drm/i915/selftests: prefer random sizes for the huge-GTT-page smoke tests

Ditch the dubious static list of sizes to enumerate, in favour of
choosing a random size within the limits of each backing store. With
repeated CI runs this should give us a wider range of object sizes, and
in turn more page-size combinations, while using less machine time.
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191025153728.23689-6-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/gem/selftests/huge_pages.c

@@ -1317,204 +1317,137 @@ static int igt_ppgtt_exhaust_huge(void *arg)
 	return err;
 }
 
-static int igt_ppgtt_internal_huge(void *arg)
-{
-	struct i915_gem_context *ctx = arg;
-	struct drm_i915_private *i915 = ctx->i915;
-	struct drm_i915_gem_object *obj;
-	static const unsigned int sizes[] = {
-		SZ_64K,
-		SZ_128K,
-		SZ_256K,
-		SZ_512K,
-		SZ_1M,
-		SZ_2M,
-	};
-	int i;
-	int err;
-
-	/*
-	 * Sanity check that the HW uses huge pages correctly through internal
-	 * -- ensure that our writes land in the right place.
-	 */
-
-	for (i = 0; i < ARRAY_SIZE(sizes); ++i) {
-		unsigned int size = sizes[i];
-
-		obj = i915_gem_object_create_internal(i915, size);
-		if (IS_ERR(obj))
-			return PTR_ERR(obj);
-
-		err = i915_gem_object_pin_pages(obj);
-		if (err)
-			goto out_put;
-
-		if (obj->mm.page_sizes.phys < I915_GTT_PAGE_SIZE_64K) {
-			pr_info("internal unable to allocate huge-page(s) with size=%u\n",
-				size);
-			goto out_unpin;
-		}
-
-		err = igt_write_huge(ctx, obj);
-		if (err) {
-			pr_err("internal write-huge failed with size=%u\n",
-			       size);
-			goto out_unpin;
-		}
-
-		i915_gem_object_unpin_pages(obj);
-		__i915_gem_object_put_pages(obj, I915_MM_NORMAL);
-		i915_gem_object_put(obj);
-	}
-
-	return 0;
-
-out_unpin:
-	i915_gem_object_unpin_pages(obj);
-out_put:
-	i915_gem_object_put(obj);
-
-	return err;
-}
+typedef struct drm_i915_gem_object *
+(*igt_create_fn)(struct drm_i915_private *i915, u32 size, u32 flags);
 
 static inline bool igt_can_allocate_thp(struct drm_i915_private *i915)
 {
 	return i915->mm.gemfs && has_transparent_hugepage();
 }
 
-static int igt_ppgtt_gemfs_huge(void *arg)
+static struct drm_i915_gem_object *
+igt_create_shmem(struct drm_i915_private *i915, u32 size, u32 flags)
 {
-	struct i915_gem_context *ctx = arg;
-	struct drm_i915_private *i915 = ctx->i915;
-	struct drm_i915_gem_object *obj;
-	static const unsigned int sizes[] = {
-		SZ_2M,
-		SZ_4M,
-		SZ_8M,
-		SZ_16M,
-		SZ_32M,
-	};
-	int i;
-	int err;
-
-	/*
-	 * Sanity check that the HW uses huge pages correctly through gemfs --
-	 * ensure that our writes land in the right place.
-	 */
-
 	if (!igt_can_allocate_thp(i915)) {
-		pr_info("missing THP support, skipping\n");
-		return 0;
+		pr_info("%s missing THP support, skipping\n", __func__);
+		return ERR_PTR(-ENODEV);
 	}
 
-	for (i = 0; i < ARRAY_SIZE(sizes); ++i) {
-		unsigned int size = sizes[i];
-
-		obj = i915_gem_object_create_shmem(i915, size);
-		if (IS_ERR(obj))
-			return PTR_ERR(obj);
-
-		err = i915_gem_object_pin_pages(obj);
-		if (err)
-			goto out_put;
+	return i915_gem_object_create_shmem(i915, size);
+}
 
-		if (obj->mm.page_sizes.phys < I915_GTT_PAGE_SIZE_2M) {
-			pr_info("finishing test early, gemfs unable to allocate huge-page(s) with size=%u\n",
-				size);
-			goto out_unpin;
-		}
+static struct drm_i915_gem_object *
+igt_create_internal(struct drm_i915_private *i915, u32 size, u32 flags)
+{
+	return i915_gem_object_create_internal(i915, size);
+}
 
-		err = igt_write_huge(ctx, obj);
-		if (err) {
-			pr_err("gemfs write-huge failed with size=%u\n",
-			       size);
-			goto out_unpin;
-		}
+static struct drm_i915_gem_object *
+igt_create_local(struct drm_i915_private *i915, u32 size, u32 flags)
+{
+	return i915_gem_object_create_lmem(i915, size, flags);
+}
 
-		i915_gem_object_unpin_pages(obj);
-		__i915_gem_object_put_pages(obj, I915_MM_NORMAL);
-		i915_gem_object_put(obj);
-	}
+static u32 igt_random_size(struct rnd_state *prng,
+			   u32 min_page_size,
+			   u32 max_page_size)
+{
+	u64 mask;
+	u32 size;
 
-	return 0;
+	GEM_BUG_ON(!is_power_of_2(min_page_size));
+	GEM_BUG_ON(!is_power_of_2(max_page_size));
+	GEM_BUG_ON(min_page_size < PAGE_SIZE);
+	GEM_BUG_ON(min_page_size > max_page_size);
 
-out_unpin:
-	i915_gem_object_unpin_pages(obj);
-out_put:
-	i915_gem_object_put(obj);
+	mask = ((max_page_size << 1ULL) - 1) & PAGE_MASK;
+	size = prandom_u32_state(prng) & mask;
+	if (size < min_page_size)
+		size |= min_page_size;
 
-	return err;
+	return size;
 }
 
-static int igt_ppgtt_lmem_huge(void *arg)
+static int igt_ppgtt_smoke_huge(void *arg)
 {
 	struct i915_gem_context *ctx = arg;
 	struct drm_i915_private *i915 = ctx->i915;
 	struct drm_i915_gem_object *obj;
-	static const unsigned int sizes[] = {
-		SZ_64K,
-		SZ_512K,
-		SZ_1M,
-		SZ_2M,
+	I915_RND_STATE(prng);
+	struct {
+		igt_create_fn fn;
+		u32 min;
+		u32 max;
+	} backends[] = {
+		{ igt_create_internal, SZ_64K, SZ_2M,  },
+		{ igt_create_shmem,    SZ_64K, SZ_32M, },
+		{ igt_create_local,    SZ_64K, SZ_1G,  },
 	};
-	int i;
 	int err;
-
-	if (!HAS_LMEM(i915)) {
-		pr_info("device lacks LMEM support, skipping\n");
-		return 0;
-	}
+	int i;
 
 	/*
-	 * Sanity check that the HW uses huge pages correctly through LMEM
-	 * -- ensure that our writes land in the right place.
+	 * Sanity check that the HW uses huge pages correctly through our
+	 * various backends -- ensure that our writes land in the right place.
 	 */
 
-	for (i = 0; i < ARRAY_SIZE(sizes); ++i) {
-		unsigned int size = sizes[i];
+	for (i = 0; i < ARRAY_SIZE(backends); ++i) {
+		u32 min = backends[i].min;
+		u32 max = backends[i].max;
+		u32 size = max;
+try_again:
+		size = igt_random_size(&prng, min, rounddown_pow_of_two(size));
 
-		obj = i915_gem_object_create_lmem(i915, size,
-						  I915_BO_ALLOC_CONTIGUOUS);
+		obj = backends[i].fn(i915, size, 0);
 		if (IS_ERR(obj)) {
 			err = PTR_ERR(obj);
 			if (err == -E2BIG) {
-				pr_info("object too big for region!\n");
-				return 0;
+				size >>= 1;
+				goto try_again;
+			} else if (err == -ENODEV) {
+				err = 0;
+				continue;
 			}
 
 			return err;
 		}
 
 		err = i915_gem_object_pin_pages(obj);
-		if (err)
+		if (err) {
+			if (err == -ENXIO) {
+				i915_gem_object_put(obj);
+				size >>= 1;
+				goto try_again;
+			}
 			goto out_put;
+		}
 
-		if (obj->mm.page_sizes.phys < I915_GTT_PAGE_SIZE_64K) {
-			pr_info("LMEM unable to allocate huge-page(s) with size=%u\n",
-				size);
+		if (obj->mm.page_sizes.phys < min) {
+			pr_info("%s unable to allocate huge-page(s) with size=%u, i=%d\n",
+				__func__, size, i);
+			err = -ENOMEM;
 			goto out_unpin;
 		}
 
 		err = igt_write_huge(ctx, obj);
 		if (err) {
-			pr_err("LMEM write-huge failed with size=%u\n", size);
-			goto out_unpin;
+			pr_err("%s write-huge failed with size=%u, i=%d\n",
+			       __func__, size, i);
 		}
-
+out_unpin:
 		i915_gem_object_unpin_pages(obj);
 		__i915_gem_object_put_pages(obj, I915_MM_NORMAL);
+out_put:
 		i915_gem_object_put(obj);
-	}
 
-	return 0;
+		if (err == -ENOMEM || err == -ENXIO)
+			err = 0;
 
-out_unpin:
-	i915_gem_object_unpin_pages(obj);
-out_put:
-	i915_gem_object_put(obj);
+		if (err)
+			break;
 
-	if (err == -ENOMEM)
-		err = 0;
+		cond_resched();
+	}
 
 	return err;
 }
@@ -1878,9 +1811,7 @@ int i915_gem_huge_page_live_selftests(struct drm_i915_private *i915)
 		SUBTEST(igt_ppgtt_pin_update),
 		SUBTEST(igt_tmpfs_fallback),
 		SUBTEST(igt_ppgtt_exhaust_huge),
-		SUBTEST(igt_ppgtt_gemfs_huge),
-		SUBTEST(igt_ppgtt_internal_huge),
-		SUBTEST(igt_ppgtt_lmem_huge),
+		SUBTEST(igt_ppgtt_smoke_huge),
 	};
 	struct drm_file *file;
 	struct i915_gem_context *ctx;