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Mon, 8 Dec 2025 12:29:44 +0100 (CET) Date: Mon, 8 Dec 2025 12:29:41 +0100 From: Boris Brezillon To: =?UTF-8?B?TG/Dr2M=?= Molinari Cc: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Tvrtko Ursulin , Rob Herring , Steven Price , Liviu Dudau , Melissa Wen , =?UTF-8?B?TWHDrXJh?= Canal , Hugh Dickins , Baolin Wang , Andrew Morton , Al Viro , =?UTF-8?B?TWlrb8WCYWo=?= Wasiak , Christian Brauner , Nitin Gote , Andi Shyti , Jonathan Corbet , Christopher Healy , Matthew Wilcox , Bagas Sanjaya , 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: Re: [PATCH v13 00/10] drm: Reduce page tables overhead with THP Message-ID: <20251208122941.61bea21d@fedora> In-Reply-To: <20251205182231.194072-1-loic.molinari@collabora.com> References: <20251205182231.194072-1-loic.molinari@collabora.com> Organization: Collabora X-Mailer: Claws Mail 4.3.1 (GTK 3.24.51; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: B492640010 X-Stat-Signature: r77utfaprmgzw66391jgjjdqonqewczm X-Rspam-User: X-HE-Tag: 1765193388-766838 X-HE-Meta: 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 vyohCuA+ TaY89f06JEiAzH6eswwkz1oCTctrORH+BxvKuG7XsYwxzseieuFWJEXijXli1U546ixZM9kmsfvXSIUfxmZzXlcRv1WSC/orJ1gCq+0Qb1/kFD15miiYhy5/VNRSM+kS5IjmLPB0t7AnWQG+9XAKqED5+2gKQVlOKNM5Ka/N8gl2R8+l4nBpQHiVLEgn99Y/PQDZAEj5We5x/cCx5n5xaYH4Bkwd8ZpsNOgLj1zWgimv5q56DF8ni3ZCgkwqyhLbjpCTL4/APKSGeDO76hi7YHhtpRlNkw3VxKblpNbPapnafvUT5JdMoiH/vOC455oRsj/XImzW1n0rp1DeP4DElC77f3Z/SXORZAw9js4HR5DLx0/oAFCqIqmClPw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, 5 Dec 2025 19:22:21 +0100 Lo=C3=AFc Molinari 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. >=20 > 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. >=20 > 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. >=20 > 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. >=20 > 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. >=20 > Lo=C3=AFc 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. >=20 > 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 >=20