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 (11): 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/panthor: Improve IOMMU map/unmap debugging logs drm/panfrost: Introduce huge tmpfs mountpoint option Documentation/gpu/drm-mm: Add THP paragraph to GEM mapping section Documentation/gpu/drm-mm.rst | 22 +- drivers/gpu/drm/drm_gem.c | 203 +++++++++++++----- drivers/gpu/drm/drm_gem_shmem_helper.c | 97 +++++---- drivers/gpu/drm/i915/Makefile | 3 +- drivers/gpu/drm/i915/gem/i915_gem_shmem.c | 51 +++-- 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 | 17 +- 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/panthor/panthor_mmu.c | 19 +- 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 | 27 ++- 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, 452 insertions(+), 296 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 -- 2.47.3
