drm/i915: Replace execbuf vma ht with an idr

This was the competing idea long ago, but it was only with the rewrite
of the idr as an radixtree and using the radixtree directly ourselves,
along with the realisation that we can store the vma directly in the
radixtree and only need a list for the reverse mapping, that made the
patch performant enough to displace using a hashtable. Though the vma ht
is fast and doesn't require any extra allocation (as we can embed the node
inside the vma), it does require a thread for resizing and serialization
and will have the occasional slow lookup. That is hairy enough to
investigate alternatives and favour them if equivalent in peak performance.
One advantage of allocating an indirection entry is that we can support a
single shared bo between many clients, something that was done on a
first-come first-serve basis for shared GGTT vma previously. To offset
the extra allocations, we create yet another kmem_cache for them.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170816085210.4199-5-chris@chris-wilson.co.uk

1 files changed, 0 insertions, 22 deletions

diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index 958be0a95960..02d1a5eacb00 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -597,33 +597,11 @@ static void i915_vma_destroy(struct i915_vma *vma)
 	kmem_cache_free(to_i915(vma->obj->base.dev)->vmas, vma);
 }
 
-void i915_vma_unlink_ctx(struct i915_vma *vma)
-{
-	struct i915_gem_context *ctx = vma->ctx;
-
-	if (ctx->vma_lut.ht_size & I915_CTX_RESIZE_IN_PROGRESS) {
-		cancel_work_sync(&ctx->vma_lut.resize);
-		ctx->vma_lut.ht_size &= ~I915_CTX_RESIZE_IN_PROGRESS;
-	}
-
-	__hlist_del(&vma->ctx_node);
-	ctx->vma_lut.ht_count--;
-
-	if (i915_vma_is_ggtt(vma))
-		vma->obj->vma_hashed = NULL;
-	vma->ctx = NULL;
-
-	i915_vma_put(vma);
-}
-
 void i915_vma_close(struct i915_vma *vma)
 {
 	GEM_BUG_ON(i915_vma_is_closed(vma));
 	vma->flags |= I915_VMA_CLOSED;
 
-	if (vma->ctx)
-		i915_vma_unlink_ctx(vma);
-
 	list_del(&vma->obj_link);
 	rb_erase(&vma->obj_node, &vma->obj->vma_tree);