Re: [PATCH 10/20] drm/i915/selftests: mock test io_size

["Thomas Hellström" <thomas.hellstrom@linux.intel.com>]

On 1/26/22 16:21, Matthew Auld wrote:
> Check that mappable vs non-mappable matches our expectations.
>
> Signed-off-by: Matthew Auld <matthew.auld@intel.com>
> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>

Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>


> ---
>   .../drm/i915/selftests/intel_memory_region.c  | 143 ++++++++++++++++++
>   1 file changed, 143 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/selftests/intel_memory_region.c b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
> index 247f65f02bbf..04ae29779206 100644
> --- a/drivers/gpu/drm/i915/selftests/intel_memory_region.c
> +++ b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
> @@ -17,6 +17,7 @@
>   #include "gem/i915_gem_context.h"
>   #include "gem/i915_gem_lmem.h"
>   #include "gem/i915_gem_region.h"
> +#include "gem/i915_gem_ttm.h"
>   #include "gem/selftests/igt_gem_utils.h"
>   #include "gem/selftests/mock_context.h"
>   #include "gt/intel_engine_pm.h"
> @@ -512,6 +513,147 @@ static int igt_mock_max_segment(void *arg)
>   	return err;
>   }
>   
> +static u64 igt_object_mappable_total(struct drm_i915_gem_object *obj)
> +{
> +	struct intel_memory_region *mr = obj->mm.region;
> +	struct i915_ttm_buddy_resource *bman_res =
> +		to_ttm_buddy_resource(obj->mm.res);
> +	struct drm_buddy *mm = bman_res->mm;
> +	struct drm_buddy_block *block;
> +	u64 total;
> +
> +	total = 0;
> +	list_for_each_entry(block, &bman_res->blocks, link) {
> +		u64 start = drm_buddy_block_offset(block);
> +		u64 end = start + drm_buddy_block_size(mm, block);
> +
> +		if (start < mr->io_size)
> +			total += min_t(u64, end, mr->io_size) - start;
> +	}
> +
> +	return total;
> +}
> +
> +static int igt_mock_io_size(void *arg)
> +{
> +	struct intel_memory_region *mr = arg;
> +	struct drm_i915_private *i915 = mr->i915;
> +	struct drm_i915_gem_object *obj;
> +	u64 mappable_theft_total;
> +	u64 io_size;
> +	u64 total;
> +	u64 ps;
> +	u64 rem;
> +	u64 size;
> +	I915_RND_STATE(prng);
> +	LIST_HEAD(objects);
> +	int err = 0;
> +
> +	ps = SZ_4K;
> +	if (i915_prandom_u64_state(&prng) & 1)
> +		ps = SZ_64K; /* For something like DG2 */
> +
> +	div64_u64_rem(i915_prandom_u64_state(&prng), SZ_8G, &total);
> +	total = round_down(total, ps);
> +	total = max_t(u64, total, SZ_1G);
> +
> +	div64_u64_rem(i915_prandom_u64_state(&prng), total - ps, &io_size);
> +	io_size = round_down(io_size, ps);
> +	io_size = max_t(u64, io_size, SZ_256M); /* 256M seems to be the common lower limit */
> +
> +	pr_info("%s with ps=%llx, io_size=%llx, total=%llx\n",
> +		__func__, ps, io_size, total);
> +
> +	mr = mock_region_create(i915, 0, total, ps, 0, io_size);
> +	if (IS_ERR(mr)) {
> +		err = PTR_ERR(mr);
> +		goto out_err;
> +	}
> +
> +	mappable_theft_total = 0;
> +	rem = total - io_size;
> +	do {
> +		div64_u64_rem(i915_prandom_u64_state(&prng), rem, &size);
> +		size = round_down(size, ps);
> +		size = max(size, ps);
> +
> +		obj = igt_object_create(mr, &objects, size,
> +					I915_BO_ALLOC_TOPDOWN);
> +		if (IS_ERR(obj)) {
> +			pr_err("%s TOPDOWN failed with rem=%llx, size=%llx\n",
> +			       __func__, rem, size);
> +			err = PTR_ERR(obj);
> +			goto out_close;
> +		}
> +
> +		mappable_theft_total += igt_object_mappable_total(obj);
> +		rem -= size;
> +	} while (rem);
> +
> +	pr_info("%s mappable theft=(%lluMiB/%lluMiB), total=%lluMiB\n",
> +		__func__,
> +		(u64)mappable_theft_total >> 20,
> +		(u64)io_size >> 20,
> +		(u64)total >> 20);
> +
> +	/*
> +	 * Even if we allocate all of the non-mappable portion, we should still
> +	 * be able to dip into the mappable portion.
> +	 */
> +	obj = igt_object_create(mr, &objects, io_size,
> +				I915_BO_ALLOC_TOPDOWN);
> +	if (IS_ERR(obj)) {
> +		pr_err("%s allocation unexpectedly failed\n", __func__);
> +		err = PTR_ERR(obj);
> +		goto out_close;
> +	}
> +
> +	close_objects(mr, &objects);
> +
> +	rem = io_size;
> +	do {
> +		div64_u64_rem(i915_prandom_u64_state(&prng), rem, &size);
> +		size = round_down(size, ps);
> +		size = max(size, ps);
> +
> +		obj = igt_object_create(mr, &objects, size, 0);
> +		if (IS_ERR(obj)) {
> +			pr_err("%s MAPPABLE failed with rem=%llx, size=%llx\n",
> +			       __func__, rem, size);
> +			err = PTR_ERR(obj);
> +			goto out_close;
> +		}
> +
> +		if (igt_object_mappable_total(obj) != size) {
> +			pr_err("%s allocation is not mappable(size=%llx)\n",
> +			       __func__, size);
> +			err = -EINVAL;
> +			goto out_close;
> +		}
> +		rem -= size;
> +	} while (rem);
> +
> +	/*
> +	 * We assume CPU access is required by default, which should result in a
> +	 * failure here, even though the non-mappable portion is free.
> +	 */
> +	obj = igt_object_create(mr, &objects, ps, 0);
> +	if (!IS_ERR(obj)) {
> +		pr_err("%s allocation unexpectedly succeeded\n", __func__);
> +		err = -EINVAL;
> +		goto out_close;
> +	}
> +
> +out_close:
> +	close_objects(mr, &objects);
> +	intel_memory_region_destroy(mr);
> +out_err:
> +	if (err == -ENOMEM)
> +		err = 0;
> +
> +	return err;
> +}
> +
>   static int igt_gpu_write_dw(struct intel_context *ce,
>   			    struct i915_vma *vma,
>   			    u32 dword,
> @@ -1179,6 +1321,7 @@ int intel_memory_region_mock_selftests(void)
>   		SUBTEST(igt_mock_contiguous),
>   		SUBTEST(igt_mock_splintered_region),
>   		SUBTEST(igt_mock_max_segment),
> +		SUBTEST(igt_mock_io_size),
>   	};
>   	struct intel_memory_region *mem;
>   	struct drm_i915_private *i915;