[RFC, DEBUGGING 1/2] mm: pass NR_FILE_PAGES/NR_SHMEM into node_page_state

From: Arnd Bergmann
Date: Thu Jun 23 2016 - 06:03:38 EST


I see some new warnings from a recent mm change:

mm/filemap.c: In function '__delete_from_page_cache':
include/linux/vmstat.h:116:2: error: array subscript is above array bounds [-Werror=array-bounds]
atomic_long_add(x, &zone->vm_stat[item]);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/vmstat.h:116:35: error: array subscript is above array bounds [-Werror=array-bounds]
atomic_long_add(x, &zone->vm_stat[item]);
~~~~~~~~~~~~~^~~~~~
include/linux/vmstat.h:116:35: error: array subscript is above array bounds [-Werror=array-bounds]
include/linux/vmstat.h:117:2: error: array subscript is above array bounds [-Werror=array-bounds]

Looking deeper into it, I find that we pass the wrong enum
into some functions after the type for the symbol has changed.

This changes the code to use the other function for those that
are using the incorrect type. I've done this blindly just going
by warnings I got from a debug patch I did for this, so it's likely
that some cases are more subtle and need another change, so please
treat this as a bug-report rather than a patch for applying.

Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Fixes: e426f7b4ade5 ("mm: move most file-based accounting to the node")
---
mm/filemap.c | 4 ++--
mm/page_alloc.c | 15 ++++++++-------
mm/rmap.c | 4 ++--
mm/shmem.c | 4 ++--
mm/vmscan.c | 2 +-
5 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index 6cb19e012887..77e902bf04f4 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -218,9 +218,9 @@ void __delete_from_page_cache(struct page *page, void *shadow)

/* hugetlb pages do not participate in page cache accounting. */
if (!PageHuge(page))
- __mod_zone_page_state(page_zone(page), NR_FILE_PAGES, -nr);
+ __mod_node_page_state(page_zone(page)->zone_pgdat, NR_FILE_PAGES, -nr);
if (PageSwapBacked(page)) {
- __mod_zone_page_state(page_zone(page), NR_SHMEM, -nr);
+ __mod_node_page_state(page_zone(page)->zone_pgdat, NR_SHMEM, -nr);
if (PageTransHuge(page))
__dec_zone_page_state(page, NR_SHMEM_THPS);
} else {
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 23b5044f5ced..d5287011ed27 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3484,9 +3484,10 @@ should_reclaim_retry(gfp_t gfp_mask, unsigned order,
unsigned long writeback;
unsigned long dirty;

- writeback = zone_page_state_snapshot(zone,
+ writeback = node_page_state_snapshot(zone->zone_pgdat,
NR_WRITEBACK);
- dirty = zone_page_state_snapshot(zone, NR_FILE_DIRTY);
+ dirty = node_page_state_snapshot(zone->zone_pgdat,
+ NR_FILE_DIRTY);

if (2*(writeback + dirty) > reclaimable) {
congestion_wait(BLK_RW_ASYNC, HZ/10);
@@ -4396,9 +4397,9 @@ void show_free_areas(unsigned int filter)
K(zone->present_pages),
K(zone->managed_pages),
K(zone_page_state(zone, NR_MLOCK)),
- K(zone_page_state(zone, NR_FILE_DIRTY)),
- K(zone_page_state(zone, NR_WRITEBACK)),
- K(zone_page_state(zone, NR_SHMEM)),
+ K(node_page_state(zone->zone_pgdat, NR_FILE_DIRTY)),
+ K(node_page_state(zone, NR_WRITEBACK)),
+ K(node_page_state(zone, NR_SHMEM)),
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
K(zone_page_state(zone, NR_SHMEM_THPS) * HPAGE_PMD_NR),
K(zone_page_state(zone, NR_SHMEM_PMDMAPPED)
@@ -4410,12 +4411,12 @@ void show_free_areas(unsigned int filter)
zone_page_state(zone, NR_KERNEL_STACK) *
THREAD_SIZE / 1024,
K(zone_page_state(zone, NR_PAGETABLE)),
- K(zone_page_state(zone, NR_UNSTABLE_NFS)),
+ K(node_page_state(zone, NR_UNSTABLE_NFS)),
K(zone_page_state(zone, NR_BOUNCE)),
K(free_pcp),
K(this_cpu_read(zone->pageset->pcp.count)),
K(zone_page_state(zone, NR_FREE_CMA_PAGES)),
- K(zone_page_state(zone, NR_WRITEBACK_TEMP)),
+ K(node_page_state(zone, NR_WRITEBACK_TEMP)),
K(node_page_state(zone->zone_pgdat, NR_PAGES_SCANNED)));
printk("lowmem_reserve[]:");
for (i = 0; i < MAX_NR_ZONES; i++)
diff --git a/mm/rmap.c b/mm/rmap.c
index 4deff963ea8a..898b2b7806ca 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1296,7 +1296,7 @@ void page_add_file_rmap(struct page *page, bool compound)
if (!atomic_inc_and_test(&page->_mapcount))
goto out;
}
- __mod_zone_page_state(page_zone(page), NR_FILE_MAPPED, nr);
+ __mod_node_page_state(page_zone(page)->zone_pgdat, NR_FILE_MAPPED, nr);
mem_cgroup_inc_page_stat(page, MEM_CGROUP_STAT_FILE_MAPPED);
out:
unlock_page_memcg(page);
@@ -1336,7 +1336,7 @@ static void page_remove_file_rmap(struct page *page, bool compound)
* these counters are not modified in interrupt context, and
* pte lock(a spinlock) is held, which implies preemption disabled.
*/
- __mod_zone_page_state(page_zone(page), NR_FILE_MAPPED, -nr);
+ __mod_node_page_state(page_zone(page)->zone_pgdat, NR_FILE_MAPPED, -nr);
mem_cgroup_dec_page_stat(page, MEM_CGROUP_STAT_FILE_MAPPED);

if (unlikely(PageMlocked(page)))
diff --git a/mm/shmem.c b/mm/shmem.c
index e5c50fb0d4a4..99dcb8e5642d 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -576,8 +576,8 @@ static int shmem_add_to_page_cache(struct page *page,
mapping->nrpages += nr;
if (PageTransHuge(page))
__inc_zone_page_state(page, NR_SHMEM_THPS);
- __mod_zone_page_state(page_zone(page), NR_FILE_PAGES, nr);
- __mod_zone_page_state(page_zone(page), NR_SHMEM, nr);
+ __mod_node_page_state(page_zone(page)->zone_pgdat, NR_FILE_PAGES, nr);
+ __mod_node_page_state(page_zone(page)->zone_pgdat, NR_SHMEM, nr);
spin_unlock_irq(&mapping->tree_lock);
} else {
page->mapping = NULL;
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 07e17dac1793..4702069cc80b 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2079,7 +2079,7 @@ static void get_scan_count(struct lruvec *lruvec, struct mem_cgroup *memcg,
int z;
unsigned long total_high_wmark = 0;

- pgdatfree = sum_zone_node_page_state(pgdat->node_id, NR_FREE_PAGES);
+ pgdatfree = global_page_state(NR_FREE_PAGES);
pgdatfile = node_page_state(pgdat, NR_ACTIVE_FILE) +
node_page_state(pgdat, NR_INACTIVE_FILE);

--
2.9.0