[RFC 7/7] mm: Drop __GFP_DIRECT_RECLAIM flag if PF_MEMALLOC is set

Uladzislau Rezki (Sony)
2025-07-04T15:26:04Z

The memory allocator already avoids reclaim when PF_MEMALLOC is set.
Clear __GFP_DIRECT_RECLAIM explicitly to suppress might_alloc() warnings
to make more correct behavior.

Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
---
include/linux/sched/mm.h | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
index b13474825130..40757173acb1 100644
--- a/include/linux/sched/mm.h
+++ b/include/linux/sched/mm.h
@@ -246,12 +246,14 @@ static inline bool in_vfork(struct task_struct *tsk)
* PF_MEMALLOC_NOIO implies GFP_NOIO
* PF_MEMALLOC_NOFS implies GFP_NOFS
* PF_MEMALLOC_PIN implies !GFP_MOVABLE
+ * PF_MEMALLOC implies !__GFP_DIRECT_RECLAIM
*/
static inline gfp_t current_gfp_context(gfp_t flags)
{
unsigned int pflags = READ_ONCE(current->flags);

- if (unlikely(pflags & (PF_MEMALLOC_NOIO | PF_MEMALLOC_NOFS | PF_MEMALLOC_PIN))) {
+ if (unlikely(pflags & (PF_MEMALLOC_NOIO | PF_MEMALLOC_NOFS |
+ PF_MEMALLOC_PIN | PF_MEMALLOC))) {
/*
* NOIO implies both NOIO and NOFS and it is a weaker context
* so always make sure it makes precedence
@@ -263,6 +265,9 @@ static inline gfp_t current_gfp_context(gfp_t flags)

if (pflags & PF_MEMALLOC_PIN)
flags &= ~__GFP_MOVABLE;
+
+ if (pflags & PF_MEMALLOC)
+ flags &= ~__GFP_DIRECT_RECLAIM;
}
return flags;
}
--
2.39.5