[PATCH] mm: memcontrol: fix kernel stack account

[Muchun Song]

The alloc_thread_stack_node() cannot guarantee that allocated stack pages
are in the same node when CONFIG_VMAP_STACK. Because we do not specify
__GFP_THISNODE to __vmalloc_node_range(). Fix it by caling
mod_lruvec_page_state() for each page one by one.

Fixes: 991e7673859e ("mm: memcontrol: account kernel stack per node")
Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
---
 kernel/fork.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/kernel/fork.c b/kernel/fork.c
index d66cd1014211..6e2201feb524 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -379,14 +379,19 @@ static void account_kernel_stack(struct task_struct *tsk, int account)
 	void *stack = task_stack_page(tsk);
 	struct vm_struct *vm = task_stack_vm_area(tsk);
 
+	if (vm) {
+		int i;
 
-	/* All stack pages are in the same node. */
-	if (vm)
-		mod_lruvec_page_state(vm->pages[0], NR_KERNEL_STACK_KB,
-				      account * (THREAD_SIZE / 1024));
-	else
+		BUG_ON(vm->nr_pages != THREAD_SIZE / PAGE_SIZE);
+
+		for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++)
+			mod_lruvec_page_state(vm->pages[i], NR_KERNEL_STACK_KB,
+					      account * (PAGE_SIZE / 1024));
+	} else {
+		/* All stack pages are in the same node. */
 		mod_lruvec_kmem_state(stack, NR_KERNEL_STACK_KB,
 				      account * (THREAD_SIZE / 1024));
+	}
 }
 
 static int memcg_charge_kernel_stack(struct task_struct *tsk)
-- 
2.11.0