_shmem.c | 58 +++-- > drivers/gpu/drm/i915/gem/i915_gemfs.c | 71 ------ > drivers/gpu/drm/i915/gem/i915_gemfs.h | 14 -- > .../gpu/drm/i915/gem/selftests/huge_pages.c | 15 +- > drivers/gpu/drm/i915/i915_drv.h | 5 - > drivers/gpu/drm/panfrost/panfrost_device.c | 3 + > drivers/gpu/drm/panfrost/panfrost_drv.c | 6 + > drivers/gpu/drm/panfrost/panfrost_drv.h | 9 + > drivers/gpu/drm/panfrost/panfrost_gem.c | 18 ++ > drivers/gpu/drm/panfrost/panfrost_gem.h | 2 + > drivers/gpu/drm/panthor/panthor_device.c | 3 + > drivers/gpu/drm/panthor/panthor_drv.c | 7 + > drivers/gpu/drm/panthor/panthor_drv.h | 9 + > drivers/gpu/drm/panthor/panthor_gem.c | 18 ++ > drivers/gpu/drm/panthor/panthor_gem.h | 2 + > drivers/gpu/drm/v3d/Makefile | 3 +- > drivers/gpu/drm/v3d/v3d_bo.c | 6 +- > drivers/gpu/drm/v3d/v3d_drv.c | 2 +- > drivers/gpu/drm/v3d/v3d_drv.h | 11 +- > drivers/gpu/drm/v3d/v3d_gem.c | 21 +- > drivers/gpu/drm/v3d/v3d_gemfs.c | 62 ------ > include/drm/drm_device.h | 15 ++ > include/drm/drm_gem.h | 40 +++- > include/drm/drm_gem_shmem_helper.h | 3 - > 29 files changed, 420 insertions(+), 303 deletions(-) > delete mode 100644 drivers/gpu/drm/i915/gem/i915_gemfs.c > delete mode 100644 drivers/gpu/drm/i915/gem/i915_gemfs.h > create mode 100644 drivers/gpu/drm/panfrost/panfrost_drv.h > create mode 100644 drivers/gpu/drm/panthor/panthor_drv.h > delete mode 100644 drivers/gpu/drm/v3d/v3d_gemfs.c >
