[PATCH slab/for-next 06/14] kernel/fork: specify SLAB_MAY_ACCOUNT for thread_stack cache

[Harry Yoo (Meta)]

When THREAD_SIZE < PAGE_SIZE, thread stacks are allocated from a slab
cache with THREADINFO_GFP, which includes __GFP_ACCOUNT. Specify
SLAB_MAY_ACCOUNT when the object may be charged to a memcg.
__GFP_ACCOUNT without SLAB_MAY_ACCOUNT will not be allowed.

Path (e.g. ppc64le, 64K pages, !VMAP_STACK): copy_process()
  -> dup_task_struct() -> alloc_thread_stack_node()
  -> kmem_cache_alloc_node(thread_stack_cache, THREADINFO_GFP)

Assisted-by: LLM
Cc: Kees Cook <kees@xxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Lorenzo Stoakes <ljs@xxxxxxxxxx>
Cc: "Liam R. Howlett" <liam@xxxxxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Juri Lelli <juri.lelli@xxxxxxxxxx>
Cc: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
Cc: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Ben Segall <bsegall@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Valentin Schneider <vschneid@xxxxxxxxxx>
Cc: K Prateek Nayak <kprateek.nayak@xxxxxxx>
Signed-off-by: Harry Yoo (Meta) <harry@xxxxxxxxxx>
---
 kernel/fork.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/fork.c b/kernel/fork.c
index 416758c8a3d4..3ad31c5ae0b6 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -459,7 +459,8 @@ static void free_thread_stack(struct task_struct *tsk)
 void thread_stack_cache_init(void)
 {
 	thread_stack_cache = kmem_cache_create_usercopy("thread_stack",
-					THREAD_SIZE, THREAD_SIZE, 0, 0,
+					THREAD_SIZE, THREAD_SIZE,
+					SLAB_MAY_ACCOUNT, 0,
 					THREAD_SIZE, NULL);
 	BUG_ON(thread_stack_cache == NULL);
 }

-- 
2.54.0