drm/i915: Store a direct lookup from object handle to vma

The advent of full-ppgtt lead to an extra indirection between the object
and its binding. That extra indirection has a noticeable impact on how
fast we can convert from the user handles to our internal vma for
execbuffer. In order to bypass the extra indirection, we use a
resizable hashtable to jump from the object to the per-ctx vma.
rhashtable was considered but we don't need the online resizing feature
and the extra complexity proved to undermine its usefulness. Instead, we
simply reallocate the hastable on demand in a background task and
serialize it before iterating.

In non-full-ppgtt modes, multiple files and multiple contexts can share
the same vma. This leads to having multiple possible handle->vma links,
so we only use the first to establish the fast path. The majority of
buffers are not shared and so we should still be able to realise
speedups with multiple clients.

v2: Prettier names, more magic.
v3: Many style tweaks, most notably hiding the misuse of execobj[].rsvd2

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/i915_vma.h b/drivers/gpu/drm/i915/i915_vma.h
index 11ce83a8adf0..ea98e6e4262f 100644
--- a/drivers/gpu/drm/i915/i915_vma.h
+++ b/drivers/gpu/drm/i915/i915_vma.h
@@ -99,6 +99,7 @@ struct i915_vma {
 
 	struct list_head obj_link; /* Link in the object's VMA list */
 	struct rb_node obj_node;
+	struct hlist_node obj_hash;
 
 	/** This vma's place in the execbuf reservation list */
 	struct list_head exec_link;
@@ -110,8 +111,12 @@ struct i915_vma {
 	 * Used for performing relocations during execbuffer insertion.
 	 */
 	struct hlist_node exec_node;
-	unsigned long exec_handle;
 	struct drm_i915_gem_exec_object2 *exec_entry;
+	u32 exec_handle;
+
+	struct i915_gem_context *ctx;
+	struct hlist_node ctx_node;
+	u32 ctx_handle;
 };
 
 struct i915_vma *
@@ -235,6 +240,7 @@ bool i915_vma_misplaced(const struct i915_vma *vma,
 			u64 size, u64 alignment, u64 flags);
 void __i915_vma_set_map_and_fenceable(struct i915_vma *vma);
 int __must_check i915_vma_unbind(struct i915_vma *vma);
+void i915_vma_unlink_ctx(struct i915_vma *vma);
 void i915_vma_close(struct i915_vma *vma);
 
 int __i915_vma_do_pin(struct i915_vma *vma,