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authorHugh Dickins <hugh.dickins@tiscali.co.uk>2009-09-22 00:03:33 (GMT)
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-22 14:17:41 (GMT)
commit3ae77f43b1118a76ea37952d444319c15e002c03 (patch)
tree78152c28d4c8be8da36148e2e38e87e1b08b839b /mm/hugetlb.c
parent6e919717c82c5773ac671816c8392c70d261685f (diff)
mm: hugetlbfs_pagecache_present
Rename hugetlbfs_backed() to hugetlbfs_pagecache_present() and add more comments, as suggested by Mel Gorman. Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: Rik van Riel <riel@redhat.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/hugetlb.c')
-rw-r--r--mm/hugetlb.c16
1 files changed, 11 insertions, 5 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 6b41f70..815dbd4 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2016,8 +2016,11 @@ static struct page *hugetlbfs_pagecache_page(struct hstate *h,
return find_lock_page(mapping, idx);
}
-/* Return whether there is a pagecache page to back given address within VMA */
-static bool hugetlbfs_backed(struct hstate *h,
+/*
+ * Return whether there is a pagecache page to back given address within VMA.
+ * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
+ */
+static bool hugetlbfs_pagecache_present(struct hstate *h,
struct vm_area_struct *vma, unsigned long address)
{
struct address_space *mapping;
@@ -2254,10 +2257,13 @@ int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
/*
* When coredumping, it suits get_dump_page if we just return
- * an error if there's a hole and no huge pagecache to back it.
+ * an error where there's an empty slot with no huge pagecache
+ * to back it. This way, we avoid allocating a hugepage, and
+ * the sparse dumpfile avoids allocating disk blocks, but its
+ * huge holes still show up with zeroes where they need to be.
*/
- if (absent &&
- ((flags & FOLL_DUMP) && !hugetlbfs_backed(h, vma, vaddr))) {
+ if (absent && (flags & FOLL_DUMP) &&
+ !hugetlbfs_pagecache_present(h, vma, vaddr)) {
remainder = 0;
break;
}

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