[igt-dev] [PATCH i-g-t] tests/i915/madvise: verify async eviction with madvise

[Matthew Auld]

Simple regression test for lmem to check if an in-progress async unbind
and eviction is syncronised with discarding the pages when marking
the object as DONTNEED.

Signed-off-by: Matthew Auld <matthew.auld at intel.com>
Cc: Niranjana Vishwanathapura <niranjana.vishwanathapura at intel.com>
Cc: Andrzej Hajda <andrzej.hajda at intel.com>
Cc: Nirmoy Das <nirmoy.das at intel.com>
---
 tests/i915/gem_madvise.c | 130 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 129 insertions(+), 1 deletion(-)

diff --git a/tests/i915/gem_madvise.c b/tests/i915/gem_madvise.c
index 2502d84c..d164df3a 100644
--- a/tests/i915/gem_madvise.c
+++ b/tests/i915/gem_madvise.c
@@ -36,8 +36,9 @@
 #include <setjmp.h>
 #include <signal.h>
 
-#include "drm.h"
+#include "igt_kmod.h"
 #include "i915/gem_create.h"
+#include "i915/gem.h"
 
 IGT_TEST_DESCRIPTION("Checks that the kernel reports EFAULT when trying to use"
 		     " purged bo.");
@@ -188,6 +189,76 @@ dontneed_before_exec(void)
 	close(fd);
 }
 
+#define PAGE_SIZE 4096
+
+static uint32_t batch_create_size(int fd, uint64_t size)
+{
+	const uint32_t bbe = MI_BATCH_BUFFER_END;
+	uint32_t handle;
+
+	handle = gem_create(fd, size);
+	gem_write(fd, handle, 0, &bbe, sizeof(bbe));
+
+	return handle;
+}
+
+static int upload(int fd, uint32_t handle)
+{
+	struct drm_i915_gem_exec_object2 exec[2] = {};
+	struct drm_i915_gem_execbuffer2 execbuf = {
+		.buffers_ptr = to_user_pointer(&exec),
+		.buffer_count = 2,
+	};
+
+	exec[0].handle = handle;
+	exec[0].flags = EXEC_OBJECT_SUPPORTS_48B_ADDRESS;
+	exec[1].handle = batch_create_size(fd, PAGE_SIZE);
+	exec[1].flags = EXEC_OBJECT_SUPPORTS_48B_ADDRESS;
+
+	gem_execbuf(fd, &execbuf);
+	return 0;
+}
+
+static void test_dontneed_evict_race(int fd,
+				     struct gem_memory_region *region)
+{
+	const uint64_t size = region->size >> 1;
+	uint64_t ahnd = get_reloc_ahnd(fd, 0);
+	uint32_t handle1;
+	igt_spin_t *spin;
+
+	handle1 = gem_create_in_memory_region_list(fd, size, 0,
+						   &region->ci, 1);
+	spin = igt_spin_new(fd,
+			    .ahnd = ahnd,
+			    .dependency = handle1);
+
+	igt_fork(child, 1) {
+		uint32_t handle2;
+
+		fd = gem_reopen_driver(fd);
+
+		handle2 = gem_create_in_memory_region_list(fd,
+							   size, 0,
+							   &region->ci, 1);
+		/*
+		 * The actual move when evicting will be pipelined
+		 * behind the spinner, so can't fire until the spinner
+		 * is killed.
+		 */
+		upload(fd, handle2);
+		gem_close(fd, handle2);
+	}
+
+	sleep(2); /* Give eviction time to find handle1 */
+	igt_spin_end(spin);
+	gem_madvise(fd, handle1, I915_MADV_DONTNEED);
+	igt_waitchildren();
+
+	igt_spin_free(fd, spin);
+	gem_close(fd, handle1);
+}
+
 igt_main
 {
 	igt_describe("Check signal for Segmentation Fault and bus error before"
@@ -209,4 +280,61 @@ igt_main
 		     " purged bo for GPU.");
 	igt_subtest("dontneed-before-exec")
 		dontneed_before_exec();
+
+	igt_subtest_group {
+		struct drm_i915_query_memory_regions *regions;
+		int i915 = -1;
+
+		igt_fixture {
+			char *tmp;
+
+			if (igt_kmod_is_loaded("i915")) {
+				i915 = __drm_open_driver(DRIVER_INTEL);
+				igt_require_fd(i915);
+				igt_require_gem(i915);
+				igt_require(gem_has_lmem(i915));
+				close(i915);
+			}
+
+			igt_i915_driver_unload();
+			/*
+			 * To avoid running of ring space and stalling during evicting
+			 * (while holding the dma-resv lock), we need to use a smaller
+			 * lmem size, such we can easliy trigger eviction without
+			 * needing to wait for more ring space. The point of the test is
+			 * to mark the object as DONTNEED which has an in-progress
+			 * pipilined unbind/move, which also requires grabbing the
+			 * dma-resv lock.
+			 */
+			igt_assert_eq(igt_i915_driver_load("lmem_size=128"), 0);
+
+			i915 = __drm_open_driver(DRIVER_INTEL);
+			igt_require_fd(i915);
+			igt_require_gem(i915);
+			igt_require(gem_has_lmem(i915));
+
+			tmp = __igt_params_get(i915, "lmem_size");
+			igt_skip_on(!tmp);
+			free(tmp);
+
+			regions = gem_get_query_memory_regions(i915);
+			igt_require(regions);
+		}
+
+		igt_describe("Regression test to verify that madvise will sync against busy dma-resv object for lmem");
+		igt_subtest("dontneed-evict-race") {
+			for_each_memory_region(r, i915) {
+				if (r->ci.memory_class == I915_MEMORY_CLASS_DEVICE) {
+					test_dontneed_evict_race(i915, r);
+					break;
+				}
+			}
+
+		}
+
+		igt_fixture {
+			close(i915);
+			igt_i915_driver_unload();
+		}
+	}
 }
-- 
2.38.1