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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 22:04:56 +0100
commit39d4834483cf013a64de556c925e22614bb7e7bc (patch)
treef82aae8f0871b5560f1e26f0deaa4a03f2bb4b37
parent64dc7c68e040251d9ec6e989acb69f8f6ae4a10b (diff)
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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 f7c1d9f4f58d..4c23b6a435e1 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1909,9 +1909,18 @@ 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;
}