[PATCH v3 04/13] mm: Track NR_KERNEL_STACK in KiB instead of number of stacks

Andy Lutomirski
2016-06-20T23:45:12Z

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.

Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: linux-mm@kvack.org
Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
drivers/base/node.c | 3 +--
fs/proc/meminfo.c | 2 +-
include/linux/mmzone.h | 2 +-
kernel/fork.c | 3 ++-
mm/page_alloc.c | 3 +--
5 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/base/node.c b/drivers/base/node.c
index 560751bad294..27dc68a0ed2d 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -121,8 +121,7 @@ static ssize_t node_read_meminfo(struct device *dev,
nid, K(node_page_state(nid, NR_FILE_MAPPED)),
nid, K(node_page_state(nid, NR_ANON_PAGES)),
nid, K(i.sharedram),
- nid, node_page_state(nid, NR_KERNEL_STACK) *
- THREAD_SIZE / 1024,
+ nid, node_page_state(nid, NR_KERNEL_STACK_KB),
nid, K(node_page_state(nid, NR_PAGETABLE)),
nid, K(node_page_state(nid, NR_UNSTABLE_NFS)),
nid, K(node_page_state(nid, NR_BOUNCE)),
diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c
index 83720460c5bc..239b5a06cee0 100644
--- a/fs/proc/meminfo.c
+++ b/fs/proc/meminfo.c
@@ -145,7 +145,7 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
global_page_state(NR_SLAB_UNRECLAIMABLE)),
K(global_page_state(NR_SLAB_RECLAIMABLE)),
K(global_page_state(NR_SLAB_UNRECLAIMABLE)),
- global_page_state(NR_KERNEL_STACK) * THREAD_SIZE / 1024,
+ global_page_state(NR_KERNEL_STACK_KB),
K(global_page_state(NR_PAGETABLE)),
#ifdef CONFIG_QUICKLIST
K(quicklist_total_size()),
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 02069c23486d..63f05a7efb54 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -127,7 +127,7 @@ enum zone_stat_item {
NR_SLAB_RECLAIMABLE,
NR_SLAB_UNRECLAIMABLE,
NR_PAGETABLE, /* used for pagetables */
- NR_KERNEL_STACK,
+ NR_KERNEL_STACK_KB, /* measured in KiB */
/* Second 128 byte cacheline */
NR_UNSTABLE_NFS, /* NFS unstable pages */
NR_BOUNCE,
diff --git a/kernel/fork.c b/kernel/fork.c
index 5c2c355aa97f..be7f006af727 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -225,7 +225,8 @@ static void account_kernel_stack(struct thread_info *ti, int account)
{
struct zone *zone = page_zone(virt_to_page(ti));

- mod_zone_page_state(zone, NR_KERNEL_STACK, account);
+ mod_zone_page_state(zone, NR_KERNEL_STACK_KB,
+ THREAD_SIZE / 1024 * account);
}

void free_task(struct task_struct *tsk)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 6903b695ebae..a277dea926c9 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4457,8 +4457,7 @@ void show_free_areas(unsigned int filter)
K(zone_page_state(zone, NR_SHMEM)),
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_UNSTABLE_NFS)),
K(zone_page_state(zone, NR_BOUNCE)),
--
2.5.5