| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20250408134932.2986280-1-joshua.hahnjy@gmail.com>
Date: Tue, 8 Apr 2025 06:49:30 -0700
From: Joshua Hahn <joshua.hahnjy@...il.com>
To: Rakie Kim <rakie.kim@...com>
Cc: akpm@...ux-foundation.org,
gourry@...rry.net,
linux-mm@...ck.org,
linux-kernel@...r.kernel.org,
linux-cxl@...r.kernel.org,
joshua.hahnjy@...il.com,
dan.j.williams@...el.com,
ying.huang@...ux.alibaba.com,
david@...hat.com,
Jonathan.Cameron@...wei.com,
osalvador@...e.de,
kernel_team@...ynix.com,
honggyu.kim@...com,
yunjeong.mun@...com
Subject: Re: [PATCH v7 2/3] mm/mempolicy: Prepare weighted interleave sysfs for memory hotplug
On Tue, 8 Apr 2025 16:32:41 +0900 Rakie Kim <rakie.kim@...com> wrote:
Hi Rakie,
This also looks good to me!
Reviewed-by: Joshua Hahn <joshua.hahnjy@...il.com>
> 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 <rakie.kim@...com>
> Signed-off-by: Honggyu Kim <honggyu.kim@...com>
> Signed-off-by: Yunjeong Mun <yunjeong.mun@...com>
> Reviewed-by: Gregory Price <gourry@...rry.net>
> ---
> mm/mempolicy.c | 61 ++++++++++++++++++++++++--------------------------
> 1 file changed, 29 insertions(+), 32 deletions(-)
>
> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> index 0da102aa1cfc..988575f29c53 100644
> --- a/mm/mempolicy.c
> +++ b/mm/mempolicy.c
> @@ -3419,6 +3419,13 @@ struct iw_node_attr {
> int nid;
> };
>
> +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)
> {
> @@ -3461,27 +3468,24 @@ static ssize_t node_store(struct kobject *kobj, struct kobj_attribute *attr,
> return count;
> }
>
> -static struct iw_node_attr **node_attrs;
> -
> -static void sysfs_wi_node_release(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]);
> }
>
> static void sysfs_wi_release(struct kobject *wi_kobj)
> {
> - int i;
> -
> - for (i = 0; i < nr_node_ids; i++)
> - sysfs_wi_node_release(node_attrs[i], wi_kobj);
> + int nid;
>
> - kfree(node_attrs);
> - kfree(wi_kobj);
> + for (nid = 0; nid < nr_node_ids; nid++)
> + sysfs_wi_node_delete(nid);
> + kfree(wi_group);
> }
>
> static const struct kobj_type wi_ktype = {
> @@ -3489,7 +3493,7 @@ static const struct kobj_type wi_ktype = {
> .release = sysfs_wi_release,
> };
>
> -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;
> @@ -3511,40 +3515,33 @@ static int add_weight_node(int nid, struct kobject *wi_kobj)
> node_attr->kobj_attr.store = node_store;
> node_attr->nid = nid;
>
> - 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;
> }
>
> - node_attrs[nid] = node_attr;
> + wi_group->nattrs[nid] = node_attr;
> return 0;
> }
>
> -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;
>
> - node_attrs = kcalloc(nr_node_ids, sizeof(struct iw_node_attr *),
> - GFP_KERNEL);
> - if (!node_attrs)
> + wi_group = kzalloc(struct_size(wi_group, nattrs, nr_node_ids),
> + GFP_KERNEL);
> + if (!wi_group)
> return -ENOMEM;
>
> - wi_kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);
> - if (!wi_kobj) {
> - kfree(node_attrs);
> - return -ENOMEM;
> - }
> -
> - err = kobject_init_and_add(wi_kobj, &wi_ktype, root_kobj,
> + err = kobject_init_and_add(&wi_group->wi_kobj, &wi_ktype, mempolicy_kobj,
> "weighted_interleave");
> if (err)
> goto err_put_kobj;
>
> for_each_node_state(nid, N_POSSIBLE) {
> - err = add_weight_node(nid, wi_kobj);
> + err = sysfs_wi_node_add(nid);
> if (err) {
> pr_err("failed to add sysfs [node%d]\n", nid);
> goto err_del_kobj;
> @@ -3554,9 +3551,9 @@ static int add_weighted_interleave_group(struct kobject *root_kobj)
> return 0;
>
> err_del_kobj:
> - kobject_del(wi_kobj);
> + kobject_del(&wi_group->wi_kobj);
> err_put_kobj:
> - kobject_put(wi_kobj);
> + kobject_put(&wi_group->wi_kobj);
> return err;
> }
>
> --
> 2.34.1
Sent using hkml (https://github.com/sjp38/hackermail)
Powered by blists - more mailing lists