Commit 9f01b495 authored by Shakeel Butt's avatar Shakeel Butt Committed by Andrew Morton
Browse files

memcg: drain obj stock on cpu hotplug teardown 

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: bf4f0599 ("mm: memcg/slab: obj_cgroup API")
Signed-off-by: default avatarShakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: default avatarRoman Gushchin <roman.gushchin@linux.dev>
Acked-by: default avatarJohannes 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: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 14efb479

mm/memcontrol.c

+9 −0
Original line number Diff line number Diff line
@@ -1921,9 +1921,18 @@ 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;

}