[PATCHv1, RFC 12/33] truncate: make sure invalidate_mapping_pages() can discard huge pages
From: Kirill A. Shutemov <hidden>
Date: 2016-07-26 00:35:14
Also in:
linux-block, linux-fsdevel, linux-mm, lkml
Subsystem:
memory management, page cache, the rest · Maintainers:
Andrew Morton, Matthew Wilcox, Linus Torvalds
invalidate_inode_page() has expectation about page_count() of the page -- if it's not 2 (one to caller, one to radix-tree), it will not be dropped. That condition almost never met for THPs -- tail pages are pinned to the pagevec. Let's drop them, before calling invalidate_inode_page(). Signed-off-by: Kirill A. Shutemov <redacted> --- mm/truncate.c | 11 +++++++++++ 1 file changed, 11 insertions(+)
diff --git a/mm/truncate.c b/mm/truncate.c
index a01cce450a26..ce904e4b1708 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c@@ -504,10 +504,21 @@ unsigned long invalidate_mapping_pages(struct address_space *mapping, /* 'end' is in the middle of THP */ if (index == round_down(end, HPAGE_PMD_NR)) continue; + /* + * invalidate_inode_page() expects + * page_count(page) == 2 to drop page from page + * cache -- drop tail pages references. + */ + get_page(page); + pagevec_release(&pvec); } ret = invalidate_inode_page(page); unlock_page(page); + + if (PageTransHuge(page)) + put_page(page); + /* * Invalidation is a hint that the page is no longer * of interest and try to speed up its reclaim.
--
2.8.1
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