The patch titled
Subject: dax: ensure that zero pages are removed from other processes
has been removed from the -mm tree. Its filename was
dax-ensure-that-zero-pages-are-removed-from-other-processes.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
Subject: dax: ensure that zero pages are removed from other processes
If the first access to a huge page was a store, there would be no existing
zero pmd in this process's page tables. There could be a zero pmd in
another process's page tables, if it had done a load. We can detect this
case by noticing that the buffer_head returned from the filesystem is New,
and ensure that other processes mapping this huge page have their page
tables flushed.
Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
Reported-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/dax.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff -puN fs/dax.c~dax-ensure-that-zero-pages-are-removed-from-other-processes fs/dax.c
--- a/fs/dax.c~dax-ensure-that-zero-pages-are-removed-from-other-processes
+++ a/fs/dax.c
@@ -568,7 +568,11 @@ int __dax_pmd_fault(struct vm_area_struc
if ((pgoff | PG_PMD_COLOUR) >= size)
goto fallback;
- if (is_huge_zero_pmd(*pmd))
+ /*
+ * If we allocated new storage, make sure no process has any
+ * zero pages covering this hole
+ */
+ if (buffer_new(&bh))
unmap_mapping_range(mapping, pgoff << PAGE_SHIFT, PMD_SIZE, 0);
if (!write && !buffer_mapped(&bh) && buffer_uptodate(&bh)) {
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxxxx are
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
