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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 <kirill.shutemov@linux.intel.com>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
hifive-unleashed-5.1
Kirill A. Shutemov 2016-01-20 14:58:12 -08:00 committed by Linus Torvalds
parent 0b9b6fff7b
commit f4be6153cc
1 changed files with 1 additions and 1 deletions

View File

@ -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))