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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Wed, 28 Oct 2020 18:15:32 +0100
Subject: [PATCH 332/351] mm/memcontrol: Disable preemption in
__mod_memcg_lruvec_state()
Origin: https://git.kernel.org/cgit/linux/kernel/git/rt/linux-stable-rt.git/commit?id=c8d747a7c7dd6b59f68b8466893b0c18d1fa2074
[ Upstream commit 74858f0d38a8d3c069a0745ff53ae084c8e7cabb ]
The callers expect disabled preemption/interrupts while invoking
__mod_memcg_lruvec_state(). This works mainline because a lock of
somekind is acquired.
Use preempt_disable_rt() where per-CPU variables are accessed and a
stable pointer is expected. This is also done in __mod_zone_page_state()
for the same reason.
Cc: stable-rt@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Conflicts:
mm/memcontrol.c
---
include/linux/memcontrol.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index cc6b6532eb56..dbb2c4e27277 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -665,6 +665,7 @@ static inline void __mod_lruvec_state(struct lruvec *lruvec,
pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
+ preempt_disable_rt();
/* Update memcg */
__mod_memcg_state(pn->memcg, idx, val);
@@ -675,6 +676,7 @@ static inline void __mod_lruvec_state(struct lruvec *lruvec,
x = 0;
}
__this_cpu_write(pn->lruvec_stat_cpu->count[idx], x);
+ preempt_enable_rt();
}
static inline void mod_lruvec_state(struct lruvec *lruvec,
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