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drm: Add colouring to the range allocator
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In order to support snoopable memory on non-LLC architectures (so that
we can bind vgem objects into the i915 GATT for example), we have to
avoid the prefetcher on the GPU from crossing memory domains and so
prevent allocation of a snoopable PTE immediately following an uncached
PTE. To do that, we need to extend the range allocator with support for
tracking and segregating different node colours.

This will be used by i915 to segregate memory domains within the GTT.

v2: Now with more drm_mm helpers and less driver interference.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Dave Airlie <airlied@redhat.com
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@gmail.com>
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Chris Wilson authored and Dave Airlie committed Jul 15, 2012
1 parent 49099c4 commit 6b9d89b
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Showing 5 changed files with 191 additions and 88 deletions.
2 changes: 1 addition & 1 deletion drivers/gpu/drm/drm_gem.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -354,7 +354,7 @@ drm_gem_create_mmap_offset(struct drm_gem_object *obj)

/* Get a DRM GEM mmap offset allocated... */
list->file_offset_node = drm_mm_search_free(&mm->offset_manager,
obj->size / PAGE_SIZE, 0, 0);
obj->size / PAGE_SIZE, 0, false);

if (!list->file_offset_node) {
DRM_ERROR("failed to allocate offset for bo %d\n", obj->name);
Expand Down
169 changes: 104 additions & 65 deletions drivers/gpu/drm/drm_mm.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -118,45 +118,53 @@ static inline unsigned long drm_mm_hole_node_end(struct drm_mm_node *hole_node)

static void drm_mm_insert_helper(struct drm_mm_node *hole_node,
struct drm_mm_node *node,
unsigned long size, unsigned alignment)
unsigned long size, unsigned alignment,
unsigned long color)
{
struct drm_mm *mm = hole_node->mm;
unsigned long tmp = 0, wasted = 0;
unsigned long hole_start = drm_mm_hole_node_start(hole_node);
unsigned long hole_end = drm_mm_hole_node_end(hole_node);
unsigned long adj_start = hole_start;
unsigned long adj_end = hole_end;

BUG_ON(!hole_node->hole_follows || node->allocated);

if (alignment)
tmp = hole_start % alignment;
if (mm->color_adjust)
mm->color_adjust(hole_node, color, &adj_start, &adj_end);

if (!tmp) {
if (alignment) {
unsigned tmp = adj_start % alignment;
if (tmp)
adj_start += alignment - tmp;
}

if (adj_start == hole_start) {
hole_node->hole_follows = 0;
list_del_init(&hole_node->hole_stack);
} else
wasted = alignment - tmp;
list_del(&hole_node->hole_stack);
}

node->start = hole_start + wasted;
node->start = adj_start;
node->size = size;
node->mm = mm;
node->color = color;
node->allocated = 1;

INIT_LIST_HEAD(&node->hole_stack);
list_add(&node->node_list, &hole_node->node_list);

BUG_ON(node->start + node->size > hole_end);
BUG_ON(node->start + node->size > adj_end);

node->hole_follows = 0;
if (node->start + node->size < hole_end) {
list_add(&node->hole_stack, &mm->hole_stack);
node->hole_follows = 1;
} else {
node->hole_follows = 0;
}
}

struct drm_mm_node *drm_mm_get_block_generic(struct drm_mm_node *hole_node,
unsigned long size,
unsigned alignment,
unsigned long color,
int atomic)
{
struct drm_mm_node *node;
Expand All @@ -165,7 +173,7 @@ struct drm_mm_node *drm_mm_get_block_generic(struct drm_mm_node *hole_node,
if (unlikely(node == NULL))
return NULL;

drm_mm_insert_helper(hole_node, node, size, alignment);
drm_mm_insert_helper(hole_node, node, size, alignment, color);

return node;
}
Expand All @@ -181,11 +189,11 @@ int drm_mm_insert_node(struct drm_mm *mm, struct drm_mm_node *node,
{
struct drm_mm_node *hole_node;

hole_node = drm_mm_search_free(mm, size, alignment, 0);
hole_node = drm_mm_search_free(mm, size, alignment, false);
if (!hole_node)
return -ENOSPC;

drm_mm_insert_helper(hole_node, node, size, alignment);
drm_mm_insert_helper(hole_node, node, size, alignment, 0);

return 0;
}
Expand All @@ -194,50 +202,57 @@ EXPORT_SYMBOL(drm_mm_insert_node);
static void drm_mm_insert_helper_range(struct drm_mm_node *hole_node,
struct drm_mm_node *node,
unsigned long size, unsigned alignment,
unsigned long color,
unsigned long start, unsigned long end)
{
struct drm_mm *mm = hole_node->mm;
unsigned long tmp = 0, wasted = 0;
unsigned long hole_start = drm_mm_hole_node_start(hole_node);
unsigned long hole_end = drm_mm_hole_node_end(hole_node);
unsigned long adj_start = hole_start;
unsigned long adj_end = hole_end;

BUG_ON(!hole_node->hole_follows || node->allocated);

if (hole_start < start)
wasted += start - hole_start;
if (alignment)
tmp = (hole_start + wasted) % alignment;
if (mm->color_adjust)
mm->color_adjust(hole_node, color, &adj_start, &adj_end);

if (tmp)
wasted += alignment - tmp;
if (adj_start < start)
adj_start = start;

if (alignment) {
unsigned tmp = adj_start % alignment;
if (tmp)
adj_start += alignment - tmp;
}

if (!wasted) {
if (adj_start == hole_start) {
hole_node->hole_follows = 0;
list_del_init(&hole_node->hole_stack);
list_del(&hole_node->hole_stack);
}

node->start = hole_start + wasted;
node->start = adj_start;
node->size = size;
node->mm = mm;
node->color = color;
node->allocated = 1;

INIT_LIST_HEAD(&node->hole_stack);
list_add(&node->node_list, &hole_node->node_list);

BUG_ON(node->start + node->size > hole_end);
BUG_ON(node->start + node->size > adj_end);
BUG_ON(node->start + node->size > end);

node->hole_follows = 0;
if (node->start + node->size < hole_end) {
list_add(&node->hole_stack, &mm->hole_stack);
node->hole_follows = 1;
} else {
node->hole_follows = 0;
}
}

struct drm_mm_node *drm_mm_get_block_range_generic(struct drm_mm_node *hole_node,
unsigned long size,
unsigned alignment,
unsigned long color,
unsigned long start,
unsigned long end,
int atomic)
Expand All @@ -248,7 +263,7 @@ struct drm_mm_node *drm_mm_get_block_range_generic(struct drm_mm_node *hole_node
if (unlikely(node == NULL))
return NULL;

drm_mm_insert_helper_range(hole_node, node, size, alignment,
drm_mm_insert_helper_range(hole_node, node, size, alignment, color,
start, end);

return node;
Expand All @@ -267,11 +282,11 @@ int drm_mm_insert_node_in_range(struct drm_mm *mm, struct drm_mm_node *node,
struct drm_mm_node *hole_node;

hole_node = drm_mm_search_free_in_range(mm, size, alignment,
start, end, 0);
start, end, false);
if (!hole_node)
return -ENOSPC;

drm_mm_insert_helper_range(hole_node, node, size, alignment,
drm_mm_insert_helper_range(hole_node, node, size, alignment, 0,
start, end);

return 0;
Expand Down Expand Up @@ -336,27 +351,23 @@ EXPORT_SYMBOL(drm_mm_put_block);
static int check_free_hole(unsigned long start, unsigned long end,
unsigned long size, unsigned alignment)
{
unsigned wasted = 0;

if (end - start < size)
return 0;

if (alignment) {
unsigned tmp = start % alignment;
if (tmp)
wasted = alignment - tmp;
}

if (end >= start + size + wasted) {
return 1;
start += alignment - tmp;
}

return 0;
return end >= start + size;
}

struct drm_mm_node *drm_mm_search_free(const struct drm_mm *mm,
unsigned long size,
unsigned alignment, int best_match)
struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm,
unsigned long size,
unsigned alignment,
unsigned long color,
bool best_match)
{
struct drm_mm_node *entry;
struct drm_mm_node *best;
Expand All @@ -368,10 +379,17 @@ struct drm_mm_node *drm_mm_search_free(const struct drm_mm *mm,
best_size = ~0UL;

list_for_each_entry(entry, &mm->hole_stack, hole_stack) {
unsigned long adj_start = drm_mm_hole_node_start(entry);
unsigned long adj_end = drm_mm_hole_node_end(entry);

if (mm->color_adjust) {
mm->color_adjust(entry, color, &adj_start, &adj_end);
if (adj_end <= adj_start)
continue;
}

BUG_ON(!entry->hole_follows);
if (!check_free_hole(drm_mm_hole_node_start(entry),
drm_mm_hole_node_end(entry),
size, alignment))
if (!check_free_hole(adj_start, adj_end, size, alignment))
continue;

if (!best_match)
Expand All @@ -385,14 +403,15 @@ struct drm_mm_node *drm_mm_search_free(const struct drm_mm *mm,

return best;
}
EXPORT_SYMBOL(drm_mm_search_free);

struct drm_mm_node *drm_mm_search_free_in_range(const struct drm_mm *mm,
unsigned long size,
unsigned alignment,
unsigned long start,
unsigned long end,
int best_match)
EXPORT_SYMBOL(drm_mm_search_free_generic);

struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_mm *mm,
unsigned long size,
unsigned alignment,
unsigned long color,
unsigned long start,
unsigned long end,
bool best_match)
{
struct drm_mm_node *entry;
struct drm_mm_node *best;
Expand All @@ -410,6 +429,13 @@ struct drm_mm_node *drm_mm_search_free_in_range(const struct drm_mm *mm,
end : drm_mm_hole_node_end(entry);

BUG_ON(!entry->hole_follows);

if (mm->color_adjust) {
mm->color_adjust(entry, color, &adj_start, &adj_end);
if (adj_end <= adj_start)
continue;
}

if (!check_free_hole(adj_start, adj_end, size, alignment))
continue;

Expand All @@ -424,7 +450,7 @@ struct drm_mm_node *drm_mm_search_free_in_range(const struct drm_mm *mm,

return best;
}
EXPORT_SYMBOL(drm_mm_search_free_in_range);
EXPORT_SYMBOL(drm_mm_search_free_in_range_generic);

/**
* Moves an allocation. To be used with embedded struct drm_mm_node.
Expand All @@ -437,6 +463,7 @@ void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new)
new->mm = old->mm;
new->start = old->start;
new->size = old->size;
new->color = old->color;

old->allocated = 0;
new->allocated = 1;
Expand All @@ -452,9 +479,12 @@ EXPORT_SYMBOL(drm_mm_replace_node);
* Warning: As long as the scan list is non-empty, no other operations than
* adding/removing nodes to/from the scan list are allowed.
*/
void drm_mm_init_scan(struct drm_mm *mm, unsigned long size,
unsigned alignment)
void drm_mm_init_scan(struct drm_mm *mm,
unsigned long size,
unsigned alignment,
unsigned long color)
{
mm->scan_color = color;
mm->scan_alignment = alignment;
mm->scan_size = size;
mm->scanned_blocks = 0;
Expand All @@ -474,11 +504,14 @@ EXPORT_SYMBOL(drm_mm_init_scan);
* Warning: As long as the scan list is non-empty, no other operations than
* adding/removing nodes to/from the scan list are allowed.
*/
void drm_mm_init_scan_with_range(struct drm_mm *mm, unsigned long size,
void drm_mm_init_scan_with_range(struct drm_mm *mm,
unsigned long size,
unsigned alignment,
unsigned long color,
unsigned long start,
unsigned long end)
{
mm->scan_color = color;
mm->scan_alignment = alignment;
mm->scan_size = size;
mm->scanned_blocks = 0;
Expand Down Expand Up @@ -522,17 +555,21 @@ int drm_mm_scan_add_block(struct drm_mm_node *node)

hole_start = drm_mm_hole_node_start(prev_node);
hole_end = drm_mm_hole_node_end(prev_node);

adj_start = hole_start;
adj_end = hole_end;

if (mm->color_adjust)
mm->color_adjust(prev_node, mm->scan_color, &adj_start, &adj_end);

if (mm->scan_check_range) {
adj_start = hole_start < mm->scan_start ?
mm->scan_start : hole_start;
adj_end = hole_end > mm->scan_end ?
mm->scan_end : hole_end;
} else {
adj_start = hole_start;
adj_end = hole_end;
if (adj_start < mm->scan_start)
adj_start = mm->scan_start;
if (adj_end > mm->scan_end)
adj_end = mm->scan_end;
}

if (check_free_hole(adj_start , adj_end,
if (check_free_hole(adj_start, adj_end,
mm->scan_size, mm->scan_alignment)) {
mm->scan_hit_start = hole_start;
mm->scan_hit_size = hole_end;
Expand Down Expand Up @@ -616,6 +653,8 @@ int drm_mm_init(struct drm_mm * mm, unsigned long start, unsigned long size)
mm->head_node.size = start - mm->head_node.start;
list_add_tail(&mm->head_node.hole_stack, &mm->hole_stack);

mm->color_adjust = NULL;

return 0;
}
EXPORT_SYMBOL(drm_mm_init);
Expand Down
6 changes: 3 additions & 3 deletions drivers/gpu/drm/i915/i915_gem.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2748,8 +2748,8 @@ i915_gem_object_bind_to_gtt(struct drm_i915_gem_object *obj,
if (map_and_fenceable)
free_space =
drm_mm_search_free_in_range(&dev_priv->mm.gtt_space,
size, alignment, 0,
dev_priv->mm.gtt_mappable_end,
size, alignment,
0, dev_priv->mm.gtt_mappable_end,
0);
else
free_space = drm_mm_search_free(&dev_priv->mm.gtt_space,
Expand All @@ -2760,7 +2760,7 @@ i915_gem_object_bind_to_gtt(struct drm_i915_gem_object *obj,
obj->gtt_space =
drm_mm_get_block_range_generic(free_space,
size, alignment, 0,
dev_priv->mm.gtt_mappable_end,
0, dev_priv->mm.gtt_mappable_end,
0);
else
obj->gtt_space =
Expand Down
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