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authorMichel Lespinasse <walken@google.com>2012-12-11 16:01:49 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-12-11 17:22:25 -0800
commitdb4fbfb9523c93583c339e66023506f651c1d54b (patch)
tree8dfc250bb2249feaafe27c11cc4de5a654815833 /include
parente4c6bfd2d79d063017ab19a18915f0bc759f32d9 (diff)
mm: vm_unmapped_area() lookup function
Implement vm_unmapped_area() using the rb_subtree_gap and highest_vm_end information to look up for suitable virtual address space gaps. struct vm_unmapped_area_info is used to define the desired allocation request: - lowest or highest possible address matching the remaining constraints - desired gap length - low/high address limits that the gap must fit into - alignment mask and offset Also update the generic arch_get_unmapped_area[_topdown] functions to make use of vm_unmapped_area() instead of implementing a brute force search. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/mm.h31
1 files changed, 31 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h
index bcaab4e6fe9..4af4f0b1be4 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1456,6 +1456,37 @@ extern unsigned long vm_mmap(struct file *, unsigned long,
unsigned long, unsigned long,
unsigned long, unsigned long);
+struct vm_unmapped_area_info {
+#define VM_UNMAPPED_AREA_TOPDOWN 1
+ unsigned long flags;
+ unsigned long length;
+ unsigned long low_limit;
+ unsigned long high_limit;
+ unsigned long align_mask;
+ unsigned long align_offset;
+};
+
+extern unsigned long unmapped_area(struct vm_unmapped_area_info *info);
+extern unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info);
+
+/*
+ * Search for an unmapped address range.
+ *
+ * We are looking for a range that:
+ * - does not intersect with any VMA;
+ * - is contained within the [low_limit, high_limit) interval;
+ * - is at least the desired size.
+ * - satisfies (begin_addr & align_mask) == (align_offset & align_mask)
+ */
+static inline unsigned long
+vm_unmapped_area(struct vm_unmapped_area_info *info)
+{
+ if (!(info->flags & VM_UNMAPPED_AREA_TOPDOWN))
+ return unmapped_area(info);
+ else
+ return unmapped_area_topdown(info);
+}
+
/* truncate.c */
extern void truncate_inode_pages(struct address_space *, loff_t);
extern void truncate_inode_pages_range(struct address_space *,