Date:   Tue, 19 Dec 2017 13:28:48 +0100
From:   Michal Hocko <mhocko@...nel.org>
To:     Kemi Wang <kemi.wang@...el.com>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Vlastimil Babka <vbabka@...e.cz>,
        Mel Gorman <mgorman@...hsingularity.net>,
        Johannes Weiner <hannes@...xchg.org>,
        Christopher Lameter <cl@...ux.com>,
        YASUAKI ISHIMATSU <yasu.isimatu@...il.com>,
        Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Nikolay Borisov <nborisov@...e.com>,
        Pavel Tatashin <pasha.tatashin@...cle.com>,
        David Rientjes <rientjes@...gle.com>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Dave <dave.hansen@...ux.intel.com>,
        Andi Kleen <andi.kleen@...el.com>,
        Tim Chen <tim.c.chen@...el.com>,
        Jesper Dangaard Brouer <brouer@...hat.com>,
        Ying Huang <ying.huang@...el.com>,
        Aaron Lu <aaron.lu@...el.com>, Aubrey Li <aubrey.li@...el.com>,
        Linux MM <linux-mm@...ck.org>,
        Linux Kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 1/5] mm: migrate NUMA stats from per-zone to per-node

On Tue 19-12-17 14:39:22, Kemi Wang wrote:
> There is not really any use to get NUMA stats separated by zone, and
> current per-zone NUMA stats is only consumed in /proc/zoneinfo. For code
> cleanup purpose, we move NUMA stats from per-zone to per-node and reuse the
> existed per-cpu infrastructure.

Let's hope that nobody really depends on the per-zone numbers. It would
be really strange as those counters are inherently per-node and that is
what users should care about but who knows...

Anyway, I hoped we could get rid of NR_VM_NUMA_STAT_ITEMS but your patch
keeps it and follow up patches even use it further. I will comment on
those separately but this still makes these few counters really special
which I think is wrong.

> Suggested-by: Andi Kleen <ak@...ux.intel.com>
> Suggested-by: Michal Hocko <mhocko@...nel.com>
> Signed-off-by: Kemi Wang <kemi.wang@...el.com>

I have to fully grasp the rest of the series before I'll give my Ack,
but I _really_ like the simplification this adds to the code. I believe
it can be even simpler.

> ---
>  drivers/base/node.c    |  23 +++----
>  include/linux/mmzone.h |  27 ++++----
>  include/linux/vmstat.h |  31 ---------
>  mm/mempolicy.c         |   2 +-
>  mm/page_alloc.c        |  16 +++--
>  mm/vmstat.c            | 177 +++++--------------------------------------------
>  6 files changed, 46 insertions(+), 230 deletions(-)
> 
> diff --git a/drivers/base/node.c b/drivers/base/node.c
> index ee090ab..a045ea1 100644
> --- a/drivers/base/node.c
> +++ b/drivers/base/node.c
> @@ -169,13 +169,14 @@ static ssize_t node_read_numastat(struct device *dev,
>  		       "interleave_hit %lu\n"
>  		       "local_node %lu\n"
>  		       "other_node %lu\n",
> -		       sum_zone_numa_state(dev->id, NUMA_HIT),
> -		       sum_zone_numa_state(dev->id, NUMA_MISS),
> -		       sum_zone_numa_state(dev->id, NUMA_FOREIGN),
> -		       sum_zone_numa_state(dev->id, NUMA_INTERLEAVE_HIT),
> -		       sum_zone_numa_state(dev->id, NUMA_LOCAL),
> -		       sum_zone_numa_state(dev->id, NUMA_OTHER));
> +		       node_page_state(NODE_DATA(dev->id), NUMA_HIT),
> +		       node_page_state(NODE_DATA(dev->id), NUMA_MISS),
> +		       node_page_state(NODE_DATA(dev->id), NUMA_FOREIGN),
> +		       node_page_state(NODE_DATA(dev->id), NUMA_INTERLEAVE_HIT),
> +		       node_page_state(NODE_DATA(dev->id), NUMA_LOCAL),
> +		       node_page_state(NODE_DATA(dev->id), NUMA_OTHER));
>  }
> +
>  static DEVICE_ATTR(numastat, S_IRUGO, node_read_numastat, NULL);
>  
>  static ssize_t node_read_vmstat(struct device *dev,
> @@ -190,17 +191,9 @@ static ssize_t node_read_vmstat(struct device *dev,
>  		n += sprintf(buf+n, "%s %lu\n", vmstat_text[i],
>  			     sum_zone_node_page_state(nid, i));
>  
> -#ifdef CONFIG_NUMA
> -	for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
> -		n += sprintf(buf+n, "%s %lu\n",
> -			     vmstat_text[i + NR_VM_ZONE_STAT_ITEMS],
> -			     sum_zone_numa_state(nid, i));
> -#endif
> -
>  	for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
>  		n += sprintf(buf+n, "%s %lu\n",
> -			     vmstat_text[i + NR_VM_ZONE_STAT_ITEMS +
> -			     NR_VM_NUMA_STAT_ITEMS],
> +			     vmstat_text[i + NR_VM_ZONE_STAT_ITEMS],
>  			     node_page_state(pgdat, i));
>  
>  	return n;
> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index 67f2e3c..c06d880 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -115,20 +115,6 @@ struct zone_padding {
>  #define ZONE_PADDING(name)
>  #endif
>  
> -#ifdef CONFIG_NUMA
> -enum numa_stat_item {
> -	NUMA_HIT,		/* allocated in intended node */
> -	NUMA_MISS,		/* allocated in non intended node */
> -	NUMA_FOREIGN,		/* was intended here, hit elsewhere */
> -	NUMA_INTERLEAVE_HIT,	/* interleaver preferred this zone */
> -	NUMA_LOCAL,		/* allocation from local node */
> -	NUMA_OTHER,		/* allocation from other node */
> -	NR_VM_NUMA_STAT_ITEMS
> -};
> -#else
> -#define NR_VM_NUMA_STAT_ITEMS 0
> -#endif
> -
>  enum zone_stat_item {
>  	/* First 128 byte cacheline (assuming 64 bit words) */
>  	NR_FREE_PAGES,
> @@ -151,7 +137,18 @@ enum zone_stat_item {
>  	NR_VM_ZONE_STAT_ITEMS };
>  
>  enum node_stat_item {
> -	NR_LRU_BASE,
> +#ifdef CONFIG_NUMA
> +	NUMA_HIT,		/* allocated in intended node */
> +	NUMA_MISS,		/* allocated in non intended node */
> +	NUMA_FOREIGN,		/* was intended here, hit elsewhere */
> +	NUMA_INTERLEAVE_HIT,	/* interleaver preferred this zone */
> +	NUMA_LOCAL,		/* allocation from local node */
> +	NUMA_OTHER,		/* allocation from other node */
> +	NR_VM_NUMA_STAT_ITEMS,
> +#else
> +#define	NR_VM_NUMA_STAT_ITEMS 0
> +#endif
> +	NR_LRU_BASE = NR_VM_NUMA_STAT_ITEMS,
>  	NR_INACTIVE_ANON = NR_LRU_BASE, /* must match order of LRU_[IN]ACTIVE */
>  	NR_ACTIVE_ANON,		/*  "     "     "   "       "         */
>  	NR_INACTIVE_FILE,	/*  "     "     "   "       "         */
> diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
> index 1779c98..80bf290 100644
> --- a/include/linux/vmstat.h
> +++ b/include/linux/vmstat.h
> @@ -118,37 +118,8 @@ static inline void vm_events_fold_cpu(int cpu)
>   * Zone and node-based page accounting with per cpu differentials.
>   */
>  extern atomic_long_t vm_zone_stat[NR_VM_ZONE_STAT_ITEMS];
> -extern atomic_long_t vm_numa_stat[NR_VM_NUMA_STAT_ITEMS];
>  extern atomic_long_t vm_node_stat[NR_VM_NODE_STAT_ITEMS];
>  
> -#ifdef CONFIG_NUMA
> -static inline void zone_numa_state_add(long x, struct zone *zone,
> -				 enum numa_stat_item item)
> -{
> -	atomic_long_add(x, &zone->vm_numa_stat[item]);
> -	atomic_long_add(x, &vm_numa_stat[item]);
> -}
> -
> -static inline unsigned long global_numa_state(enum numa_stat_item item)
> -{
> -	long x = atomic_long_read(&vm_numa_stat[item]);
> -
> -	return x;
> -}
> -
> -static inline unsigned long zone_numa_state_snapshot(struct zone *zone,
> -					enum numa_stat_item item)
> -{
> -	long x = atomic_long_read(&zone->vm_numa_stat[item]);
> -	int cpu;
> -
> -	for_each_online_cpu(cpu)
> -		x += per_cpu_ptr(zone->pageset, cpu)->vm_numa_stat_diff[item];
> -
> -	return x;
> -}
> -#endif /* CONFIG_NUMA */
> -
>  static inline void zone_page_state_add(long x, struct zone *zone,
>  				 enum zone_stat_item item)
>  {
> @@ -234,10 +205,8 @@ static inline unsigned long node_page_state_snapshot(pg_data_t *pgdat,
>  
>  
>  #ifdef CONFIG_NUMA
> -extern void __inc_numa_state(struct zone *zone, enum numa_stat_item item);
>  extern unsigned long sum_zone_node_page_state(int node,
>  					      enum zone_stat_item item);
> -extern unsigned long sum_zone_numa_state(int node, enum numa_stat_item item);
>  extern unsigned long node_page_state(struct pglist_data *pgdat,
>  						enum node_stat_item item);
>  #else
> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> index 4ce44d3..b2293e3 100644
> --- a/mm/mempolicy.c
> +++ b/mm/mempolicy.c
> @@ -1920,7 +1920,7 @@ static struct page *alloc_page_interleave(gfp_t gfp, unsigned order,
>  		return page;
>  	if (page && page_to_nid(page) == nid) {
>  		preempt_disable();
> -		__inc_numa_state(page_zone(page), NUMA_INTERLEAVE_HIT);
> +		inc_node_state(page_pgdat(page), NUMA_INTERLEAVE_HIT);
>  		preempt_enable();
>  	}
>  	return page;
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 7e5e775..81e8d8f 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -2793,22 +2793,24 @@ int __isolate_free_page(struct page *page, unsigned int order)
>  static inline void zone_statistics(struct zone *preferred_zone, struct zone *z)
>  {
>  #ifdef CONFIG_NUMA
> -	enum numa_stat_item local_stat = NUMA_LOCAL;
> +	int preferred_nid = preferred_zone->node;
> +	int nid = z->node;
> +	enum node_stat_item local_stat = NUMA_LOCAL;
>  
>  	/* skip numa counters update if numa stats is disabled */
>  	if (!static_branch_likely(&vm_numa_stat_key))
>  		return;
>  
> -	if (z->node != numa_node_id())
> +	if (nid != numa_node_id())
>  		local_stat = NUMA_OTHER;
>  
> -	if (z->node == preferred_zone->node)
> -		__inc_numa_state(z, NUMA_HIT);
> +	if (nid == preferred_nid)
> +		inc_node_state(NODE_DATA(nid), NUMA_HIT);
>  	else {
> -		__inc_numa_state(z, NUMA_MISS);
> -		__inc_numa_state(preferred_zone, NUMA_FOREIGN);
> +		inc_node_state(NODE_DATA(nid), NUMA_MISS);
> +		inc_node_state(NODE_DATA(preferred_nid), NUMA_FOREIGN);
>  	}
> -	__inc_numa_state(z, local_stat);
> +	inc_node_state(NODE_DATA(nid), local_stat);
>  #endif
>  }
>  
> diff --git a/mm/vmstat.c b/mm/vmstat.c
> index 40b2db6..1dd12ae 100644
> --- a/mm/vmstat.c
> +++ b/mm/vmstat.c
> @@ -30,46 +30,44 @@
>  
>  #include "internal.h"
>  
> -#define NUMA_STATS_THRESHOLD (U16_MAX - 2)
> -
>  #ifdef CONFIG_NUMA
>  int sysctl_vm_numa_stat = ENABLE_NUMA_STAT;
>  
> -/* zero numa counters within a zone */
> -static void zero_zone_numa_counters(struct zone *zone)
> +/* zero numa stats within a node */
> +static void zero_node_numa_stats(int node)
>  {
>  	int item, cpu;
>  
>  	for (item = 0; item < NR_VM_NUMA_STAT_ITEMS; item++) {
> -		atomic_long_set(&zone->vm_numa_stat[item], 0);
> +		atomic_long_set(&(NODE_DATA(node)->vm_stat[item]), 0);
>  		for_each_online_cpu(cpu)
> -			per_cpu_ptr(zone->pageset, cpu)->vm_numa_stat_diff[item]
> -						= 0;
> +			per_cpu_ptr(NODE_DATA(node)->per_cpu_nodestats,
> +					cpu)->vm_node_stat_diff[item] = 0;
>  	}
>  }
>  
> -/* zero numa counters of all the populated zones */
> -static void zero_zones_numa_counters(void)
> +/* zero numa stats of all the online nodes */
> +static void zero_nodes_numa_stats(void)
>  {
> -	struct zone *zone;
> +	int node;
>  
> -	for_each_populated_zone(zone)
> -		zero_zone_numa_counters(zone);
> +	for_each_online_node(node)
> +		zero_node_numa_stats(node);
>  }
>  
> -/* zero global numa counters */
> -static void zero_global_numa_counters(void)
> +/* zero global numa stats */
> +static void zero_global_numa_stats(void)
>  {
>  	int item;
>  
>  	for (item = 0; item < NR_VM_NUMA_STAT_ITEMS; item++)
> -		atomic_long_set(&vm_numa_stat[item], 0);
> +		atomic_long_set(&vm_node_stat[item], 0);
>  }
>  
>  static void invalid_numa_statistics(void)
>  {
> -	zero_zones_numa_counters();
> -	zero_global_numa_counters();
> +	zero_nodes_numa_stats();
> +	zero_global_numa_stats();
>  }
>  
>  static DEFINE_MUTEX(vm_numa_stat_lock);
> @@ -160,10 +158,8 @@ void vm_events_fold_cpu(int cpu)
>   * vm_stat contains the global counters
>   */
>  atomic_long_t vm_zone_stat[NR_VM_ZONE_STAT_ITEMS] __cacheline_aligned_in_smp;
> -atomic_long_t vm_numa_stat[NR_VM_NUMA_STAT_ITEMS] __cacheline_aligned_in_smp;
>  atomic_long_t vm_node_stat[NR_VM_NODE_STAT_ITEMS] __cacheline_aligned_in_smp;
>  EXPORT_SYMBOL(vm_zone_stat);
> -EXPORT_SYMBOL(vm_numa_stat);
>  EXPORT_SYMBOL(vm_node_stat);
>  
>  #ifdef CONFIG_SMP
> @@ -679,32 +675,6 @@ EXPORT_SYMBOL(dec_node_page_state);
>   * Fold a differential into the global counters.
>   * Returns the number of counters updated.
>   */
> -#ifdef CONFIG_NUMA
> -static int fold_diff(int *zone_diff, int *numa_diff, int *node_diff)
> -{
> -	int i;
> -	int changes = 0;
> -
> -	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
> -		if (zone_diff[i]) {
> -			atomic_long_add(zone_diff[i], &vm_zone_stat[i]);
> -			changes++;
> -	}
> -
> -	for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
> -		if (numa_diff[i]) {
> -			atomic_long_add(numa_diff[i], &vm_numa_stat[i]);
> -			changes++;
> -	}
> -
> -	for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
> -		if (node_diff[i]) {
> -			atomic_long_add(node_diff[i], &vm_node_stat[i]);
> -			changes++;
> -	}
> -	return changes;
> -}
> -#else
>  static int fold_diff(int *zone_diff, int *node_diff)
>  {
>  	int i;
> @@ -723,7 +693,6 @@ static int fold_diff(int *zone_diff, int *node_diff)
>  	}
>  	return changes;
>  }
> -#endif /* CONFIG_NUMA */
>  
>  /*
>   * Update the zone counters for the current cpu.
> @@ -747,9 +716,6 @@ static int refresh_cpu_vm_stats(bool do_pagesets)
>  	struct zone *zone;
>  	int i;
>  	int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
> -#ifdef CONFIG_NUMA
> -	int global_numa_diff[NR_VM_NUMA_STAT_ITEMS] = { 0, };
> -#endif
>  	int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
>  	int changes = 0;
>  
> @@ -771,18 +737,6 @@ static int refresh_cpu_vm_stats(bool do_pagesets)
>  			}
>  		}
>  #ifdef CONFIG_NUMA
> -		for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++) {
> -			int v;
> -
> -			v = this_cpu_xchg(p->vm_numa_stat_diff[i], 0);
> -			if (v) {
> -
> -				atomic_long_add(v, &zone->vm_numa_stat[i]);
> -				global_numa_diff[i] += v;
> -				__this_cpu_write(p->expire, 3);
> -			}
> -		}
> -
>  		if (do_pagesets) {
>  			cond_resched();
>  			/*
> @@ -829,12 +783,7 @@ static int refresh_cpu_vm_stats(bool do_pagesets)
>  		}
>  	}
>  
> -#ifdef CONFIG_NUMA
> -	changes += fold_diff(global_zone_diff, global_numa_diff,
> -			     global_node_diff);
> -#else
>  	changes += fold_diff(global_zone_diff, global_node_diff);
> -#endif
>  	return changes;
>  }
>  
> @@ -849,9 +798,6 @@ void cpu_vm_stats_fold(int cpu)
>  	struct zone *zone;
>  	int i;
>  	int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
> -#ifdef CONFIG_NUMA
> -	int global_numa_diff[NR_VM_NUMA_STAT_ITEMS] = { 0, };
> -#endif
>  	int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
>  
>  	for_each_populated_zone(zone) {
> @@ -868,18 +814,6 @@ void cpu_vm_stats_fold(int cpu)
>  				atomic_long_add(v, &zone->vm_stat[i]);
>  				global_zone_diff[i] += v;
>  			}
> -
> -#ifdef CONFIG_NUMA
> -		for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
> -			if (p->vm_numa_stat_diff[i]) {
> -				int v;
> -
> -				v = p->vm_numa_stat_diff[i];
> -				p->vm_numa_stat_diff[i] = 0;
> -				atomic_long_add(v, &zone->vm_numa_stat[i]);
> -				global_numa_diff[i] += v;
> -			}
> -#endif
>  	}
>  
>  	for_each_online_pgdat(pgdat) {
> @@ -898,11 +832,7 @@ void cpu_vm_stats_fold(int cpu)
>  			}
>  	}
>  
> -#ifdef CONFIG_NUMA
> -	fold_diff(global_zone_diff, global_numa_diff, global_node_diff);
> -#else
>  	fold_diff(global_zone_diff, global_node_diff);
> -#endif
>  }
>  
>  /*
> @@ -920,36 +850,10 @@ void drain_zonestat(struct zone *zone, struct per_cpu_pageset *pset)
>  			atomic_long_add(v, &zone->vm_stat[i]);
>  			atomic_long_add(v, &vm_zone_stat[i]);
>  		}
> -
> -#ifdef CONFIG_NUMA
> -	for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
> -		if (pset->vm_numa_stat_diff[i]) {
> -			int v = pset->vm_numa_stat_diff[i];
> -
> -			pset->vm_numa_stat_diff[i] = 0;
> -			atomic_long_add(v, &zone->vm_numa_stat[i]);
> -			atomic_long_add(v, &vm_numa_stat[i]);
> -		}
> -#endif
>  }
>  #endif
>  
>  #ifdef CONFIG_NUMA
> -void __inc_numa_state(struct zone *zone,
> -				 enum numa_stat_item item)
> -{
> -	struct per_cpu_pageset __percpu *pcp = zone->pageset;
> -	u16 __percpu *p = pcp->vm_numa_stat_diff + item;
> -	u16 v;
> -
> -	v = __this_cpu_inc_return(*p);
> -
> -	if (unlikely(v > NUMA_STATS_THRESHOLD)) {
> -		zone_numa_state_add(v, zone, item);
> -		__this_cpu_write(*p, 0);
> -	}
> -}
> -
>  /*
>   * Determine the per node value of a stat item. This function
>   * is called frequently in a NUMA machine, so try to be as
> @@ -969,23 +873,6 @@ unsigned long sum_zone_node_page_state(int node,
>  }
>  
>  /*
> - * Determine the per node value of a numa stat item. To avoid deviation,
> - * the per cpu stat number in vm_numa_stat_diff[] is also included.
> - */
> -unsigned long sum_zone_numa_state(int node,
> -				 enum numa_stat_item item)
> -{
> -	struct zone *zones = NODE_DATA(node)->node_zones;
> -	int i;
> -	unsigned long count = 0;
> -
> -	for (i = 0; i < MAX_NR_ZONES; i++)
> -		count += zone_numa_state_snapshot(zones + i, item);
> -
> -	return count;
> -}
> -
> -/*
>   * Determine the per node value of a stat item.
>   */
>  unsigned long node_page_state(struct pglist_data *pgdat,
> @@ -1569,8 +1456,7 @@ static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
>  		seq_printf(m, "\n  per-node stats");
>  		for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
>  			seq_printf(m, "\n      %-12s %lu",
> -				vmstat_text[i + NR_VM_ZONE_STAT_ITEMS +
> -				NR_VM_NUMA_STAT_ITEMS],
> +				vmstat_text[i + NR_VM_ZONE_STAT_ITEMS],
>  				node_page_state(pgdat, i));
>  		}
>  	}
> @@ -1607,13 +1493,6 @@ static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
>  		seq_printf(m, "\n      %-12s %lu", vmstat_text[i],
>  				zone_page_state(zone, i));
>  
> -#ifdef CONFIG_NUMA
> -	for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
> -		seq_printf(m, "\n      %-12s %lu",
> -				vmstat_text[i + NR_VM_ZONE_STAT_ITEMS],
> -				zone_numa_state_snapshot(zone, i));
> -#endif
> -
>  	seq_printf(m, "\n  pagesets");
>  	for_each_online_cpu(i) {
>  		struct per_cpu_pageset *pageset;
> @@ -1688,7 +1567,6 @@ static void *vmstat_start(struct seq_file *m, loff_t *pos)
>  	if (*pos >= ARRAY_SIZE(vmstat_text))
>  		return NULL;
>  	stat_items_size = NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long) +
> -			  NR_VM_NUMA_STAT_ITEMS * sizeof(unsigned long) +
>  			  NR_VM_NODE_STAT_ITEMS * sizeof(unsigned long) +
>  			  NR_VM_WRITEBACK_STAT_ITEMS * sizeof(unsigned long);
>  
> @@ -1704,12 +1582,6 @@ static void *vmstat_start(struct seq_file *m, loff_t *pos)
>  		v[i] = global_zone_page_state(i);
>  	v += NR_VM_ZONE_STAT_ITEMS;
>  
> -#ifdef CONFIG_NUMA
> -	for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
> -		v[i] = global_numa_state(i);
> -	v += NR_VM_NUMA_STAT_ITEMS;
> -#endif
> -
>  	for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
>  		v[i] = global_node_page_state(i);
>  	v += NR_VM_NODE_STAT_ITEMS;
> @@ -1811,16 +1683,6 @@ int vmstat_refresh(struct ctl_table *table, int write,
>  			err = -EINVAL;
>  		}
>  	}
> -#ifdef CONFIG_NUMA
> -	for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++) {
> -		val = atomic_long_read(&vm_numa_stat[i]);
> -		if (val < 0) {
> -			pr_warn("%s: %s %ld\n",
> -				__func__, vmstat_text[i + NR_VM_ZONE_STAT_ITEMS], val);
> -			err = -EINVAL;
> -		}
> -	}
> -#endif
>  	if (err)
>  		return err;
>  	if (write)
> @@ -1862,9 +1724,6 @@ static bool need_update(int cpu)
>  		struct per_cpu_pageset *p = per_cpu_ptr(zone->pageset, cpu);
>  
>  		BUILD_BUG_ON(sizeof(p->vm_stat_diff[0]) != 1);
> -#ifdef CONFIG_NUMA
> -		BUILD_BUG_ON(sizeof(p->vm_numa_stat_diff[0]) != 2);
> -#endif
>  
>  		/*
>  		 * The fast way of checking if there are any vmstat diffs.
> @@ -1872,10 +1731,6 @@ static bool need_update(int cpu)
>  		 */
>  		if (memchr_inv(p->vm_stat_diff, 0, NR_VM_ZONE_STAT_ITEMS))
>  			return true;
> -#ifdef CONFIG_NUMA
> -		if (memchr_inv(p->vm_numa_stat_diff, 0, NR_VM_NUMA_STAT_ITEMS))
> -			return true;
> -#endif
>  	}
>  	return false;
>  }
> -- 
> 2.7.4
> 

-- 
Michal Hocko
SUSE Labs

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