[109/212] memcg: replace in_interrupt() by !in_task() in active_memcg()

Commit Message

Andrew Morton Sept. 2, 2021, 9:55 p.m. UTC

From: Vasily Averin <[e-mail]>
Subject: memcg: replace in_interrupt() by !in_task() in active_memcg()

set_active_memcg() uses in_interrupt() check to select proper storage for
cgroup: pointer on task struct or per-cpu pointer.

It isn't fully correct: obsoleted in_interrupt() includes tasks with
disabled BH.  It's better to use '!in_task()' instead.

Link: https://lkml.org/lkml/2021/7/26/487
Link: https://lkml.kernel.org/r/[e-mail]
Fixes: 37d5985c003d ("mm: kmem: prepare remote memcg charging infra for interrupt contexts")
Signed-off-by: Vasily Averin <[e-mail]>
Reviewed-by: Shakeel Butt <[e-mail]>
Cc: Johannes Weiner <[e-mail]>
Cc: Michal Hocko <[e-mail]>
Cc: Roman Gushchin <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 include/linux/sched/mm.h |    2 +-
 mm/memcontrol.c          |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

Patch

--- a/include/linux/sched/mm.h~memcg-replace-in_interrupt-by-in_task-in-active_memcg
+++ a/include/linux/sched/mm.h
@@ -306,7 +306,7 @@  set_active_memcg(struct mem_cgroup *memc
 {
 	struct mem_cgroup *old;
 
-	if (in_interrupt()) {
+	if (!in_task()) {
 		old = this_cpu_read(int_active_memcg);
 		this_cpu_write(int_active_memcg, memcg);
 	} else {
--- a/mm/memcontrol.c~memcg-replace-in_interrupt-by-in_task-in-active_memcg
+++ a/mm/memcontrol.c
@@ -878,7 +878,7 @@  EXPORT_SYMBOL(mem_cgroup_from_task);
 
 static __always_inline struct mem_cgroup *active_memcg(void)
 {
-	if (in_interrupt())
+	if (!in_task())
 		return this_cpu_read(int_active_memcg);
 	else
 		return current->active_memcg;