From: Shakeel Butt <shakeel.butt@linux.dev>
Date: Fri, 4 Apr 2025 01:39:11 +0000 (-0700)
Subject: memcg: use __mod_memcg_state in drain_obj_stock
X-Git-Tag: v6.16-rc1~92^2~243
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=42a1910cfd23c46307a000a81127e02df247284c;p=thirdparty%2Flinux.git

memcg: use __mod_memcg_state in drain_obj_stock

For non-PREEMPT_RT kernels, drain_obj_stock() is always called with irq
disabled, so we can use __mod_memcg_state() instead of mod_memcg_state().
For PREEMPT_RT, we need to add memcg_stats_[un]lock in
__mod_memcg_state().

Link: https://lkml.kernel.org/r/20250404013913.1663035-8-shakeel.butt@linux.dev
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 7988a42b29bfc..33aeddfff0ba6 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -710,10 +710,12 @@ void __mod_memcg_state(struct mem_cgroup *memcg, enum memcg_stat_item idx,
 	if (WARN_ONCE(BAD_STAT_IDX(i), "%s: missing stat item %d\n", __func__, idx))
 		return;
 
+	memcg_stats_lock();
 	__this_cpu_add(memcg->vmstats_percpu->state[i], val);
 	val = memcg_state_val_in_pages(idx, val);
 	memcg_rstat_updated(memcg, val);
 	trace_mod_memcg_state(memcg, idx, val);
+	memcg_stats_unlock();
 }
 
 #ifdef CONFIG_MEMCG_V1
@@ -2866,7 +2868,7 @@ static void drain_obj_stock(struct memcg_stock_pcp *stock)
 
 			memcg = get_mem_cgroup_from_objcg(old);
 
-			mod_memcg_state(memcg, MEMCG_KMEM, -nr_pages);
+			__mod_memcg_state(memcg, MEMCG_KMEM, -nr_pages);
 			memcg1_account_kmem(memcg, -nr_pages);
 			if (!mem_cgroup_is_root(memcg))
 				memcg_uncharge(memcg, nr_pages);