mm: oom analysis: Show kernel stack usage in /proc/meminfo and OOM log output

The amount of memory allocated to kernel stacks can become significant and
cause OOM conditions.  However, we do not display the amount of memory
consumed by stacks.

Add code to display the amount of memory used for stacks in /proc/meminfo.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index 2cebfb23b0b8..d4638c8cc19e 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -136,9 +136,17 @@ struct kmem_cache *vm_area_cachep;
 /* SLAB cache for mm_struct structures (tsk->mm) */
 static struct kmem_cache *mm_cachep;
 
+static void account_kernel_stack(struct thread_info *ti, int account)
+{
+        struct zone *zone = page_zone(virt_to_page(ti));
+
+        mod_zone_page_state(zone, NR_KERNEL_STACK, account);
+}
+
 void free_task(struct task_struct *tsk)
 {
         prop_local_destroy_single(&tsk->dirties);
+        account_kernel_stack(tsk->stack, -1);
         free_thread_info(tsk->stack);
         rt_mutex_debug_task_free(tsk);
         ftrace_graph_exit_task(tsk);
@@ -253,6 +261,9 @@ static struct task_struct *dup_task_struct(struct task_struct *orig)
         tsk->btrace_seq = 0;
 #endif
         tsk->splice_pipe = NULL;
+
+        account_kernel_stack(ti, 1);
+
         return tsk;
 
 out: