diff mbox series

[019/156] mm/filemap: fix page cache removal for arbitrary sized THPs

Message ID 20201016024203.sQRJX93MR%akpm@linux-foundation.org
State New
Headers show
Series [001/156] device-dax/kmem: fix resource release | expand

Commit Message

Andrew Morton Oct. 16, 2020, 2:42 a.m. UTC
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Subject: mm/filemap: fix page cache removal for arbitrary sized THPs

Patch series "Remove assumptions of THP size".

There are a number of places in the VM which assume that a THP is a PMD in
size.  That's true today, and remains true after this patch series, but
this is a prerequisite for switching to arbitrary-sized THPs. 
thp_nr_pages() still returns either HPAGE_PMD_NR or 1, but will be changed
later.


This patch (of 11):

page_cache_free_page() assumes THPs are PMD_SIZE; fix that assumption.

Link: https://lkml.kernel.org/r/20200908195539.25896-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20200908195539.25896-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/filemap.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

--- a/mm/filemap.c~mm-filemap-fix-page-cache-removal-for-arbitrary-sized-thps
+++ a/mm/filemap.c
@@ -249,7 +249,7 @@  static void page_cache_free_page(struct
 		freepage(page);
 
 	if (PageTransHuge(page) && !PageHuge(page)) {
-		page_ref_sub(page, HPAGE_PMD_NR);
+		page_ref_sub(page, thp_nr_pages(page));
 		VM_BUG_ON_PAGE(page_count(page) <= 0, page);
 	} else {
 		put_page(page);