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authorEric B Munson <ebmunson@us.ibm.com>2009-09-21 17:03:47 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-22 07:17:42 -0700
commit4e52780d41a741fb4861ae1df2413dd816ec11b1 (patch)
treeb3722349661ed0ce87841b110f568616892cf719 /mm/mmap.c
parent90f72aa58bbf076b68e289fbd71eb829bc505923 (diff)
downloadvexpress-lsk-4e52780d41a741fb4861ae1df2413dd816ec11b1.tar.gz
hugetlb: add MAP_HUGETLB for mmaping pseudo-anonymous huge page regions
Add a flag for mmap that will be used to request a huge page region that will look like anonymous memory to userspace. This is accomplished by using a file on the internal vfsmount. MAP_HUGETLB is a modifier of MAP_ANONYMOUS and so must be specified with it. The region will behave the same as a MAP_ANONYMOUS region using small pages. [akpm@linux-foundation.org: fix arch definitions of MAP_HUGETLB] Signed-off-by: Eric B Munson <ebmunson@us.ibm.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Adam Litke <agl@us.ibm.com> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/mmap.c')
-rw-r--r--mm/mmap.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index 1aeef6625e6..21d4029a07b 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -949,6 +949,24 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
if (mm->map_count > sysctl_max_map_count)
return -ENOMEM;
+ if (flags & MAP_HUGETLB) {
+ struct user_struct *user = NULL;
+ if (file)
+ return -EINVAL;
+
+ /*
+ * VM_NORESERVE is used because the reservations will be
+ * taken when vm_ops->mmap() is called
+ * A dummy user value is used because we are not locking
+ * memory so no accounting is necessary
+ */
+ len = ALIGN(len, huge_page_size(&default_hstate));
+ file = hugetlb_file_setup(HUGETLB_ANON_FILE, len, VM_NORESERVE,
+ &user, HUGETLB_ANONHUGE_INODE);
+ if (IS_ERR(file))
+ return PTR_ERR(file);
+ }
+
/* Obtain the address to map to. we verify (or select) it and ensure
* that it represents a valid section of the address space.
*/