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authorDaniel Vetter <daniel.vetter@ffwll.ch>2010-07-02 15:02:16 +0100
committerDave Airlie <airlied@redhat.com>2010-07-07 12:29:51 +1000
commit709ea97145c125b3811ff70429e90ebdb0e832e5 (patch)
tree222c5cafcae50f06e0e2c2591ab09f3bd1e89827 /drivers/gpu/drm/drm_mm.c
parent7a6b2896f261894dde287d3faefa4b432cddca53 (diff)
drm: implement helper functions for scanning lru list
These helper functions can be used to efficiently scan lru list for eviction. Eviction becomes a three stage process: 1. Scanning through the lru list until a suitable hole has been found. 2. Scan backwards to restore drm_mm consistency and find out which objects fall into the hole. 3. Evict the objects that fall into the hole. These helper functions don't allocate any memory (at the price of not allowing any other concurrent operations). Hence this can also be used for ttm (which does lru scanning under a spinlock). Evicting objects in this fashion should be more fair than the current approach by i915 (scan the lru for a object large enough to contain the new object). It's also more efficient than the current approach used by ttm (uncoditionally evict objects from the lru until there's enough free space). Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Acked-by: Thomas Hellstrom <thellstrom@vmwgfx.com> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Dave Airlie <airlied@redhat.com>
Diffstat (limited to 'drivers/gpu/drm/drm_mm.c')
-rw-r--r--drivers/gpu/drm/drm_mm.c167
1 files changed, 163 insertions, 4 deletions
diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c
index fd86a6c13aac..da99edc50888 100644
--- a/drivers/gpu/drm/drm_mm.c
+++ b/drivers/gpu/drm/drm_mm.c
@@ -53,9 +53,9 @@ static struct drm_mm_node *drm_mm_kmalloc(struct drm_mm *mm, int atomic)
struct drm_mm_node *child;
if (atomic)
- child = kmalloc(sizeof(*child), GFP_ATOMIC);
+ child = kzalloc(sizeof(*child), GFP_ATOMIC);
else
- child = kmalloc(sizeof(*child), GFP_KERNEL);
+ child = kzalloc(sizeof(*child), GFP_KERNEL);
if (unlikely(child == NULL)) {
spin_lock(&mm->unused_lock);
@@ -85,7 +85,7 @@ int drm_mm_pre_get(struct drm_mm *mm)
spin_lock(&mm->unused_lock);
while (mm->num_unused < MM_UNUSED_TARGET) {
spin_unlock(&mm->unused_lock);
- node = kmalloc(sizeof(*node), GFP_KERNEL);
+ node = kzalloc(sizeof(*node), GFP_KERNEL);
spin_lock(&mm->unused_lock);
if (unlikely(node == NULL)) {
@@ -134,7 +134,6 @@ static struct drm_mm_node *drm_mm_split_at_start(struct drm_mm_node *parent,
INIT_LIST_HEAD(&child->free_stack);
- child->free = 0;
child->size = size;
child->start = parent->start;
child->mm = parent->mm;
@@ -235,6 +234,9 @@ void drm_mm_put_block(struct drm_mm_node *cur)
int merged = 0;
+ BUG_ON(cur->scanned_block || cur->scanned_prev_free
+ || cur->scanned_next_free);
+
if (cur_head->prev != root_head) {
prev_node =
list_entry(cur_head->prev, struct drm_mm_node, node_list);
@@ -312,6 +314,8 @@ struct drm_mm_node *drm_mm_search_free(const struct drm_mm *mm,
struct drm_mm_node *best;
unsigned long best_size;
+ BUG_ON(mm->scanned_blocks);
+
best = NULL;
best_size = ~0UL;
@@ -343,6 +347,8 @@ struct drm_mm_node *drm_mm_search_free_in_range(const struct drm_mm *mm,
struct drm_mm_node *best;
unsigned long best_size;
+ BUG_ON(mm->scanned_blocks);
+
best = NULL;
best_size = ~0UL;
@@ -366,6 +372,158 @@ struct drm_mm_node *drm_mm_search_free_in_range(const struct drm_mm *mm,
}
EXPORT_SYMBOL(drm_mm_search_free_in_range);
+/**
+ * Initializa lru scanning.
+ *
+ * This simply sets up the scanning routines with the parameters for the desired
+ * hole.
+ *
+ * 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)
+{
+ mm->scan_alignment = alignment;
+ mm->scan_size = size;
+ mm->scanned_blocks = 0;
+ mm->scan_hit_start = 0;
+ mm->scan_hit_size = 0;
+}
+EXPORT_SYMBOL(drm_mm_init_scan);
+
+/**
+ * Add a node to the scan list that might be freed to make space for the desired
+ * hole.
+ *
+ * Returns non-zero, if a hole has been found, zero otherwise.
+ */
+int drm_mm_scan_add_block(struct drm_mm_node *node)
+{
+ struct drm_mm *mm = node->mm;
+ struct list_head *prev_free, *next_free;
+ struct drm_mm_node *prev_node, *next_node;
+
+ mm->scanned_blocks++;
+
+ prev_free = next_free = NULL;
+
+ BUG_ON(node->free);
+ node->scanned_block = 1;
+ node->free = 1;
+
+ if (node->node_list.prev != &mm->node_list) {
+ prev_node = list_entry(node->node_list.prev, struct drm_mm_node,
+ node_list);
+
+ if (prev_node->free) {
+ list_del(&prev_node->node_list);
+
+ node->start = prev_node->start;
+ node->size += prev_node->size;
+
+ prev_node->scanned_prev_free = 1;
+
+ prev_free = &prev_node->free_stack;
+ }
+ }
+
+ if (node->node_list.next != &mm->node_list) {
+ next_node = list_entry(node->node_list.next, struct drm_mm_node,
+ node_list);
+
+ if (next_node->free) {
+ list_del(&next_node->node_list);
+
+ node->size += next_node->size;
+
+ next_node->scanned_next_free = 1;
+
+ next_free = &next_node->free_stack;
+ }
+ }
+
+ /* The free_stack list is not used for allocated objects, so these two
+ * pointers can be abused (as long as no allocations in this memory
+ * manager happens). */
+ node->free_stack.prev = prev_free;
+ node->free_stack.next = next_free;
+
+ if (check_free_mm_node(node, mm->scan_size, mm->scan_alignment)) {
+ mm->scan_hit_start = node->start;
+ mm->scan_hit_size = node->size;
+
+ return 1;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(drm_mm_scan_add_block);
+
+/**
+ * Remove a node from the scan list.
+ *
+ * Nodes _must_ be removed in the exact same order from the scan list as they
+ * have been added, otherwise the internal state of the memory manager will be
+ * corrupted.
+ *
+ * When the scan list is empty, the selected memory nodes can be freed. An
+ * immediatly following drm_mm_search_free with best_match = 0 will then return
+ * the just freed block (because its at the top of the free_stack list).
+ *
+ * Returns one if this block should be evicted, zero otherwise. Will always
+ * return zero when no hole has been found.
+ */
+int drm_mm_scan_remove_block(struct drm_mm_node *node)
+{
+ struct drm_mm *mm = node->mm;
+ struct drm_mm_node *prev_node, *next_node;
+
+ mm->scanned_blocks--;
+
+ BUG_ON(!node->scanned_block);
+ node->scanned_block = 0;
+ node->free = 0;
+
+ prev_node = list_entry(node->free_stack.prev, struct drm_mm_node,
+ free_stack);
+ next_node = list_entry(node->free_stack.next, struct drm_mm_node,
+ free_stack);
+
+ if (prev_node) {
+ BUG_ON(!prev_node->scanned_prev_free);
+ prev_node->scanned_prev_free = 0;
+
+ list_add_tail(&prev_node->node_list, &node->node_list);
+
+ node->start = prev_node->start + prev_node->size;
+ node->size -= prev_node->size;
+ }
+
+ if (next_node) {
+ BUG_ON(!next_node->scanned_next_free);
+ next_node->scanned_next_free = 0;
+
+ list_add(&next_node->node_list, &node->node_list);
+
+ node->size -= next_node->size;
+ }
+
+ INIT_LIST_HEAD(&node->free_stack);
+
+ /* Only need to check for containement because start&size for the
+ * complete resulting free block (not just the desired part) is
+ * stored. */
+ if (node->start >= mm->scan_hit_start &&
+ node->start + node->size
+ <= mm->scan_hit_start + mm->scan_hit_size) {
+ return 1;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(drm_mm_scan_remove_block);
+
int drm_mm_clean(struct drm_mm * mm)
{
struct list_head *head = &mm->node_list;
@@ -380,6 +538,7 @@ int drm_mm_init(struct drm_mm * mm, unsigned long start, unsigned long size)
INIT_LIST_HEAD(&mm->free_stack);
INIT_LIST_HEAD(&mm->unused_nodes);
mm->num_unused = 0;
+ mm->scanned_blocks = 0;
spin_lock_init(&mm->unused_lock);
return drm_mm_create_tail_node(mm, start, size, 0);