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DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1765956850; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=EV6q27Ww1Pi8gdjbSvPXKtgD9Ua4KYVSU4hxepzaQ/c=; b=AXc74V+X5J85APZtey4ZYmzvZIJ2n7TB8CPnOTzJ7cjlFcn2vZ3x3ewYMJKyeAZsbiEzDu FKOiBmq0kxoybbzgvggqr2RteHqX3hID9EFLyHUtckL6onKDbRzk9Ec261fXIQOpz1aFq2 eiGoRqCmHtDMmXsNBl3TymksjA3OhxA= From: Qi Zheng To: 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, 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 Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Qi Zheng Subject: [PATCH v2 26/28] mm: memcontrol: refactor memcg_reparent_objcgs() Date: Wed, 17 Dec 2025 15:27:50 +0800 Message-ID: <8e4dff3139390fc0f18546a770d2b35c9c148b8b.1765956026.git.zhengqi.arch@bytedance.com> In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam02 X-Stat-Signature: wjzi4drrufky8d6y5w1xbjpt4r1rqrzk X-Rspam-User: X-Rspamd-Queue-Id: 6D1ED1A000D X-HE-Tag: 1765956857-741096 X-HE-Meta: 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 7meoVsls hOlIfXMOvCTUrO8Fk5gyRwZsdmxk/exIKieXuTleFssaLVoy5lMc3Oqed4VSo/lu0VMRiyflAVfDHmszCA8wBfxXlXyjk6y+vUu7M2fbKmjSSAEptEJfj2TOfoaW0j1/N5BcrzQIepOiXVNF4fvv2TuKRMbDsK4xd8sC9ZsmC8fdb8mflrwGPUcOw7F+0o9s+sWg8hOtWoEylmaHV5vyG8mYmzxd5D6ItrzfdJBlOWmzPrzf1ieQXy+uuOg8OtLBo1h5Ckz/Nj5TgidU= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Qi Zheng Refactor the memcg_reparent_objcgs() to facilitate subsequent reparenting LRU folios here. Signed-off-by: Qi Zheng --- mm/memcontrol.c | 37 +++++++++++++++++++++++++++---------- 1 file changed, 27 insertions(+), 10 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 930dacd6ce31a..3daa99a0c65fe 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -206,24 +206,41 @@ static struct obj_cgroup *obj_cgroup_alloc(void) return objcg; } -static void memcg_reparent_objcgs(struct mem_cgroup *memcg) +static inline void __memcg_reparent_objcgs(struct mem_cgroup *src, + struct mem_cgroup *dst) { struct obj_cgroup *objcg, *iter; - struct mem_cgroup *parent = parent_mem_cgroup(memcg); - - objcg = rcu_replace_pointer(memcg->objcg, NULL, true); - - spin_lock_irq(&objcg_lock); + objcg = rcu_replace_pointer(src->objcg, NULL, true); /* 1) Ready to reparent active objcg. */ - list_add(&objcg->list, &memcg->objcg_list); + list_add(&objcg->list, &src->objcg_list); /* 2) Reparent active objcg and already reparented objcgs to parent. */ - list_for_each_entry(iter, &memcg->objcg_list, list) - WRITE_ONCE(iter->memcg, parent); + list_for_each_entry(iter, &src->objcg_list, list) + WRITE_ONCE(iter->memcg, dst); /* 3) Move already reparented objcgs to the parent's list */ - list_splice(&memcg->objcg_list, &parent->objcg_list); + list_splice(&src->objcg_list, &dst->objcg_list); +} + +static inline void reparent_locks(struct mem_cgroup *src, struct mem_cgroup *dst) +{ + spin_lock_irq(&objcg_lock); +} +static inline void reparent_unlocks(struct mem_cgroup *src, struct mem_cgroup *dst) +{ spin_unlock_irq(&objcg_lock); +} + +static void memcg_reparent_objcgs(struct mem_cgroup *src) +{ + struct obj_cgroup *objcg = rcu_dereference_protected(src->objcg, true); + struct mem_cgroup *dst = parent_mem_cgroup(src); + + reparent_locks(src, dst); + + __memcg_reparent_objcgs(src, dst); + + reparent_unlocks(src, dst); percpu_ref_kill(&objcg->refcnt); } -- 2.20.1