mm: track NR_KERNEL_STACK in KiB instead of number of stacks

Currently, NR_KERNEL_STACK tracks the number of kernel stacks in a zone.
This only makes sense if each kernel stack exists entirely in one zone,
and allowing vmapped stacks could break this assumption.

Since frv has THREAD_SIZE < PAGE_SIZE, we need to track kernel stack
allocations in a unit that divides both THREAD_SIZE and PAGE_SIZE on all
architectures.  Keep it simple and use KiB.

Link: http://lkml.kernel.org/r/083c71e642c5fa5f1b6898902e1b2db7b48940d4.1468523549.git.luto@kernel.org
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 2 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index dfdb608f7b3d..c281125b2349 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4359,8 +4359,7 @@ void show_free_areas(unsigned int filter)
                         K(zone_page_state(zone, NR_MLOCK)),
                         K(zone_page_state(zone, NR_SLAB_RECLAIMABLE)),
                         K(zone_page_state(zone, NR_SLAB_UNRECLAIMABLE)),
-                        zone_page_state(zone, NR_KERNEL_STACK) *
-                                THREAD_SIZE / 1024,
+                        zone_page_state(zone, NR_KERNEL_STACK_KB),
                         K(zone_page_state(zone, NR_PAGETABLE)),
                         K(zone_page_state(zone, NR_BOUNCE)),
                         K(free_pcp),