On 08.10.25 13:53, Tvrtko Ursulin wrote: > Disclaimer: > Please note that as this series includes a patch which touches a good number > of > drivers I will only copy everyone in the cover letter and the respective > patch. > Assumption is people are subscribed to dri-devel so can look at the whole > series > there. I know someone is bound to complain for both the case when everyone is > copied on everything for getting too much email, and also for this other case. > So please be flexible. > > Description: > > All drivers which use the TTM pool allocator end up requesting large order > allocations when allocating large buffers. Those can be slow due memory > pressure > and so add latency to buffer creation. But there is often also a size limit > above which contiguous blocks do not bring any performance benefits. This > series > allows drivers to say when it is okay for the TTM to try a bit less hard. > > We do this by allowing drivers to specify this cut off point when creating the > TTM device and pools. Allocations above this size will skip direct reclaim so > under memory pressure worst case latency will improve. Background reclaim is > still kicked off and both before and after the memory pressure all the TTM > pool > buckets remain to be used as they are today. > > This is especially interesting if someone has configured MAX_PAGE_ORDER to > higher than the default. And even with the default, with amdgpu for example, > the last patch in the series makes use of the new feature by telling TTM that > above 2MiB we do not expect performance benefits. Which makes TTM not try > direct > reclaim for the top bucket (4MiB). > > End result is TTM drivers become a tiny bit nicer mm citizens and users > benefit > from better worst case buffer creation latencies. As a side benefit we get rid > of two instances of those often very unreadable mutliple nameless booleans > function signatures. > > If this sounds interesting and gets merge the invidual drivers can follow up > with patches configuring their thresholds. > > v2: > * Christian suggested to pass in the new data by changing the function > signatures. > > v3: > * Moved ttm pool helpers into new ttm_pool_internal.h. (Christian)
Patch #3 is Acked-by: Christian König <christian.koe...@amd.com>. The rest is Reviewed-by: Christian König <christian.koe...@amd.com> Thanks, Christian. > > v1 thread: > https://lore.kernel.org/dri-devel/20250919131127.90932-1-tvrtko.ursu...@igalia.com/ > > Cc: Alex Deucher <alexander.deuc...@amd.com> > Cc: Christian König <christian.koe...@amd.com> > Cc: Danilo Krummrich <d...@kernel.org> > Cc: Dave Airlie <airl...@redhat.com> > Cc: Gerd Hoffmann <kra...@redhat.com> > Cc: Joonas Lahtinen <joonas.lahti...@linux.intel.com> > Cc: Lucas De Marchi <lucas.demar...@intel.com> > Cc: Lyude Paul <ly...@redhat.com> > Cc: Maarten Lankhorst <maarten.lankho...@linux.intel.com> > Cc: Maxime Ripard <mrip...@kernel.org> > Cc: Rodrigo Vivi <rodrigo.v...@intel.com> > Cc: Sui Jingfeng <suijingf...@loongson.cn> > Cc: Thadeu Lima de Souza Cascardo <casca...@igalia.com> > Cc: Thomas Hellström <thomas.hellst...@linux.intel.com> > Cc: Thomas Zimmermann <tzimmerm...@suse.de> > Cc: Zack Rusin <zack.ru...@broadcom.com> > > Tvrtko Ursulin (5): > drm/ttm: Add getter for some pool properties > drm/ttm: Replace multiple booleans with flags in pool init > drm/ttm: Replace multiple booleans with flags in device init > drm/ttm: Allow drivers to specify maximum beneficial TTM pool size > drm/amdgpu: Configure max beneficial TTM pool allocation order > > drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 7 +-- > drivers/gpu/drm/drm_gem_vram_helper.c | 2 +- > drivers/gpu/drm/i915/intel_region_ttm.c | 2 +- > drivers/gpu/drm/loongson/lsdc_ttm.c | 2 +- > drivers/gpu/drm/nouveau/nouveau_ttm.c | 4 +- > drivers/gpu/drm/qxl/qxl_ttm.c | 2 +- > drivers/gpu/drm/radeon/radeon_ttm.c | 4 +- > drivers/gpu/drm/ttm/tests/ttm_bo_test.c | 16 +++---- > .../gpu/drm/ttm/tests/ttm_bo_validate_test.c | 2 +- > drivers/gpu/drm/ttm/tests/ttm_device_test.c | 31 +++++-------- > drivers/gpu/drm/ttm/tests/ttm_kunit_helpers.c | 22 ++++----- > drivers/gpu/drm/ttm/tests/ttm_kunit_helpers.h | 7 +-- > drivers/gpu/drm/ttm/tests/ttm_pool_test.c | 23 +++++----- > drivers/gpu/drm/ttm/ttm_device.c | 7 ++- > drivers/gpu/drm/ttm/ttm_pool.c | 45 +++++++++++-------- > drivers/gpu/drm/ttm/ttm_pool_internal.h | 24 ++++++++++ > drivers/gpu/drm/ttm/ttm_tt.c | 10 +++-- > drivers/gpu/drm/vmwgfx/vmwgfx_drv.c | 4 +- > drivers/gpu/drm/xe/xe_device.c | 2 +- > include/drm/ttm/ttm_device.h | 2 +- > include/drm/ttm/ttm_pool.h | 13 +++--- > 21 files changed, 125 insertions(+), 106 deletions(-) > create mode 100644 drivers/gpu/drm/ttm/ttm_pool_internal.h >
