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Commit a3d0c6aa authored by Nishanth Aravamudan's avatar Nishanth Aravamudan Committed by Linus Torvalds
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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: default avatarNishanth Aravamudan <nacc@us.ibm.com>
Acked-by: default avatarAdam 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ac74c00e

include/linux/hugetlb.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

kernel/sysctl.c

+1 −1
Original line number Diff line number Diff line
@@ -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

	{

mm/hugetlb.c

+10 −0
Original line number Diff line number Diff line
@@ -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)