From nobody Fri Dec 19 19:20:07 2025 Received: from out-180.mta0.migadu.com (out-180.mta0.migadu.com [91.218.175.180]) (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 B6FF8344056 for ; Wed, 17 Dec 2025 07:34:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.180 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765956859; cv=none; b=sPlit5hoVzZSguurRyrorV4xrwC/rToXhK5ZaA+ZcIzdr9kdd0D2VZ2yuQVJ9p48q5klOG3ICqR+m09Ws7wB1vrKuDz+uvNyUeErm49YHUs18TM88ojQuZSR4KPJEbcPCDm5dz6jAx7pJ5vBEETB8JM6Esl4CFxrSIgUWtqdHIk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765956859; c=relaxed/simple; bh=ApGhz8PrqdtnYhglElt3PQ8WpfkLuxmUgCZ4HCQcF7E=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=AreATwyJx+55DvOiBC2949CFB2O+D/Nlrc2dH+ppYj1SoLmXF5S6ez2nY9fZcTIRWAbFfDq865AsfLmIlFKHHNIoGd5kih1FBuxXDRwPeAVDleIOGbSfa/2ZCWNKf9YpQY8DvDX7ZlMUx6Ah4v1T6e81Fh8MxjcH9ZleYzMQlsc= 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=AXc74V+X; arc=none smtp.client-ip=91.218.175.180 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="AXc74V+X" 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=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: 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 --- 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; } =20 -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 =3D parent_mem_cgroup(memcg); - - objcg =3D rcu_replace_pointer(memcg->objcg, NULL, true); - - spin_lock_irq(&objcg_lock); =20 + objcg =3D 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_cgrou= p *dst) +{ + spin_lock_irq(&objcg_lock); +} =20 +static inline void reparent_unlocks(struct mem_cgroup *src, struct mem_cgr= oup *dst) +{ spin_unlock_irq(&objcg_lock); +} + +static void memcg_reparent_objcgs(struct mem_cgroup *src) +{ + struct obj_cgroup *objcg =3D rcu_dereference_protected(src->objcg, true); + struct mem_cgroup *dst =3D parent_mem_cgroup(src); + + reparent_locks(src, dst); + + __memcg_reparent_objcgs(src, dst); + + reparent_unlocks(src, dst); =20 percpu_ref_kill(&objcg->refcnt); } --=20 2.20.1