Re: [PATCH] ttm/pool: Use sentinels in debugfs

[Tvrtko Ursulin]

On 21/05/2026 05:30, Mario Limonciello wrote:

On 4/27/26 11:22, Mario Limonciello wrote:

The values in the `page_pool_shrink` debugfs file should recognize
the sentinels rather than causing an underflow.

Closes: https://gitlab.freedesktop.org/drm/amd/-/work_items/5218
Signed-off-by: Mario Limonciello <mario.limoncie...@amd.com>
---
  drivers/gpu/drm/ttm/ttm_pool.c | 13 ++++++++++---
  1 file changed, 10 insertions(+), 3 deletions(-)

ping?

LGTM.

Reviewed-by: Tvrtko Ursulin <tvrtko.ursu...@igalia.com>

Regards,

Tvrtko

diff --git a/drivers/gpu/drm/ttm/ttm_pool.c b/drivers/gpu/drm/ttm/ ttm_pool.c

index 26a3689e5fd90..4e83f4978b136 100644
--- a/drivers/gpu/drm/ttm/ttm_pool.c
+++ b/drivers/gpu/drm/ttm/ttm_pool.c

@@ -1335,15 +1335,22 @@ static int ttm_pool_debugfs_shrink_show(struct seq_file *m, void *data)

          .gfp_mask = GFP_NOFS,
          .nr_to_scan = TTM_SHRINKER_BATCH,
      };
-    unsigned long count;
+    unsigned long count, scanned;
      int nid;
      fs_reclaim_acquire(GFP_KERNEL);
      for_each_node(nid) {
          sc.nid = nid;
          count = ttm_pool_shrinker_count(mm_shrinker, &sc);
-        seq_printf(m, "%d: %lu/%lu\n", nid, count,
-               ttm_pool_shrinker_scan(mm_shrinker, &sc));
+        scanned = ttm_pool_shrinker_scan(mm_shrinker, &sc);
+

+        /* Convert shrinker API sentinel values to 0 for debugfs output */

+        if (count == SHRINK_EMPTY)
+            count = 0;
+        if (scanned == SHRINK_STOP)
+            scanned = 0;
+
+        seq_printf(m, "%d: %lu/%lu\n", nid, count, scanned);
      }
      fs_reclaim_release(GFP_KERNEL);