Re: [PATCH v2 04/37] drm/i915/region: support continuous allocations

Chris Wilson
2019-06-27T23:01:45Z

Quoting Matthew Auld (2019-06-27 21:56:00)
> Some objects may need to be allocated as a continuous block, thinking
> ahead the various kernel io_mapping interfaces seem to expect it.
>
> Signed-off-by: Matthew Auld <matthew.auld@intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>
> ---
> .../gpu/drm/i915/gem/i915_gem_object_types.h | 4 +
> drivers/gpu/drm/i915/intel_memory_region.c | 7 +-
> .../drm/i915/selftests/intel_memory_region.c | 152 +++++++++++++++++-
> drivers/gpu/drm/i915/selftests/mock_region.c | 3 +
> 4 files changed, 160 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
> index 87000fc24ab3..1c4b99e507c3 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
> @@ -133,6 +133,10 @@ struct drm_i915_gem_object {
> struct list_head batch_pool_link;
> I915_SELFTEST_DECLARE(struct list_head st_link);
>
> + unsigned long flags;
> +#define I915_BO_ALLOC_CONTIGUOUS (1<<0)
BIT(0)
> +#define I915_BO_ALLOC_FLAGS (I915_BO_ALLOC_CONTIGUOUS)
> +
> /*
> * Is the object to be mapped as read-only to the GPU
> * Only honoured if hardware has relevant pte bit
> diff --git a/drivers/gpu/drm/i915/intel_memory_region.c b/drivers/gpu/drm/i915/intel_memory_region.c
> index 721b47e46492..9b6a32bfa20d 100644
> --- a/drivers/gpu/drm/i915/intel_memory_region.c
> +++ b/drivers/gpu/drm/i915/intel_memory_region.c
> @@ -90,6 +90,7 @@ i915_memory_region_get_pages_buddy(struct drm_i915_gem_object *obj)
> {
> struct intel_memory_region *mem = obj->memory_region;
> resource_size_t size = obj->base.size;
> + unsigned int flags = obj->flags;

Was unsigned long.

> struct sg_table *st;
> struct scatterlist *sg;
> unsigned int sg_page_sizes;
> @@ -130,7 +131,7 @@ i915_memory_region_get_pages_buddy(struct drm_i915_gem_object *obj)
> if (!IS_ERR(block))
> break;
>
> - if (!order--) {
> + if (flags & I915_BO_ALLOC_CONTIGUOUS || !order--) {
> resource_size_t target;
> int err;
>
> @@ -219,6 +220,9 @@ i915_gem_object_create_region(struct intel_memory_region *mem,
> if (!mem)
> return ERR_PTR(-ENODEV);
>
> + if (flags & ~I915_BO_ALLOC_FLAGS)
> + return ERR_PTR(-EINVAL);
> +
> size = round_up(size, mem->min_page_size);
>
> GEM_BUG_ON(!size);
> @@ -236,6 +240,7 @@ i915_gem_object_create_region(struct intel_memory_region *mem,
>
> INIT_LIST_HEAD(&obj->blocks);
> obj->memory_region = mem;
> + obj->flags = flags;
>
> mutex_lock(&mem->obj_lock);
> list_add(&obj->region_link, &mem->objects);
> diff --git a/drivers/gpu/drm/i915/selftests/intel_memory_region.c b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
> index ece499869747..c9de8b5039e4 100644
> --- a/drivers/gpu/drm/i915/selftests/intel_memory_region.c
> +++ b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
> @@ -78,17 +78,17 @@ static int igt_mock_fill(void *arg)
>
> static void igt_mark_evictable(struct drm_i915_gem_object *obj)
> {
> - i915_gem_object_unpin_pages(obj);
> + if (i915_gem_object_has_pinned_pages(obj))
> + i915_gem_object_unpin_pages(obj);
> obj->mm.madv = I915_MADV_DONTNEED;
> list_move(&obj->region_link, &obj->memory_region->purgeable);
> }
>
> -static int igt_mock_evict(void *arg)
> +static int igt_frag_region(struct intel_memory_region *mem,
> + struct list_head *objects)
> {
> - struct intel_memory_region *mem = arg;
> struct drm_i915_gem_object *obj;
> unsigned long n_objects;
> - LIST_HEAD(objects);
> resource_size_t target;
> resource_size_t total;
> int err = 0;
> @@ -104,7 +104,7 @@ static int igt_mock_evict(void *arg)
> goto err_close_objects;
> }
>
> - list_add(&obj->st_link, &objects);
> + list_add(&obj->st_link, objects);
>
> err = i915_gem_object_pin_pages(obj);
> if (err)
> @@ -118,6 +118,39 @@ static int igt_mock_evict(void *arg)
> igt_mark_evictable(obj);
> }
>
> + return 0;
> +
> +err_close_objects:
> + close_objects(objects);
> + return err;
> +}
> +
> +static void igt_defrag_region(struct list_head *objects)
> +{
> + struct drm_i915_gem_object *obj;
> +
> + list_for_each_entry(obj, objects, st_link) {
> + if (obj->mm.madv == I915_MADV_WILLNEED)
> + igt_mark_evictable(obj);
> + }
> +}
> +
> +static int igt_mock_evict(void *arg)
> +{
> + struct intel_memory_region *mem = arg;
> + struct drm_i915_gem_object *obj;
> + LIST_HEAD(objects);
> + resource_size_t target;
> + resource_size_t total;
> + int err;
> +
> + err = igt_frag_region(mem, &objects);
> + if (err)
> + return err;
> +
> + total = resource_size(&mem->region);
> + target = mem->mm.min_size;
> +
> while (target <= total / 2) {
> obj = i915_gem_object_create_region(mem, target, 0);
> if (IS_ERR(obj)) {
> @@ -148,11 +181,120 @@ static int igt_mock_evict(void *arg)
> return err;
> }
>
> +static int igt_mock_continuous(void *arg)
> +{
> + struct intel_memory_region *mem = arg;
> + struct drm_i915_gem_object *obj;
> + LIST_HEAD(objects);
> + resource_size_t target;
> + resource_size_t total;
> + int err;
> +
> + err = igt_frag_region(mem, &objects);
> + if (err)
> + return err;
> +
> + total = resource_size(&mem->region);
> + target = total / 2;
> +
> + /*
> + * Sanity check that we can allocate all of the available fragmented
> + * space.
> + */
> + obj = i915_gem_object_create_region(mem, target, 0);
> + if (IS_ERR(obj)) {
> + err = PTR_ERR(obj);
> + goto err_close_objects;
> + }
> +
> + list_add(&obj->st_link, &objects);
> +
> + err = i915_gem_object_pin_pages(obj);
> + if (err) {
> + pr_err("failed to allocate available space\n");
> + goto err_close_objects;
> + }
> +
> + igt_mark_evictable(obj);
> +
> + /* Try the smallest possible size -- should succeed */
> + obj = i915_gem_object_create_region(mem, mem->mm.min_size,
> + I915_BO_ALLOC_CONTIGUOUS);
> + if (IS_ERR(obj)) {
> + err = PTR_ERR(obj);
> + goto err_close_objects;
> + }
> +
> + list_add(&obj->st_link, &objects);
> +
> + err = i915_gem_object_pin_pages(obj);
> + if (err) {
> + pr_err("failed to allocate smallest possible size\n");
> + goto err_close_objects;
> + }
> +
> + igt_mark_evictable(obj);
> +
> + if (obj->mm.pages->nents != 1) {
> + pr_err("[1]object spans multiple sg entries\n");
> + err = -EINVAL;
> + goto err_close_objects;
> + }
> +
> + /*
> + * Even though there is enough free space for the allocation, we
> + * shouldn't be able to allocate it, given that it is fragmented, and
> + * non-continuous.
> + */
> + obj = i915_gem_object_create_region(mem, target, I915_BO_ALLOC_CONTIGUOUS);
> + if (IS_ERR(obj)) {
> + err = PTR_ERR(obj);
> + goto err_close_objects;
> + }
> +
> + list_add(&obj->st_link, &objects);
> +
> + err = i915_gem_object_pin_pages(obj);
> + if (!err) {
> + pr_err("expected allocation to fail\n");
> + err = -EINVAL;
> + goto err_close_objects;
> + }
> +
> + igt_defrag_region(&objects);
> +
> + /* Should now succeed */
> + obj = i915_gem_object_create_region(mem, target, I915_BO_ALLOC_CONTIGUOUS);
> + if (IS_ERR(obj)) {
> + err = PTR_ERR(obj);
> + goto err_close_objects;
> + }
> +
> + list_add(&obj->st_link, &objects);
> +
> + err = i915_gem_object_pin_pages(obj);
> + if (err) {
> + pr_err("failed to allocate from defraged area\n");
> + goto err_close_objects;
> + }
> +
> + if (obj->mm.pages->nents != 1) {
> + pr_err("object spans multiple sg entries\n");
> + err = -EINVAL;
> + }
> +
> +err_close_objects:
> + close_objects(&objects);
> +
> + return err;
> +}
> +
> int intel_memory_region_mock_selftests(void)
> {
> static const struct i915_subtest tests[] = {
> SUBTEST(igt_mock_fill),
> SUBTEST(igt_mock_evict),
> + SUBTEST(igt_mock_continuous),
> };
> struct intel_memory_region *mem;
> struct drm_i915_private *i915;
> diff --git a/drivers/gpu/drm/i915/selftests/mock_region.c b/drivers/gpu/drm/i915/selftests/mock_region.c
> index 80eafdc54927..9eeda8f45f38 100644
> --- a/drivers/gpu/drm/i915/selftests/mock_region.c
> +++ b/drivers/gpu/drm/i915/selftests/mock_region.c
> @@ -20,6 +20,9 @@ mock_object_create(struct intel_memory_region *mem,
> struct drm_i915_gem_object *obj;
> unsigned int cache_level;
>
> + if (flags & I915_BO_ALLOC_CONTIGUOUS)
> + size = roundup_pow_of_two(size);
> +
> if (size > BIT(mem->mm.max_order) * mem->mm.min_size)
> return ERR_PTR(-E2BIG);
>
> --
> 2.20.1
>
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