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([2a02:6b6f:e752:9400:18cf:c773:ee86:c436]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48320719b8fsm143031285e9.9.2026.02.07.11.59.52 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 07 Feb 2026 11:59:52 -0800 (PST) Message-ID: Date: Sat, 7 Feb 2026 19:59:51 +0000 Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 30/31] mm: memcontrol: eliminate the problem of dying memory cgroup for LRU folios Content-Language: en-GB To: Qi Zheng , hannes@cmpxchg.org, hughd@google.com, mhocko@suse.com, roman.gushchin@linux.dev, shakeel.butt@linux.dev, muchun.song@linux.dev, david@kernel.org, lorenzo.stoakes@oracle.com, ziy@nvidia.com, harry.yoo@oracle.com, yosry.ahmed@linux.dev, imran.f.khan@oracle.com, kamalesh.babulal@oracle.com, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, chenridong@huaweicloud.com, mkoutny@suse.com, akpm@linux-foundation.org, hamzamahfooz@linux.microsoft.com, apais@linux.microsoft.com, lance.yang@linux.dev, bhe@redhat.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Muchun Song , Qi Zheng References: <9e332cc8436b6092dd6ef9c2d5f69072bb38eaf6.1770279888.git.zhengqi.arch@bytedance.com> From: Usama Arif In-Reply-To: <9e332cc8436b6092dd6ef9c2d5f69072bb38eaf6.1770279888.git.zhengqi.arch@bytedance.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index e7d4e4ff411b6..0e0efaa511d3d 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -247,11 +247,25 @@ static inline void reparent_state_local(struct mem_cgroup *memcg, struct mem_cgr > > static inline void reparent_locks(struct mem_cgroup *memcg, struct mem_cgroup *parent) > { > + int nid, nest = 0; > + > spin_lock_irq(&objcg_lock); > + for_each_node(nid) { > + spin_lock_nested(&mem_cgroup_lruvec(memcg, > + NODE_DATA(nid))->lru_lock, nest++); > + spin_lock_nested(&mem_cgroup_lruvec(parent, > + NODE_DATA(nid))->lru_lock, nest++); > + } > } > mWould this break lockdep on more than 4 NUMA nodes as MAX_LOCKDEP_SUBCLASSES = 8 and 2 locks are being acquired per node. > static inline void reparent_unlocks(struct mem_cgroup *memcg, struct mem_cgroup *parent) > { > + int nid; > + > + for_each_node(nid) { > + spin_unlock(&mem_cgroup_lruvec(parent, NODE_DATA(nid))->lru_lock); > + spin_unlock(&mem_cgroup_lruvec(memcg, NODE_DATA(nid))->lru_lock); > + } > spin_unlock_irq(&objcg_lock); > }