On 11/05/2022 15:14, Thomas Hellström wrote:
On Tue, 2022-05-03 at 19:13 +0000, Robert Beckett wrote:refactor internal buffer backend to allocate volatile pages via ttm pool allocator Signed-off-by: Robert Beckett <bob.beckett@xxxxxxxxxxxxx> --- drivers/gpu/drm/i915/gem/i915_gem_internal.c | 264 ++++++++--------- -- drivers/gpu/drm/i915/gem/i915_gem_internal.h | 5 - drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 12 +- drivers/gpu/drm/i915/gem/i915_gem_ttm.h | 12 +- 4 files changed, 125 insertions(+), 168 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_internal.c b/drivers/gpu/drm/i915/gem/i915_gem_internal.c index c698f95af15f..815ec9466cc0 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_internal.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_internal.c @@ -4,156 +4,119 @@ * Copyright © 2014-2016 Intel Corporation */-#include <linux/scatterlist.h>-#include <linux/slab.h> -#include <linux/swiotlb.h> - +#include <drm/ttm/ttm_bo_driver.h> +#include <drm/ttm/ttm_placement.h> +#include "drm/ttm/ttm_bo_api.h" +#include "gem/i915_gem_internal.h" +#include "gem/i915_gem_region.h" +#include "gem/i915_gem_ttm.h" #include "i915_drv.h" -#include "i915_gem.h" -#include "i915_gem_internal.h" -#include "i915_gem_object.h" -#include "i915_scatterlist.h" -#include "i915_utils.h" - -#define QUIET (__GFP_NORETRY | __GFP_NOWARN) -#define MAYFAIL (__GFP_RETRY_MAYFAIL | __GFP_NOWARN) - -static void internal_free_pages(struct sg_table *st) -{ - struct scatterlist *sg; - - for (sg = st->sgl; sg; sg = __sg_next(sg)) { - if (sg_page(sg)) - __free_pages(sg_page(sg), get_order(sg-length));- } - - sg_free_table(st); - kfree(st); -}-static int i915_gem_object_get_pages_internal(structdrm_i915_gem_object *obj) +static int i915_internal_get_pages(struct drm_i915_gem_object *obj) { - struct drm_i915_private *i915 = to_i915(obj->base.dev); - struct sg_table *st; - struct scatterlist *sg; - unsigned int sg_page_sizes; - unsigned int npages; - int max_order; - gfp_t gfp; - - max_order = MAX_ORDER; -#ifdef CONFIG_SWIOTLB - if (is_swiotlb_active(obj->base.dev->dev)) { - unsigned int max_segment; - - max_segment = swiotlb_max_segment(); - if (max_segment) { - max_segment = max_t(unsigned int, max_segment, - PAGE_SIZE) >> PAGE_SHIFT; - max_order = min(max_order, ilog2(max_segment)); - } + struct ttm_buffer_object *bo = i915_gem_to_ttm(obj); + struct ttm_operation_ctx ctx = { + .interruptible = true, + .no_wait_gpu = false, + }; + struct ttm_place place = { + .fpfn = 0, + .lpfn = 0, + .mem_type = I915_PL_SYSTEM, + .flags = 0, + }; + struct ttm_placement placement = { + .num_placement = 1, + .placement = &place, + .num_busy_placement = 0, + .busy_placement = NULL, + }; + int ret; + + ret = ttm_bo_validate(bo, &placement, &ctx); + if (ret) { + ret = i915_ttm_err_to_gem(ret); + return ret; } -#endif- gfp = GFP_KERNEL | __GFP_HIGHMEM | __GFP_RECLAIMABLE;- if (IS_I965GM(i915) || IS_I965G(i915)) { - /* 965gm cannot relocate objects above 4GiB. */ - gfp &= ~__GFP_HIGHMEM; - gfp |= __GFP_DMA32;It looks like we're losing this restriction? There is a flag to ttm_device_init() to make TTM only do __GFP_DMA32 allocations.
agreed. will fix for v2
+ if (bo->ttm && !ttm_tt_is_populated(bo->ttm)) { + ret = ttm_tt_populate(bo->bdev, bo->ttm, &ctx); + if (ret) + return ret; }-create_st:- st = kmalloc(sizeof(*st), GFP_KERNEL); - if (!st) - return -ENOMEM; + if (!i915_gem_object_has_pages(obj)) { + struct i915_refct_sgt *rsgt = + i915_ttm_resource_get_st(obj, bo->resource);- npages = obj->base.size / PAGE_SIZE;- if (sg_alloc_table(st, npages, GFP_KERNEL)) { - kfree(st); - return -ENOMEM; - } + if (IS_ERR(rsgt)) + return PTR_ERR(rsgt);- sg = st->sgl;- st->nents = 0; - sg_page_sizes = 0; - - do { - int order = min(fls(npages) - 1, max_order); - struct page *page; - - do { - page = alloc_pages(gfp | (order ? QUIET : MAYFAIL), - order); - if (page) - break; - if (!order--) - goto err; - - /* Limit subsequent allocations as well */ - max_order = order; - } while (1); - - sg_set_page(sg, page, PAGE_SIZE << order, 0); - sg_page_sizes |= PAGE_SIZE << order; - st->nents++; - - npages -= 1 << order; - if (!npages) { - sg_mark_end(sg); - break; - } - - sg = __sg_next(sg); - } while (1); - - if (i915_gem_gtt_prepare_pages(obj, st)) { - /* Failed to dma-map try again with single page sg segments */ - if (get_order(st->sgl->length)) { - internal_free_pages(st); - max_order = 0; - goto create_st; - } - goto err; + 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));}- __i915_gem_object_set_pages(obj, st, sg_page_sizes);+ GEM_BUG_ON(bo->ttm && ((obj->base.size >> PAGE_SHIFT) < bo-ttm->num_pages));+ i915_ttm_adjust_lru(obj);return 0;+}-err:- sg_set_page(sg, NULL, 0, 0); - sg_mark_end(sg); - internal_free_pages(st); +static const struct drm_i915_gem_object_ops i915_gem_object_internal_ops = { + .name = "i915_gem_object_ttm", + .flags = I915_GEM_OBJECT_IS_SHRINKABLE,- return -ENOMEM;-} + .get_pages = i915_internal_get_pages, + .put_pages = i915_ttm_put_pages, + .adjust_lru = i915_ttm_adjust_lru, + .delayed_free = i915_ttm_delayed_free, +};-static void i915_gem_object_put_pages_internal(structdrm_i915_gem_object *obj, - struct sg_table *pages) +void i915_ttm_internal_bo_destroy(struct ttm_buffer_object *bo) { - i915_gem_gtt_finish_pages(obj, pages); - internal_free_pages(pages); + struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);- obj->mm.dirty = false;+ mutex_destroy(&obj->ttm.get_io_page.lock);- __start_cpu_write(obj);-} + if (obj->ttm.created) { + /* This releases all gem object bindings to the backend. */ + __i915_gem_free_object(obj);-static const struct drm_i915_gem_object_opsi915_gem_object_internal_ops = { - .name = "i915_gem_object_internal", - .flags = I915_GEM_OBJECT_IS_SHRINKABLE, - .get_pages = i915_gem_object_get_pages_internal, - .put_pages = i915_gem_object_put_pages_internal, -}; + call_rcu(&obj->rcu, __i915_gem_free_object_rcu); + } else { + __i915_gem_object_fini(obj); + } +}+/**+ * i915_gem_object_create_internal: create an object with volatile pages + * @i915: the i915 device + * @size: the size in bytes of backing storage to allocate for the object + * + * Creates a new object that wraps some internal memory for private use. + * This object is not backed by swappable storage, and as such its contents + * are volatile and only valid whilst pinned. If the object is reaped by the + * shrinker, its pages and data will be discarded. Equally, it is not a full + * GEM object and so not valid for access from userspace. This makes it useful + * for hardware interfaces like ringbuffers (which are pinned from the time + * the request is written to the time the hardware stops accessing it), but + * not for contexts (which need to be preserved when not active for later + * reuse). Note that it is not cleared upon allocation. + */ struct drm_i915_gem_object * -__i915_gem_object_create_internal(struct drm_i915_private *i915, - const struct drm_i915_gem_object_ops *ops, - phys_addr_t size) +i915_gem_object_create_internal(struct drm_i915_private *i915, + phys_addr_t size) { static struct lock_class_key lock_class; struct drm_i915_gem_object *obj; unsigned int cache_level; + struct ttm_operation_ctx ctx = { + .interruptible = true, + .no_wait_gpu = false, + }; + int ret;GEM_BUG_ON(!size);GEM_BUG_ON(!IS_ALIGNED(size, PAGE_SIZE)); @@ -166,45 +129,34 @@ __i915_gem_object_create_internal(struct drm_i915_private *i915, return ERR_PTR(-ENOMEM);drm_gem_private_object_init(&i915->drm, &obj->base, size);- i915_gem_object_init(obj, ops, &lock_class, 0); - obj->mem_flags |= I915_BO_FLAG_STRUCT_PAGE; + i915_gem_object_init(obj, &i915_gem_object_internal_ops, &lock_class, + I915_BO_ALLOC_VOLATILE); + + 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);- /*- * Mark the object as volatile, such that the pages are marked as - * dontneed whilst they are still pinned. As soon as they are unpinned - * they are allowed to be reaped by the shrinker, and the caller is - * expected to repopulate - the contents of this object are only valid - * whilst active and pinned. - */ - i915_gem_object_set_volatile(obj); + obj->base.vma_node.driver_private = i915_gem_to_ttm(obj);+ ret = ttm_bo_init_reserved(&i915->bdev, i915_gem_to_ttm(obj),size, + ttm_bo_type_kernel, i915_ttm_sys_placement(), + 0, &ctx, NULL, NULL, i915_ttm_internal_bo_destroy); + if (ret) { + ret = i915_ttm_err_to_gem(ret); + i915_gem_object_free(obj); + return ERR_PTR(ret); + } + + obj->ttm.created = true; obj->read_domains = I915_GEM_DOMAIN_CPU; obj->write_domain = I915_GEM_DOMAIN_CPU; - + obj->mem_flags &= ~I915_BO_FLAG_IOMEM; + obj->mem_flags |= I915_BO_FLAG_STRUCT_PAGE; cache_level = HAS_LLC(i915) ? I915_CACHE_LLC : I915_CACHE_NONE; i915_gem_object_set_cache_coherency(obj, cache_level); + i915_gem_object_unlock(obj);return obj;}-/**- * i915_gem_object_create_internal: create an object with volatile pages - * @i915: the i915 device - * @size: the size in bytes of backing storage to allocate for the object - * - * Creates a new object that wraps some internal memory for private use. - * This object is not backed by swappable storage, and as such its contents - * are volatile and only valid whilst pinned. If the object is reaped by the - * shrinker, its pages and data will be discarded. Equally, it is not a full - * GEM object and so not valid for access from userspace. This makes it useful - * for hardware interfaces like ringbuffers (which are pinned from the time - * the request is written to the time the hardware stops accessing it), but - * not for contexts (which need to be preserved when not active for later - * reuse). Note that it is not cleared upon allocation. - */ -struct drm_i915_gem_object * -i915_gem_object_create_internal(struct drm_i915_private *i915, - phys_addr_t size) -{ - return __i915_gem_object_create_internal(i915, &i915_gem_object_internal_ops, size);While we don't have a TTM shmem backend ready yet for internal, Did you consider setting up just yet another region, INTEL_REGION_INTERNAL, .class = INTEL_MEMORY_SYSTEM and .instance = 1, And make it create a TTM system region on integrated, and use same region as INTEL_REGION_SMEM on dgfx. I think ttm should automatically map that to I915_PL_SYSTEM and the backwards mapping in i915_ttm_region() should never get called since the object is never moved. Then I figure it should suffice to just call __i915_gem_ttm_object_init() and we could drop a lot of code.
i briefly considered using a new fake region, but with current precedent mapping memory regions to real segemented memory areas I considered it an abuse of the semantics of memory regions.
If we are happy to have fake regions, I can revert it back to a previous design of using system region for discreet and add a fake region setup for integrated.
Would this be preferred over the current design?
/Thomas-} diff --git a/drivers/gpu/drm/i915/gem/i915_gem_internal.h b/drivers/gpu/drm/i915/gem/i915_gem_internal.h index 6664e06112fc..524e1042b20f 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_internal.h +++ b/drivers/gpu/drm/i915/gem/i915_gem_internal.h @@ -15,9 +15,4 @@ struct drm_i915_private; struct drm_i915_gem_object * i915_gem_object_create_internal(struct drm_i915_private *i915, phys_addr_t size); -struct drm_i915_gem_object * -__i915_gem_object_create_internal(struct drm_i915_private *i915, - const struct drm_i915_gem_object_ops *ops, - phys_addr_t size); - #endif /* __I915_GEM_INTERNAL_H__ */ diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c index fdb3a1c18cb6..92195ead8c11 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c @@ -83,7 +83,7 @@ struct ttm_placement *i915_ttm_sys_placement(void) return &i915_sys_placement; }-static int i915_ttm_err_to_gem(int err)+int i915_ttm_err_to_gem(int err) { /* Fastpath */ if (likely(!err)) @@ -745,8 +745,8 @@ 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) +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 = { @@ -871,8 +871,8 @@ static int i915_ttm_migrate(struct drm_i915_gem_object *obj, return __i915_ttm_migrate(obj, mr, obj->flags); }-static void i915_ttm_put_pages(struct drm_i915_gem_object *obj,- struct sg_table *st) +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() @@ -995,7 +995,7 @@ void i915_ttm_adjust_lru(struct drm_i915_gem_object *obj) * 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) +void i915_ttm_delayed_free(struct drm_i915_gem_object *obj) { GEM_BUG_ON(!obj->ttm.created);diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.hb/drivers/gpu/drm/i915/gem/i915_gem_ttm.h index 73e371aa3850..06701c46d8e2 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.h +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.h @@ -26,6 +26,7 @@ i915_gem_to_ttm(struct drm_i915_gem_object *obj) * i915 ttm gem object destructor. Internal use only. */ void i915_ttm_bo_destroy(struct ttm_buffer_object *bo); +void i915_ttm_internal_bo_destroy(struct ttm_buffer_object *bo);/*** i915_ttm_to_gem - Convert a struct ttm_buffer_object to an embedding @@ -37,8 +38,10 @@ void i915_ttm_bo_destroy(struct ttm_buffer_object *bo); static inline struct drm_i915_gem_object * i915_ttm_to_gem(struct ttm_buffer_object *bo) { - if (bo->destroy != i915_ttm_bo_destroy) + if (bo->destroy != i915_ttm_bo_destroy && + bo->destroy != i915_ttm_internal_bo_destroy) { return NULL; + }return container_of(bo, struct drm_i915_gem_object,__do_not_access); } @@ -66,6 +69,7 @@ i915_ttm_resource_get_st(struct drm_i915_gem_object *obj, struct ttm_resource *res);void i915_ttm_adjust_lru(struct drm_i915_gem_object *obj);+void i915_ttm_delayed_free(struct drm_i915_gem_object *obj);int i915_ttm_purge(struct drm_i915_gem_object *obj); @@ -92,4 +96,10 @@ static inline bool i915_ttm_cpu_maps_iomem(structttm_resource *mem) /* Once / if we support GGTT, this is also false for cached ttm_tts */ return mem->mem_type != I915_PL_SYSTEM; } + +int __i915_ttm_get_pages(struct drm_i915_gem_object *obj, + struct ttm_placement *placement); +void i915_ttm_put_pages(struct drm_i915_gem_object *obj, struct sg_table *st); +int i915_ttm_err_to_gem(int err); + #endif
