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authorShakeel Butt <shakeel.butt@linux.dev>2025-03-10 16:09:34 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2025-03-28 22:03:30 +0100
commit2e1dfe3105ab946bf7a3fa04d197ac38d2080ef9 (patch)
treec411a5308c557f94a24064c3934a12da3134302a
parentede3e8ac90ae106f0b29cd759aadebc1568f1308 (diff)
memcg: drain obj stock on cpu hotplug teardown
commit 9f01b4954490d4ccdbcc2b9be34a9921ceee9cbb upstream. Currently on cpu hotplug teardown, only memcg stock is drained but we need to drain the obj stock as well otherwise we will miss the stats accumulated on the target cpu as well as the nr_bytes cached. The stats include MEMCG_KMEM, NR_SLAB_RECLAIMABLE_B & NR_SLAB_UNRECLAIMABLE_B. In addition we are leaking reference to struct obj_cgroup object. Link: https://lkml.kernel.org/r/20250310230934.2913113-1-shakeel.butt@linux.dev Fixes: bf4f059954dc ("mm: memcg/slab: obj_cgroup API") Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--mm/memcontrol.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index ae1d184d035a..2d1e402f06f2 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1882,9 +1882,18 @@ void drain_all_stock(struct mem_cgroup *root_memcg)
static int memcg_hotplug_cpu_dead(unsigned int cpu)
{
struct memcg_stock_pcp *stock;
+ struct obj_cgroup *old;
+ unsigned long flags;
stock = &per_cpu(memcg_stock, cpu);
+
+ /* drain_obj_stock requires stock_lock */
+ local_lock_irqsave(&memcg_stock.stock_lock, flags);
+ old = drain_obj_stock(stock);
+ local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
+
drain_stock(stock);
+ obj_cgroup_put(old);
return 0;
}