[Intel-gfx] [PATCH 06/20] drm/i915: add I915_BO_ALLOC_TOPDOWN

Matthew Auld
2022-01-26T15:22:42Z

If the user doesn't require CPU access for the buffer, then
ALLOC_TOPDOWN should be used, in order to prioritise allocating in the
non-mappable portion of LMEM.

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
---
drivers/gpu/drm/i915/gem/i915_gem_object_types.h | 15 +++++++++++----
drivers/gpu/drm/i915/gem/i915_gem_pages.c | 3 +++
drivers/gpu/drm/i915/gem/i915_gem_region.c | 5 +++++
drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 13 ++++++++++---
drivers/gpu/drm/i915/gt/intel_gt.c | 4 +++-
drivers/gpu/drm/i915/i915_vma.c | 3 +++
drivers/gpu/drm/i915/intel_region_ttm.c | 11 ++++++++---
drivers/gpu/drm/i915/selftests/mock_region.c | 7 +------
8 files changed, 44 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
index 71e778ecaeb8..29285aaf0477 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
@@ -319,15 +319,22 @@ struct drm_i915_gem_object {
#define I915_BO_ALLOC_PM_VOLATILE BIT(4)
/* Object needs to be restored early using memcpy during resume */
#define I915_BO_ALLOC_PM_EARLY BIT(5)
+/*
+ * Object is likely never accessed by the CPU. This will prioritise the BO to be
+ * allocated in the non-mappable portion of lmem. This is merely a hint, and if
+ * dealing with userspace objects the CPU fault handler is free to ignore this.
+ */
+#define I915_BO_ALLOC_TOPDOWN BIT(6)
#define I915_BO_ALLOC_FLAGS (I915_BO_ALLOC_CONTIGUOUS | \
I915_BO_ALLOC_VOLATILE | \
I915_BO_ALLOC_CPU_CLEAR | \
I915_BO_ALLOC_USER | \
I915_BO_ALLOC_PM_VOLATILE | \
- I915_BO_ALLOC_PM_EARLY)
-#define I915_BO_READONLY BIT(6)
-#define I915_TILING_QUIRK_BIT 7 /* unknown swizzling; do not release! */
-#define I915_BO_PROTECTED BIT(8)
+ I915_BO_ALLOC_PM_EARLY | \
+ I915_BO_ALLOC_TOPDOWN)
+#define I915_BO_READONLY BIT(7)
+#define I915_TILING_QUIRK_BIT 8 /* unknown swizzling; do not release! */
+#define I915_BO_PROTECTED BIT(9)
/**
* @mem_flags - Mutable placement-related flags
*
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pages.c b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
index 7d2211fbe548..a95b4d72619f 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_pages.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
@@ -346,6 +346,9 @@ void *i915_gem_object_pin_map(struct drm_i915_gem_object *obj,
!i915_gem_object_has_iomem(obj))
return ERR_PTR(-ENXIO);

+ if (WARN_ON_ONCE(obj->flags & I915_BO_ALLOC_TOPDOWN))
+ return ERR_PTR(-EINVAL);
+
assert_object_held(obj);

pinned = !(type & I915_MAP_OVERRIDE);
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_region.c b/drivers/gpu/drm/i915/gem/i915_gem_region.c
index a4350227e9ae..f91e5a9c759d 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_region.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_region.c
@@ -45,6 +45,11 @@ i915_gem_object_create_region(struct intel_memory_region *mem,

GEM_BUG_ON(flags & ~I915_BO_ALLOC_FLAGS);

+ if (WARN_ON_ONCE(flags & I915_BO_ALLOC_TOPDOWN &&
+ (flags & I915_BO_ALLOC_CPU_CLEAR ||
+ flags & I915_BO_ALLOC_PM_EARLY)))
+ return ERR_PTR(-EINVAL);
+
if (!mem)
return ERR_PTR(-ENODEV);

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
index d9a04c7d41b1..e60b677ecd54 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
@@ -127,10 +127,14 @@ i915_ttm_place_from_region(const struct intel_memory_region *mr,
place->mem_type = intel_region_to_ttm_type(mr);

if (flags & I915_BO_ALLOC_CONTIGUOUS)
- place->flags = TTM_PL_FLAG_CONTIGUOUS;
+ place->flags |= TTM_PL_FLAG_CONTIGUOUS;
if (mr->io_size && mr->io_size < mr->total) {
- place->fpfn = 0;
- place->lpfn = mr->io_size >> PAGE_SHIFT;
+ if (flags & I915_BO_ALLOC_TOPDOWN) {
+ place->flags |= TTM_PL_FLAG_TOPDOWN;
+ } else {
+ place->fpfn = 0;
+ place->lpfn = mr->io_size >> PAGE_SHIFT;
+ }
}
}

@@ -890,6 +894,9 @@ static vm_fault_t vm_fault_ttm(struct vm_fault *vmf)
if (!obj)
return VM_FAULT_SIGBUS;

+ if (obj->flags & I915_BO_ALLOC_TOPDOWN)
+ return -EINVAL;
+
/* Sanity check that we allow writing into this object */
if (unlikely(i915_gem_object_is_readonly(obj) &&
area->vm_flags & VM_WRITE))
diff --git a/drivers/gpu/drm/i915/gt/intel_gt.c b/drivers/gpu/drm/i915/gt/intel_gt.c
index 622cdfed8a8b..8b83a771a2f7 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt.c
@@ -454,7 +454,9 @@ static int intel_gt_init_scratch(struct intel_gt *gt, unsigned int size)
struct i915_vma *vma;
int ret;

- obj = i915_gem_object_create_lmem(i915, size, I915_BO_ALLOC_VOLATILE);
+ obj = i915_gem_object_create_lmem(i915, size,
+ I915_BO_ALLOC_VOLATILE |
+ I915_BO_ALLOC_TOPDOWN);
if (IS_ERR(obj))
obj = i915_gem_object_create_stolen(i915, size);
if (IS_ERR(obj))
diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index b1816a835abf..b2fdaa74e4b6 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -528,6 +528,9 @@ void __iomem *i915_vma_pin_iomap(struct i915_vma *vma)
void __iomem *ptr;
int err;

+ if (WARN_ON_ONCE(vma->obj->flags & I915_BO_ALLOC_TOPDOWN))
+ return IO_ERR_PTR(-EINVAL);
+
if (!i915_gem_object_is_lmem(vma->obj)) {
if (GEM_WARN_ON(!i915_vma_is_map_and_fenceable(vma))) {
err = -ENODEV;
diff --git a/drivers/gpu/drm/i915/intel_region_ttm.c b/drivers/gpu/drm/i915/intel_region_ttm.c
index 4689192d5e8d..282802aed174 100644
--- a/drivers/gpu/drm/i915/intel_region_ttm.c
+++ b/drivers/gpu/drm/i915/intel_region_ttm.c
@@ -199,13 +199,18 @@ intel_region_ttm_resource_alloc(struct intel_memory_region *mem,
struct ttm_resource *res;
int ret;

+ if (flags & I915_BO_ALLOC_CONTIGUOUS)
+ place.flags |= TTM_PL_FLAG_CONTIGUOUS;
if (mem->io_size && mem->io_size < mem->total) {
- place.fpfn = 0;
- place.lpfn = mem->io_size >> PAGE_SHIFT;
+ if (flags & I915_BO_ALLOC_TOPDOWN) {
+ place.flags |= TTM_PL_FLAG_TOPDOWN;
+ } else {
+ place.fpfn = 0;
+ place.lpfn = mem->io_size >> PAGE_SHIFT;
+ }
}

mock_bo.base.size = size;
- place.flags = flags;

ret = man->func->alloc(man, &mock_bo, &place, &res);
if (ret == -ENOSPC)
diff --git a/drivers/gpu/drm/i915/selftests/mock_region.c b/drivers/gpu/drm/i915/selftests/mock_region.c
index 467eeae6d5f0..f64325491f35 100644
--- a/drivers/gpu/drm/i915/selftests/mock_region.c
+++ b/drivers/gpu/drm/i915/selftests/mock_region.c
@@ -22,17 +22,12 @@ static void mock_region_put_pages(struct drm_i915_gem_object *obj,

static int mock_region_get_pages(struct drm_i915_gem_object *obj)
{
- unsigned int flags;
struct sg_table *pages;
int err;

- flags = 0;
- if (obj->flags & I915_BO_ALLOC_CONTIGUOUS)
- flags |= TTM_PL_FLAG_CONTIGUOUS;
-
obj->mm.res = intel_region_ttm_resource_alloc(obj->mm.region,
obj->base.size,
- flags);
+ obj->flags);
if (IS_ERR(obj->mm.res))
return PTR_ERR(obj->mm.res);

--
2.34.1