On Fri, Aug 16, 2024 at 03:37:15PM +0200, Thomas Hellström wrote: > Following the design direction communicated here: > > https://lore.kernel.org/linux-mm/b7491378-defd-4f1c-31e2-29e4c77e2d67@xxxxxxx/T/#ma918844aa8a6efe8768fdcda0c6590d5c93850c9 > > Export the LRU walker for driver shrinker use and add a bo > shrinker helper for initial use by the xe driver. > > v8: > - Split out from another patch. > - Use a struct for bool arguments to increase readability (Matt Brost). > - Unmap user-space cpu-mappings before shrinking pages. > - Explain non-fatal error codes (Matt Brost) > > Signed-off-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx> Reviewed-by: Matthew Brost <matthew.brost@xxxxxxxxx> > --- > drivers/gpu/drm/ttm/ttm_bo_util.c | 65 +++++++++++++++++++++++++++++++ > include/drm/ttm/ttm_bo.h | 17 ++++++++ > 2 files changed, 82 insertions(+) > > diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c > index 3c07f4712d5c..3490e3347de9 100644 > --- a/drivers/gpu/drm/ttm/ttm_bo_util.c > +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c > @@ -919,3 +919,68 @@ s64 ttm_lru_walk_for_evict(struct ttm_lru_walk *walk, struct ttm_device *bdev, > > return progress; > } > +EXPORT_SYMBOL(ttm_lru_walk_for_evict); > + > +/** > + * ttm_bo_try_shrink - LRU walk helper to shrink a ttm buffer object. > + * @walk: The struct xe_ttm_lru_walk that describes the walk. > + * @bo: The buffer object. > + * @flags: Flags governing the shrinking behaviour. > + * > + * The function uses the ttm_tt_back_up functionality to back up or > + * purge a struct ttm_tt. If the bo is not in system, it's first > + * moved there, unless @flags.allow_move is false. > + * > + * Return: The number of pages shrunken or purged, or > + * negative error code on failure. > + */ > +long ttm_bo_try_shrink(struct ttm_lru_walk *walk, struct ttm_buffer_object *bo, > + const struct ttm_bo_shrink_flags flags) > +{ > + static const struct ttm_place sys_placement_flags = { > + .fpfn = 0, > + .lpfn = 0, > + .mem_type = TTM_PL_SYSTEM, > + .flags = 0, > + }; > + static struct ttm_placement sys_placement = { > + .num_placement = 1, > + .placement = &sys_placement_flags, > + }; > + struct ttm_operation_ctx *ctx = walk->ctx; > + struct ttm_tt *tt = bo->ttm; > + long lret; > + > + dma_resv_assert_held(bo->base.resv); > + > + if (!tt || !ttm_tt_is_populated(tt)) > + return 0; > + > + if (flags.allow_move && bo->resource->mem_type != TTM_PL_SYSTEM) { > + int ret = ttm_bo_validate(bo, &sys_placement, ctx); > + > + /* Consider -ENOMEM and -ENOSPC non-fatal. */ > + if (ret) { > + if (ret == -ENOMEM || ret == -ENOSPC) > + ret = -EBUSY; > + return ret; > + } > + } > + > + ttm_bo_unmap_virtual(bo); > + lret = ttm_bo_wait_ctx(bo, ctx); > + if (lret < 0) { > + if (lret == -ERESTARTSYS) > + return lret; > + return 0; > + } > + > + lret = ttm_tt_backup(bo->bdev, tt, (struct ttm_backup_flags) > + {.purge = flags.purge, > + .writeback = flags.writeback}); > + if (lret < 0 && lret != -EINTR) > + return 0; > + > + return lret; > +} > +EXPORT_SYMBOL(ttm_bo_try_shrink); > diff --git a/include/drm/ttm/ttm_bo.h b/include/drm/ttm/ttm_bo.h > index d1a732d56259..479ada85cea1 100644 > --- a/include/drm/ttm/ttm_bo.h > +++ b/include/drm/ttm/ttm_bo.h > @@ -229,6 +229,23 @@ struct ttm_lru_walk { > s64 ttm_lru_walk_for_evict(struct ttm_lru_walk *walk, struct ttm_device *bdev, > struct ttm_resource_manager *man, s64 target); > > +/** > + * struct ttm_bo_shrink_flags - flags to govern the bo shrinking behaviour > + * @purge: Purge the content rather than backing it up. > + * @writeback: Attempt to immediately write content to swap space. > + * @allow_move: Allow moving to system before shrinking. This is typically > + * not desired for zombie- or ghost objects (with zombie object meaning > + * objects with a zero gem object refcount) > + */ > +struct ttm_bo_shrink_flags { > + u32 purge : 1; > + u32 writeback : 1; > + u32 allow_move : 1; > +}; > + > +long ttm_bo_try_shrink(struct ttm_lru_walk *walk, struct ttm_buffer_object *bo, > + const struct ttm_bo_shrink_flags flags); > + > /** > * ttm_bo_get - reference a struct ttm_buffer_object > * > -- > 2.44.0 >
