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hugetlb: add locking for overcommit sysctl

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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>
This commit is contained in:
Nishanth Aravamudan 2008-02-08 04:18:18 -08:00 committed by Linus Torvalds
parent ac74c00e49
commit a3d0c6aa1b
3 changed files with 12 additions and 1 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

1
include/linux/hugetlb.h
View file

@ -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);

2
kernel/sysctl.c
View file

@ -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
{

10
mm/hugetlb.c
View file

@ -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)