[PATCH 14/27] drm/i915/ttm: make eviction mappable aware

[Matthew Auld]

If we need to make room for some mappable object, then we should
only victimize objects that have one or pages that occupy the visible
portion of LMEM. Let's also create a new priority hint for objects that
are placed in mappable memory, where we know that CPU access was
requested, that way we hopefully victimize these last.

v2(Thomas): s/TTM_PL_PRIV/I915_PL_LMEM0/

Signed-off-by: Matthew Auld <matthew.auld at intel.com>
Cc: Thomas Hellström <thomas.hellstrom at linux.intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 65 ++++++++++++++++++++++++-
 1 file changed, 63 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
index 36e77fcf2ef9..3790e569d6a9 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
@@ -5,8 +5,10 @@
 
 #include <drm/ttm/ttm_bo_driver.h>
 #include <drm/ttm/ttm_placement.h>
+#include <drm/drm_buddy.h>
 
 #include "i915_drv.h"
+#include "i915_ttm_buddy_manager.h"
 #include "intel_memory_region.h"
 #include "intel_region_ttm.h"
 
@@ -20,6 +22,7 @@
 #define I915_TTM_PRIO_PURGE     0
 #define I915_TTM_PRIO_NO_PAGES  1
 #define I915_TTM_PRIO_HAS_PAGES 2
+#define I915_TTM_PRIO_NEEDS_CPU_ACCESS 3
 
 /*
  * Size of struct ttm_place vector in on-stack struct ttm_placement allocs
@@ -337,6 +340,7 @@ static bool i915_ttm_eviction_valuable(struct ttm_buffer_object *bo,
 				       const struct ttm_place *place)
 {
 	struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
+	struct ttm_resource *res = bo->resource;
 
 	if (!obj)
 		return false;
@@ -350,7 +354,48 @@ static bool i915_ttm_eviction_valuable(struct ttm_buffer_object *bo,
 		return false;
 
 	/* Will do for now. Our pinned objects are still on TTM's LRU lists */
-	return i915_gem_object_evictable(obj);
+	if (!i915_gem_object_evictable(obj))
+		return false;
+
+	switch (res->mem_type) {
+	case I915_PL_LMEM0: {
+		struct ttm_resource_manager *man =
+			ttm_manager_type(bo->bdev, res->mem_type);
+		struct i915_ttm_buddy_resource *bman_res =
+			to_ttm_buddy_resource(res);
+		struct drm_buddy *mm = bman_res->mm;
+		struct drm_buddy_block *block;
+
+		if (!place->fpfn && !place->lpfn)
+			return true;
+
+		GEM_BUG_ON(!place->lpfn);
+
+		/*
+		 * If we just want something mappable then we can quickly check
+		 * if the current victim resource is using any of the CPU
+		 * visible portion.
+		 */
+		if (!place->fpfn &&
+		    place->lpfn == i915_ttm_buddy_man_visible_size(man))
+			return bman_res->used_visible_size > 0;
+
+		/* Real range allocation */
+		list_for_each_entry(block, &bman_res->blocks, link) {
+			unsigned long fpfn =
+				drm_buddy_block_offset(block) >> PAGE_SHIFT;
+			unsigned long lpfn = fpfn +
+				(drm_buddy_block_size(mm, block) >> PAGE_SHIFT);
+
+			if (place->fpfn < lpfn && place->lpfn > fpfn)
+				return true;
+		}
+		return false;
+	} default:
+		break;
+	}
+
+	return true;
 }
 
 static void i915_ttm_evict_flags(struct ttm_buffer_object *bo,
@@ -850,7 +895,23 @@ void i915_ttm_adjust_lru(struct drm_i915_gem_object *obj)
 	} else if (!i915_gem_object_has_pages(obj)) {
 		bo->priority = I915_TTM_PRIO_NO_PAGES;
 	} else {
-		bo->priority = I915_TTM_PRIO_HAS_PAGES;
+		struct ttm_resource_manager *man =
+			ttm_manager_type(bo->bdev, bo->resource->mem_type);
+
+		/*
+		 * If we need to place an LMEM resource which doesn't need CPU
+		 * access then we should try not to victimize mappable objects
+		 * first, since we likely end up stealing more of the mappable
+		 * portion. And likewise when we try to find space for a mappble
+		 * object, we know not to ever victimize objects that don't
+		 * occupy any mappable pages.
+		 */
+		if (i915_ttm_cpu_maps_iomem(bo->resource) &&
+		    i915_ttm_buddy_man_visible_size(man) < man->size &&
+		    !(obj->flags & I915_BO_ALLOC_GPU_ONLY))
+			bo->priority = I915_TTM_PRIO_NEEDS_CPU_ACCESS;
+		else
+			bo->priority = I915_TTM_PRIO_HAS_PAGES;
 	}
 
 	ttm_bo_move_to_lru_tail(bo, bo->resource, NULL);
-- 
2.34.1