[igt-dev] [PATCH i-g-t] igt/prime_vgem: Ask the shrinker to purge a vgem bo from inside i915

[Chris Wilson]

Link a vgem dmabuf into an i915 bo and then ask the i915 shrinker to
purge/invalidate its pages. This should establish the lockdep link from
the fs_reclaim shrinker section to whatever locks are used to
acquire/release dmabuf mappings; if any are required ofc.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
Cc: Daniel Vetter <daniel at ffwll.ch>
---
 tests/prime_vgem.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/tests/prime_vgem.c b/tests/prime_vgem.c
index d886044a4..3b3dcc910 100644
--- a/tests/prime_vgem.c
+++ b/tests/prime_vgem.c
@@ -237,6 +237,32 @@ static void test_gtt(int vgem, int i915)
 	gem_close(vgem, scratch.handle);
 }
 
+static void test_shrink(int vgem, int i915)
+{
+	struct vgem_bo scratch = {
+		.width = 1024,
+		.height = 1024,
+		.bpp = 32
+	};
+	int dmabuf;
+
+	vgem_create(vgem, &scratch);
+
+	dmabuf = prime_handle_to_fd(vgem, scratch.handle);
+	gem_close(vgem, scratch.handle);
+
+	scratch.handle = prime_fd_to_handle(i915, dmabuf);
+	close(dmabuf);
+
+	/* Populate the i915_bo->pages. */
+	gem_set_domain(i915, scratch.handle, I915_GEM_DOMAIN_GTT, 0);
+
+	/* Now evict them, establising the link from i915:shrinker to vgem. */
+	igt_drop_caches_set(i915, DROP_SHRINK_ALL);
+
+	gem_close(i915, scratch.handle);
+}
+
 static bool is_coherent(int i915)
 {
 	int val = 1; /* by default, we assume GTT is coherent, hence the test */
@@ -794,6 +820,9 @@ igt_main
 	igt_subtest("basic-gtt")
 		test_gtt(vgem, i915);
 
+	igt_subtest("shrink")
+		test_shrink(vgem, i915);
+
 	igt_subtest("coherency-gtt")
 		test_gtt_interleaved(vgem, i915);
 
-- 
2.18.0