From 3ae77f43b1118a76ea37952d444319c15e002c03 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Mon, 21 Sep 2009 17:03:33 -0700 Subject: [PATCH] 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 Cc: Rik van Riel Cc: KAMEZAWA Hiroyuki Cc: KOSAKI Motohiro Cc: Nick Piggin Cc: Mel Gorman Cc: Minchan Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/hugetlb.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 6b41f70bbc7f..815dbd4a6dcb 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; }