drm: Compute tight evictions for drm_mm_scan
Compute the minimal required hole during scan and only evict those nodes
that overlap. This enables us to reduce the number of nodes we need to
evict to the bare minimum.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20161222083641.2691-31-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c
index 1b5613b..189ab84 100644
--- a/drivers/gpu/drm/drm_mm.c
+++ b/drivers/gpu/drm/drm_mm.c
@@ -718,10 +718,10 @@
* @color: opaque tag value to use for the allocation
* @start: start of the allowed range for the allocation
* @end: end of the allowed range for the allocation
+ * @flags: flags to specify how the allocation will be performed afterwards
*
* 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.
+ * hole.
*
* Warning:
* As long as the scan list is non-empty, no other operations than
@@ -733,7 +733,8 @@
u64 alignment,
unsigned long color,
u64 start,
- u64 end)
+ u64 end,
+ unsigned int flags)
{
DRM_MM_BUG_ON(start >= end);
DRM_MM_BUG_ON(!size || size > end - start);
@@ -744,6 +745,7 @@
scan->color = color;
scan->alignment = alignment;
scan->size = size;
+ scan->flags = flags;
DRM_MM_BUG_ON(end <= start);
scan->range_start = start;
@@ -778,7 +780,7 @@
DRM_MM_BUG_ON(node->mm != mm);
DRM_MM_BUG_ON(!node->allocated);
DRM_MM_BUG_ON(node->scanned_block);
- node->scanned_block = 1;
+ node->scanned_block = true;
mm->scan_active++;
hole = list_prev_entry(node, node_list);
@@ -800,15 +802,53 @@
adj_start = max(col_start, scan->range_start);
adj_end = min(col_end, scan->range_end);
+ if (adj_end <= adj_start || adj_end - adj_start < scan->size)
+ return false;
- if (check_free_hole(adj_start, adj_end,
- scan->size, scan->alignment)) {
- scan->hit_start = hole_start;
- scan->hit_end = hole_end;
- return true;
+ if (scan->flags == DRM_MM_CREATE_TOP)
+ adj_start = adj_end - scan->size;
+
+ if (scan->alignment) {
+ u64 rem;
+
+ div64_u64_rem(adj_start, scan->alignment, &rem);
+ if (rem) {
+ adj_start -= rem;
+ if (scan->flags != DRM_MM_CREATE_TOP)
+ adj_start += scan->alignment;
+ if (adj_start < max(col_start, scan->range_start) ||
+ min(col_end, scan->range_end) - adj_start < scan->size)
+ return false;
+
+ if (adj_end <= adj_start ||
+ adj_end - adj_start < scan->size)
+ return false;
+ }
}
- return false;
+ if (mm->color_adjust) {
+ /* If allocations need adjusting due to neighbouring colours,
+ * we do not have enough information to decide if we need
+ * to evict nodes on either side of [adj_start, adj_end].
+ * What almost works is
+ * hit_start = adj_start + (hole_start - col_start);
+ * hit_end = adj_start + scan->size + (hole_end - col_end);
+ * but because the decision is only made on the final hole,
+ * we may underestimate the required adjustments for an
+ * interior allocation.
+ */
+ scan->hit_start = hole_start;
+ scan->hit_end = hole_end;
+ } else {
+ scan->hit_start = adj_start;
+ scan->hit_end = adj_start + scan->size;
+ }
+
+ DRM_MM_BUG_ON(scan->hit_start >= scan->hit_end);
+ DRM_MM_BUG_ON(scan->hit_start < hole_start);
+ DRM_MM_BUG_ON(scan->hit_end > hole_end);
+
+ return true;
}
EXPORT_SYMBOL(drm_mm_scan_add_block);
@@ -836,7 +876,7 @@
DRM_MM_BUG_ON(node->mm != scan->mm);
DRM_MM_BUG_ON(!node->scanned_block);
- node->scanned_block = 0;
+ node->scanned_block = false;
DRM_MM_BUG_ON(!node->mm->scan_active);
node->mm->scan_active--;
@@ -846,7 +886,7 @@
prev_node->hole_follows = node->scanned_preceeds_hole;
list_add(&node->node_list, &prev_node->node_list);
- return (drm_mm_hole_node_end(node) > scan->hit_start &&
+ return (node->start + node->size > scan->hit_start &&
node->start < scan->hit_end);
}
EXPORT_SYMBOL(drm_mm_scan_remove_block);
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_mmu.c b/drivers/gpu/drm/etnaviv/etnaviv_mmu.c
index 379ea3a..ae2733a 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_mmu.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_mmu.c
@@ -135,7 +135,7 @@
}
/* Try to retire some entries */
- drm_mm_scan_init(&scan, &mmu->mm, size, 0, 0);
+ drm_mm_scan_init(&scan, &mmu->mm, size, 0, 0, 0);
found = 0;
INIT_LIST_HEAD(&list);
diff --git a/drivers/gpu/drm/i915/i915_gem_evict.c b/drivers/gpu/drm/i915/i915_gem_evict.c
index a6d5bab..fa90a0c 100644
--- a/drivers/gpu/drm/i915/i915_gem_evict.c
+++ b/drivers/gpu/drm/i915/i915_gem_evict.c
@@ -128,7 +128,8 @@
*/
drm_mm_scan_init_with_range(&scan, &vm->mm,
min_size, alignment, cache_level,
- start, end);
+ start, end,
+ flags & PIN_HIGH ? DRM_MM_CREATE_TOP : 0);
if (flags & PIN_NONBLOCK)
phases[1] = NULL;
diff --git a/drivers/gpu/drm/selftests/test-drm_mm.c b/drivers/gpu/drm/selftests/test-drm_mm.c
index 997f2bc..1bbfc24 100644
--- a/drivers/gpu/drm/selftests/test-drm_mm.c
+++ b/drivers/gpu/drm/selftests/test-drm_mm.c
@@ -1199,7 +1199,7 @@
struct drm_mm_node *node;
unsigned int n;
- drm_mm_scan_init(&scan, mm, 1, 0, 0);
+ drm_mm_scan_init(&scan, mm, 1, 0, 0, 0);
for (n = 0; n < total_size; n++) {
e = &nodes[n];
list_add(&e->link, &evict_list);
@@ -1246,7 +1246,7 @@
unsigned int n;
int err;
- drm_mm_scan_init(&scan, mm, total_size, 0, 0);
+ drm_mm_scan_init(&scan, mm, total_size, 0, 0, 0);
for (n = 0; n < total_size; n++) {
e = &nodes[n];
list_add(&e->link, &evict_list);
@@ -1296,7 +1296,8 @@
drm_mm_scan_init_with_range(&scan, mm,
size, alignment, 0,
- range_start, range_end);
+ range_start, range_end,
+ mode->create_flags);
if (!evict_nodes(&scan,
nodes, order, count,
&evict_list))
@@ -1874,7 +1875,8 @@
drm_mm_scan_init_with_range(&scan, mm,
size, alignment, color,
- range_start, range_end);
+ range_start, range_end,
+ mode->create_flags);
if (!evict_nodes(&scan,
nodes, order, count,
&evict_list))
diff --git a/include/drm/drm_mm.h b/include/drm/drm_mm.h
index bae0f10..606336f 100644
--- a/include/drm/drm_mm.h
+++ b/include/drm/drm_mm.h
@@ -120,6 +120,7 @@
struct drm_mm_node *prev_scanned_node;
unsigned long color;
+ unsigned int flags;
};
/**
@@ -388,11 +389,9 @@
void drm_mm_scan_init_with_range(struct drm_mm_scan *scan,
struct drm_mm *mm,
- u64 size,
- u64 alignment,
- unsigned long color,
- u64 start,
- u64 end);
+ u64 size, u64 alignment, unsigned long color,
+ u64 start, u64 end,
+ unsigned int flags);
/**
* drm_mm_scan_init - initialize lru scanning
@@ -401,10 +400,10 @@
* @size: size of the allocation
* @alignment: alignment of the allocation
* @color: opaque tag value to use for the allocation
+ * @flags: flags to specify how the allocation will be performed afterwards
*
* 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.
+ * hole.
*
* Warning:
* As long as the scan list is non-empty, no other operations than
@@ -414,10 +413,13 @@
struct drm_mm *mm,
u64 size,
u64 alignment,
- unsigned long color)
+ unsigned long color,
+ unsigned int flags)
{
- drm_mm_scan_init_with_range(scan, mm, size, alignment, color,
- 0, U64_MAX);
+ drm_mm_scan_init_with_range(scan, mm,
+ size, alignment, color,
+ 0, U64_MAX,
+ flags);
}
bool drm_mm_scan_add_block(struct drm_mm_scan *scan,