From: Vasily Averin <vvs@virtuozzo.com>
Date: Mon, 23 Aug 2021 23:59:17 +0000 (+1000)
Subject: memcg: replace in_interrupt() by !in_task() in active_memcg()
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=db82343a9748d3746dd1cc32c5e6ea981ec07f22;p=users%2Fjedix%2Flinux-maple.git

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/ed4448b0-4970-616f-7368-ef9dd3cb628d@virtuozzo.com
Fixes: 37d5985c003d ("mm: kmem: prepare remote memcg charging infra for interrupt contexts")
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
---

diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
index 8894825cc4db..5561486fddef 100644
--- a/include/linux/sched/mm.h
+++ b/include/linux/sched/mm.h
@@ -306,7 +306,7 @@ set_active_memcg(struct mem_cgroup *memcg)
 {
 	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 {
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 4d8c9afecf98..b09f2639f28b 100644
--- a/mm/memcontrol.c
+++ b/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;