From f4be6153cca6c88eaf1e52931d9a010ad4ad940e Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Wed, 20 Jan 2016 14:58:12 -0800 Subject: [PATCH] fs/proc/task_mmu.c: add workaround for old compilers For THP=n, HPAGE_PMD_NR in smaps_account() expands to BUILD_BUG(). That's fine since this codepath is eliminated by modern compilers. But older compilers have not that efficient dead code elimination. It causes problem at least with gcc 4.1.2 on m68k: fs/built-in.o: In function `smaps_account': task_mmu.c:(.text+0x4f8fa): undefined reference to `__compiletime_assert_471' Let's replace HPAGE_PMD_NR with 1 << compound_order(page). Signed-off-by: Kirill A. Shutemov Reported-by: Geert Uytterhoeven Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/proc/task_mmu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 65a1b6c69c11..71ffc91060f6 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -468,7 +468,7 @@ struct mem_size_stats { static void smaps_account(struct mem_size_stats *mss, struct page *page, bool compound, bool young, bool dirty) { - int i, nr = compound ? HPAGE_PMD_NR : 1; + int i, nr = compound ? 1 << compound_order(page) : 1; unsigned long size = nr * PAGE_SIZE; if (PageAnon(page)) -- 2.20.1