[PATCHv8 20/32] truncate: handle file thp

Kirill A. Shutemov
2016-05-12T15:42:07Z

For shmem/tmpfs we only need to tweak truncate_inode_page() and
invalidate_mapping_pages().

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
mm/truncate.c | 22 ++++++++++++++++++++--
1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/mm/truncate.c b/mm/truncate.c
index b00272810871..4f931ca9333b 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -157,10 +157,14 @@ invalidate_complete_page(struct address_space *mapping, struct page *page)

int truncate_inode_page(struct address_space *mapping, struct page *page)
{
+ loff_t holelen;
+ VM_BUG_ON_PAGE(PageTail(page), page);
+
+ holelen = PageTransHuge(page) ? HPAGE_PMD_SIZE : PAGE_SIZE;
if (page_mapped(page)) {
unmap_mapping_range(mapping,
(loff_t)page->index << PAGE_SHIFT,
- PAGE_SIZE, 0);
+ holelen, 0);
}
return truncate_complete_page(mapping, page);
}
@@ -489,7 +493,21 @@ unsigned long invalidate_mapping_pages(struct address_space *mapping,

if (!trylock_page(page))
continue;
- WARN_ON(page->index != index);
+
+ WARN_ON(page_to_pgoff(page) != index);
+
+ /* Middle of THP: skip */
+ if (PageTransTail(page)) {
+ unlock_page(page);
+ continue;
+ } else if (PageTransHuge(page)) {
+ index += HPAGE_PMD_NR - 1;
+ i += HPAGE_PMD_NR - 1;
+ /* 'end' is in the middle of THP */
+ if (index == round_down(end, HPAGE_PMD_NR))
+ continue;
+ }
+
ret = invalidate_inode_page(page);
unlock_page(page);
/*
--
2.8.1