[PATCH v8 3/6] drm/ttm: Use fault-injection to test error paths
Thomas Hellström
thomas.hellstrom at linux.intel.com
Fri Aug 16 13:37:14 UTC 2024
Use fault-injection to test partial TTM swapout and interrupted swapin.
Return -EINTR for swapin to test the callers ability to handle and
restart the swapin, and on swapout perform a partial swapout to test that
the swapin and release_shrunken functionality.
v8:
- Use the core fault-injection system.
Cc: Christian König <christian.koenig at amd.com>
Cc: Somalapuram Amaranath <Amaranath.Somalapuram at amd.com>
Cc: Matthew Brost <matthew.brost at intel.com>
Cc: <dri-devel at lists.freedesktop.org>
Signed-off-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost at intel.com> #v7
---
drivers/gpu/drm/ttm/ttm_pool.c | 25 ++++++++++++++++++++++++-
1 file changed, 24 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/ttm/ttm_pool.c b/drivers/gpu/drm/ttm/ttm_pool.c
index 0d224cd9f8eb..0824b66a9aac 100644
--- a/drivers/gpu/drm/ttm/ttm_pool.c
+++ b/drivers/gpu/drm/ttm/ttm_pool.c
@@ -48,6 +48,11 @@
#include "ttm_module.h"
+#ifdef CONFIG_FAULT_INJECTION
+#include <linux/fault-inject.h>
+static DECLARE_FAULT_ATTR(backup_fault_inject);
+#endif
+
/**
* struct ttm_pool_dma - Helper object for coherent DMA mappings
*
@@ -431,6 +436,7 @@ static int ttm_pool_restore_tt(struct ttm_pool_tt_restore *restore,
struct ttm_backup *backup,
struct ttm_operation_ctx *ctx)
{
+ static unsigned long __maybe_unused swappedin;
unsigned int i, nr = 1 << restore->order;
int ret = 0;
@@ -446,6 +452,12 @@ static int ttm_pool_restore_tt(struct ttm_pool_tt_restore *restore,
if (handle == 0)
continue;
+ if (IS_ENABLED(CONFIG_FAULT_INJECTION) && ctx->interruptible &&
+ should_fail(&backup_fault_inject, 1)) {
+ ret = -EINTR;
+ break;
+ }
+
ret = backup->ops->copy_backed_up_page
(backup, restore->first_page[i],
handle, ctx->interruptible);
@@ -889,7 +901,14 @@ long ttm_pool_backup_tt(struct ttm_pool *pool, struct ttm_tt *ttm,
alloc_gfp = GFP_KERNEL | __GFP_HIGH | __GFP_NOWARN | __GFP_RETRY_MAYFAIL;
- for (i = 0; i < ttm->num_pages; ++i) {
+ num_pages = ttm->num_pages;
+
+ /* Pretend doing fault injection by shrinking only half of the pages. */
+
+ if (IS_ENABLED(CONFIG_FAULT_INJECTION) && should_fail(&backup_fault_inject, 1))
+ num_pages = DIV_ROUND_UP(num_pages, 2);
+
+ for (i = 0; i < num_pages; ++i) {
page = ttm->pages[i];
if (unlikely(!page))
continue;
@@ -1178,6 +1197,10 @@ int ttm_pool_mgr_init(unsigned long num_pages)
&ttm_pool_debugfs_globals_fops);
debugfs_create_file("page_pool_shrink", 0400, ttm_debugfs_root, NULL,
&ttm_pool_debugfs_shrink_fops);
+#ifdef CONFIG_FAULT_INJECTION
+ fault_create_debugfs_attr("backup_fault_inject", ttm_debugfs_root,
+ &backup_fault_inject);
+#endif
#endif
mm_shrinker = shrinker_alloc(0, "drm-ttm_pool");
--
2.44.0
More information about the dri-devel
mailing list