From nobody Tue Feb 10 05:48:36 2026 Received: from invmail4.hynix.com (exvmail4.hynix.com [166.125.252.92]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 0ED7421C163; Thu, 17 Apr 2025 07:29:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=166.125.252.92 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744874958; cv=none; b=NmhlMqaXbZgblMWX/zPeKe2luRLW28I4IBMu1uEjiMvKvbmrWElihWFPXbIJ7j9NXYiIBWW1jMnAcjQWtV8f/6KNvfS6cluY1BdJkxnKnvmaC7Yc+VHz9srCdGEfenbQ5wy3OVqriiSJoZI7hWEG8saCTh4QdlfY+BQKu17fNWI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744874958; c=relaxed/simple; bh=7OT01MoGWMstMxt1ZCpNYviXmh+PWcMQps7TxC2tqnU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=F3QstYeCL6kM28306uZmf7TAM/FY8EYRYG96ucz/ZGke/apEm2J7R3rICJmAUMnHyqQU3OigoCegi5UIr5z2UmIja7I8cGJ8q1GHeDl4bZcuz+AGhd7GP5gwP77enaGHUx1sIStt1ouNrabGa1AnhhqafO6IYe0edkrTwH54+bw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sk.com; spf=pass smtp.mailfrom=sk.com; arc=none smtp.client-ip=166.125.252.92 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sk.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sk.com X-AuditID: a67dfc5b-669ff7000002311f-0b-6800adc3d9e0 From: Rakie Kim To: akpm@linux-foundation.org Cc: gourry@gourry.net, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-cxl@vger.kernel.org, joshua.hahnjy@gmail.com, dan.j.williams@intel.com, ying.huang@linux.alibaba.com, david@redhat.com, Jonathan.Cameron@huawei.com, osalvador@suse.de, kernel_team@skhynix.com, honggyu.kim@sk.com, yunjeong.mun@sk.com, rakie.kim@sk.com Subject: [PATCH v9 2/3] mm/mempolicy: Prepare weighted interleave sysfs for memory hotplug Date: Thu, 17 Apr 2025 16:28:36 +0900 Message-ID: <20250417072839.711-3-rakie.kim@sk.com> X-Mailer: git-send-email 2.48.1.windows.1 In-Reply-To: <20250417072839.711-1-rakie.kim@sk.com> References: <20250417072839.711-1-rakie.kim@sk.com> 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-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrJLMWRmVeSWpSXmKPExsXC9ZZnoe7htQwZBo+buSzmrF/DZjF96gVG i6/rfzFb/Lx7nN1i1cJrbBbHt85jtzg/6xSLxeVdc9gs7q35z2pxZlqRxeo1GQ7cHjtn3WX3 6G67zO7RcuQtq8fiPS+ZPDZ9msTucWLGbxaPnQ8tPd7vu8rmsfl0tcfnTXIBXFFcNimpOZll qUX6dglcGVd3/Gcs+KFZse/aSaYGxtdKXYycHBICJhKrrz5lg7GbehpZuxg5ONgElCSO7Y0B CYsIyEpM/XuepYuRi4NZ4DGTxKPnLxhBEsICURL/9rxhArFZBFQlLlzYDmbzChhLnNp+nxli pqZEw6V7YHFOoPnTdreAxYWAama+ms4GUS8ocXLmExYQm1lAXqJ562xmkGUSAp/ZJObuP8QK MUhS4uCKGywTGPlnIemZhaRnASPTKkahzLyy3MTMHBO9jMq8zAq95PzcTYzACFhW+yd6B+On C8GHGAU4GJV4eE8s+p8uxJpYVlyZe4hRgoNZSYT3nPm/dCHelMTKqtSi/Pii0pzU4kOM0hws SuK8Rt/KU4QE0hNLUrNTUwtSi2CyTBycUg2MS5Y0uB/Jn/HuNdsR10OVcR23WHTX/OSNYjSW e/Uzc7vOVs1X0yY5Supxtb7qiXm8/s20QL9mvZ33Ay/0fdU4PC/3arP8y5dfZwleUVTwlXil YPfyajNnh/2X+Dn3DONe2hdcPVigu+7KPgklh5xlduoP/y3Yx5F/SZrFon3ptoYHXuJf5Qrb lViKMxINtZiLihMBCzq7+HwCAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrMLMWRmVeSWpSXmKPExsXCNUNNS/fQWoYMgw+nrS3mrF/DZjF96gVG i6/rfzFb/Lx7nN3i87PXzBarFl5jszi+dR67xeG5J1ktzs86xWJxedccNot7a/6zWpyZVmRx 6NpzVovVazIsfm9bwebA77Fz1l12j+62y+weLUfesnos3vOSyWPTp0nsHidm/Gbx2PnQ0uP9 vqtsHt9ue3gsfvGByWPz6WqPz5vkAniiuGxSUnMyy1KL9O0SuDKu7vjPWPBDs2LftZNMDYyv lboYOTkkBEwkmnoaWbsYOTjYBJQkju2NAQmLCMhKTP17nqWLkYuDWeAxk8Sj5y8YQRLCAlES //a8YQKxWQRUJS5c2A5m8woYS5zafp8ZYqamRMOle2BxTqD503a3gMWFgGpmvprOBlEvKHFy 5hMWEJtZQF6ieets5gmMPLOQpGYhSS1gZFrFKJKZV5abmJljqlecnVGZl1mhl5yfu4kRGPTL av9M3MH45bL7IUYBDkYlHt4Ti/6nC7EmlhVX5h5ilOBgVhLhPWf+L12INyWxsiq1KD++qDQn tfgQozQHi5I4r1d4aoKQQHpiSWp2ampBahFMlomDU6qB8Y5cyodVbCVdtgl1T/0iPjft1y2/ n8hVJeqQrNMqURE8STVDIVFe9rbu/PdzQmfsTKmyXRgb7Jax873K0rb/aZKea34E5d7SU564 e4vJXY2ceIXs0ucNKqZLtQvvxLjdvr2RZ63/f3Hf018O3bb7f6Do5GaPUyG/n+40O2iy0d2u PIJTsfKzEktxRqKhFnNRcSIAgF5fKXYCAAA= X-CFilter-Loop: Reflected Content-Type: text/plain; charset="utf-8" Previously, the weighted interleave sysfs structure was statically managed during initialization. This prevented new nodes from being recognized when memory hotplug events occurred, limiting the ability to update or extend sysfs entries dynamically at runtime. To address this, this patch refactors the sysfs infrastructure and encapsulates it within a new structure, `sysfs_wi_group`, which holds both the kobject and an array of node attribute pointers. By allocating this group structure globally, the per-node sysfs attributes can be managed beyond initialization time, enabling external modules to insert or remove node entries in response to events such as memory hotplug or node online/offline transitions. Instead of allocating all per-node sysfs attributes at once, the initialization path now uses the existing sysfs_wi_node_add() and sysfs_wi_node_delete() helpers. This refactoring makes it possible to modularly manage per-node sysfs entries and ensures the infrastructure is ready for runtime extension. Signed-off-by: Rakie Kim Reviewed-by: Gregory Price Reviewed-by: Joshua Hahn Reviewed-by: Dan Williams --- mm/mempolicy.c | 64 ++++++++++++++++++++++++-------------------------- 1 file changed, 31 insertions(+), 33 deletions(-) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 293b4b347975..97b52d65b3ba 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -3419,6 +3419,13 @@ struct iw_node_attr { int nid; }; =20 +struct sysfs_wi_group { + struct kobject wi_kobj; + struct iw_node_attr *nattrs[]; +}; + +static struct sysfs_wi_group *wi_group; + static ssize_t node_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { @@ -3461,24 +3468,23 @@ static ssize_t node_store(struct kobject *kobj, str= uct kobj_attribute *attr, return count; } =20 -static struct iw_node_attr **node_attrs; - -static void sysfs_wi_node_delete(struct iw_node_attr *node_attr, - struct kobject *parent) +static void sysfs_wi_node_delete(int nid) { - if (!node_attr) + if (!wi_group->nattrs[nid]) return; - sysfs_remove_file(parent, &node_attr->kobj_attr.attr); - kfree(node_attr->kobj_attr.attr.name); - kfree(node_attr); + + sysfs_remove_file(&wi_group->wi_kobj, + &wi_group->nattrs[nid]->kobj_attr.attr); + kfree(wi_group->nattrs[nid]->kobj_attr.attr.name); + kfree(wi_group->nattrs[nid]); } =20 -static void sysfs_wi_node_delete_all(struct kobject *wi_kobj) +static void sysfs_wi_node_delete_all(void) { int nid; =20 for (nid =3D 0; nid < nr_node_ids; nid++) - sysfs_wi_node_delete(node_attrs[nid], wi_kobj); + sysfs_wi_node_delete(nid); } =20 static void iw_table_free(void) @@ -3495,15 +3501,14 @@ static void iw_table_free(void) kfree(old); } =20 -static void wi_cleanup(struct kobject *wi_kobj) { - sysfs_wi_node_delete_all(wi_kobj); +static void wi_cleanup(void) { + sysfs_wi_node_delete_all(); iw_table_free(); - kfree(node_attrs); } =20 static void wi_kobj_release(struct kobject *wi_kobj) { - kfree(wi_kobj); + kfree(wi_group); } =20 static const struct kobj_type wi_ktype =3D { @@ -3511,7 +3516,7 @@ static const struct kobj_type wi_ktype =3D { .release =3D wi_kobj_release, }; =20 -static int add_weight_node(int nid, struct kobject *wi_kobj) +static int sysfs_wi_node_add(int nid) { struct iw_node_attr *node_attr; char *name; @@ -3533,40 +3538,33 @@ static int add_weight_node(int nid, struct kobject = *wi_kobj) node_attr->kobj_attr.store =3D node_store; node_attr->nid =3D nid; =20 - if (sysfs_create_file(wi_kobj, &node_attr->kobj_attr.attr)) { + if (sysfs_create_file(&wi_group->wi_kobj, &node_attr->kobj_attr.attr)) { kfree(node_attr->kobj_attr.attr.name); kfree(node_attr); pr_err("failed to add attribute to weighted_interleave\n"); return -ENOMEM; } =20 - node_attrs[nid] =3D node_attr; + wi_group->nattrs[nid] =3D node_attr; return 0; } =20 -static int add_weighted_interleave_group(struct kobject *root_kobj) +static int __init add_weighted_interleave_group(struct kobject *mempolicy_= kobj) { - struct kobject *wi_kobj; int nid, err; =20 - node_attrs =3D kcalloc(nr_node_ids, sizeof(struct iw_node_attr *), - GFP_KERNEL); - if (!node_attrs) - return -ENOMEM; - - wi_kobj =3D kzalloc(sizeof(struct kobject), GFP_KERNEL); - if (!wi_kobj) { - kfree(node_attrs); + wi_group =3D kzalloc(struct_size(wi_group, nattrs, nr_node_ids), + GFP_KERNEL); + if (!wi_group) return -ENOMEM; - } =20 - err =3D kobject_init_and_add(wi_kobj, &wi_ktype, root_kobj, + err =3D kobject_init_and_add(&wi_group->wi_kobj, &wi_ktype, mempolicy_kob= j, "weighted_interleave"); if (err) goto err_put_kobj; =20 for_each_node_state(nid, N_POSSIBLE) { - err =3D add_weight_node(nid, wi_kobj); + err =3D sysfs_wi_node_add(nid); if (err) { pr_err("failed to add sysfs [node%d]\n", nid); goto err_cleanup_kobj; @@ -3576,10 +3574,10 @@ static int add_weighted_interleave_group(struct kob= ject *root_kobj) return 0; =20 err_cleanup_kobj: - wi_cleanup(wi_kobj); - kobject_del(wi_kobj); + wi_cleanup(); + kobject_del(&wi_group->wi_kobj); err_put_kobj: - kobject_put(wi_kobj); + kobject_put(&wi_group->wi_kobj); return err; } =20 --=20 2.34.1