Commit 0f1dd022 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915/gem: Split eb_vma into its own allocation 

Use a separate array allocation for the execbuf vma, so that we can
track their lifetime independently from the copy of the user arguments.
With luck, this has a secondary benefit of splitting the malloc size to
within reason and avoid vmalloc. The downside is that we might require
two separate vmallocs -- but much less likely.

In the process, this prevents a memory leak on the ww_mutex error
unwind.

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/1390


Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200330133710.14385-1-chris@chris-wilson.co.uk
parent d7d50f80

drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c

+73 −58
Original line number Diff line number Diff line
@@ -40,6 +40,11 @@ struct eb_vma { 
	u32 handle;

};



struct eb_vma_array {

	struct kref kref;

	struct eb_vma vma[];

};



enum {

	FORCE_CPU_RELOC = 1,

	FORCE_GTT_RELOC,
@@ -52,7 +57,6 @@ enum { 
#define __EXEC_OBJECT_NEEDS_MAP		BIT(29)

#define __EXEC_OBJECT_NEEDS_BIAS	BIT(28)

#define __EXEC_OBJECT_INTERNAL_FLAGS	(~0u << 28) /* all of the above */

#define __EXEC_OBJECT_RESERVED (__EXEC_OBJECT_HAS_PIN | __EXEC_OBJECT_HAS_FENCE)



#define __EXEC_HAS_RELOC	BIT(31)

#define __EXEC_INTERNAL_FLAGS	(~0u << 31)
@@ -283,6 +287,7 @@ struct i915_execbuffer { 
	 */

	int lut_size;

	struct hlist_head *buckets; /** ht for relocation handles */

	struct eb_vma_array *array;

};



static inline bool eb_use_cmdparser(const struct i915_execbuffer *eb)
@@ -292,8 +297,62 @@ static inline bool eb_use_cmdparser(const struct i915_execbuffer *eb) 
		 eb->args->batch_len);

}



static struct eb_vma_array *eb_vma_array_create(unsigned int count)

{

	struct eb_vma_array *arr;



	arr = kvmalloc(struct_size(arr, vma, count), GFP_KERNEL | __GFP_NOWARN);

	if (!arr)

		return NULL;



	kref_init(&arr->kref);

	arr->vma[0].vma = NULL;



	return arr;

}



static inline void eb_unreserve_vma(struct eb_vma *ev)

{

	struct i915_vma *vma = ev->vma;



	if (unlikely(ev->flags & __EXEC_OBJECT_HAS_FENCE))

		__i915_vma_unpin_fence(vma);



	if (ev->flags & __EXEC_OBJECT_HAS_PIN)

		__i915_vma_unpin(vma);



	ev->flags &= ~(__EXEC_OBJECT_HAS_PIN |

		       __EXEC_OBJECT_HAS_FENCE);

}



static void eb_vma_array_destroy(struct kref *kref)

{

	struct eb_vma_array *arr = container_of(kref, typeof(*arr), kref);

	struct eb_vma *ev = arr->vma;



	while (ev->vma) {

		eb_unreserve_vma(ev);

		i915_vma_put(ev->vma);

		ev++;

	}



	kvfree(arr);

}



static void eb_vma_array_put(struct eb_vma_array *arr)

{

	kref_put(&arr->kref, eb_vma_array_destroy);

}



static int eb_create(struct i915_execbuffer *eb)

{

	/* Allocate an extra slot for use by the command parser + sentinel */

	eb->array = eb_vma_array_create(eb->buffer_count + 2);

	if (!eb->array)

		return -ENOMEM;



	eb->vma = eb->array->vma;



	if (!(eb->args->flags & I915_EXEC_HANDLE_LUT)) {

		unsigned int size = 1 + ilog2(eb->buffer_count);
@@ -327,8 +386,10 @@ static int eb_create(struct i915_execbuffer *eb) 
				break;

		} while (--size);



		if (unlikely(!size))

		if (unlikely(!size)) {

			eb_vma_array_put(eb->array);

			return -ENOMEM;

		}



		eb->lut_size = size;

	} else {
@@ -402,26 +463,6 @@ eb_pin_vma(struct i915_execbuffer *eb, 
	return !eb_vma_misplaced(entry, vma, ev->flags);

}



static inline void __eb_unreserve_vma(struct i915_vma *vma, unsigned int flags)

{

	GEM_BUG_ON(!(flags & __EXEC_OBJECT_HAS_PIN));



	if (unlikely(flags & __EXEC_OBJECT_HAS_FENCE))

		__i915_vma_unpin_fence(vma);



	__i915_vma_unpin(vma);

}



static inline void

eb_unreserve_vma(struct eb_vma *ev)

{

	if (!(ev->flags & __EXEC_OBJECT_HAS_PIN))

		return;



	__eb_unreserve_vma(ev->vma, ev->flags);

	ev->flags &= ~__EXEC_OBJECT_RESERVED;

}



static int

eb_validate_vma(struct i915_execbuffer *eb,

		struct drm_i915_gem_exec_object2 *entry,
@@ -863,31 +904,13 @@ eb_get_vma(const struct i915_execbuffer *eb, unsigned long handle) 
	}

}



static void eb_release_vmas(const struct i915_execbuffer *eb)

{

	const unsigned int count = eb->buffer_count;

	unsigned int i;



	for (i = 0; i < count; i++) {

		struct eb_vma *ev = &eb->vma[i];

		struct i915_vma *vma = ev->vma;



		if (!vma)

			break;



		eb->vma[i].vma = NULL;



		if (ev->flags & __EXEC_OBJECT_HAS_PIN)

			__eb_unreserve_vma(vma, ev->flags);



		i915_vma_put(vma);

	}

}



static void eb_destroy(const struct i915_execbuffer *eb)

{

	GEM_BUG_ON(eb->reloc_cache.rq);



	if (eb->array)

		eb_vma_array_put(eb->array);



	if (eb->lut_size > 0)

		kfree(eb->buckets);

}
@@ -1635,19 +1658,15 @@ static int eb_move_to_gpu(struct i915_execbuffer *eb) 
			err = i915_vma_move_to_active(vma, eb->request, flags);



		i915_vma_unlock(vma);



		__eb_unreserve_vma(vma, flags);

		i915_vma_put(vma);



		ev->vma = NULL;

		eb_unreserve_vma(ev);

	}

	ww_acquire_fini(&acquire);



	eb_vma_array_put(fetch_and_zero(&eb->array));



	if (unlikely(err))

		goto err_skip;



	eb->exec = NULL;



	/* Unconditionally flush any chipset caches (for streaming writes). */

	intel_gt_chipset_flush(eb->engine->gt);

	return 0;
@@ -1899,6 +1918,7 @@ static int eb_parse(struct i915_execbuffer *eb) 
	eb->vma[eb->buffer_count].vma = i915_vma_get(shadow);

	eb->vma[eb->buffer_count].flags = __EXEC_OBJECT_HAS_PIN;

	eb->batch = &eb->vma[eb->buffer_count++];

	eb->vma[eb->buffer_count].vma = NULL;



	eb->trampoline = trampoline;

	eb->batch_start_offset = 0;
@@ -2422,8 +2442,6 @@ i915_gem_do_execbuffer(struct drm_device *dev, 
		args->flags |= __EXEC_HAS_RELOC;



	eb.exec = exec;

	eb.vma = (struct eb_vma *)(exec + args->buffer_count + 1);

	eb.vma[0].vma = NULL;



	eb.invalid_flags = __EXEC_OBJECT_UNKNOWN_FLAGS;

	reloc_cache_init(&eb.reloc_cache, eb.i915);
@@ -2630,8 +2648,6 @@ err_parse: 
	if (batch->private)

		intel_engine_pool_put(batch->private);

err_vma:

	if (eb.exec)

		eb_release_vmas(&eb);

	if (eb.trampoline)

		i915_vma_unpin(eb.trampoline);

	eb_unpin_engine(&eb);
@@ -2651,7 +2667,7 @@ err_in_fence: 


static size_t eb_element_size(void)

{

	return sizeof(struct drm_i915_gem_exec_object2) + sizeof(struct eb_vma);

	return sizeof(struct drm_i915_gem_exec_object2);

}



static bool check_buffer_count(size_t count)
@@ -2707,7 +2723,7 @@ i915_gem_execbuffer_ioctl(struct drm_device *dev, void *data, 
	/* Copy in the exec list from userland */

	exec_list = kvmalloc_array(count, sizeof(*exec_list),

				   __GFP_NOWARN | GFP_KERNEL);

	exec2_list = kvmalloc_array(count + 1, eb_element_size(),

	exec2_list = kvmalloc_array(count, eb_element_size(),

				    __GFP_NOWARN | GFP_KERNEL);

	if (exec_list == NULL || exec2_list == NULL) {

		drm_dbg(&i915->drm,
@@ -2785,8 +2801,7 @@ i915_gem_execbuffer2_ioctl(struct drm_device *dev, void *data, 
	if (err)

		return err;



	/* Allocate an extra slot for use by the command parser */

	exec2_list = kvmalloc_array(count + 1, eb_element_size(),

	exec2_list = kvmalloc_array(count, eb_element_size(),

				    __GFP_NOWARN | GFP_KERNEL);

	if (exec2_list == NULL) {

		drm_dbg(&i915->drm, "Failed to allocate exec list for %zd buffers\n",

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