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SubjectRe: [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@linux.intel.com>
> Suggested-by: Michal Hocko <mhocko@kernel.com>
> Signed-off-by: Kemi Wang <kemi.wang@intel.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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