// SPDX-License-Identifier: MIT /* * Copyright © 2021 Intel Corporation */ #include #include #include #include #include "i915_drv.h" #include "i915_ttm_buddy_manager.h" #include "intel_memory_region.h" #include "intel_region_ttm.h" #include "gem/i915_gem_mman.h" #include "gem/i915_gem_object.h" #include "gem/i915_gem_region.h" #include "gem/i915_gem_ttm.h" #include "gem/i915_gem_ttm_move.h" #include "gem/i915_gem_ttm_pm.h" #include "gt/intel_gpu_commands.h" #define I915_TTM_PRIO_PURGE 0 #define I915_TTM_PRIO_NO_PAGES 1 #define I915_TTM_PRIO_HAS_PAGES 2 #define I915_TTM_PRIO_NEEDS_CPU_ACCESS 3 /* * Size of struct ttm_place vector in on-stack struct ttm_placement allocs */ #define I915_TTM_MAX_PLACEMENTS INTEL_REGION_UNKNOWN /** * struct i915_ttm_tt - TTM page vector with additional private information * @ttm: The base TTM page vector. * @dev: The struct device used for dma mapping and unmapping. * @cached_rsgt: The cached scatter-gather table. * @is_shmem: Set if using shmem. * @filp: The shmem file, if using shmem backend. * * Note that DMA may be going on right up to the point where the page- * vector is unpopulated in delayed destroy. Hence keep the * scatter-gather table mapped and cached up to that point. This is * different from the cached gem object io scatter-gather table which * doesn't have an associated dma mapping. */ struct i915_ttm_tt { struct ttm_tt ttm; struct device *dev; struct i915_refct_sgt cached_rsgt; bool is_shmem; struct file *filp; }; static const struct ttm_place sys_placement_flags = { .fpfn = 0, .lpfn = 0, .mem_type = I915_PL_SYSTEM, .flags = 0, }; static struct ttm_placement i915_sys_placement = { .num_placement = 1, .placement = &sys_placement_flags, .num_busy_placement = 1, .busy_placement = &sys_placement_flags, }; /** * i915_ttm_sys_placement - Return the struct ttm_placement to be * used for an object in system memory. * * Rather than making the struct extern, use this * function. * * Return: A pointer to a static variable for sys placement. */ struct ttm_placement *i915_ttm_sys_placement(void) { return &i915_sys_placement; } static int i915_ttm_err_to_gem(int err) { /* Fastpath */ if (likely(!err)) return 0; switch (err) { case -EBUSY: /* * TTM likes to convert -EDEADLK to -EBUSY, and wants us to * restart the operation, since we don't record the contending * lock. We use -EAGAIN to restart. */ return -EAGAIN; case -ENOSPC: /* * Memory type / region is full, and we can't evict. * Except possibly system, that returns -ENOMEM; */ return -ENXIO; default: break; } return err; } static enum ttm_caching i915_ttm_select_tt_caching(const struct drm_i915_gem_object *obj) { /* * Objects only allowed in system get cached cpu-mappings, or when * evicting lmem-only buffers to system for swapping. Other objects get * WC mapping for now. Even if in system. */ if (obj->mm.n_placements <= 1) return ttm_cached; return ttm_write_combined; } static void i915_ttm_place_from_region(const struct intel_memory_region *mr, struct ttm_place *place, resource_size_t offset, resource_size_t size, unsigned int flags) { memset(place, 0, sizeof(*place)); place->mem_type = intel_region_to_ttm_type(mr); if (mr->type == INTEL_MEMORY_SYSTEM) return; if (flags & I915_BO_ALLOC_CONTIGUOUS) place->flags |= TTM_PL_FLAG_CONTIGUOUS; if (offset != I915_BO_INVALID_OFFSET) { place->fpfn = offset >> PAGE_SHIFT; place->lpfn = place->fpfn + (size >> PAGE_SHIFT); } else if (mr->io_size && mr->io_size < mr->total) { if (flags & I915_BO_ALLOC_GPU_ONLY) { place->flags |= TTM_PL_FLAG_TOPDOWN; } else { place->fpfn = 0; place->lpfn = mr->io_size >> PAGE_SHIFT; } } } static void i915_ttm_placement_from_obj(const struct drm_i915_gem_object *obj, struct ttm_place *requested, struct ttm_place *busy, struct ttm_placement *placement) { unsigned int num_allowed = obj->mm.n_placements; unsigned int flags = obj->flags; unsigned int i; placement->num_placement = 1; i915_ttm_place_from_region(num_allowed ? obj->mm.placements[0] : obj->mm.region, requested, obj->bo_offset, obj->base.size, flags); /* Cache this on object? */ placement->num_busy_placement = num_allowed; for (i = 0; i < placement->num_busy_placement; ++i) i915_ttm_place_from_region(obj->mm.placements[i], busy + i, obj->bo_offset, obj->base.size, flags); if (num_allowed == 0) { *busy = *requested; placement->num_busy_placement = 1; } placement->placement = requested; placement->busy_placement = busy; } static int i915_ttm_tt_shmem_populate(struct ttm_device *bdev, struct ttm_tt *ttm, struct ttm_operation_ctx *ctx) { struct drm_i915_private *i915 = container_of(bdev, typeof(*i915), bdev); struct intel_memory_region *mr = i915->mm.regions[INTEL_MEMORY_SYSTEM]; struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm); const unsigned int max_segment = i915_sg_segment_size(); const size_t size = (size_t)ttm->num_pages << PAGE_SHIFT; struct file *filp = i915_tt->filp; struct sgt_iter sgt_iter; struct sg_table *st; struct page *page; unsigned long i; int err; if (!filp) { struct address_space *mapping; gfp_t mask; filp = shmem_file_setup("i915-shmem-tt", size, VM_NORESERVE); if (IS_ERR(filp)) return PTR_ERR(filp); mask = GFP_HIGHUSER | __GFP_RECLAIMABLE; mapping = filp->f_mapping; mapping_set_gfp_mask(mapping, mask); GEM_BUG_ON(!(mapping_gfp_mask(mapping) & __GFP_RECLAIM)); i915_tt->filp = filp; } st = &i915_tt->cached_rsgt.table; err = shmem_sg_alloc_table(i915, st, size, mr, filp->f_mapping, max_segment); if (err) return err; err = dma_map_sgtable(i915_tt->dev, st, DMA_BIDIRECTIONAL, DMA_ATTR_SKIP_CPU_SYNC); if (err) goto err_free_st; i = 0; for_each_sgt_page(page, sgt_iter, st) ttm->pages[i++] = page; if (ttm->page_flags & TTM_TT_FLAG_SWAPPED) ttm->page_flags &= ~TTM_TT_FLAG_SWAPPED; return 0; err_free_st: shmem_sg_free_table(st, filp->f_mapping, false, false); return err; } static void i915_ttm_tt_shmem_unpopulate(struct ttm_tt *ttm) { struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm); bool backup = ttm->page_flags & TTM_TT_FLAG_SWAPPED; struct sg_table *st = &i915_tt->cached_rsgt.table; shmem_sg_free_table(st, file_inode(i915_tt->filp)->i_mapping, backup, backup); } static void i915_ttm_tt_release(struct kref *ref) { struct i915_ttm_tt *i915_tt = container_of(ref, typeof(*i915_tt), cached_rsgt.kref); struct sg_table *st = &i915_tt->cached_rsgt.table; GEM_WARN_ON(st->sgl); kfree(i915_tt); } static const struct i915_refct_sgt_ops tt_rsgt_ops = { .release = i915_ttm_tt_release }; static struct ttm_tt *i915_ttm_tt_create(struct ttm_buffer_object *bo, uint32_t page_flags) { struct drm_i915_private *i915 = container_of(bo->bdev, typeof(*i915), bdev); struct ttm_resource_manager *man = ttm_manager_type(bo->bdev, bo->resource->mem_type); struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo); unsigned long ccs_pages = 0; enum ttm_caching caching; struct i915_ttm_tt *i915_tt; int ret; if (!obj) return NULL; i915_tt = kzalloc(sizeof(*i915_tt), GFP_KERNEL); if (!i915_tt) return NULL; if (obj->flags & I915_BO_ALLOC_CPU_CLEAR && man->use_tt) page_flags |= TTM_TT_FLAG_ZERO_ALLOC; caching = i915_ttm_select_tt_caching(obj); if (i915_gem_object_is_shrinkable(obj) && caching == ttm_cached) { page_flags |= TTM_TT_FLAG_EXTERNAL | TTM_TT_FLAG_EXTERNAL_MAPPABLE; i915_tt->is_shmem = true; } if (i915_gem_object_needs_ccs_pages(obj)) ccs_pages = DIV_ROUND_UP(DIV_ROUND_UP(bo->base.size, NUM_BYTES_PER_CCS_BYTE), PAGE_SIZE); ret = ttm_tt_init(&i915_tt->ttm, bo, page_flags, caching, ccs_pages); if (ret) goto err_free; __i915_refct_sgt_init(&i915_tt->cached_rsgt, bo->base.size, &tt_rsgt_ops); i915_tt->dev = obj->base.dev->dev; return &i915_tt->ttm; err_free: kfree(i915_tt); return NULL; } static int i915_ttm_tt_populate(struct ttm_device *bdev, struct ttm_tt *ttm, struct ttm_operation_ctx *ctx) { struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm); if (i915_tt->is_shmem) return i915_ttm_tt_shmem_populate(bdev, ttm, ctx); return ttm_pool_alloc(&bdev->pool, ttm, ctx); } static void i915_ttm_tt_unpopulate(struct ttm_device *bdev, struct ttm_tt *ttm) { struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm); struct sg_table *st = &i915_tt->cached_rsgt.table; if (st->sgl) dma_unmap_sgtable(i915_tt->dev, st, DMA_BIDIRECTIONAL, 0); if (i915_tt->is_shmem) { i915_ttm_tt_shmem_unpopulate(ttm); } else { sg_free_table(st); ttm_pool_free(&bdev->pool, ttm); } } static void i915_ttm_tt_destroy(struct ttm_device *bdev, struct ttm_tt *ttm) { struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm); if (i915_tt->filp) fput(i915_tt->filp); ttm_tt_fini(ttm); i915_refct_sgt_put(&i915_tt->cached_rsgt); } static bool i915_ttm_eviction_valuable(struct ttm_buffer_object *bo, const struct ttm_place *place) { struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo); struct ttm_resource *res = bo->resource; if (!obj) return false; /* * EXTERNAL objects should never be swapped out by TTM, instead we need * to handle that ourselves. TTM will already skip such objects for us, * but we would like to avoid grabbing locks for no good reason. */ if (bo->ttm && bo->ttm->page_flags & TTM_TT_FLAG_EXTERNAL) return false; /* Will do for now. Our pinned objects are still on TTM's LRU lists */ if (!i915_gem_object_evictable(obj)) return false; switch (res->mem_type) { case I915_PL_LMEM0: { struct ttm_resource_manager *man = ttm_manager_type(bo->bdev, res->mem_type); struct i915_ttm_buddy_resource *bman_res = to_ttm_buddy_resource(res); struct drm_buddy *mm = bman_res->mm; struct drm_buddy_block *block; if (!place->fpfn && !place->lpfn) return true; GEM_BUG_ON(!place->lpfn); /* * If we just want something mappable then we can quickly check * if the current victim resource is using any of the CPU * visible portion. */ if (!place->fpfn && place->lpfn == i915_ttm_buddy_man_visible_size(man)) return bman_res->used_visible_size > 0; /* Real range allocation */ list_for_each_entry(block, &bman_res->blocks, link) { unsigned long fpfn = drm_buddy_block_offset(block) >> PAGE_SHIFT; unsigned long lpfn = fpfn + (drm_buddy_block_size(mm, block) >> PAGE_SHIFT); if (place->fpfn < lpfn && place->lpfn > fpfn) return true; } return false; } default: break; } return true; } static void i915_ttm_evict_flags(struct ttm_buffer_object *bo, struct ttm_placement *placement) { *placement = i915_sys_placement; } /** * i915_ttm_free_cached_io_rsgt - Free object cached LMEM information * @obj: The GEM object * This function frees any LMEM-related information that is cached on * the object. For example the radix tree for fast page lookup and the * cached refcounted sg-table */ void i915_ttm_free_cached_io_rsgt(struct drm_i915_gem_object *obj) { struct radix_tree_iter iter; void __rcu **slot; if (!obj->ttm.cached_io_rsgt) return; rcu_read_lock(); radix_tree_for_each_slot(slot, &obj->ttm.get_io_page.radix, &iter, 0) radix_tree_delete(&obj->ttm.get_io_page.radix, iter.index); rcu_read_unlock(); i915_refct_sgt_put(obj->ttm.cached_io_rsgt); obj->ttm.cached_io_rsgt = NULL; } /** * i915_ttm_purge - Clear an object of its memory * @obj: The object * * This function is called to clear an object of it's memory when it is * marked as not needed anymore. * * Return: 0 on success, negative error code on failure. */ int i915_ttm_purge(struct drm_i915_gem_object *obj) { struct ttm_buffer_object *bo = i915_gem_to_ttm(obj); struct i915_ttm_tt *i915_tt = container_of(bo->ttm, typeof(*i915_tt), ttm); struct ttm_operation_ctx ctx = { .interruptible = true, .no_wait_gpu = false, }; struct ttm_placement place = {}; int ret; if (obj->mm.madv == __I915_MADV_PURGED) return 0; ret = ttm_bo_validate(bo, &place, &ctx); if (ret) return ret; if (bo->ttm && i915_tt->filp) { /* * The below fput(which eventually calls shmem_truncate) might * be delayed by worker, so when directly called to purge the * pages(like by the shrinker) we should try to be more * aggressive and release the pages immediately. */ shmem_truncate_range(file_inode(i915_tt->filp), 0, (loff_t)-1); fput(fetch_and_zero(&i915_tt->filp)); } obj->write_domain = 0; obj->read_domains = 0; i915_ttm_adjust_gem_after_move(obj); i915_ttm_free_cached_io_rsgt(obj); obj->mm.madv = __I915_MADV_PURGED; return 0; } static int i915_ttm_shrink(struct drm_i915_gem_object *obj, unsigned int flags) { struct ttm_buffer_object *bo = i915_gem_to_ttm(obj); struct i915_ttm_tt *i915_tt = container_of(bo->ttm, typeof(*i915_tt), ttm); struct ttm_operation_ctx ctx = { .interruptible = true, .no_wait_gpu = flags & I915_GEM_OBJECT_SHRINK_NO_GPU_WAIT, }; struct ttm_placement place = {}; int ret; if (!bo->ttm || bo->resource->mem_type != TTM_PL_SYSTEM) return 0; GEM_BUG_ON(!i915_tt->is_shmem); if (!i915_tt->filp) return 0; ret = ttm_bo_wait_ctx(bo, &ctx); if (ret) return ret; switch (obj->mm.madv) { case I915_MADV_DONTNEED: return i915_ttm_purge(obj); case __I915_MADV_PURGED: return 0; } if (bo->ttm->page_flags & TTM_TT_FLAG_SWAPPED) return 0; bo->ttm->page_flags |= TTM_TT_FLAG_SWAPPED; ret = ttm_bo_validate(bo, &place, &ctx); if (ret) { bo->ttm->page_flags &= ~TTM_TT_FLAG_SWAPPED; return ret; } if (flags & I915_GEM_OBJECT_SHRINK_WRITEBACK) __shmem_writeback(obj->base.size, i915_tt->filp->f_mapping); return 0; } static void i915_ttm_delete_mem_notify(struct ttm_buffer_object *bo) { struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo); if (likely(obj)) { __i915_gem_object_pages_fini(obj); i915_ttm_free_cached_io_rsgt(obj); } } static struct i915_refct_sgt *i915_ttm_tt_get_st(struct ttm_tt *ttm) { struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm); struct sg_table *st; int ret; if (i915_tt->cached_rsgt.table.sgl) return i915_refct_sgt_get(&i915_tt->cached_rsgt); st = &i915_tt->cached_rsgt.table; ret = sg_alloc_table_from_pages_segment(st, ttm->pages, ttm->num_pages, 0, (unsigned long)ttm->num_pages << PAGE_SHIFT, i915_sg_segment_size(), GFP_KERNEL); if (ret) { st->sgl = NULL; return ERR_PTR(ret); } ret = dma_map_sgtable(i915_tt->dev, st, DMA_BIDIRECTIONAL, 0); if (ret) { sg_free_table(st); return ERR_PTR(ret); } return i915_refct_sgt_get(&i915_tt->cached_rsgt); } /** * i915_ttm_resource_get_st - Get a refcounted sg-table pointing to the * resource memory * @obj: The GEM object used for sg-table caching * @res: The struct ttm_resource for which an sg-table is requested. * * This function returns a refcounted sg-table representing the memory * pointed to by @res. If @res is the object's current resource it may also * cache the sg_table on the object or attempt to access an already cached * sg-table. The refcounted sg-table needs to be put when no-longer in use. * * Return: A valid pointer to a struct i915_refct_sgt or error pointer on * failure. */ struct i915_refct_sgt * i915_ttm_resource_get_st(struct drm_i915_gem_object *obj, struct ttm_resource *res) { struct ttm_buffer_object *bo = i915_gem_to_ttm(obj); u32 page_alignment; if (!i915_ttm_gtt_binds_lmem(res)) return i915_ttm_tt_get_st(bo->ttm); page_alignment = bo->page_alignment << PAGE_SHIFT; if (!page_alignment) page_alignment = obj->mm.region->min_page_size; /* * If CPU mapping differs, we need to add the ttm_tt pages to * the resulting st. Might make sense for GGTT. */ GEM_WARN_ON(!i915_ttm_cpu_maps_iomem(res)); if (bo->resource == res) { if (!obj->ttm.cached_io_rsgt) { struct i915_refct_sgt *rsgt; rsgt = intel_region_ttm_resource_to_rsgt(obj->mm.region, res, page_alignment); if (IS_ERR(rsgt)) return rsgt; obj->ttm.cached_io_rsgt = rsgt; } return i915_refct_sgt_get(obj->ttm.cached_io_rsgt); } return intel_region_ttm_resource_to_rsgt(obj->mm.region, res, page_alignment); } static int i915_ttm_truncate(struct drm_i915_gem_object *obj) { struct ttm_buffer_object *bo = i915_gem_to_ttm(obj); int err; WARN_ON_ONCE(obj->mm.madv == I915_MADV_WILLNEED); err = i915_ttm_move_notify(bo); if (err) return err; return i915_ttm_purge(obj); } static void i915_ttm_swap_notify(struct ttm_buffer_object *bo) { struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo); int ret; if (!obj) return; ret = i915_ttm_move_notify(bo); GEM_WARN_ON(ret); GEM_WARN_ON(obj->ttm.cached_io_rsgt); if (!ret && obj->mm.madv != I915_MADV_WILLNEED) i915_ttm_purge(obj); } /** * i915_ttm_resource_mappable - Return true if the ttm resource is CPU * accessible. * @res: The TTM resource to check. * * This is interesting on small-BAR systems where we may encounter lmem objects * that can't be accessed via the CPU. */ bool i915_ttm_resource_mappable(struct ttm_resource *res) { struct i915_ttm_buddy_resource *bman_res = to_ttm_buddy_resource(res); if (!i915_ttm_cpu_maps_iomem(res)) return true; return bman_res->used_visible_size == bman_res->base.num_pages; } static int i915_ttm_io_mem_reserve(struct ttm_device *bdev, struct ttm_resource *mem) { struct drm_i915_gem_object *obj = i915_ttm_to_gem(mem->bo); bool unknown_state; if (!obj) return -EINVAL; if (!kref_get_unless_zero(&obj->base.refcount)) return -EINVAL; assert_object_held(obj); unknown_state = i915_gem_object_has_unknown_state(obj); i915_gem_object_put(obj); if (unknown_state) return -EINVAL; if (!i915_ttm_cpu_maps_iomem(mem)) return 0; if (!i915_ttm_resource_mappable(mem)) return -EINVAL; mem->bus.caching = ttm_write_combined; mem->bus.is_iomem = true; return 0; } static unsigned long i915_ttm_io_mem_pfn(struct ttm_buffer_object *bo, unsigned long page_offset) { struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo); struct scatterlist *sg; unsigned long base; unsigned int ofs; GEM_BUG_ON(!obj); GEM_WARN_ON(bo->ttm); base = obj->mm.region->iomap.base - obj->mm.region->region.start; sg = __i915_gem_object_get_sg(obj, &obj->ttm.get_io_page, page_offset, &ofs, true); return ((base + sg_dma_address(sg)) >> PAGE_SHIFT) + ofs; } /* * All callbacks need to take care not to downcast a struct ttm_buffer_object * without checking its subclass, since it might be a TTM ghost object. */ static struct ttm_device_funcs i915_ttm_bo_driver = { .ttm_tt_create = i915_ttm_tt_create, .ttm_tt_populate = i915_ttm_tt_populate, .ttm_tt_unpopulate = i915_ttm_tt_unpopulate, .ttm_tt_destroy = i915_ttm_tt_destroy, .eviction_valuable = i915_ttm_eviction_valuable, .evict_flags = i915_ttm_evict_flags, .move = i915_ttm_move, .swap_notify = i915_ttm_swap_notify, .delete_mem_notify = i915_ttm_delete_mem_notify, .io_mem_reserve = i915_ttm_io_mem_reserve, .io_mem_pfn = i915_ttm_io_mem_pfn, }; /** * i915_ttm_driver - Return a pointer to the TTM device funcs * * Return: Pointer to statically allocated TTM device funcs. */ struct ttm_device_funcs *i915_ttm_driver(void) { return &i915_ttm_bo_driver; } static int __i915_ttm_get_pages(struct drm_i915_gem_object *obj, struct ttm_placement *placement) { struct ttm_buffer_object *bo = i915_gem_to_ttm(obj); struct ttm_operation_ctx ctx = { .interruptible = true, .no_wait_gpu = false, }; int real_num_busy; int ret; /* First try only the requested placement. No eviction. */ real_num_busy = fetch_and_zero(&placement->num_busy_placement); ret = ttm_bo_validate(bo, placement, &ctx); if (ret) { ret = i915_ttm_err_to_gem(ret); /* * Anything that wants to restart the operation gets to * do that. */ if (ret == -EDEADLK || ret == -EINTR || ret == -ERESTARTSYS || ret == -EAGAIN) return ret; /* * If the initial attempt fails, allow all accepted placements, * evicting if necessary. */ placement->num_busy_placement = real_num_busy; ret = ttm_bo_validate(bo, placement, &ctx); if (ret) return i915_ttm_err_to_gem(ret); } if (bo->ttm && !ttm_tt_is_populated(bo->ttm)) { ret = ttm_tt_populate(bo->bdev, bo->ttm, &ctx); if (ret) return ret; i915_ttm_adjust_domains_after_move(obj); i915_ttm_adjust_gem_after_move(obj); } if (!i915_gem_object_has_pages(obj)) { struct i915_refct_sgt *rsgt = i915_ttm_resource_get_st(obj, bo->resource); if (IS_ERR(rsgt)) return PTR_ERR(rsgt); GEM_BUG_ON(obj->mm.rsgt); obj->mm.rsgt = rsgt; __i915_gem_object_set_pages(obj, &rsgt->table, i915_sg_dma_sizes(rsgt->table.sgl)); } GEM_BUG_ON(bo->ttm && ((obj->base.size >> PAGE_SHIFT) < bo->ttm->num_pages)); i915_ttm_adjust_lru(obj); return ret; } static int i915_ttm_get_pages(struct drm_i915_gem_object *obj) { struct ttm_place requested, busy[I915_TTM_MAX_PLACEMENTS]; struct ttm_placement placement; GEM_BUG_ON(obj->mm.n_placements > I915_TTM_MAX_PLACEMENTS); /* Move to the requested placement. */ i915_ttm_placement_from_obj(obj, &requested, busy, &placement); return __i915_ttm_get_pages(obj, &placement); } /** * DOC: Migration vs eviction * * GEM migration may not be the same as TTM migration / eviction. If * the TTM core decides to evict an object it may be evicted to a * TTM memory type that is not in the object's allowable GEM regions, or * in fact theoretically to a TTM memory type that doesn't correspond to * a GEM memory region. In that case the object's GEM region is not * updated, and the data is migrated back to the GEM region at * get_pages time. TTM may however set up CPU ptes to the object even * when it is evicted. * Gem forced migration using the i915_ttm_migrate() op, is allowed even * to regions that are not in the object's list of allowable placements. */ static int __i915_ttm_migrate(struct drm_i915_gem_object *obj, struct intel_memory_region *mr, unsigned int flags) { struct ttm_place requested; struct ttm_placement placement; int ret; i915_ttm_place_from_region(mr, &requested, obj->bo_offset, obj->base.size, flags); placement.num_placement = 1; placement.num_busy_placement = 1; placement.placement = &requested; placement.busy_placement = &requested; ret = __i915_ttm_get_pages(obj, &placement); if (ret) return ret; /* * Reinitialize the region bindings. This is primarily * required for objects where the new region is not in * its allowable placements. */ if (obj->mm.region != mr) { i915_gem_object_release_memory_region(obj); i915_gem_object_init_memory_region(obj, mr); } return 0; } static int i915_ttm_migrate(struct drm_i915_gem_object *obj, struct intel_memory_region *mr) { return __i915_ttm_migrate(obj, mr, obj->flags); } static void i915_ttm_put_pages(struct drm_i915_gem_object *obj, struct sg_table *st) { /* * We're currently not called from a shrinker, so put_pages() * typically means the object is about to destroyed, or called * from move_notify(). So just avoid doing much for now. * If the object is not destroyed next, The TTM eviction logic * and shrinkers will move it out if needed. */ if (obj->mm.rsgt) i915_refct_sgt_put(fetch_and_zero(&obj->mm.rsgt)); } /** * i915_ttm_adjust_lru - Adjust an object's position on relevant LRU lists. * @obj: The object */ void i915_ttm_adjust_lru(struct drm_i915_gem_object *obj) { struct ttm_buffer_object *bo = i915_gem_to_ttm(obj); struct i915_ttm_tt *i915_tt = container_of(bo->ttm, typeof(*i915_tt), ttm); bool shrinkable = bo->ttm && i915_tt->filp && ttm_tt_is_populated(bo->ttm); /* * Don't manipulate the TTM LRUs while in TTM bo destruction. * We're called through i915_ttm_delete_mem_notify(). */ if (!kref_read(&bo->kref)) return; /* * We skip managing the shrinker LRU in set_pages() and just manage * everything here. This does at least solve the issue with having * temporary shmem mappings(like with evicted lmem) not being visible to * the shrinker. Only our shmem objects are shrinkable, everything else * we keep as unshrinkable. * * To make sure everything plays nice we keep an extra shrink pin in TTM * if the underlying pages are not currently shrinkable. Once we release * our pin, like when the pages are moved to shmem, the pages will then * be added to the shrinker LRU, assuming the caller isn't also holding * a pin. * * TODO: consider maybe also bumping the shrinker list here when we have * already unpinned it, which should give us something more like an LRU. * * TODO: There is a small window of opportunity for this function to * get called from eviction after we've dropped the last GEM refcount, * but before the TTM deleted flag is set on the object. Avoid * adjusting the shrinker list in such cases, since the object is * not available to the shrinker anyway due to its zero refcount. * To fix this properly we should move to a TTM shrinker LRU list for * these objects. */ if (kref_get_unless_zero(&obj->base.refcount)) { if (shrinkable != obj->mm.ttm_shrinkable) { if (shrinkable) { if (obj->mm.madv == I915_MADV_WILLNEED) __i915_gem_object_make_shrinkable(obj); else __i915_gem_object_make_purgeable(obj); } else { i915_gem_object_make_unshrinkable(obj); } obj->mm.ttm_shrinkable = shrinkable; } i915_gem_object_put(obj); } /* * Put on the correct LRU list depending on the MADV status */ spin_lock(&bo->bdev->lru_lock); if (shrinkable) { /* Try to keep shmem_tt from being considered for shrinking. */ bo->priority = TTM_MAX_BO_PRIORITY - 1; } else if (obj->mm.madv != I915_MADV_WILLNEED) { bo->priority = I915_TTM_PRIO_PURGE; } else if (!i915_gem_object_has_pages(obj)) { bo->priority = I915_TTM_PRIO_NO_PAGES; } else { struct ttm_resource_manager *man = ttm_manager_type(bo->bdev, bo->resource->mem_type); /* * If we need to place an LMEM resource which doesn't need CPU * access then we should try not to victimize mappable objects * first, since we likely end up stealing more of the mappable * portion. And likewise when we try to find space for a mappble * object, we know not to ever victimize objects that don't * occupy any mappable pages. */ if (i915_ttm_cpu_maps_iomem(bo->resource) && i915_ttm_buddy_man_visible_size(man) < man->size && !(obj->flags & I915_BO_ALLOC_GPU_ONLY)) bo->priority = I915_TTM_PRIO_NEEDS_CPU_ACCESS; else bo->priority = I915_TTM_PRIO_HAS_PAGES; } ttm_bo_move_to_lru_tail(bo); spin_unlock(&bo->bdev->lru_lock); } /* * TTM-backed gem object destruction requires some clarification. * Basically we have two possibilities here. We can either rely on the * i915 delayed destruction and put the TTM object when the object * is idle. This would be detected by TTM which would bypass the * TTM delayed destroy handling. The other approach is to put the TTM * object early and rely on the TTM destroyed handling, and then free * the leftover parts of the GEM object once TTM's destroyed list handling is * complete. For now, we rely on the latter for two reasons: * a) TTM can evict an object even when it's on the delayed destroy list, * which in theory allows for complete eviction. * b) There is work going on in TTM to allow freeing an object even when * it's not idle, and using the TTM destroyed list handling could help us * benefit from that. */ static void i915_ttm_delayed_free(struct drm_i915_gem_object *obj) { GEM_BUG_ON(!obj->ttm.created); ttm_bo_put(i915_gem_to_ttm(obj)); } static vm_fault_t vm_fault_ttm(struct vm_fault *vmf) { struct vm_area_struct *area = vmf->vma; struct ttm_buffer_object *bo = area->vm_private_data; struct drm_device *dev = bo->base.dev; struct drm_i915_gem_object *obj; vm_fault_t ret; int idx; obj = i915_ttm_to_gem(bo); if (!obj) return VM_FAULT_SIGBUS; /* Sanity check that we allow writing into this object */ if (unlikely(i915_gem_object_is_readonly(obj) && area->vm_flags & VM_WRITE)) return VM_FAULT_SIGBUS; ret = ttm_bo_vm_reserve(bo, vmf); if (ret) return ret; if (obj->mm.madv != I915_MADV_WILLNEED) { dma_resv_unlock(bo->base.resv); return VM_FAULT_SIGBUS; } if (!i915_ttm_resource_mappable(bo->resource)) { int err = -ENODEV; int i; for (i = 0; i < obj->mm.n_placements; i++) { struct intel_memory_region *mr = obj->mm.placements[i]; unsigned int flags; if (!mr->io_size && mr->type != INTEL_MEMORY_SYSTEM) continue; flags = obj->flags; flags &= ~I915_BO_ALLOC_GPU_ONLY; err = __i915_ttm_migrate(obj, mr, flags); if (!err) break; } if (err) { drm_dbg(dev, "Unable to make resource CPU accessible\n"); dma_resv_unlock(bo->base.resv); return VM_FAULT_SIGBUS; } } if (drm_dev_enter(dev, &idx)) { ret = ttm_bo_vm_fault_reserved(vmf, vmf->vma->vm_page_prot, TTM_BO_VM_NUM_PREFAULT); drm_dev_exit(idx); } else { ret = ttm_bo_vm_dummy_page(vmf, vmf->vma->vm_page_prot); } if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) return ret; i915_ttm_adjust_lru(obj); dma_resv_unlock(bo->base.resv); return ret; } static int vm_access_ttm(struct vm_area_struct *area, unsigned long addr, void *buf, int len, int write) { struct drm_i915_gem_object *obj = i915_ttm_to_gem(area->vm_private_data); if (i915_gem_object_is_readonly(obj) && write) return -EACCES; return ttm_bo_vm_access(area, addr, buf, len, write); } static void ttm_vm_open(struct vm_area_struct *vma) { struct drm_i915_gem_object *obj = i915_ttm_to_gem(vma->vm_private_data); GEM_BUG_ON(!obj); i915_gem_object_get(obj); } static void ttm_vm_close(struct vm_area_struct *vma) { struct drm_i915_gem_object *obj = i915_ttm_to_gem(vma->vm_private_data); GEM_BUG_ON(!obj); i915_gem_object_put(obj); } static const struct vm_operations_struct vm_ops_ttm = { .fault = vm_fault_ttm, .access = vm_access_ttm, .open = ttm_vm_open, .close = ttm_vm_close, }; static u64 i915_ttm_mmap_offset(struct drm_i915_gem_object *obj) { /* The ttm_bo must be allocated with I915_BO_ALLOC_USER */ GEM_BUG_ON(!drm_mm_node_allocated(&obj->base.vma_node.vm_node)); return drm_vma_node_offset_addr(&obj->base.vma_node); } static void i915_ttm_unmap_virtual(struct drm_i915_gem_object *obj) { ttm_bo_unmap_virtual(i915_gem_to_ttm(obj)); } static const struct drm_i915_gem_object_ops i915_gem_ttm_obj_ops = { .name = "i915_gem_object_ttm", .flags = I915_GEM_OBJECT_IS_SHRINKABLE | I915_GEM_OBJECT_SELF_MANAGED_SHRINK_LIST, .get_pages = i915_ttm_get_pages, .put_pages = i915_ttm_put_pages, .truncate = i915_ttm_truncate, .shrink = i915_ttm_shrink, .adjust_lru = i915_ttm_adjust_lru, .delayed_free = i915_ttm_delayed_free, .migrate = i915_ttm_migrate, .mmap_offset = i915_ttm_mmap_offset, .unmap_virtual = i915_ttm_unmap_virtual, .mmap_ops = &vm_ops_ttm, }; void i915_ttm_bo_destroy(struct ttm_buffer_object *bo) { struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo); i915_gem_object_release_memory_region(obj); mutex_destroy(&obj->ttm.get_io_page.lock); if (obj->ttm.created) { /* * We freely manage the shrinker LRU outide of the mm.pages life * cycle. As a result when destroying the object we should be * extra paranoid and ensure we remove it from the LRU, before * we free the object. * * Touching the ttm_shrinkable outside of the object lock here * should be safe now that the last GEM object ref was dropped. */ if (obj->mm.ttm_shrinkable) i915_gem_object_make_unshrinkable(obj); i915_ttm_backup_free(obj); /* This releases all gem object bindings to the backend. */ __i915_gem_free_object(obj); call_rcu(&obj->rcu, __i915_gem_free_object_rcu); } else { __i915_gem_object_fini(obj); } } /** * __i915_gem_ttm_object_init - Initialize a ttm-backed i915 gem object * @mem: The initial memory region for the object. * @obj: The gem object. * @size: Object size in bytes. * @flags: gem object flags. * * Return: 0 on success, negative error code on failure. */ int __i915_gem_ttm_object_init(struct intel_memory_region *mem, struct drm_i915_gem_object *obj, resource_size_t offset, resource_size_t size, resource_size_t page_size, unsigned int flags) { static struct lock_class_key lock_class; struct drm_i915_private *i915 = mem->i915; struct ttm_operation_ctx ctx = { .interruptible = true, .no_wait_gpu = false, }; enum ttm_bo_type bo_type; int ret; drm_gem_private_object_init(&i915->drm, &obj->base, size); i915_gem_object_init(obj, &i915_gem_ttm_obj_ops, &lock_class, flags); obj->bo_offset = offset; /* Don't put on a region list until we're either locked or fully initialized. */ obj->mm.region = mem; INIT_LIST_HEAD(&obj->mm.region_link); INIT_RADIX_TREE(&obj->ttm.get_io_page.radix, GFP_KERNEL | __GFP_NOWARN); mutex_init(&obj->ttm.get_io_page.lock); bo_type = (obj->flags & I915_BO_ALLOC_USER) ? ttm_bo_type_device : ttm_bo_type_kernel; obj->base.vma_node.driver_private = i915_gem_to_ttm(obj); /* Forcing the page size is kernel internal only */ GEM_BUG_ON(page_size && obj->mm.n_placements); /* * Keep an extra shrink pin to prevent the object from being made * shrinkable too early. If the ttm_tt is ever allocated in shmem, we * drop the pin. The TTM backend manages the shrinker LRU itself, * outside of the normal mm.pages life cycle. */ i915_gem_object_make_unshrinkable(obj); /* * If this function fails, it will call the destructor, but * our caller still owns the object. So no freeing in the * destructor until obj->ttm.created is true. * Similarly, in delayed_destroy, we can't call ttm_bo_put() * until successful initialization. */ ret = ttm_bo_init_reserved(&i915->bdev, i915_gem_to_ttm(obj), size, bo_type, &i915_sys_placement, page_size >> PAGE_SHIFT, &ctx, NULL, NULL, i915_ttm_bo_destroy); if (ret) return i915_ttm_err_to_gem(ret); obj->ttm.created = true; i915_gem_object_release_memory_region(obj); i915_gem_object_init_memory_region(obj, mem); i915_ttm_adjust_domains_after_move(obj); i915_ttm_adjust_gem_after_move(obj); i915_gem_object_unlock(obj); return 0; } static const struct intel_memory_region_ops ttm_system_region_ops = { .init_object = __i915_gem_ttm_object_init, .release = intel_region_ttm_fini, }; struct intel_memory_region * i915_gem_ttm_system_setup(struct drm_i915_private *i915, u16 type, u16 instance) { struct intel_memory_region *mr; mr = intel_memory_region_create(i915, 0, totalram_pages() << PAGE_SHIFT, PAGE_SIZE, 0, 0, type, instance, &ttm_system_region_ops); if (IS_ERR(mr)) return mr; intel_memory_region_set_name(mr, "system-ttm"); return mr; }