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drm/i915/execbuffer: Reorder binding of objects to favour restrictions
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As the mappable portion of the aperture is always a small subset at the
start of the GTT, it is allocated preferentially by drm_mm. This is
useful in case we ever need to map an object later. However, if you have
a large object that can consume the entire mappable region of the
GTT this prevents the batchbuffer from fitting and so causing an error.
Instead allocate all those that require a mapping up front in order to
improve the likelihood of finding sufficient space to bind them.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
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Chris Wilson committed Jan 11, 2011
1 parent 809b633 commit 6fe4f14
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Showing 2 changed files with 47 additions and 26 deletions.
1 change: 1 addition & 0 deletions drivers/gpu/drm/i915/i915_drv.h
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Original file line number Diff line number Diff line change
Expand Up @@ -796,6 +796,7 @@ struct drm_i915_gem_object {
*/
struct hlist_node exec_node;
unsigned long exec_handle;
struct drm_i915_gem_exec_object2 *exec_entry;

/**
* Current offset of the object in GTT space.
Expand Down
72 changes: 46 additions & 26 deletions drivers/gpu/drm/i915/i915_gem_execbuffer.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -268,7 +268,6 @@ eb_destroy(struct eb_objects *eb)
static int
i915_gem_execbuffer_relocate_entry(struct drm_i915_gem_object *obj,
struct eb_objects *eb,
struct drm_i915_gem_exec_object2 *entry,
struct drm_i915_gem_relocation_entry *reloc)
{
struct drm_device *dev = obj->base.dev;
Expand Down Expand Up @@ -411,10 +410,10 @@ i915_gem_execbuffer_relocate_entry(struct drm_i915_gem_object *obj,

static int
i915_gem_execbuffer_relocate_object(struct drm_i915_gem_object *obj,
struct eb_objects *eb,
struct drm_i915_gem_exec_object2 *entry)
struct eb_objects *eb)
{
struct drm_i915_gem_relocation_entry __user *user_relocs;
struct drm_i915_gem_exec_object2 *entry = obj->exec_entry;
int i, ret;

user_relocs = (void __user *)(uintptr_t)entry->relocs_ptr;
Expand All @@ -426,7 +425,7 @@ i915_gem_execbuffer_relocate_object(struct drm_i915_gem_object *obj,
sizeof(reloc)))
return -EFAULT;

ret = i915_gem_execbuffer_relocate_entry(obj, eb, entry, &reloc);
ret = i915_gem_execbuffer_relocate_entry(obj, eb, &reloc);
if (ret)
return ret;

Expand All @@ -442,13 +441,13 @@ i915_gem_execbuffer_relocate_object(struct drm_i915_gem_object *obj,
static int
i915_gem_execbuffer_relocate_object_slow(struct drm_i915_gem_object *obj,
struct eb_objects *eb,
struct drm_i915_gem_exec_object2 *entry,
struct drm_i915_gem_relocation_entry *relocs)
{
const struct drm_i915_gem_exec_object2 *entry = obj->exec_entry;
int i, ret;

for (i = 0; i < entry->relocation_count; i++) {
ret = i915_gem_execbuffer_relocate_entry(obj, eb, entry, &relocs[i]);
ret = i915_gem_execbuffer_relocate_entry(obj, eb, &relocs[i]);
if (ret)
return ret;
}
Expand All @@ -459,16 +458,15 @@ i915_gem_execbuffer_relocate_object_slow(struct drm_i915_gem_object *obj,
static int
i915_gem_execbuffer_relocate(struct drm_device *dev,
struct eb_objects *eb,
struct list_head *objects,
struct drm_i915_gem_exec_object2 *exec)
struct list_head *objects)
{
struct drm_i915_gem_object *obj;
int ret;

list_for_each_entry(obj, objects, exec_list) {
obj->base.pending_read_domains = 0;
obj->base.pending_write_domain = 0;
ret = i915_gem_execbuffer_relocate_object(obj, eb, exec++);
ret = i915_gem_execbuffer_relocate_object(obj, eb);
if (ret)
return ret;
}
Expand All @@ -479,13 +477,36 @@ i915_gem_execbuffer_relocate(struct drm_device *dev,
static int
i915_gem_execbuffer_reserve(struct intel_ring_buffer *ring,
struct drm_file *file,
struct list_head *objects,
struct drm_i915_gem_exec_object2 *exec)
struct list_head *objects)
{
struct drm_i915_gem_object *obj;
struct drm_i915_gem_exec_object2 *entry;
int ret, retry;
bool has_fenced_gpu_access = INTEL_INFO(ring->dev)->gen < 4;
struct list_head ordered_objects;

INIT_LIST_HEAD(&ordered_objects);
while (!list_empty(objects)) {
struct drm_i915_gem_exec_object2 *entry;
bool need_fence, need_mappable;

obj = list_first_entry(objects,
struct drm_i915_gem_object,
exec_list);
entry = obj->exec_entry;

need_fence =
has_fenced_gpu_access &&
entry->flags & EXEC_OBJECT_NEEDS_FENCE &&
obj->tiling_mode != I915_TILING_NONE;
need_mappable =
entry->relocation_count ? true : need_fence;

if (need_mappable)
list_move(&obj->exec_list, &ordered_objects);
else
list_move_tail(&obj->exec_list, &ordered_objects);
}
list_splice(&ordered_objects, objects);

/* Attempt to pin all of the buffers into the GTT.
* This is done in 3 phases:
Expand All @@ -504,14 +525,11 @@ i915_gem_execbuffer_reserve(struct intel_ring_buffer *ring,
ret = 0;

/* Unbind any ill-fitting objects or pin. */
entry = exec;
list_for_each_entry(obj, objects, exec_list) {
struct drm_i915_gem_exec_object2 *entry = obj->exec_entry;
bool need_fence, need_mappable;

if (!obj->gtt_space) {
entry++;
if (!obj->gtt_space)
continue;
}

need_fence =
has_fenced_gpu_access &&
Expand All @@ -534,8 +552,8 @@ i915_gem_execbuffer_reserve(struct intel_ring_buffer *ring,
}

/* Bind fresh objects */
entry = exec;
list_for_each_entry(obj, objects, exec_list) {
struct drm_i915_gem_exec_object2 *entry = obj->exec_entry;
bool need_fence;

need_fence =
Expand Down Expand Up @@ -570,7 +588,6 @@ i915_gem_execbuffer_reserve(struct intel_ring_buffer *ring,
}

entry->offset = obj->gtt_offset;
entry++;
}

/* Decrement pin count for bound objects */
Expand Down Expand Up @@ -680,10 +697,11 @@ i915_gem_execbuffer_relocate_slow(struct drm_device *dev,

list_add_tail(&obj->exec_list, objects);
obj->exec_handle = exec[i].handle;
obj->exec_entry = &exec[i];
eb_add_object(eb, obj);
}

ret = i915_gem_execbuffer_reserve(ring, file, objects, exec);
ret = i915_gem_execbuffer_reserve(ring, file, objects);
if (ret)
goto err;

Expand All @@ -692,7 +710,6 @@ i915_gem_execbuffer_relocate_slow(struct drm_device *dev,
obj->base.pending_read_domains = 0;
obj->base.pending_write_domain = 0;
ret = i915_gem_execbuffer_relocate_object_slow(obj, eb,
exec,
reloc + total);
if (ret)
goto err;
Expand Down Expand Up @@ -1110,16 +1127,22 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,

list_add_tail(&obj->exec_list, &objects);
obj->exec_handle = exec[i].handle;
obj->exec_entry = &exec[i];
eb_add_object(eb, obj);
}

/* take note of the batch buffer before we might reorder the lists */
batch_obj = list_entry(objects.prev,
struct drm_i915_gem_object,
exec_list);

/* Move the objects en-masse into the GTT, evicting if necessary. */
ret = i915_gem_execbuffer_reserve(ring, file, &objects, exec);
ret = i915_gem_execbuffer_reserve(ring, file, &objects);
if (ret)
goto err;

/* The objects are in their final locations, apply the relocations. */
ret = i915_gem_execbuffer_relocate(dev, eb, &objects, exec);
ret = i915_gem_execbuffer_relocate(dev, eb, &objects);
if (ret) {
if (ret == -EFAULT) {
ret = i915_gem_execbuffer_relocate_slow(dev, file, ring,
Expand All @@ -1133,9 +1156,6 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
}

/* Set the pending read domains for the batch buffer to COMMAND */
batch_obj = list_entry(objects.prev,
struct drm_i915_gem_object,
exec_list);
if (batch_obj->base.pending_write_domain) {
DRM_ERROR("Attempting to use self-modifying batch buffer\n");
ret = -EINVAL;
Expand Down

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