hugetlbfs: per mount huge page sizes

Add the ability to configure the hugetlb hstate used on a per mount basis.

- Add a new pagesize= option to the hugetlbfs mount that allows setting
  the page size
- This option causes the mount code to find the hstate corresponding to the
  specified size, and sets up a pointer to the hstate in the mount's
  superblock.
- Change the hstate accessors to use this information rather than the
  global_hstate they were using (requires a slight change in mm/memory.c
  so we don't NULL deref in the error-unmap path -- see comments).

[np: take hstate out of hugetlbfs inode and vma->vm_private_data]

Acked-by: Adam Litke <agl@us.ibm.com>
Acked-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 9 insertions, 5 deletions

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index b75bdb4..ba9263e 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -100,6 +100,7 @@ struct hugetlbfs_config {
 	umode_t mode;
 	long	nr_blocks;
 	long	nr_inodes;
+	struct hstate *hstate;
 };
 
 struct hugetlbfs_sb_info {
@@ -108,6 +109,7 @@ struct hugetlbfs_sb_info {
 	long	max_inodes;   /* inodes allowed */
 	long	free_inodes;  /* inodes free */
 	spinlock_t	stat_lock;
+	struct hstate *hstate;
 };
 
 
@@ -191,19 +193,21 @@ extern unsigned int default_hstate_idx;
 
 #define default_hstate (hstates[default_hstate_idx])
 
-static inline struct hstate *hstate_vma(struct vm_area_struct *vma)
+static inline struct hstate *hstate_inode(struct inode *i)
 {
-	return &default_hstate;
+	struct hugetlbfs_sb_info *hsb;
+	hsb = HUGETLBFS_SB(i->i_sb);
+	return hsb->hstate;
 }
 
 static inline struct hstate *hstate_file(struct file *f)
 {
-	return &default_hstate;
+	return hstate_inode(f->f_dentry->d_inode);
 }
 
-static inline struct hstate *hstate_inode(struct inode *i)
+static inline struct hstate *hstate_vma(struct vm_area_struct *vma)
 {
-	return &default_hstate;
+	return hstate_file(vma->vm_file);
 }
 
 static inline unsigned long huge_page_size(struct hstate *h)