lwn.git/Documentation/gpu/drm-mm.rst, branch docs-fixes

gpu: Move DRM buddy allocator one level up (part two)

2026-02-06T01:38:35+00:00

Move the DRM buddy allocator one level up so that it can be used by GPU drivers (example, nova-core) that have usecases other than DRM (such as VFIO vGPU support). Modify the API, structures and Kconfigs to use "gpu_buddy" terminology. Adapt the drivers and tests to use the new API. The commit cannot be split due to bisectability, however no functional change is intended. Verified by running K-UNIT tests and build tested various configurations. Signed-off-by: Joel Fernandes Reviewed-by: Dave Airlie [airlied: I've split this into two so git can find copies easier. I've also just nuked drm_random library, that stuff needs to be done elsewhere and only the buddy tests seem to be using it]. Signed-off-by: Dave Airlie

gpu: Move DRM buddy allocator one level up (part one)

2026-02-06T01:34:02+00:00

Documentation/gpu/drm-mm: Add THP paragraph to GEM mapping section

2025-12-08T09:56:34+00:00

Add a paragraph to the GEM Objects Creation section about the drm_gem_huge_mnt_create() helper and to the GEM objects mapping section explaining how transparent huge pages are handled by GEM. v4: - fix wording after huge_pages handler removal v6: - fix wording after map_pages handler removal v11: - mention drm_gem_huge_mnt_create() helper - add Boris and Maíra R-bs Signed-off-by: Loïc Molinari Reviewed-by: Bagas Sanjaya Reviewed-by: Boris Brezillon Reviewed-by: Maíra Canal Link: https://patch.msgid.link/20251205182231.194072-11-loic.molinari@collabora.com Signed-off-by: Boris Brezillon

Documentation/gpu: VM_BIND locking document

2023-11-29T19:54:43+00:00

Add the first version of the VM_BIND locking document which is intended to be part of the xe driver upstreaming agreement. The document describes and discuss the locking used during exec- functions, evicton and for userptr gpu-vmas. Intention is to be using the same nomenclature as the drm-vm-bind-async.rst. v2: - s/gvm/gpu_vm/g (Rodrigo Vivi) - Clarify the userptr seqlock with a pointer to mm/mmu_notifier.c (Rodrigo Vivi) - Adjust commit message accordingly. - Add SPDX license header. v3: - Large update to align with the drm_gpuvm manager locking - Add "Efficient userptr gpu_vma exec function iteration" section - Add "Locking at bind- and unbind time" section. v4: - Fix tabs vs space errors by untabifying (Rodrigo Vivi) - Minor style fixes and typos (Rodrigo Vivi) - Clarify situations where stale GPU mappings are occurring and how access through these mappings are blocked. (Rodrigo Vivi) - Insert into the toctree in implementation_guidelines.rst v5: - Add a section about recoverable page-faults. - Use local references to other documentation where possible (Bagas Sanjaya) - General documentation fixes and typos (Danilo Krummrich and Boris Brezillon) - Improve the documentation around locks that need to be grabbed from the dm-fence critical section (Boris Brezillon) - Add more references to the DRM GPUVM helpers (Danilo Krummrich and Boriz Brezillon) - Update the rfc/xe.rst document. v6: - Rework wording to improve readability (Boris Brezillon, Rodrigo Vivi, Bagas Sanjaya) - Various minor fixes across the document (Boris Brezillon) Cc: Rodrigo Vivi Signed-off-by: Thomas Hellström Reviewed-by: Boris Brezillon Reviewed-by: Rodrigo Vivi Reviewed-by: Danilo Krummrich Acked-by: John Hubbard # Documentation/core-api/pin_user_pages.rst changes Link: https://patchwork.freedesktop.org/patch/msgid/20231129090637.2629-1-thomas.hellstrom@linux.intel.com

drm/sched: implement dynamic job-flow control

2023-11-10T01:54:29+00:00

Currently, job flow control is implemented simply by limiting the number of jobs in flight. Therefore, a scheduler is initialized with a credit limit that corresponds to the number of jobs which can be sent to the hardware. This implies that for each job, drivers need to account for the maximum job size possible in order to not overflow the ring buffer. However, there are drivers, such as Nouveau, where the job size has a rather large range. For such drivers it can easily happen that job submissions not even filling the ring by 1% can block subsequent submissions, which, in the worst case, can lead to the ring run dry. In order to overcome this issue, allow for tracking the actual job size instead of the number of jobs. Therefore, add a field to track a job's credit count, which represents the number of credits a job contributes to the scheduler's credit limit. Signed-off-by: Danilo Krummrich Reviewed-by: Luben Tuikov Link: https://patchwork.freedesktop.org/patch/msgid/20231110001638.71750-1-dakr@redhat.com

drm/gpuvm: doc: fix filename references

2023-09-27T15:49:38+00:00

Commit f72c2db47080 ("drm/gpuvm: rename struct drm_gpuva_manager to struct drm_gpuvm") did also change the corresponding filenames which are referenced from the documentation, but were not adjusted accordingly. Hence, fix up those filenames. Fixes: f72c2db47080 ("drm/gpuvm: rename struct drm_gpuva_manager to struct drm_gpuvm") Reported-by: Stephen Rothwell Closes: https://lore.kernel.org/dri-devel/20230926150725.4cca5fc5@canb.auug.org.au/ Signed-off-by: Danilo Krummrich Acked-by: Dave Airlie Link: https://patchwork.freedesktop.org/patch/msgid/20230926105146.10808-1-dakr@redhat.com

drm/doc: fix underline for section "DRM Sync Objects"

2023-08-03T15:16:12+00:00

It doesn't line up. Signed-off-by: Simon Ser Suggested-by: Jani Nikula Reviewed-by: Jani Nikula Link: https://patchwork.freedesktop.org/patch/msgid/20230803102505.392577-1-contact@emersion.fr

drm/doc: use proper cross-references for sections

2023-08-03T10:17:29+00:00

When I originally wrote these docs, I couldn't manage to insert a cross-reference to a section. Here's how it can be done. Signed-off-by: Simon Ser Reviewed-by: Jani Nikula Acked-by: Daniel Vetter Cc: Pekka Paalanen Link: https://patchwork.freedesktop.org/patch/msgid/20230803095734.386761-1-contact@emersion.fr

drm: manager to keep track of GPUs VA mappings

2023-07-20T03:15:53+00:00

Add infrastructure to keep track of GPU virtual address (VA) mappings with a decicated VA space manager implementation. New UAPIs, motivated by Vulkan sparse memory bindings graphics drivers start implementing, allow userspace applications to request multiple and arbitrary GPU VA mappings of buffer objects. The DRM GPU VA manager is intended to serve the following purposes in this context. 1) Provide infrastructure to track GPU VA allocations and mappings, using an interval tree (RB-tree). 2) Generically connect GPU VA mappings to their backing buffers, in particular DRM GEM objects. 3) Provide a common implementation to perform more complex mapping operations on the GPU VA space. In particular splitting and merging of GPU VA mappings, e.g. for intersecting mapping requests or partial unmap requests. Acked-by: Thomas Hellström Acked-by: Matthew Brost Reviewed-by: Boris Brezillon Tested-by: Matthew Brost Tested-by: Donald Robson Suggested-by: Dave Airlie Signed-off-by: Danilo Krummrich Link: https://patchwork.freedesktop.org/patch/msgid/20230720001443.2380-2-dakr@redhat.com

drm: execution context for GEM buffers v7

2023-07-12T12:14:20+00:00

This adds the infrastructure for an execution context for GEM buffers which is similar to the existing TTMs execbuf util and intended to replace it in the long term. The basic functionality is that we abstracts the necessary loop to lock many different GEM buffers with automated deadlock and duplicate handling. v2: drop xarray and use dynamic resized array instead, the locking overhead is unnecessary and measurable. v3: drop duplicate tracking, radeon is really the only one needing that. v4: fixes issues pointed out by Danilo, some typos in comments and a helper for lock arrays of GEM objects. v5: some suggestions by Boris Brezillon, especially just use one retry macro, drop loop in prepare_array, use flags instead of bool v6: minor changes suggested by Thomas, Boris and Danilo v7: minor typos pointed out by checkpatch.pl fixed Signed-off-by: Christian König Reviewed-by: Boris Brezillon Reviewed-by: Danilo Krummrich Tested-by: Danilo Krummrich Acked-by: Alex Deucher Link: https://patchwork.freedesktop.org/patch/msgid/20230711133122.3710-2-christian.koenig@amd.com