+ mm-hugetlb-extract-sysctl-into-hugetlb_sysctlc.patch added to mm-new branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm/hugetlb: extract sysctl into hugetlb_sysctl.c
has been added to the -mm mm-new branch.  Its filename is
     mm-hugetlb-extract-sysctl-into-hugetlb_sysctlc.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-hugetlb-extract-sysctl-into-hugetlb_sysctlc.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days

------------------------------------------------------
From: Hui Zhu <zhuhui@kylinos.cn>
Subject: mm/hugetlb: extract sysctl into hugetlb_sysctl.c
Date: Tue, 4 Nov 2025 16:37:43 +0800

Patch series "mm/hugetlb: refactor sysfs/sysctl interfaces", v3.

The hugetlb.c file has grown significantly and become difficult to
maintain.  This patch series extracts the sysfs and sysctl interface code
into separate dedicated files to improve code organization.

The refactoring includes:
- Patch 1: Extract sysfs interface into mm/hugetlb_sysfs.c
- Patch 2: Extract sysctl interface into mm/hugetlb_sysctl.c

No functional changes are introduced in this series.  The code is moved
as-is, with only minor formatting adjustments for code style consistency. 
This should make future maintenance and enhancements to the hugetlb
subsystem easier.

Testing: The patch series has been compile-tested and maintains the same
functionality as the original code.


This patch (of 2)

Following the extraction of sysfs code, this patch moves the sysctl
interface implementation into a dedicated file to further improve code
organization and maintainability of the hugetlb subsystem.

The following components are moved to mm/hugetlb_sysctl.c:
- proc_hugetlb_doulongvec_minmax()
- hugetlb_sysctl_handler_common()
- hugetlb_sysctl_handler()
- hugetlb_mempolicy_sysctl_handler() (CONFIG_NUMA)
- hugetlb_overcommit_handler()
- hugetlb_table[] sysctl table definition
- hugetlb_sysctl_init()

The hugetlb_internal.h header file is updated to declare the sysctl
initialization function with proper #ifdef guards for configurations
without CONFIG_SYSCTL support.

The Makefile is updated to compile hugetlb_sysctl.o when CONFIG_HUGETLBFS
is enabled.  This refactoring reduces the size of hugetlb.c and logically
separates the sysctl interface from core hugetlb management code.

MAINTAINERS is updated to add new file hugetlb_sysctl.c.

No functional changes are introduced; all code is moved as-is from
hugetlb.c with consistent formatting.

Link: https://lkml.kernel.org/r/cover.1762245157.git.zhuhui@kylinos.cn
Link: https://lkml.kernel.org/r/8176f89d16f601ab460c9fb4c9c9af7dd9ef4a0e.1762245158.git.zhuhui@kylinos.cn
Signed-off-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Hui Zhu <zhuhui@kylinos.cn>
Cc: David Hildenbrand <david@redhat.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 MAINTAINERS           |    1 
 mm/Makefile           |    2 
 mm/hugetlb.c          |  132 ---------------------------------------
 mm/hugetlb_internal.h |    6 +
 mm/hugetlb_sysctl.c   |  133 ++++++++++++++++++++++++++++++++++++++++
 5 files changed, 141 insertions(+), 133 deletions(-)

--- a/MAINTAINERS~mm-hugetlb-extract-sysctl-into-hugetlb_sysctlc
+++ a/MAINTAINERS
@@ -11539,6 +11539,7 @@ F:	mm/hugetlb.c
 F:	mm/hugetlb_cgroup.c
 F:	mm/hugetlb_cma.c
 F:	mm/hugetlb_cma.h
+F:	mm/hugetlb_sysctl.c
 F:	mm/hugetlb_sysfs.c
 F:	mm/hugetlb_vmemmap.c
 F:	mm/hugetlb_vmemmap.h
--- a/mm/hugetlb.c~mm-hugetlb-extract-sysctl-into-hugetlb_sysctlc
+++ a/mm/hugetlb.c
@@ -7,7 +7,6 @@
 #include <linux/init.h>
 #include <linux/mm.h>
 #include <linux/seq_file.h>
-#include <linux/sysctl.h>
 #include <linux/highmem.h>
 #include <linux/mmu_notifier.h>
 #include <linux/nodemask.h>
@@ -3983,12 +3982,6 @@ ssize_t __nr_hugepages_store_common(bool
 	return err ? err : len;
 }
 
-#ifdef CONFIG_SYSCTL
-static void hugetlb_sysctl_init(void);
-#else
-static inline void hugetlb_sysctl_init(void) { }
-#endif
-
 static int __init hugetlb_init(void)
 {
 	int i;
@@ -4421,131 +4414,6 @@ static unsigned int allowed_mems_nr(stru
 	return nr;
 }
 
-#ifdef CONFIG_SYSCTL
-static int proc_hugetlb_doulongvec_minmax(const struct ctl_table *table, int write,
-					  void *buffer, size_t *length,
-					  loff_t *ppos, unsigned long *out)
-{
-	struct ctl_table dup_table;
-
-	/*
-	 * In order to avoid races with __do_proc_doulongvec_minmax(), we
-	 * can duplicate the @table and alter the duplicate of it.
-	 */
-	dup_table = *table;
-	dup_table.data = out;
-
-	return proc_doulongvec_minmax(&dup_table, write, buffer, length, ppos);
-}
-
-static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
-			 const struct ctl_table *table, int write,
-			 void *buffer, size_t *length, loff_t *ppos)
-{
-	struct hstate *h = &default_hstate;
-	unsigned long tmp = h->max_huge_pages;
-	int ret;
-
-	if (!hugepages_supported())
-		return -EOPNOTSUPP;
-
-	ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
-					     &tmp);
-	if (ret)
-		goto out;
-
-	if (write)
-		ret = __nr_hugepages_store_common(obey_mempolicy, h,
-						  NUMA_NO_NODE, tmp, *length);
-out:
-	return ret;
-}
-
-static int hugetlb_sysctl_handler(const struct ctl_table *table, int write,
-			  void *buffer, size_t *length, loff_t *ppos)
-{
-
-	return hugetlb_sysctl_handler_common(false, table, write,
-							buffer, length, ppos);
-}
-
-#ifdef CONFIG_NUMA
-static int hugetlb_mempolicy_sysctl_handler(const struct ctl_table *table, int write,
-			  void *buffer, size_t *length, loff_t *ppos)
-{
-	return hugetlb_sysctl_handler_common(true, table, write,
-							buffer, length, ppos);
-}
-#endif /* CONFIG_NUMA */
-
-static int hugetlb_overcommit_handler(const struct ctl_table *table, int write,
-		void *buffer, size_t *length, loff_t *ppos)
-{
-	struct hstate *h = &default_hstate;
-	unsigned long tmp;
-	int ret;
-
-	if (!hugepages_supported())
-		return -EOPNOTSUPP;
-
-	tmp = h->nr_overcommit_huge_pages;
-
-	if (write && hstate_is_gigantic_no_runtime(h))
-		return -EINVAL;
-
-	ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
-					     &tmp);
-	if (ret)
-		goto out;
-
-	if (write) {
-		spin_lock_irq(&hugetlb_lock);
-		h->nr_overcommit_huge_pages = tmp;
-		spin_unlock_irq(&hugetlb_lock);
-	}
-out:
-	return ret;
-}
-
-static const struct ctl_table hugetlb_table[] = {
-	{
-		.procname	= "nr_hugepages",
-		.data		= NULL,
-		.maxlen		= sizeof(unsigned long),
-		.mode		= 0644,
-		.proc_handler	= hugetlb_sysctl_handler,
-	},
-#ifdef CONFIG_NUMA
-	{
-		.procname       = "nr_hugepages_mempolicy",
-		.data           = NULL,
-		.maxlen         = sizeof(unsigned long),
-		.mode           = 0644,
-		.proc_handler   = &hugetlb_mempolicy_sysctl_handler,
-	},
-#endif
-	{
-		.procname	= "hugetlb_shm_group",
-		.data		= &sysctl_hugetlb_shm_group,
-		.maxlen		= sizeof(gid_t),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec,
-	},
-	{
-		.procname	= "nr_overcommit_hugepages",
-		.data		= NULL,
-		.maxlen		= sizeof(unsigned long),
-		.mode		= 0644,
-		.proc_handler	= hugetlb_overcommit_handler,
-	},
-};
-
-static void __init hugetlb_sysctl_init(void)
-{
-	register_sysctl_init("vm", hugetlb_table);
-}
-#endif /* CONFIG_SYSCTL */
-
 void hugetlb_report_meminfo(struct seq_file *m)
 {
 	struct hstate *h;
--- a/mm/hugetlb_internal.h~mm-hugetlb-extract-sysctl-into-hugetlb_sysctlc
+++ a/mm/hugetlb_internal.h
@@ -104,4 +104,10 @@ extern ssize_t __nr_hugepages_store_comm
 
 extern void hugetlb_sysfs_init(void) __init;
 
+#ifdef CONFIG_SYSCTL
+extern void hugetlb_sysctl_init(void);
+#else
+static inline void hugetlb_sysctl_init(void) { }
+#endif
+
 #endif /* _LINUX_HUGETLB_INTERNAL_H */
diff --git a/mm/hugetlb_sysctl.c a/mm/hugetlb_sysctl.c
new file mode 100644
--- /dev/null
+++ a/mm/hugetlb_sysctl.c
@@ -0,0 +1,133 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * HugeTLB sysfs interfaces.
+ */
+
+#include <linux/sysctl.h>
+
+#include "hugetlb_internal.h"
+
+#ifdef CONFIG_SYSCTL
+static int proc_hugetlb_doulongvec_minmax(const struct ctl_table *table, int write,
+					  void *buffer, size_t *length,
+					  loff_t *ppos, unsigned long *out)
+{
+	struct ctl_table dup_table;
+
+	/*
+	 * In order to avoid races with __do_proc_doulongvec_minmax(), we
+	 * can duplicate the @table and alter the duplicate of it.
+	 */
+	dup_table = *table;
+	dup_table.data = out;
+
+	return proc_doulongvec_minmax(&dup_table, write, buffer, length, ppos);
+}
+
+static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
+			 const struct ctl_table *table, int write,
+			 void *buffer, size_t *length, loff_t *ppos)
+{
+	struct hstate *h = &default_hstate;
+	unsigned long tmp = h->max_huge_pages;
+	int ret;
+
+	if (!hugepages_supported())
+		return -EOPNOTSUPP;
+
+	ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
+					     &tmp);
+	if (ret)
+		goto out;
+
+	if (write)
+		ret = __nr_hugepages_store_common(obey_mempolicy, h,
+						  NUMA_NO_NODE, tmp, *length);
+out:
+	return ret;
+}
+
+static int hugetlb_sysctl_handler(const struct ctl_table *table, int write,
+			  void *buffer, size_t *length, loff_t *ppos)
+{
+
+	return hugetlb_sysctl_handler_common(false, table, write,
+							buffer, length, ppos);
+}
+
+#ifdef CONFIG_NUMA
+static int hugetlb_mempolicy_sysctl_handler(const struct ctl_table *table, int write,
+			  void *buffer, size_t *length, loff_t *ppos)
+{
+	return hugetlb_sysctl_handler_common(true, table, write,
+							buffer, length, ppos);
+}
+#endif /* CONFIG_NUMA */
+
+static int hugetlb_overcommit_handler(const struct ctl_table *table, int write,
+		void *buffer, size_t *length, loff_t *ppos)
+{
+	struct hstate *h = &default_hstate;
+	unsigned long tmp;
+	int ret;
+
+	if (!hugepages_supported())
+		return -EOPNOTSUPP;
+
+	tmp = h->nr_overcommit_huge_pages;
+
+	if (write && hstate_is_gigantic_no_runtime(h))
+		return -EINVAL;
+
+	ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
+					     &tmp);
+	if (ret)
+		goto out;
+
+	if (write) {
+		spin_lock_irq(&hugetlb_lock);
+		h->nr_overcommit_huge_pages = tmp;
+		spin_unlock_irq(&hugetlb_lock);
+	}
+out:
+	return ret;
+}
+
+static const struct ctl_table hugetlb_table[] = {
+	{
+		.procname	= "nr_hugepages",
+		.data		= NULL,
+		.maxlen		= sizeof(unsigned long),
+		.mode		= 0644,
+		.proc_handler	= hugetlb_sysctl_handler,
+	},
+#ifdef CONFIG_NUMA
+	{
+		.procname       = "nr_hugepages_mempolicy",
+		.data           = NULL,
+		.maxlen         = sizeof(unsigned long),
+		.mode           = 0644,
+		.proc_handler   = &hugetlb_mempolicy_sysctl_handler,
+	},
+#endif
+	{
+		.procname	= "hugetlb_shm_group",
+		.data		= &sysctl_hugetlb_shm_group,
+		.maxlen		= sizeof(gid_t),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "nr_overcommit_hugepages",
+		.data		= NULL,
+		.maxlen		= sizeof(unsigned long),
+		.mode		= 0644,
+		.proc_handler	= hugetlb_overcommit_handler,
+	},
+};
+
+void __init hugetlb_sysctl_init(void)
+{
+	register_sysctl_init("vm", hugetlb_table);
+}
+#endif /* CONFIG_SYSCTL */
--- a/mm/Makefile~mm-hugetlb-extract-sysctl-into-hugetlb_sysctlc
+++ a/mm/Makefile
@@ -78,7 +78,7 @@ endif
 obj-$(CONFIG_SWAP)	+= page_io.o swap_state.o swapfile.o
 obj-$(CONFIG_ZSWAP)	+= zswap.o
 obj-$(CONFIG_HAS_DMA)	+= dmapool.o
-obj-$(CONFIG_HUGETLBFS)	+= hugetlb.o hugetlb_sysfs.o
+obj-$(CONFIG_HUGETLBFS)	+= hugetlb.o hugetlb_sysfs.o hugetlb_sysctl.o
 ifdef CONFIG_CMA
 obj-$(CONFIG_HUGETLBFS)	+= hugetlb_cma.o
 endif
_

Patches currently in -mm which might be from zhuhui@kylinos.cn are

mm-hugetlb-extract-sysfs-into-hugetlb_sysfsc.patch
mm-hugetlb-extract-sysctl-into-hugetlb_sysctlc.patch