On 02/02/2022 01:13, Vivek Kasireddy wrote:
This iterator relies on drm_mm_first_hole() and drm_mm_next_hole()
functions to identify suitable holes for an allocation of a given
size by efficently traversing the rbtree associated with the given
allocator.
It replaces the for loop in drm_mm_insert_node_in_range() and can
also be used by drm drivers to quickly identify holes of a certain
size within a given range.
Suggested-by: Tvrtko Ursulin <tvrtko.ursu...@linux.intel.com>
Signed-off-by: Vivek Kasireddy <vivek.kasire...@intel.com>
---
drivers/gpu/drm/drm_mm.c | 28 ++++++++++++----------------
include/drm/drm_mm.h | 32 ++++++++++++++++++++++++++++++++
2 files changed, 44 insertions(+), 16 deletions(-)
diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c
index 8257f9d4f619..416c849c10e5 100644
--- a/drivers/gpu/drm/drm_mm.c
+++ b/drivers/gpu/drm/drm_mm.c
@@ -352,10 +352,10 @@ static struct drm_mm_node *find_hole_addr(struct drm_mm
*mm, u64 addr, u64 size)
return node;
}
-static struct drm_mm_node *
-first_hole(struct drm_mm *mm,
- u64 start, u64 end, u64 size,
- enum drm_mm_insert_mode mode)
+struct drm_mm_node *
+drm_mm_first_hole(struct drm_mm *mm,
+ u64 start, u64 end, u64 size,
+ enum drm_mm_insert_mode mode)
{
switch (mode) {
default:
@@ -374,6 +374,7 @@ first_hole(struct drm_mm *mm,
hole_stack);
}
}
+EXPORT_SYMBOL(drm_mm_first_hole);
/**
* DECLARE_NEXT_HOLE_ADDR - macro to declare next hole functions
@@ -410,11 +411,11 @@ static struct drm_mm_node *name(struct drm_mm_node
*entry, u64 size) \
DECLARE_NEXT_HOLE_ADDR(next_hole_high_addr, rb_left, rb_right)
DECLARE_NEXT_HOLE_ADDR(next_hole_low_addr, rb_right, rb_left)
-static struct drm_mm_node *
-next_hole(struct drm_mm *mm,
- struct drm_mm_node *node,
- u64 size,
- enum drm_mm_insert_mode mode)
+struct drm_mm_node *
+drm_mm_next_hole(struct drm_mm *mm,
+ struct drm_mm_node *node,
+ u64 size,
+ enum drm_mm_insert_mode mode)
{
switch (mode) {
default:
@@ -432,6 +433,7 @@ next_hole(struct drm_mm *mm,
return &node->hole_stack == &mm->hole_stack ? NULL : node;
}
}
+EXPORT_SYMBOL(drm_mm_next_hole);
May need to add kerneldoc since first/next_hole are now exported, or
perhaps double underscore them if DRM core allows that approach to kind
of signify "it is exported by shouldn't really be used"? Question for
dri-devel I guess.
/**
* drm_mm_reserve_node - insert an pre-initialized node
@@ -520,7 +522,6 @@ int drm_mm_insert_node_in_range(struct drm_mm * const mm,
{
struct drm_mm_node *hole;
u64 remainder_mask;
- bool once;
DRM_MM_BUG_ON(range_start > range_end);
@@ -533,13 +534,8 @@ int drm_mm_insert_node_in_range(struct drm_mm * const mm,
if (alignment <= 1)
alignment = 0;
- once = mode & DRM_MM_INSERT_ONCE;
- mode &= ~DRM_MM_INSERT_ONCE;
-
remainder_mask = is_power_of_2(alignment) ? alignment - 1 : 0;
- for (hole = first_hole(mm, range_start, range_end, size, mode);
- hole;
- hole = once ? NULL : next_hole(mm, hole, size, mode)) {
+ drm_mm_for_each_best_hole(hole, mm, range_start, range_end, size, mode)
{
u64 hole_start = __drm_mm_hole_node_start(hole);
u64 hole_end = hole_start + hole->hole_size;
u64 adj_start, adj_end;
diff --git a/include/drm/drm_mm.h b/include/drm/drm_mm.h
index ac33ba1b18bc..5055447697fa 100644
--- a/include/drm/drm_mm.h
+++ b/include/drm/drm_mm.h
@@ -322,6 +322,17 @@ static inline u64 __drm_mm_hole_node_end(const struct
drm_mm_node *hole_node)
return list_next_entry(hole_node, node_list)->start;
}
+struct drm_mm_node *
+drm_mm_first_hole(struct drm_mm *mm,
+ u64 start, u64 end, u64 size,
+ enum drm_mm_insert_mode mode);
+
+struct drm_mm_node *
+drm_mm_next_hole(struct drm_mm *mm,
+ struct drm_mm_node *node,
+ u64 size,
+ enum drm_mm_insert_mode mode);
+
/**
* drm_mm_hole_node_end - computes the end of the hole following @node
* @hole_node: drm_mm_node which implicitly tracks the following hole
@@ -400,6 +411,27 @@ static inline u64 drm_mm_hole_node_end(const struct
drm_mm_node *hole_node)
1 : 0; \
pos = list_next_entry(pos, hole_stack))
+/**
+ * drm_mm_for_each_best_hole - iterator to optimally walk over all holes >=
@size
+ * @pos: &drm_mm_node used internally to track progress
+ * @mm: &drm_mm allocator to walk
+ * @range_start: start of the allowed range for the allocation
+ * @range_end: end of the allowed range for the allocation
+ * @size: size of the allocation
+ * @mode: fine-tune the allocation search
+ *
+ * This iterator walks over all holes suitable for the allocation of given
+ * @size in a very efficient manner. It is implemented by calling
+ * drm_mm_first_hole() and drm_mm_next_hole() which identify the
+ * appropriate holes within the given range by efficently traversing the
+ * rbtree associated with @mm.
+ */
+#define drm_mm_for_each_best_hole(pos, mm, range_start, range_end, size, mode)
\
Probably should not have "best" in the name since the mode is passed in
by the caller.
+ for (pos = drm_mm_first_hole(mm, range_start, range_end, size, mode); \
+ pos; \
+ pos = mode & DRM_MM_INSERT_ONCE ? \
+ NULL : drm_mm_next_hole(mm, hole, size, mode))
I think you would need to modify the first/next_hole to mask out
DRM_MM_INSERT_ONCE, otherwise it probably does not work as it stands.
Regards,
Tvrtko
+
/*
* Basic range manager support (drm_mm.c)
*/
