From nobody Mon Feb 9 18:45:18 2026 Received: from out-178.mta0.migadu.com (out-178.mta0.migadu.com [91.218.175.178]) (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 0CADF337108 for ; Tue, 28 Oct 2025 14:04:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.178 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761660286; cv=none; b=M/+VAG+PlJPvZNp9BnARCnUiod7plgzaCurfJnZBlNXfJbxKurxOuApH1ygjAs6VPE7bnVndkwnXtUGDyPAVhnRZCxLYs/S5/mTY+e5BdKmT0DIVGp0OrewZGZ8YEpsgy/ZulB71EQOHLzJIjKNe6BeRc2H4OHDO5Ds6a6qMROI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761660286; c=relaxed/simple; bh=tQPVFYoqRrmI1p/WiQPQYEXxJTCm73j5VaCKJSaWw/Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=rPBdT252PQFSCUmQfAYKcCgEL20rtJgR8DxBfshblR1inoFoKqV/ubFiVgpM8zKXs/qu+qBynK3Wo+QYED8g+uw/mrNvGS/sppiwpmVkCnxj32840KWHFCOobf+h736t1ClAik2VH0TQpPBpC3myoNGgUgJQib+1amJma+5iJN0= 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=WK8tb2Ee; arc=none smtp.client-ip=91.218.175.178 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="WK8tb2Ee" 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=1761660283; 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=f58KJTzXSs4X+PWy8zQk6jO+YawoCWN3pSg57esT6X0=; b=WK8tb2EePZkDDXUBHA8X88Oky6gXYUGXPse40fNXgFJHtOyOpwiA5y2uY/2VpOK8KvPNgg VlXvf/E84wkSoXZBGSZplP19r6Ar3cyL356W88MS4D4kSi6MltL6XLjkKUacyXhIf+LeFQ PdHFCQeViZJqPv2MfDtugYoYaxGFSEE= 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 22/26] mm: vmscan: prepare for reparenting traditional LRU folios Date: Tue, 28 Oct 2025 21:58:35 +0800 Message-ID: <77c64e29b70bad6ca303e0e591624f9cdf2a750b.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 To reslove the dying memcg issue, we need to reparent LRU folios of child memcg to its parent memcg. For traditional LRU list, each lruvec of every memcg comprises four LRU lists. Due to the symmetry of the LRU lists, it is feasible to transfer the LRU lists from a memcg to its parent memcg during the reparenting process. This commit implements the specific function, which will be used during the reparenting process. Signed-off-by: Qi Zheng Reviewed-by: Harry Yoo --- include/linux/mmzone.h | 4 ++++ mm/vmscan.c | 39 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 43 insertions(+) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 4398e027f450e..0d8776e5b6747 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -366,6 +366,10 @@ enum lruvec_flags { LRUVEC_NODE_CONGESTED, }; =20 +#ifdef CONFIG_MEMCG +void lru_reparent_memcg(struct mem_cgroup *src, struct mem_cgroup *dst); +#endif /* CONFIG_MEMCG */ + #endif /* !__GENERATING_BOUNDS_H */ =20 /* diff --git a/mm/vmscan.c b/mm/vmscan.c index 676e6270e5b45..7aa8e1472d10d 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2649,6 +2649,45 @@ 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) +{ + int zid; + struct mem_cgroup_per_node *mz_src, *mz_dst; + + mz_src =3D container_of(src, struct mem_cgroup_per_node, lruvec); + mz_dst =3D container_of(dst, struct mem_cgroup_per_node, lruvec); + + if (lru !=3D LRU_UNEVICTABLE) + list_splice_tail_init(&src->lists[lru], &dst->lists[lru]); + + for (zid =3D 0; zid < MAX_NR_ZONES; zid++) { + mz_dst->lru_zone_size[zid][lru] +=3D mz_src->lru_zone_size[zid][lru]; + mz_src->lru_zone_size[zid][lru] =3D 0; + } +} + +void lru_reparent_memcg(struct mem_cgroup *src, struct mem_cgroup *dst) +{ + int nid; + + for_each_node(nid) { + enum lru_list lru; + struct lruvec *src_lruvec, *dst_lruvec; + + src_lruvec =3D mem_cgroup_lruvec(src, NODE_DATA(nid)); + dst_lruvec =3D mem_cgroup_lruvec(dst, NODE_DATA(nid)); + dst_lruvec->anon_cost +=3D src_lruvec->anon_cost; + dst_lruvec->file_cost +=3D src_lruvec->file_cost; + + for_each_lru(lru) + lruvec_reparent_lru(src_lruvec, dst_lruvec, lru); + } +} +#endif + #ifdef CONFIG_LRU_GEN =20 #ifdef CONFIG_LRU_GEN_ENABLED --=20 2.20.1