drm/i915: Allow contexts to be unreferenced locklessly

If we move the actual cleanup of the context to a worker, we can allow
the final free to be called from any context and avoid undue latency in
the caller.

v2: Negotiate handling the delayed contexts free by flushing the
workqueue before calling i915_gem_context_fini() and performing the final
free of the kernel context directly
v3: Flush deferred frees before new context allocations

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170620110547.15947-2-chris@chris-wilson.co.uk

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/selftests/mock_context.c b/drivers/gpu/drm/i915/selftests/mock_context.c
index 243325b97d4c..9c7c68181f82 100644
--- a/drivers/gpu/drm/i915/selftests/mock_context.c
+++ b/drivers/gpu/drm/i915/selftests/mock_context.c
@@ -86,3 +86,12 @@ void mock_context_close(struct i915_gem_context *ctx)
 
 	i915_gem_context_put(ctx);
 }
+
+void mock_init_contexts(struct drm_i915_private *i915)
+{
+	INIT_LIST_HEAD(&i915->contexts.list);
+	ida_init(&i915->contexts.hw_ida);
+
+	INIT_WORK(&i915->contexts.free_work, contexts_free_worker);
+	init_llist_head(&i915->contexts.free_list);
+}