[PATCH v4 28/38] drm: Unconditionally do the range check in drm_mm_scan_add_block()

Chris Wilson
2016-12-22T08:36:31Z

Doing the check is trivial (low cost in comparison to overall eviction)
and helps simplify the code.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
---
drivers/gpu/drm/drm_mm.c | 53 +++--------------------------------
drivers/gpu/drm/i915/i915_gem_evict.c | 10 ++-----
include/drm/drm_mm.h | 33 ++++++++++++++++++----
3 files changed, 34 insertions(+), 62 deletions(-)

diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c
index 459f10ca5714..c68f79149b9a 100644
--- a/drivers/gpu/drm/drm_mm.c
+++ b/drivers/gpu/drm/drm_mm.c
@@ -710,46 +710,6 @@ EXPORT_SYMBOL(drm_mm_replace_node);
*/

/**
- * drm_mm_scan_init - initialize lru scanning
- * @scan: scan state
- * @mm: drm_mm to scan
- * @size: size of the allocation
- * @alignment: alignment of the allocation
- * @color: opaque tag value to use for the allocation
- *
- * This simply sets up the scanning routines with the parameters for the desired
- * hole. Note that there's no need to specify allocation flags, since they only
- * change the place a node is allocated from within a suitable 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_scan_init(struct drm_mm_scan *scan,
- struct drm_mm *mm,
- u64 size,
- u64 alignment,
- unsigned long color)
-{
- DRM_MM_BUG_ON(!size);
- DRM_MM_BUG_ON(mm->scan_active);
-
- scan->mm = mm;
-
- scan->color = color;
- scan->alignment = alignment;
- scan->size = size;
-
- scan->check_range = 0;
-
- scan->hit_start = U64_MAX;
- scan->hit_end = 0;
-
- scan->prev_scanned_node = NULL;
-}
-EXPORT_SYMBOL(drm_mm_scan_init);
-
-/**
* drm_mm_scan_init_with_range - initialize range-restricted lru scanning
* @scan: scan state
* @mm: drm_mm to scan
@@ -788,7 +748,6 @@ void drm_mm_scan_init_with_range(struct drm_mm_scan *scan,
DRM_MM_BUG_ON(end <= start);
scan->range_start = start;
scan->range_end = end;
- scan->check_range = 1;

scan->hit_start = U64_MAX;
scan->hit_end = 0;
@@ -830,15 +789,11 @@ bool drm_mm_scan_add_block(struct drm_mm_scan *scan,
node->node_list.next = &scan->prev_scanned_node->node_list;
scan->prev_scanned_node = node;

- adj_start = hole_start = drm_mm_hole_node_start(hole);
- adj_end = hole_end = drm_mm_hole_node_end(hole);
+ hole_start = drm_mm_hole_node_start(hole);
+ hole_end = drm_mm_hole_node_end(hole);

- if (scan->check_range) {
- if (adj_start < scan->range_start)
- adj_start = scan->range_start;
- if (adj_end > scan->range_end)
- adj_end = scan->range_end;
- }
+ adj_start = max(hole_start, scan->range_start);
+ adj_end = min(hole_end, scan->range_end);

if (mm->color_adjust)
mm->color_adjust(hole, scan->color, &adj_start, &adj_end);
diff --git a/drivers/gpu/drm/i915/i915_gem_evict.c b/drivers/gpu/drm/i915/i915_gem_evict.c
index 6db0d73c0aa7..77ded288534b 100644
--- a/drivers/gpu/drm/i915/i915_gem_evict.c
+++ b/drivers/gpu/drm/i915/i915_gem_evict.c
@@ -126,13 +126,9 @@ i915_gem_evict_something(struct i915_address_space *vm,
* On each list, the oldest objects lie at the HEAD with the freshest
* object on the TAIL.
*/
- if (start != 0 || end != vm->total) {
- drm_mm_scan_init_with_range(&scan, &vm->mm, min_size,
- alignment, cache_level,
- start, end);
- } else
- drm_mm_scan_init(&scan, &vm->mm, min_size,
- alignment, cache_level);
+ drm_mm_scan_init_with_range(&scan, &vm->mm,
+ min_size, alignment, cache_level,
+ start, end);

/* Retire before we search the active list. Although we have
* reasonable accuracy in our retirement lists, we may have
diff --git a/include/drm/drm_mm.h b/include/drm/drm_mm.h
index fcad718c5fb4..bae0f10da8e3 100644
--- a/include/drm/drm_mm.h
+++ b/include/drm/drm_mm.h
@@ -120,7 +120,6 @@ struct drm_mm_scan {
struct drm_mm_node *prev_scanned_node;

unsigned long color;
- bool check_range : 1;
};

/**
@@ -387,11 +386,6 @@ __drm_mm_interval_first(const struct drm_mm *mm, u64 start, u64 last);
node__ && node__->start < (end__); \
node__ = list_next_entry(node__, node_list))

-void drm_mm_scan_init(struct drm_mm_scan *scan,
- struct drm_mm *mm,
- u64 size,
- u64 alignment,
- unsigned long color);
void drm_mm_scan_init_with_range(struct drm_mm_scan *scan,
struct drm_mm *mm,
u64 size,
@@ -399,6 +393,33 @@ void drm_mm_scan_init_with_range(struct drm_mm_scan *scan,
unsigned long color,
u64 start,
u64 end);
+
+/**
+ * drm_mm_scan_init - initialize lru scanning
+ * @scan: scan state
+ * @mm: drm_mm to scan
+ * @size: size of the allocation
+ * @alignment: alignment of the allocation
+ * @color: opaque tag value to use for the allocation
+ *
+ * This simply sets up the scanning routines with the parameters for the desired
+ * hole. Note that there's no need to specify allocation flags, since they only
+ * change the place a node is allocated from within a suitable 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.
+ */
+static inline void drm_mm_scan_init(struct drm_mm_scan *scan,
+ struct drm_mm *mm,
+ u64 size,
+ u64 alignment,
+ unsigned long color)
+{
+ drm_mm_scan_init_with_range(scan, mm, size, alignment, color,
+ 0, U64_MAX);
+}
+
bool drm_mm_scan_add_block(struct drm_mm_scan *scan,
struct drm_mm_node *node);
bool drm_mm_scan_remove_block(struct drm_mm_scan *scan,