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.
Signed-off-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/Kconfig | 10 ++++++++++
drivers/gpu/drm/ttm/ttm_pool.c | 17 ++++++++++++++++-
2 files changed, 26 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 1efd33411a92..a78eed9af2c1 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -202,6 +202,16 @@ config DRM_TTM
GPU memory types. Will be enabled automatically if a device driver
uses it.
+config DRM_TTM_SHRINK_FAULT_INJECT
+ bool "Enable fault injection during TTM shrinking"
+ depends on DRM_TTM
+ default n
+ help
+ Inject recoverable failures during TTM shrinking and recovery of
+ shrunken objects. For DRM driver developers only.
+
+ If in doubt, choose N.
+
config DRM_BUDDY
tristate
depends on DRM
diff --git a/drivers/gpu/drm/ttm/ttm_pool.c b/drivers/gpu/drm/ttm/ttm_pool.c
index 319998b4a325..d7c604593689 100644
--- a/drivers/gpu/drm/ttm/ttm_pool.c
+++ b/drivers/gpu/drm/ttm/ttm_pool.c
@@ -453,6 +453,7 @@ static bool ttm_pool_restore_valid(const struct ttm_pool_tt_restore *restore)
static int ttm_pool_swapin(struct ttm_pool_tt_restore *restore,
struct ttm_operation_ctx *ctx)
{
+ static unsigned long __maybe_unused swappedin;
unsigned int i, nr = 1 << restore->order;
int ret = 0;
@@ -468,6 +469,13 @@ static int ttm_pool_swapin(struct ttm_pool_tt_restore *restore,
if (swap.val == 0)
continue;
+ if (IS_ENABLED(CONFIG_DRM_TTM_SHRINK_FAULT_INJECT) &&
+ ctx->interruptible &&
+ ++swappedin % 100 == 0) {
+ ret = -EINTR;
+ break;
+ }
+
ret = swap_copy_folio(swap, restore->first_page[i], 0,
ctx->interruptible);
if (ret)
@@ -905,7 +913,14 @@ long ttm_pool_shrink_tt(struct ttm_pool *pool, struct ttm_tt *ttm)
if (current_is_kswapd())
alloc_gfp |= __GFP_NOMEMALLOC;
- 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_DRM_TTM_SHRINK_FAULT_INJECT))
+ num_pages = DIV_ROUND_UP(num_pages, 2);
+
+ for (i = 0; i < num_pages; ++i) {
page = ttm->pages[i];
if (unlikely(!page))
continue;
--
2.34.1
