[PATCH v2 10/38] drm/i915: Create a fake object for testing huge allocations

[Chris Wilson <chris@chris-wilson.co.uk>]

We would like to be able to exercise huge allocations even on memory
constrained devices. To do this we create an object that allocates only
a few pages and remaps them across its whole range - each page is reused
multiple times. We can therefore pretend we are rendering into a much
larger object.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem.c                  |   1 +
 drivers/gpu/drm/i915/i915_gem_object.h           |  20 ++--
 drivers/gpu/drm/i915/selftests/huge_gem_object.c | 135 +++++++++++++++++++++++
 drivers/gpu/drm/i915/selftests/huge_gem_object.h |  33 ++++++
 4 files changed, 181 insertions(+), 8 deletions(-)
 create mode 100644 drivers/gpu/drm/i915/selftests/huge_gem_object.c
 create mode 100644 drivers/gpu/drm/i915/selftests/huge_gem_object.h

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index d93abed05631..a03eeb6d85bf 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4942,4 +4942,5 @@ i915_gem_object_get_dma_address(struct drm_i915_gem_object *obj,
 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
 #include "selftests/scatterlist.c"
 #include "selftests/mock_gem_device.c"
+#include "selftests/huge_gem_object.c"
 #endif
diff --git a/drivers/gpu/drm/i915/i915_gem_object.h b/drivers/gpu/drm/i915/i915_gem_object.h
index 290eaa7fc9eb..4114cc8a0b9b 100644
--- a/drivers/gpu/drm/i915/i915_gem_object.h
+++ b/drivers/gpu/drm/i915/i915_gem_object.h
@@ -167,14 +167,18 @@ struct drm_i915_gem_object {
 	/** Record of address bit 17 of each page at last unbind. */
 	unsigned long *bit_17;
 
-	struct i915_gem_userptr {
-		uintptr_t ptr;
-		unsigned read_only :1;
-
-		struct i915_mm_struct *mm;
-		struct i915_mmu_object *mmu_object;
-		struct work_struct *work;
-	} userptr;
+	union {
+		struct i915_gem_userptr {
+			uintptr_t ptr;
+			unsigned read_only :1;
+
+			struct i915_mm_struct *mm;
+			struct i915_mmu_object *mmu_object;
+			struct work_struct *work;
+		} userptr;
+
+		unsigned long scratch;
+	};
 
 	/** for phys allocated objects */
 	struct drm_dma_handle *phys_handle;
diff --git a/drivers/gpu/drm/i915/selftests/huge_gem_object.c b/drivers/gpu/drm/i915/selftests/huge_gem_object.c
new file mode 100644
index 000000000000..f39294f4013f
--- /dev/null
+++ b/drivers/gpu/drm/i915/selftests/huge_gem_object.c
@@ -0,0 +1,135 @@
+/*
+ * Copyright © 2016 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#include "huge_gem_object.h"
+
+static void huge_free_pages(struct drm_i915_gem_object *obj,
+			    struct sg_table *pages)
+{
+	unsigned long nreal = obj->scratch / PAGE_SIZE;
+	struct scatterlist *sg;
+
+	for (sg = pages->sgl; sg && nreal--; sg = ____sg_next(sg))
+		__free_page(sg_page(sg));
+
+	sg_free_table(pages);
+	kfree(pages);
+}
+
+static struct sg_table *
+huge_get_pages(struct drm_i915_gem_object *obj)
+{
+#define GFP (GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY)
+	const unsigned long nreal = obj->scratch / PAGE_SIZE;
+	const unsigned long npages = obj->base.size / PAGE_SIZE;
+	struct scatterlist *sg, *src, *end;
+	struct sg_table *pages;
+	unsigned long n;
+
+	pages = kmalloc(sizeof(*pages), GFP);
+	if (!pages)
+		return ERR_PTR(-ENOMEM);
+
+	if (sg_alloc_table(pages, npages, GFP)) {
+		kfree(pages);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	sg = pages->sgl;
+	for (n = 0; n < nreal; n++) {
+		struct page *page;
+
+		page = alloc_page(GFP | __GFP_HIGHMEM);
+		if (!page) {
+			sg_mark_end(sg);
+			goto err;
+		}
+
+		sg_set_page(sg, page, PAGE_SIZE, 0);
+		sg = ____sg_next(sg);
+	}
+	if (nreal < npages) {
+		for (end = sg, src = pages->sgl; sg; sg = __sg_next(sg)) {
+			sg_set_page(sg, sg_page(src), PAGE_SIZE, 0);
+			src = ____sg_next(src);
+			if (src == end)
+				src = pages->sgl;
+		}
+	}
+
+	if (i915_gem_gtt_prepare_pages(obj, pages))
+		goto err;
+
+	return pages;
+
+err:
+	huge_free_pages(obj, pages);
+	return ERR_PTR(-ENOMEM);
+#undef GFP
+}
+
+static void huge_put_pages(struct drm_i915_gem_object *obj,
+			   struct sg_table *pages)
+{
+	i915_gem_gtt_finish_pages(obj, pages);
+	huge_free_pages(obj, pages);
+
+	obj->mm.dirty = false;
+}
+
+static const struct drm_i915_gem_object_ops huge_ops = {
+	.flags = I915_GEM_OBJECT_HAS_STRUCT_PAGE |
+		 I915_GEM_OBJECT_IS_SHRINKABLE,
+	.get_pages = huge_get_pages,
+	.put_pages = huge_put_pages,
+};
+
+struct drm_i915_gem_object *
+huge_gem_object(struct drm_i915_private *i915,
+		phys_addr_t real_size,
+		phys_addr_t fake_size)
+{
+	struct drm_i915_gem_object *obj;
+
+	GEM_BUG_ON(!real_size || real_size > fake_size);
+	GEM_BUG_ON(!IS_ALIGNED(real_size, PAGE_SIZE));
+	GEM_BUG_ON(!IS_ALIGNED(fake_size, PAGE_SIZE));
+
+	if (overflows_type(fake_size, obj->base.size))
+		return ERR_PTR(-E2BIG);
+
+	obj = i915_gem_object_alloc(i915);
+	if (!obj)
+		return ERR_PTR(-ENOMEM);
+
+	drm_gem_private_object_init(&i915->drm, &obj->base, fake_size);
+	i915_gem_object_init(obj, &huge_ops);
+
+	obj->base.write_domain = I915_GEM_DOMAIN_CPU;
+	obj->base.read_domains = I915_GEM_DOMAIN_CPU;
+	obj->cache_level = HAS_LLC(i915) ? I915_CACHE_LLC : I915_CACHE_NONE;
+	obj->scratch = real_size;
+
+	return obj;
+}
diff --git a/drivers/gpu/drm/i915/selftests/huge_gem_object.h b/drivers/gpu/drm/i915/selftests/huge_gem_object.h
new file mode 100644
index 000000000000..3022a7c93844
--- /dev/null
+++ b/drivers/gpu/drm/i915/selftests/huge_gem_object.h
@@ -0,0 +1,33 @@
+/*
+ * Copyright © 2016 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#ifndef __HUGE_GEM_OBJECT_H
+#define __HUGE_GEM_OBJECT_H
+
+struct drm_i915_gem_object *
+huge_gem_object(struct drm_i915_private *i915,
+		phys_addr_t real_size,
+		phys_addr_t fake_size);
+
+#endif /* !__HUGE_GEM_OBJECT_H */
-- 
2.11.0

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