tree 1dd7be7e737649c7d346c695e0700c9732b2d681
parent fff4068cba484e6b0abe334ed6b15d5a215a3b25
author Kirill A. Shutemov <kirill.shutemov@linux.intel.com> 1387539358 +0200
committer Linus Torvalds <torvalds@linux-foundation.org> 1387571145 -0800

mm: do not allocate page->ptl dynamically, if spinlock_t fits to long

In struct page we have enough space to fit long-size page->ptl there,
but we use dynamically-allocated page->ptl if size(spinlock_t) is larger
than sizeof(int).

It hurts 64-bit architectures with CONFIG_GENERIC_LOCKBREAK, where
sizeof(spinlock_t) == 8, but it easily fits into struct page.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>