From nobody Mon Feb 9 14:37:43 2026 Received: from out-181.mta0.migadu.com (out-181.mta0.migadu.com [91.218.175.181]) (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 A5DA7339709 for ; Tue, 28 Oct 2025 14:05:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.181 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761660302; cv=none; b=gVNpkyHuaHKWfNi31HhMjQYwfMKzfHUVJGLh6ahWAz/LIpJqsqTAXjT2QHWZDC3MszLAGZ6M1duZlsXOWnjZbk9YldrETz+ETJ8cpKr5FdQum8AOKxo02R/8rh/gORZGXauff6e39qj2/V/uq6/X+t+yRm1tNbltn5Fuj+zdSr4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761660302; c=relaxed/simple; bh=JiM3ipnlBJOzX0zcLtp9ixiYB7jD4RiHN2hmztb9BG4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=eE1c2Nnq46Fywd6jiu3HuE7hecZTDIXbmgQDgMxV12jxHgULTvabXBWwjlzE8yW/dE8NrA9PZg3NZubHYeDrIVCitwDtmwRORbZmLaKtOMQeArk7PBlncBE0e9trwgN42M+Dj6nT8EitMFFViUaGGWxalTXgBUgJ1DOre5qCYKw= 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=xBN0+Xgv; arc=none smtp.client-ip=91.218.175.181 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="xBN0+Xgv" 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=1761660298; 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=u1RiVu6Vt2llYHxIz14p3hNB1v2Bo6KqNLmF3dplOT8=; b=xBN0+XgvMzEZ0CVS0wiMq+TSAfwuuche1Bos4yWYPX1Tui4h8RXSxjPTErRLvGhdCYqgHW DM2gjYat2LC4eZVWnOU0yZ14JQwberQ4wxKRvzyduIgakeP7D7tFGbwE/FVTMn/ZQp7TeB 2CuDjqJ1RidrsBxK6dAHAxAMERleDos= 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@redhat.com, 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, akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Qi Zheng Subject: [PATCH v1 24/26] mm: memcontrol: refactor memcg_reparent_objcgs() Date: Tue, 28 Oct 2025 21:58:37 +0800 Message-ID: <21f6b42ec2441372bdfb540d2e7e0fef770c0f6c.1761658311.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 --- mm/memcontrol.c | 37 +++++++++++++++++++++++++++---------- mm/vmscan.c | 1 - 2 files changed, 27 insertions(+), 11 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 7969dd93d858a..ee98c9e8fdcea 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 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 void reparent_locks(struct mem_cgroup *src, struct mem_cgroup *dst) +{ + spin_lock_irq(&objcg_lock); +} =20 +static void reparent_unlocks(struct mem_cgroup *src, struct mem_cgroup *ds= t) +{ 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); } diff --git a/mm/vmscan.c b/mm/vmscan.c index 3ee7fb96b8aeb..82c4cc6edbca5 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2649,7 +2649,6 @@ static bool can_age_anon_pages(struct lruvec *lruvec, lruvec_memcg(lruvec)); } =20 - #ifdef CONFIG_MEMCG static void lruvec_reparent_lru(struct lruvec *src, struct lruvec *dst, enum lru_list lru) --=20 2.20.1