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 7988a42b29bfcb3120cba93ec51754e53cbfaac3..33aeddfff0ba63eb5e9f5d61a82454f2393fbd45 100644 (file)
--- 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);