diff options
| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2013-11-05 17:06:59 +1100 |
|---|---|---|
| committer | Stephen Rothwell <sfr@canb.auug.org.au> | 2013-11-06 19:59:17 +1100 |
| commit | d3c809c9ee55ee5ff9441e8b94c086f4ab135b8a (patch) | |
| tree | c3e8a338d4d86c55a8a1368b09ed8147c5e54144 /Documentation | |
| parent | fa3325e656015e8e17306c53aa13551acdbe76dd (diff) | |
mm: try to detect that page->ptl is in use
prep_new_page() initialize page->private (and therefore page->ptl) with 0.
Make sure nobody took it in use in between allocation of the page and
page table constructor.
It can happen if arch try to use slab for page table allocation: slab code
uses page->slab_cache and page->first_page (for tail pages), which share
storage with page->ptl.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/vm/split_page_table_lock | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/Documentation/vm/split_page_table_lock b/Documentation/vm/split_page_table_lock index e2f617b732ff..3c54f7dca2d4 100644 --- a/Documentation/vm/split_page_table_lock +++ b/Documentation/vm/split_page_table_lock @@ -53,6 +53,10 @@ There's no need in special enabling of PTE split page table lock: everything required is done by pgtable_page_ctor() and pgtable_page_dtor(), which must be called on PTE table allocation / freeing. +Make sure the architecture doesn't use slab allocator for page table +allacation: slab uses page->slab_cache and page->first_page for its pages. +These fields share storage with page->ptl. + PMD split lock only makes sense if you have more than two page table levels. |