mm: vmstat: move slab statistics from zone to node counters

Patch series "mm: per-lruvec slab stats"

Josef is working on a new approach to balancing slab caches and the page
cache.  For this to work, he needs slab cache statistics on the lruvec
level.  These patches implement that by adding infrastructure that
allows updating and reading generic VM stat items per lruvec, then
switches some existing VM accounting sites, including the slab
accounting ones, to this new cgroup-aware API.

I'll follow up with more patches on this, because there is actually
substantial simplification that can be done to the memory controller
when we replace private memcg accounting with making the existing VM
accounting sites cgroup-aware.  But this is enough for Josef to base his
slab reclaim work on, so here goes.

This patch (of 5):

To re-implement slab cache vs.  page cache balancing, we'll need the
slab counters at the lruvec level, which, ever since lru reclaim was
moved from the zone to the node, is the intersection of the node, not
the zone, and the memcg.

We could retain the per-zone counters for when the page allocator dumps
its memory information on failures, and have counters on both levels -
which on all but NUMA node 0 is usually redundant.  But let's keep it
simple for now and just move them.  If anybody complains we can restore
the per-zone counters.

[hannes@cmpxchg.org: fix oops]
  Link: http://lkml.kernel.org/r/20170605183511.GA8915@cmpxchg.org
Link: http://lkml.kernel.org/r/20170530181724.27197-3-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 4 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8aa860017d66..a35add8d7c0b 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4643,8 +4643,6 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask)
                         " present:%lukB"
                         " managed:%lukB"
                         " mlocked:%lukB"
-                        " slab_reclaimable:%lukB"
-                        " slab_unreclaimable:%lukB"
                         " kernel_stack:%lukB"
                         " pagetables:%lukB"
                         " bounce:%lukB"
@@ -4666,8 +4664,6 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask)
                         K(zone->present_pages),
                         K(zone->managed_pages),
                         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_KB),
                         K(zone_page_state(zone, NR_PAGETABLE)),
                         K(zone_page_state(zone, NR_BOUNCE)),
@@ -5153,6 +5149,7 @@ static void build_zonelists(pg_data_t *pgdat)
  */
 static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch);
 static DEFINE_PER_CPU(struct per_cpu_pageset, boot_pageset);
+static DEFINE_PER_CPU(struct per_cpu_nodestat, boot_nodestats);
 static void setup_zone_pageset(struct zone *zone);
 
 /*
@@ -6053,6 +6050,8 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat)
         spin_lock_init(&pgdat->lru_lock);
         lruvec_init(node_lruvec(pgdat));
 
+        pgdat->per_cpu_nodestats = &boot_nodestats;
+
         for (j = 0; j < MAX_NR_ZONES; j++) {
                 struct zone *zone = pgdat->node_zones + j;
                 unsigned long size, realsize, freesize, memmap_pages;