Re: [PATCH v3 07/11] lib/ref_tracker: remove warnings in case of allocation failure

[Andrzej Hajda]

On 22.02.2022 00:54, Eric Dumazet wrote:
On Mon, Feb 21, 2022 at 3:26 PM Andrzej Hajda <andrzej.ha...@intel.com> wrote:
Library can handle allocation failures. To avoid allocation warnings
__GFP_NOWARN has been added everywhere. Moreover GFP_ATOMIC has been
replaced with GFP_NOWAIT in case of stack allocation on tracker free
call.

Signed-off-by: Andrzej Hajda <andrzej.ha...@intel.com>
---
  lib/ref_tracker.c | 5 +++--
  1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/ref_tracker.c b/lib/ref_tracker.c
index 2ef4596b6b36f..cae4498fcfd70 100644
--- a/lib/ref_tracker.c
+++ b/lib/ref_tracker.c
@@ -189,7 +189,7 @@ int ref_tracker_alloc(struct ref_tracker_dir *dir,
         unsigned long entries[REF_TRACKER_STACK_ENTRIES];
         struct ref_tracker *tracker;
         unsigned int nr_entries;
-       gfp_t gfp_mask = gfp;
+       gfp_t gfp_mask = gfp | __GFP_NOWARN;
SGTM

         unsigned long flags;

         WARN_ON_ONCE(dir->dead);
@@ -237,7 +237,8 @@ int ref_tracker_free(struct ref_tracker_dir *dir,
                 return -EEXIST;
         }
         nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 1);
-       stack_handle = stack_depot_save(entries, nr_entries, GFP_ATOMIC);
+       stack_handle = stack_depot_save(entries, nr_entries,
+                                       GFP_NOWAIT | __GFP_NOWARN);
Last time I looked at this, __GFP_NOWARN was enforced in __stack_depot_save()

You are right, however I am not sure if we should count on unexpected 
(at least for me) and undocumented behavior.
Currently we do not need to rely on some hidden feature.

Regards
Andrzej


         spin_lock_irqsave(&dir->lock, flags);
         if (tracker->dead) {
--
2.25.1