From a3d0c6aa1bb342b9b2c7b123b52ac2f48a4d4d0a Mon Sep 17 00:00:00 2001
From: Nishanth Aravamudan <nacc@us.ibm.com>
Date: Fri, 8 Feb 2008 04:18:18 -0800
Subject: [PATCH] hugetlb: add locking for overcommit sysctl
When I replaced hugetlb_dynamic_pool with nr_overcommit_hugepages I used
proc_doulongvec_minmax() directly. However, hugetlb.c's locking rules
require that all counter modifications occur under the hugetlb_lock. Add a
callback into the hugetlb code similar to the one for nr_hugepages. Grab
the lock around the manipulation of nr_overcommit_hugepages in
proc_doulongvec_minmax().
Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Acked-by: Adam Litke <agl@us.ibm.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
include/linux/hugetlb.h | 1 +
kernel/sysctl.c | 2 +-
mm/hugetlb.c | 10 ++++++++++
3 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 30d606afcafe..7ca198b379af 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -17,6 +17,7 @@ static inline int is_vm_hugetlb_page(struct vm_area_struct *vma)
}
int hugetlb_sysctl_handler(struct ctl_table *, int, struct file *, void __user *, size_t *, loff_t *);
+int hugetlb_overcommit_handler(struct ctl_table *, int, struct file *, void __user *, size_t *, loff_t *);
int hugetlb_treat_movable_handler(struct ctl_table *, int, struct file *, void __user *, size_t *, loff_t *);
int copy_hugetlb_page_range(struct mm_struct *, struct mm_struct *, struct vm_area_struct *);
int follow_hugetlb_page(struct mm_struct *, struct vm_area_struct *, struct page **, struct vm_area_struct **, unsigned long *, int *, int, int);
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 8c98d8147d88..9dadc9d88a03 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -982,7 +982,7 @@ static struct ctl_table vm_table[] = {
.data = &nr_overcommit_huge_pages,
.maxlen = sizeof(nr_overcommit_huge_pages),
.mode = 0644,
- .proc_handler = &proc_doulongvec_minmax,
+ .proc_handler = &hugetlb_overcommit_handler,
},
#endif
{
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 1a5642074e34..d9a380312467 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -605,6 +605,16 @@ int hugetlb_treat_movable_handler(struct ctl_table *table, int write,
return 0;
}
+int hugetlb_overcommit_handler(struct ctl_table *table, int write,
+ struct file *file, void __user *buffer,
+ size_t *length, loff_t *ppos)
+{
+ spin_lock(&hugetlb_lock);
+ proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
+ spin_unlock(&hugetlb_lock);
+ return 0;
+}
+
#endif /* CONFIG_SYSCTL */
int hugetlb_report_meminfo(char *buf)
--
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