[PATCH v2 1/3] mm, slab: deprecate SLAB_MEM_SPREAD flag

[Vlastimil Babka]

The SLAB_MEM_SPREAD flag used to be implemented in SLAB, which was
removed.  SLUB instead relies on the page allocator's NUMA policies.
Change the flag's value to 0 to free up the value it had, and mark it
for full removal once all users are gone.

Reported-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
Closes: https://lore.kernel.org/all/20240131172027.10f64405@xxxxxxxxxxxxxxxxxx/
Reviewed-and-tested-by: Xiongwei Song <xiongwei.song@xxxxxxxxxxxxx>
Reviewed-by: Chengming Zhou <chengming.zhou@xxxxxxxxx>
Reviewed-by: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
---
 include/linux/slab.h | 5 +++--
 mm/slab.h            | 1 -
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index b5f5ee8308d0..b1675ff6b904 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -96,8 +96,6 @@
  */
 /* Defer freeing slabs to RCU */
 #define SLAB_TYPESAFE_BY_RCU	((slab_flags_t __force)0x00080000U)
-/* Spread some memory over cpuset */
-#define SLAB_MEM_SPREAD		((slab_flags_t __force)0x00100000U)
 /* Trace allocations and frees */
 #define SLAB_TRACE		((slab_flags_t __force)0x00200000U)
 
@@ -164,6 +162,9 @@
 #endif
 #define SLAB_TEMPORARY		SLAB_RECLAIM_ACCOUNT	/* Objects are short-lived */
 
+/* Obsolete unused flag, to be removed */
+#define SLAB_MEM_SPREAD		((slab_flags_t __force)0U)
+
 /*
  * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
  *
diff --git a/mm/slab.h b/mm/slab.h
index 54deeb0428c6..f4534eefb35d 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -469,7 +469,6 @@ static inline bool is_kmalloc_cache(struct kmem_cache *s)
 			      SLAB_STORE_USER | \
 			      SLAB_TRACE | \
 			      SLAB_CONSISTENCY_CHECKS | \
-			      SLAB_MEM_SPREAD | \
 			      SLAB_NOLEAKTRACE | \
 			      SLAB_RECLAIM_ACCOUNT | \
 			      SLAB_TEMPORARY | \

-- 
2.43.2