Re: [Intel-gfx] [PATCH v2 1/6] drm/i915/ttm: Implement a function to copy the contents of two TTM-base objects

[Matthew Auld]

On 06/09/2021 17:55, Thomas Hellström wrote:

When backing up or restoring contents of pinned objects at suspend /
resume time we need to allocate a new object as the backup. Add a function
to facilitate copies between the two. Some data needs to be copied before
the migration context is ready for operation, so make sure we can
disable accelerated copies.

Signed-off-by: Thomas Hellström 
---





+
+/**
+ * i915_gem_obj_copy_ttm - Copy the contents of one ttm-based gem object to
+ * another
+ * @dst: The destination object
+ * @src: The source object
+ * @allow_accel: Allow using the blitter. Otherwise TTM memcpy is used.
+ * @intr: Whether to perform waits interruptible:
+ *
+ * Note: The caller is responsible for assuring that the underlying
+ * TTM objects are populated if needed and locked.
+ *
+ * Return: Zero on success. Negative error code on error. If @intr == true,
+ * then it may return -ERESTARTSYS or -EINTR.
+ */
+int i915_gem_obj_copy_ttm(struct drm_i915_gem_object *dst,
+ struct drm_i915_gem_object *src,
+ bool allow_accel, bool intr)
+{
+   struct ttm_buffer_object *dst_bo = i915_gem_to_ttm(dst);
+   struct ttm_buffer_object *src_bo = i915_gem_to_ttm(src);
+   struct ttm_operation_ctx ctx = {
+   .interruptible = intr,
+   };
+   struct sg_table *dst_st;
+   int ret;
+
+   assert_object_held(dst);
+   assert_object_held(src);
+
+   /*
+* Sync for now. This will change with async moves.
+*/
+   ret = ttm_bo_wait_ctx(dst_bo, );
+   if (!ret)
+   ttm_bo_wait_ctx(src_bo, );


ret = ?


+   if (ret)
+   return ret;
+
+   dst_st = gpu_binds_iomem(dst_bo->resource) ?
+   dst->ttm.cached_io_st : i915_ttm_tt_get_st(dst_bo->ttm);
+
+   __i915_ttm_move(src_bo, false, dst_bo->resource, dst_bo->ttm,
+   dst_st, allow_accel);
+
+   return 0;
+}
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.h 
b/drivers/gpu/drm/i915/gem/i915_gem_ttm.h
index 40927f67b6d9..34ac78d47b0d 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.h
@@ -46,4 +46,8 @@ int __i915_gem_ttm_object_init(struct intel_memory_region 
*mem,
   resource_size_t size,
   resource_size_t page_size,
   unsigned int flags);
+
+int i915_gem_obj_copy_ttm(struct drm_i915_gem_object *dst,
+ struct drm_i915_gem_object *src,
+ bool allow_accel, bool intr);
  #endif

[Intel-gfx] [PATCH v2 1/6] drm/i915/ttm: Implement a function to copy the contents of two TTM-base objects

[Thomas Hellström]

When backing up or restoring contents of pinned objects at suspend /
resume time we need to allocate a new object as the backup. Add a function
to facilitate copies between the two. Some data needs to be copied before
the migration context is ready for operation, so make sure we can
disable accelerated copies.

Signed-off-by: Thomas Hellström 
---
 drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 69 +
 drivers/gpu/drm/i915/gem/i915_gem_ttm.h |  4 ++
 2 files changed, 64 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c 
b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
index 59ca53a3ef6a..df2dcbad1eb9 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
@@ -432,6 +432,7 @@ i915_ttm_resource_get_st(struct drm_i915_gem_object *obj,
 static int i915_ttm_accel_move(struct ttm_buffer_object *bo,
   bool clear,
   struct ttm_resource *dst_mem,
+  struct ttm_tt *dst_ttm,
   struct sg_table *dst_st)
 {
struct drm_i915_private *i915 = container_of(bo->bdev, typeof(*i915),
@@ -441,14 +442,14 @@ static int i915_ttm_accel_move(struct ttm_buffer_object 
*bo,
struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
struct sg_table *src_st;
struct i915_request *rq;
-   struct ttm_tt *ttm = bo->ttm;
+   struct ttm_tt *src_ttm = bo->ttm;
enum i915_cache_level src_level, dst_level;
int ret;
 
if (!i915->gt.migrate.context)
return -EINVAL;
 
-   dst_level = i915_ttm_cache_level(i915, dst_mem, ttm);
+   dst_level = i915_ttm_cache_level(i915, dst_mem, dst_ttm);
if (clear) {
if (bo->type == ttm_bo_type_kernel)
return -EINVAL;
@@ -465,10 +466,10 @@ static int i915_ttm_accel_move(struct ttm_buffer_object 
*bo,
}
intel_engine_pm_put(i915->gt.migrate.context->engine);
} else {
-   src_st = src_man->use_tt ? i915_ttm_tt_get_st(ttm) :
+   src_st = src_man->use_tt ? i915_ttm_tt_get_st(src_ttm) :
obj->ttm.cached_io_st;
 
-   src_level = i915_ttm_cache_level(i915, bo->resource, ttm);
+   src_level = i915_ttm_cache_level(i915, bo->resource, src_ttm);
intel_engine_pm_get(i915->gt.migrate.context->engine);
ret = intel_context_migrate_copy(i915->gt.migrate.context,
 NULL, src_st->sgl, src_level,
@@ -488,11 +489,14 @@ static int i915_ttm_accel_move(struct ttm_buffer_object 
*bo,
 
 static void __i915_ttm_move(struct ttm_buffer_object *bo, bool clear,
struct ttm_resource *dst_mem,
-   struct sg_table *dst_st)
+   struct ttm_tt *dst_ttm,
+   struct sg_table *dst_st,
+   bool allow_accel)
 {
-   int ret;
+   int ret = -EINVAL;
 
-   ret = i915_ttm_accel_move(bo, clear, dst_mem, dst_st);
+   if (allow_accel)
+   ret = i915_ttm_accel_move(bo, clear, dst_mem, dst_ttm, dst_st);
if (ret) {
struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
struct intel_memory_region *dst_reg, *src_reg;
@@ -507,7 +511,7 @@ static void __i915_ttm_move(struct ttm_buffer_object *bo, 
bool clear,
GEM_BUG_ON(!dst_reg || !src_reg);
 
dst_iter = !cpu_maps_iomem(dst_mem) ?
-   ttm_kmap_iter_tt_init(&_dst_iter.tt, bo->ttm) :
+   ttm_kmap_iter_tt_init(&_dst_iter.tt, dst_ttm) :
ttm_kmap_iter_iomap_init(&_dst_iter.io, _reg->iomap,
 dst_st, dst_reg->region.start);
 
@@ -562,7 +566,7 @@ static int i915_ttm_move(struct ttm_buffer_object *bo, bool 
evict,
 
clear = !cpu_maps_iomem(bo->resource) && (!ttm || 
!ttm_tt_is_populated(ttm));
if (!(clear && ttm && !(ttm->page_flags & TTM_PAGE_FLAG_ZERO_ALLOC)))
-   __i915_ttm_move(bo, clear, dst_mem, dst_st);
+   __i915_ttm_move(bo, clear, dst_mem, bo->ttm, dst_st, true);
 
ttm_bo_move_sync_cleanup(bo, dst_mem);
i915_ttm_adjust_domains_after_move(obj);
@@ -973,3 +977,50 @@ i915_gem_ttm_system_setup(struct drm_i915_private *i915,
intel_memory_region_set_name(mr, "system-ttm");
return mr;
 }
+
+/**
+ * i915_gem_obj_copy_ttm - Copy the contents of one ttm-based gem object to
+ * another
+ * @dst: The destination object
+ * @src: The source object
+ * @allow_accel: Allow using the blitter. Otherwise TTM memcpy is used.
+ * @intr: Whether to perform waits interruptible:
+ *
+ * Note: The caller is responsible for assuring that the underlying
+ * TTM objects are populated if needed and locked.
+ *
+ * Return: Zero on