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(unknown [IPv6:2a01:e0a:5e3:6100:826d:bc07:e98c:84a]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: loicmolinari) by bali.collaboradmins.com (Postfix) with ESMTPSA id 0D62A17E114C; Tue, 2 Dec 2025 11:17:23 +0100 (CET) From: =?UTF-8?q?Lo=C3=AFc=20Molinari?= To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Tvrtko Ursulin , Boris Brezillon , Rob Herring , Steven Price , Liviu Dudau , Melissa Wen , =?UTF-8?q?Ma=C3=ADra=20Canal?= , Hugh Dickins , Baolin Wang , Andrew Morton , =?UTF-8?q?Lo=C3=AFc=20Molinari?= , Al Viro , =?UTF-8?q?Miko=C5=82aj=20Wasiak?= , Christian Brauner , Nitin Gote , Andi Shyti , Jonathan Corbet , Christopher Healy , Matthew Wilcox , Bagas Sanjaya Cc: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, linux-mm@kvack.org, linux-doc@vger.kernel.org, kernel@collabora.com Subject: [PATCH v11 00/10] drm: Reduce page tables overhead with THP Date: Tue, 2 Dec 2025 11:17:10 +0100 Message-ID: <20251202101720.3129-1-loic.molinari@collabora.com> X-Mailer: git-send-email 2.47.3 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" 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 Documentation/gpu/drm-mm.rst | 29 ++- drivers/gpu/drm/drm_gem.c | 202 +++++++++++++----- drivers/gpu/drm/drm_gem_shmem_helper.c | 79 +++---- drivers/gpu/drm/i915/Makefile | 3 +- drivers/gpu/drm/i915/gem/i915_gem_shmem.c | 48 +++-- 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 | 16 +- 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 - 28 files changed, 418 insertions(+), 289 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