From nobody Mon Feb 9 10:11:57 2026 Received: from out-182.mta0.migadu.com (out-182.mta0.migadu.com [91.218.175.182]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 34E8534A797 for ; Wed, 14 Jan 2026 11:36:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.182 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768390581; cv=none; b=f9wYQOZ/m7Ali5ubY0Wjy6sXiH6oJhXPII5X7dMp3y/Xf2cd/YL6WYGFPbafyi8lCwSTjXMCzk0l8gLFkGqdDqx5IkWFtZpv3OjyvKLTlMFLxu9M0Sl5LVXBOm6SSEMHq2B6/bkHc7BqTsq1VaTDwYAo8IQM6kUFIPhoGkyrwTs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768390581; c=relaxed/simple; bh=0XbaueQOyVVuQAkOOpetBOVaZX5zNrMw/q2bAD17MmA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=tM1JMWQ2FVv01eAOT2r/ATDH5SsiGTIAL0EYNCCghHey1VxTnbReXYxeVo5GE1LySd7T1SlwGE8y403ySUiy3FNHUKYjpA3ImIpEtrnL1hXKfQMBnEpRShwjHKSxBMqckE3Vypuwr0/a9/xrKu+1O8XSyl6ZSRAosLk9WQF+JIs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=Q96h2Xw2; arc=none smtp.client-ip=91.218.175.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="Q96h2Xw2" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1768390576; 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=rCn71o4CGVG6ZCimcBHoYvDX6iNx84ttSjck4drbD9c=; b=Q96h2Xw2FW89SLH/7JvVfXdzJRpn9+6lVcUlq55C3OXjGlnp637HPE+22QxBSQ77rM7yha 3Sw67e034q/9edHVNRxG3QNikHhUw4iSAMurkyZnCcIiTfUHRWAE1njcGzgltkUpE6TFfq cGAVi5cmgo6AsI55+TYXghSBv9ZzWr8= 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, 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 Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Qi Zheng Subject: [PATCH v3 27/30] mm: memcontrol: refactor memcg_reparent_objcgs() Date: Wed, 14 Jan 2026 19:32:54 +0800 Message-ID: <843e9537bf6b99cc7f19744a6f53b92338c96bfe.1768389889.git.zhengqi.arch@bytedance.com> In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset="utf-8" From: Qi Zheng Refactor the memcg_reparent_objcgs() to facilitate subsequent reparenting LRU folios here. Signed-off-by: Qi Zheng Acked-by: Johannes Weiner Acked-by: Shakeel Butt Reviewed-by: Harry Yoo Reviewed-by: Muchun Song --- mm/memcontrol.c | 29 ++++++++++++++++++++++++----- 1 file changed, 24 insertions(+), 5 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index a1573600d4188..70583394f421f 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -208,15 +208,12 @@ static struct obj_cgroup *obj_cgroup_alloc(void) return objcg; } =20 -static void memcg_reparent_objcgs(struct mem_cgroup *memcg) +static inline struct obj_cgroup *__memcg_reparent_objcgs(struct mem_cgroup= *memcg, + struct mem_cgroup *parent) { struct obj_cgroup *objcg, *iter; - struct mem_cgroup *parent =3D parent_mem_cgroup(memcg); =20 objcg =3D rcu_replace_pointer(memcg->objcg, NULL, true); - - spin_lock_irq(&objcg_lock); - /* 1) Ready to reparent active objcg. */ list_add(&objcg->list, &memcg->objcg_list); /* 2) Reparent active objcg and already reparented objcgs to parent. */ @@ -225,7 +222,29 @@ static void memcg_reparent_objcgs(struct mem_cgroup *m= emcg) /* 3) Move already reparented objcgs to the parent's list */ list_splice(&memcg->objcg_list, &parent->objcg_list); =20 + return objcg; +} + +static inline void reparent_locks(struct mem_cgroup *memcg, struct mem_cgr= oup *parent) +{ + spin_lock_irq(&objcg_lock); +} + +static inline void reparent_unlocks(struct mem_cgroup *memcg, struct mem_c= group *parent) +{ spin_unlock_irq(&objcg_lock); +} + +static void memcg_reparent_objcgs(struct mem_cgroup *memcg) +{ + struct obj_cgroup *objcg; + struct mem_cgroup *parent =3D parent_mem_cgroup(memcg); + + reparent_locks(memcg, parent); + + objcg =3D __memcg_reparent_objcgs(memcg, parent); + + reparent_unlocks(memcg, parent); =20 percpu_ref_kill(&objcg->refcnt); } --=20 2.20.1