drm/i915: Add VM to context
Pretty straightforward so far except for the bit about the refcounting.
The PPGTT will potentially be shared amongst multiple contexts. Because
contexts themselves have a refcounted lifecycle, the easiest way to
manage this will be to refcount the PPGTT. To acheive this, we piggy
back off of the existing context refcount, and will increment and
decrement the PPGTT refcount with context creation, and destruction.
To put it more clearly, if context A, and context B both use PPGTT 0, we
can't free the PPGTT until both A, and B are destroyed.
Note that because the PPGTT is permanently pinned (for now), it really
just matters for the PPGTT destruction, as opposed to making space under
memory pressure.
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index dbea50a0..a47a43e 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -655,6 +655,7 @@
struct i915_hw_ppgtt {
struct i915_address_space base;
+ struct kref ref;
struct drm_mm_node node;
unsigned num_pd_entries;
union {
@@ -704,6 +705,7 @@
struct intel_ring_buffer *last_ring;
struct drm_i915_gem_object *obj;
struct i915_ctx_hang_stats hang_stats;
+ struct i915_address_space *vm;
struct list_head link;
};
@@ -2292,6 +2294,12 @@
return HAS_ALIASING_PPGTT(dev);
}
+static inline void ppgtt_release(struct kref *kref)
+{
+ struct i915_hw_ppgtt *ppgtt = container_of(kref, struct i915_hw_ppgtt, ref);
+
+ ppgtt->base.cleanup(&ppgtt->base);
+}
/* i915_gem_evict.c */
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 149cf00..0b32bcf 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -141,9 +141,19 @@
{
struct i915_hw_context *ctx = container_of(ctx_ref,
typeof(*ctx), ref);
+ struct i915_hw_ppgtt *ppgtt = NULL;
- list_del(&ctx->link);
+ /* We refcount even the aliasing PPGTT to keep the code symmetric */
+ if (USES_ALIASING_PPGTT(ctx->obj->base.dev))
+ ppgtt = container_of(ctx->vm, struct i915_hw_ppgtt, base);
+
+ /* XXX: Free up the object before tearing down the address space, in
+ * case we're bound in the PPGTT */
drm_gem_object_unreference(&ctx->obj->base);
+
+ if (ppgtt)
+ kref_put(&ppgtt->ref, ppgtt_release);
+ list_del(&ctx->link);
kfree(ctx);
}
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index c69fa2c..bd92288 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -902,9 +902,11 @@
else
BUG();
- if (!ret)
+ if (!ret) {
+ kref_init(&ppgtt->ref);
drm_mm_init(&ppgtt->base.mm, ppgtt->base.start,
ppgtt->base.total);
+ }
return ret;
}
@@ -917,7 +919,8 @@
if (!ppgtt)
return;
- ppgtt->base.cleanup(&ppgtt->base);
+ kref_put(&dev_priv->mm.aliasing_ppgtt->ref, ppgtt_release);
+
dev_priv->mm.aliasing_ppgtt = NULL;
}