The resume clearance test skipped every other allocation, expecting an
interleaved clear/dirty layout. But the buddy allocator hands out blocks
contiguously, so this just allocated half the pages in one chunk and never
exercised gpu_buddy_reset_clear()'s force-merge of opposite-state buddies.
Allocate all pages into two lists instead and free one cleared, one dirty,
to build a truly interleaved pattern.
v2: Use for loops instead of do-while for the allocation loops (Jani Nikula)
Fixes: e3335ccbf4da ("drm/tests/gpu_buddy: add a new test case for buffer
clearance during resume")
Reported-by: Sashiko-bot <[email protected]>
Closes:
https://sashiko.dev/#/patchset/[email protected]?part=1
Cc: Matthew Auld <[email protected]>
Cc: Christian König <[email protected]>
Assisted-by: GitHub_Copilot:claude-opus-4.8
Signed-off-by: Arunpravin Paneer Selvam <[email protected]>
---
drivers/gpu/tests/gpu_buddy_test.c | 57 +++++++++++++++++-------------
1 file changed, 33 insertions(+), 24 deletions(-)
diff --git a/drivers/gpu/tests/gpu_buddy_test.c
b/drivers/gpu/tests/gpu_buddy_test.c
index 89698563c61b..e258bf1fa0fb 100644
--- a/drivers/gpu/tests/gpu_buddy_test.c
+++ b/drivers/gpu/tests/gpu_buddy_test.c
@@ -1004,42 +1004,51 @@ static void gpu_test_buddy_alloc_clear(struct kunit
*test)
gpu_buddy_fini(&mm);
/*
- * Using a non-power-of-two mm size, allocate alternating blocks of
4KiB in an
- * even sequence and free them as cleared. All blocks should be marked
as
- * dirty and the split blocks should be merged back to their original
- * size when the blocks clear reset function is called.
+ * Using a non-power-of-two mm size, allocate all 4KiB blocks and split
+ * them across two alternating lists, then free one list as cleared and
+ * the other as dirty. This interleaves cleared and dirty blocks so that
+ * neighbouring buddies cannot be merged, fragmenting the address space.
+ * After gpu_buddy_reset_clear(false) every block should be marked dirty
+ * and the split blocks should be merged back to their original size, so
+ * clear_avail must drop to 0.
*/
KUNIT_EXPECT_FALSE(test, gpu_buddy_init(&mm, mm_size, ps));
KUNIT_EXPECT_EQ(test, mm.max_order, max_order);
- i = 0;
n_pages = mm_size / ps;
- do {
- if (i % 2 == 0)
- KUNIT_ASSERT_FALSE_MSG(test,
gpu_buddy_alloc_blocks(&mm, 0, mm_size,
- ps,
ps, &allocated, 0),
- "buddy_alloc hit an error size=%lu\n",
ps);
- } while (++i < n_pages);
+ for (i = 0; i < n_pages; i++) {
+ struct list_head *list = (i % 2) ? &clean : &dirty;
- gpu_buddy_free_list(&mm, &allocated, GPU_BUDDY_CLEARED);
+ KUNIT_ASSERT_FALSE_MSG(test, gpu_buddy_alloc_blocks(&mm, 0,
mm_size,
+ ps, ps,
list, 0),
+ "buddy_alloc hit an error size=%lu\n", ps);
+ }
+
+ gpu_buddy_free_list(&mm, &clean, GPU_BUDDY_CLEARED);
+ gpu_buddy_free_list(&mm, &dirty, 0);
gpu_buddy_reset_clear(&mm, false);
KUNIT_EXPECT_EQ(test, mm.clear_avail, 0);
+ gpu_buddy_fini(&mm);
/*
- * Using a non-power-of-two mm size, allocate alternating blocks of
4KiB in an
- * odd sequence and free them as cleared. All blocks should be marked as
- * cleared and the split blocks should be merged back to their original
- * size when the blocks clear reset function is called.
+ * Repeat the same fragmented setup, but this time call
+ * gpu_buddy_reset_clear(true). Every block should be marked cleared and
+ * the split blocks should be merged back to their original size, so the
+ * whole address space (clear_avail) must equal mm_size.
*/
- i = 0;
- do {
- if (i % 2 != 0)
- KUNIT_ASSERT_FALSE_MSG(test,
gpu_buddy_alloc_blocks(&mm, 0, mm_size,
- ps,
ps, &allocated, 0),
- "buddy_alloc hit an error size=%lu\n",
ps);
- } while (++i < n_pages);
+ KUNIT_EXPECT_FALSE(test, gpu_buddy_init(&mm, mm_size, ps));
+ KUNIT_EXPECT_EQ(test, mm.max_order, max_order);
- gpu_buddy_free_list(&mm, &allocated, GPU_BUDDY_CLEARED);
+ for (i = 0; i < n_pages; i++) {
+ struct list_head *list = (i % 2) ? &clean : &dirty;
+
+ KUNIT_ASSERT_FALSE_MSG(test, gpu_buddy_alloc_blocks(&mm, 0,
mm_size,
+ ps, ps,
list, 0),
+ "buddy_alloc hit an error size=%lu\n", ps);
+ }
+
+ gpu_buddy_free_list(&mm, &clean, GPU_BUDDY_CLEARED);
+ gpu_buddy_free_list(&mm, &dirty, 0);
gpu_buddy_reset_clear(&mm, true);
KUNIT_EXPECT_EQ(test, mm.clear_avail, mm_size);
gpu_buddy_fini(&mm);
base-commit: bc47d5937f21c5fc94504f03e18f1adb56d97634
--
2.34.1
