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From: Rakie Kim <rakie.kim@sk.com>
To: gourry@gourry.net
Cc: akpm@linux-foundation.org,
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,
kernel_team@skhynix.com,
honggyu.kim@sk.com,
yunjeong.mun@sk.com,
rakie.kim@sk.com
Subject: [PATCH v4 1/3] mm/mempolicy: Fix memory leaks in weighted interleave
sysfs
Date: Tue, 1 Apr 2025 18:08:57 +0900
Message-ID: <20250401090901.1050-2-rakie.kim@sk.com>
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X-CFilter-Loop: Reflected
Content-Type: text/plain; charset="utf-8"
Memory leaks occurred when removing sysfs attributes for weighted
interleave. Improper kobject deallocation led to unreleased memory
when initialization failed or when nodes were removed.
This patch resolves the issue by replacing unnecessary `kfree()`
calls with `kobject_put()`, ensuring proper cleanup and preventing
memory leaks.
By correctly using `kobject_put()`, the release function now
properly deallocates memory without causing resource leaks,
thereby improving system stability.
Fixes: dce41f5ae253 ("mm/mempolicy: implement the sysfs-based weighted_inte=
rleave interface")
Signed-off-by: Rakie Kim <rakie.kim@sk.com>
Signed-off-by: Honggyu Kim <honggyu.kim@sk.com>
Signed-off-by: Yunjeong Mun <yunjeong.mun@sk.com>
Reviewed-by: Gregory Price <gourry@gourry.net>
---
mm/mempolicy.c | 61 +++++++++++++++++++++++++-------------------------
1 file changed, 31 insertions(+), 30 deletions(-)
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index bbaadbeeb291..5950d5d5b85e 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -3448,7 +3448,9 @@ static void sysfs_wi_release(struct kobject *wi_kobj)
=20
for (i =3D 0; i < nr_node_ids; i++)
sysfs_wi_node_release(node_attrs[i], wi_kobj);
- kobject_put(wi_kobj);
+
+ kfree(node_attrs);
+ kfree(wi_kobj);
}
=20
static const struct kobj_type wi_ktype =3D {
@@ -3494,15 +3496,22 @@ static int add_weighted_interleave_group(struct kob=
ject *root_kobj)
struct kobject *wi_kobj;
int nid, err;
=20
- wi_kobj =3D kzalloc(sizeof(struct kobject), GFP_KERNEL);
- if (!wi_kobj)
+ node_attrs =3D kcalloc(nr_node_ids, sizeof(struct iw_node_attr *),
+ GFP_KERNEL);
+ if (!node_attrs)
return -ENOMEM;
=20
+ wi_kobj =3D kzalloc(sizeof(struct kobject), GFP_KERNEL);
+ if (!wi_kobj) {
+ err =3D -ENOMEM;
+ goto node_out;
+ }
+
err =3D kobject_init_and_add(wi_kobj, &wi_ktype, root_kobj,
"weighted_interleave");
if (err) {
- kfree(wi_kobj);
- return err;
+ kobject_put(wi_kobj);
+ goto err_out;
}
=20
for_each_node_state(nid, N_POSSIBLE) {
@@ -3512,9 +3521,17 @@ static int add_weighted_interleave_group(struct kobj=
ect *root_kobj)
break;
}
}
- if (err)
+ if (err) {
kobject_put(wi_kobj);
+ goto err_out;
+ }
+
return 0;
+
+node_out:
+ kfree(node_attrs);
+err_out:
+ return err;
}
=20
static void mempolicy_kobj_release(struct kobject *kobj)
@@ -3528,7 +3545,6 @@ static void mempolicy_kobj_release(struct kobject *ko=
bj)
mutex_unlock(&iw_table_lock);
synchronize_rcu();
kfree(old);
- kfree(node_attrs);
kfree(kobj);
}
=20
@@ -3542,37 +3558,22 @@ static int __init mempolicy_sysfs_init(void)
static struct kobject *mempolicy_kobj;
=20
mempolicy_kobj =3D kzalloc(sizeof(*mempolicy_kobj), GFP_KERNEL);
- if (!mempolicy_kobj) {
- err =3D -ENOMEM;
- goto err_out;
- }
-
- node_attrs =3D kcalloc(nr_node_ids, sizeof(struct iw_node_attr *),
- GFP_KERNEL);
- if (!node_attrs) {
- err =3D -ENOMEM;
- goto mempol_out;
- }
+ if (!mempolicy_kobj)
+ return -ENOMEM;
=20
err =3D kobject_init_and_add(mempolicy_kobj, &mempolicy_ktype, mm_kobj,
"mempolicy");
if (err)
- goto node_out;
+ goto err_out;
=20
err =3D add_weighted_interleave_group(mempolicy_kobj);
- if (err) {
- pr_err("mempolicy sysfs structure failed to initialize\n");
- kobject_put(mempolicy_kobj);
- return err;
- }
+ if (err)
+ goto err_out;
+
+ return 0;
=20
- return err;
-node_out:
- kfree(node_attrs);
-mempol_out:
- kfree(mempolicy_kobj);
err_out:
- pr_err("failed to add mempolicy kobject to the system\n");
+ kobject_put(mempolicy_kobj);
return err;
}
=20
--=20
2.34.1
From nobody Tue May 13 06:16:40 2025
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From: Rakie Kim <rakie.kim@sk.com>
To: gourry@gourry.net
Cc: akpm@linux-foundation.org,
linux-mm@kvack.org,
linux-kernel@vger.kernel.org,
linux-cxl@vger.kernel.org,
joshua.hahnjy@gmail.com,
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Jonathan.Cameron@huawei.com,
kernel_team@skhynix.com,
honggyu.kim@sk.com,
yunjeong.mun@sk.com,
rakie.kim@sk.com
Subject: [PATCH v4 2/3] mm/mempolicy: Support dynamic sysfs updates for
weighted interleave
Date: Tue, 1 Apr 2025 18:08:58 +0900
Message-ID: <20250401090901.1050-3-rakie.kim@sk.com>
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X-CFilter-Loop: Reflected
Content-Type: text/plain; charset="utf-8"
Previously, the weighted interleave sysfs structure was statically
managed, preventing dynamic updates when nodes were added or removed.
This patch restructures the weighted interleave sysfs to support
dynamic insertion and deletion. The sysfs that was part of
the 'weighted_interleave_group' is now globally accessible,
allowing external access to that sysfs.
With this change, sysfs management for weighted interleave is
more flexible, supporting hotplug events and runtime updates
more effectively.
Signed-off-by: Rakie Kim <rakie.kim@sk.com>
Signed-off-by: Honggyu Kim <honggyu.kim@sk.com>
Signed-off-by: Yunjeong Mun <yunjeong.mun@sk.com>
Reviewed-by: Gregory Price <gourry@gourry.net>
---
mm/mempolicy.c | 71 ++++++++++++++++++++++----------------------------
1 file changed, 31 insertions(+), 40 deletions(-)
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 5950d5d5b85e..3092a792bd28 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -3388,6 +3388,13 @@ 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)
{
@@ -3430,27 +3437,24 @@ 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_release(struct iw_node_attr *node_attr,
- struct kobject *parent)
+static void sysfs_wi_node_release(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_release(struct kobject *wi_kobj)
{
- int i;
-
- for (i =3D 0; i < nr_node_ids; i++)
- sysfs_wi_node_release(node_attrs[i], wi_kobj);
+ int nid;
=20
- kfree(node_attrs);
- kfree(wi_kobj);
+ for (nid =3D 0; nid < nr_node_ids; nid++)
+ sysfs_wi_node_release(nid);
+ kfree(wi_group);
}
=20
static const struct kobj_type wi_ktype =3D {
@@ -3458,7 +3462,7 @@ static const struct kobj_type wi_ktype =3D {
.release =3D sysfs_wi_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;
@@ -3480,57 +3484,44 @@ 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 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)
+ wi_group =3D kzalloc(sizeof(struct sysfs_wi_group) + \
+ nr_node_ids * sizeof(struct iw_node_attr *), \
+ GFP_KERNEL);
+ if (!wi_group)
return -ENOMEM;
=20
- wi_kobj =3D kzalloc(sizeof(struct kobject), GFP_KERNEL);
- if (!wi_kobj) {
- err =3D -ENOMEM;
- goto node_out;
- }
-
- 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) {
- kobject_put(wi_kobj);
+ if (err)
goto err_out;
- }
=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);
- break;
+ goto err_out;
}
}
- if (err) {
- kobject_put(wi_kobj);
- goto err_out;
- }
=20
return 0;
=20
-node_out:
- kfree(node_attrs);
err_out:
+ kobject_put(&wi_group->wi_kobj);
return err;
}
=20
--=20
2.34.1
From nobody Tue May 13 06:16:40 2025
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From: Rakie Kim <rakie.kim@sk.com>
To: gourry@gourry.net
Cc: akpm@linux-foundation.org,
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,
kernel_team@skhynix.com,
honggyu.kim@sk.com,
yunjeong.mun@sk.com,
rakie.kim@sk.com
Subject: [PATCH v4 3/3] mm/mempolicy: Support memory hotplug in weighted
interleave
Date: Tue, 1 Apr 2025 18:08:59 +0900
Message-ID: <20250401090901.1050-4-rakie.kim@sk.com>
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In-Reply-To: <20250401090901.1050-1-rakie.kim@sk.com>
References: <20250401090901.1050-1-rakie.kim@sk.com>
Precedence: bulk
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Content-Type: text/plain; charset="utf-8"
The weighted interleave policy distributes page allocations across multiple
NUMA nodes based on their performance weight, thereby improving memory
bandwidth utilization. The weight values for each node are configured
through sysfs.
Previously, sysfs entries for configuring weighted interleave were created
for all possible nodes (N_POSSIBLE) at initialization, including nodes that
might not have memory. However, not all nodes in N_POSSIBLE are usable at
runtime, as some may remain memoryless or offline.
This led to sysfs entries being created for unusable nodes, causing
potential misconfiguration issues.
To address this issue, this patch modifies the sysfs creation logic to:
1) Limit sysfs entries to nodes that are online and have memory, avoiding
the creation of sysfs entries for nodes that cannot be used.
2) Support memory hotplug by dynamically adding and removing sysfs entries
based on whether a node transitions into or out of the N_MEMORY state.
Additionally, the patch ensures that sysfs attributes are properly managed
when nodes go offline, preventing stale or redundant entries from persisting
in the system.
By making these changes, the weighted interleave policy now manages its
sysfs entries more efficiently, ensuring that only relevant nodes are
considered for interleaving, and dynamically adapting to memory hotplug
events.
Signed-off-by: Rakie Kim <rakie.kim@sk.com>
Signed-off-by: Honggyu Kim <honggyu.kim@sk.com>
Signed-off-by: Yunjeong Mun <yunjeong.mun@sk.com>
---
mm/mempolicy.c | 113 +++++++++++++++++++++++++++++++++++++++----------
1 file changed, 90 insertions(+), 23 deletions(-)
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 3092a792bd28..fa755d20780c 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -113,6 +113,7 @@
#include <asm/tlbflush.h>
#include <asm/tlb.h>
#include <linux/uaccess.h>
+#include <linux/memory.h>
=20
#include "internal.h"
=20
@@ -3390,6 +3391,7 @@ struct iw_node_attr {
=20
struct sysfs_wi_group {
struct kobject wi_kobj;
+ struct mutex kobj_lock;
struct iw_node_attr *nattrs[];
};
=20
@@ -3439,13 +3441,24 @@ static ssize_t node_store(struct kobject *kobj, str=
uct kobj_attribute *attr,
=20
static void sysfs_wi_node_release(int nid)
{
- if (!wi_group->nattrs[nid])
+ struct iw_node_attr *attr;
+
+ if (nid < 0 || nid >=3D nr_node_ids)
+ return;
+
+ mutex_lock(&wi_group->kobj_lock);
+ attr =3D wi_group->nattrs[nid];
+ if (!attr) {
+ mutex_unlock(&wi_group->kobj_lock);
return;
+ }
=20
- 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]);
+ wi_group->nattrs[nid] =3D NULL;
+ mutex_unlock(&wi_group->kobj_lock);
+
+ sysfs_remove_file(&wi_group->wi_kobj, &attr->kobj_attr.attr);
+ kfree(attr->kobj_attr.attr.name);
+ kfree(attr);
}
=20
static void sysfs_wi_release(struct kobject *wi_kobj)
@@ -3464,35 +3477,84 @@ static const struct kobj_type wi_ktype =3D {
=20
static int sysfs_wi_node_add(int nid)
{
- struct iw_node_attr *node_attr;
+ int ret =3D 0;
char *name;
+ struct iw_node_attr *new_attr =3D NULL;
=20
- node_attr =3D kzalloc(sizeof(*node_attr), GFP_KERNEL);
- if (!node_attr)
+ if (nid < 0 || nid >=3D nr_node_ids) {
+ pr_err("Invalid node id: %d\n", nid);
+ return -EINVAL;
+ }
+
+ new_attr =3D kzalloc(sizeof(struct iw_node_attr), GFP_KERNEL);
+ if (!new_attr)
return -ENOMEM;
=20
name =3D kasprintf(GFP_KERNEL, "node%d", nid);
if (!name) {
- kfree(node_attr);
+ kfree(new_attr);
return -ENOMEM;
}
=20
- sysfs_attr_init(&node_attr->kobj_attr.attr);
- node_attr->kobj_attr.attr.name =3D name;
- node_attr->kobj_attr.attr.mode =3D 0644;
- node_attr->kobj_attr.show =3D node_show;
- node_attr->kobj_attr.store =3D node_store;
- node_attr->nid =3D nid;
+ mutex_lock(&wi_group->kobj_lock);
+ if (wi_group->nattrs[nid]) {
+ mutex_unlock(&wi_group->kobj_lock);
+ pr_info("Node [%d] already exists\n", nid);
+ kfree(new_attr);
+ kfree(name);
+ return 0;
+ }
=20
- 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;
+ wi_group->nattrs[nid] =3D new_attr;
+ mutex_unlock(&wi_group->kobj_lock);
+
+ sysfs_attr_init(&wi_group->nattrs[nid]->kobj_attr.attr);
+ wi_group->nattrs[nid]->kobj_attr.attr.name =3D name;
+ wi_group->nattrs[nid]->kobj_attr.attr.mode =3D 0644;
+ wi_group->nattrs[nid]->kobj_attr.show =3D node_show;
+ wi_group->nattrs[nid]->kobj_attr.store =3D node_store;
+ wi_group->nattrs[nid]->nid =3D nid;
+
+ ret =3D sysfs_create_file(&wi_group->wi_kobj,
+ &wi_group->nattrs[nid]->kobj_attr.attr);
+ if (ret) {
+ kfree(wi_group->nattrs[nid]->kobj_attr.attr.name);
+ kfree(wi_group->nattrs[nid]);
+ wi_group->nattrs[nid] =3D NULL;
+ pr_err("Failed to add attribute to weighted_interleave: %d\n", ret);
}
=20
- wi_group->nattrs[nid] =3D node_attr;
- return 0;
+ return ret;
+}
+
+static int wi_node_notifier(struct notifier_block *nb,
+ unsigned long action, void *data)
+{
+ int err;
+ struct memory_notify *arg =3D data;
+ int nid =3D arg->status_change_nid;
+
+ if (nid < 0)
+ goto notifier_end;
+
+ switch(action) {
+ case MEM_ONLINE:
+ if (node_state(nid, N_MEMORY)) {
+ err =3D sysfs_wi_node_add(nid);
+ if (err) {
+ pr_err("failed to add sysfs [node%d]\n", nid);
+ return NOTIFY_BAD;
+ }
+ }
+ break;
+ case MEM_OFFLINE:
+ if (!node_state(nid, N_MEMORY))
+ sysfs_wi_node_release(nid);
+ break;
+ }
+
+notifier_end:
+ return NOTIFY_OK;
}
=20
static int add_weighted_interleave_group(struct kobject *mempolicy_kobj)
@@ -3504,13 +3566,17 @@ static int add_weighted_interleave_group(struct kob=
ject *mempolicy_kobj)
GFP_KERNEL);
if (!wi_group)
return -ENOMEM;
+ mutex_init(&wi_group->kobj_lock);
=20
err =3D kobject_init_and_add(&wi_group->wi_kobj, &wi_ktype, mempolicy_kob=
j,
"weighted_interleave");
if (err)
goto err_out;
=20
- for_each_node_state(nid, N_POSSIBLE) {
+ for_each_online_node(nid) {
+ if (!node_state(nid, N_MEMORY))
+ continue;
+
err =3D sysfs_wi_node_add(nid);
if (err) {
pr_err("failed to add sysfs [node%d]\n", nid);
@@ -3518,6 +3584,7 @@ static int add_weighted_interleave_group(struct kobje=
ct *mempolicy_kobj)
}
}
=20
+ hotplug_memory_notifier(wi_node_notifier, DEFAULT_CALLBACK_PRI);
return 0;
=20
err_out:
--=20
2.34.1