mm: change the call sites of numa statistics items
Patch series "Separate NUMA statistics from zone statistics", v2.
Each page allocation updates a set of per-zone statistics with a call to
zone_statistics(). As discussed in 2017 MM summit, these are a
substantial source of overhead in the page allocator and are very rarely
consumed. This significant overhead in cache bouncing caused by zone
counters (NUMA associated counters) update in parallel in multi-threaded
page allocation (pointed out by Dave Hansen).
A link to the MM summit slides:
http://people.netfilter.org/hawk/presentations/MM-summit2017/MM-summit2017-JesperBrouer.pdf
To mitigate this overhead, this patchset separates NUMA statistics from
zone statistics framework, and update NUMA counter threshold to a fixed
size of MAX_U16 - 2, as a small threshold greatly increases the update
frequency of the global counter from local per cpu counter (suggested by
Ying Huang). The rationality is that these statistics counters don't
need to be read often, unlike other VM counters, so it's not a problem
to use a large threshold and make readers more expensive.
With this patchset, we see 31.3% drop of CPU cycles(537-->369, see
below) for per single page allocation and reclaim on Jesper's
page_bench03 benchmark. Meanwhile, this patchset keeps the same style
of virtual memory statistics with little end-user-visible effects (only
move the numa stats to show behind zone page stats, see the first patch
for details).
I did an experiment of single page allocation and reclaim concurrently
using Jesper's page_bench03 benchmark on a 2-Socket Broadwell-based
server (88 processors with 126G memory) with different size of threshold
of pcp counter.
Benchmark provided by Jesper D Brouer(increase loop times to 10000000):
https://github.com/netoptimizer/prototype-kernel/tree/master/kernel/mm/bench
Threshold CPU cycles Throughput(88 threads)
32 799 241760478
64 640 301628829
125 537 358906028 <==> system by default
256 468 412397590
512 428 450550704
4096 399 482520943
20000 394 489009617
30000 395 488017817
65533 369(-31.3%) 521661345(+45.3%) <==> with this patchset
N/A 342(-36.3%) 562900157(+56.8%) <==> disable zone_statistics
This patch (of 3):
In this patch, NUMA statistics is separated from zone statistics
framework, all the call sites of NUMA stats are changed to use
numa-stats-specific functions, it does not have any functionality change
except that the number of NUMA stats is shown behind zone page stats
when users *read* the zone info.
E.g. cat /proc/zoneinfo
***Base*** ***With this patch***
nr_free_pages 3976 nr_free_pages 3976
nr_zone_inactive_anon 0 nr_zone_inactive_anon 0
nr_zone_active_anon 0 nr_zone_active_anon 0
nr_zone_inactive_file 0 nr_zone_inactive_file 0
nr_zone_active_file 0 nr_zone_active_file 0
nr_zone_unevictable 0 nr_zone_unevictable 0
nr_zone_write_pending 0 nr_zone_write_pending 0
nr_mlock 0 nr_mlock 0
nr_page_table_pages 0 nr_page_table_pages 0
nr_kernel_stack 0 nr_kernel_stack 0
nr_bounce 0 nr_bounce 0
nr_zspages 0 nr_zspages 0
numa_hit 0 *nr_free_cma 0*
numa_miss 0 numa_hit 0
numa_foreign 0 numa_miss 0
numa_interleave 0 numa_foreign 0
numa_local 0 numa_interleave 0
numa_other 0 numa_local 0
*nr_free_cma 0* numa_other 0
... ...
vm stats threshold: 10 vm stats threshold: 10
... ...
The next patch updates the numa stats counter size and threshold.
[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/1503568801-21305-2-git-send-email-kemi.wang@intel.com
Signed-off-by: Kemi Wang <kemi.wang@intel.com>
Reported-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christopher Lameter <cl@linux.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <andi.kleen@intel.com>
Cc: Ying Huang <ying.huang@intel.com>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/base/node.c b/drivers/base/node.c
index d8dc830..3855902 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -160,12 +160,12 @@
"interleave_hit %lu\n"
"local_node %lu\n"
"other_node %lu\n",
- sum_zone_node_page_state(dev->id, NUMA_HIT),
- sum_zone_node_page_state(dev->id, NUMA_MISS),
- sum_zone_node_page_state(dev->id, NUMA_FOREIGN),
- sum_zone_node_page_state(dev->id, NUMA_INTERLEAVE_HIT),
- sum_zone_node_page_state(dev->id, NUMA_LOCAL),
- sum_zone_node_page_state(dev->id, NUMA_OTHER));
+ 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));
}
static DEVICE_ATTR(numastat, S_IRUGO, node_read_numastat, NULL);
@@ -181,9 +181,17 @@
n += sprintf(buf+n, "%s %lu\n", vmstat_text[i],
sum_zone_node_page_state(nid, i));
- for (i = 0; i < NR_VM_NODE_STAT_ITEMS; 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],
node_page_state(pgdat, i));
return n;
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index e7e92c8..e65d91c 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -114,6 +114,20 @@
#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,
@@ -132,14 +146,6 @@
#if IS_ENABLED(CONFIG_ZSMALLOC)
NR_ZSPAGES, /* allocated in zsmalloc */
#endif
-#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 */
-#endif
NR_FREE_CMA_PAGES,
NR_VM_ZONE_STAT_ITEMS };
@@ -276,6 +282,8 @@
struct per_cpu_pages pcp;
#ifdef CONFIG_NUMA
s8 expire;
+ s8 numa_stat_threshold;
+ s8 vm_numa_stat_diff[NR_VM_NUMA_STAT_ITEMS];
#endif
#ifdef CONFIG_SMP
s8 stat_threshold;
@@ -496,6 +504,7 @@
ZONE_PADDING(_pad3_)
/* Zone statistics */
atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS];
+ atomic_long_t vm_numa_stat[NR_VM_NUMA_STAT_ITEMS];
} ____cacheline_internodealigned_in_smp;
enum pgdat_flags {
diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index 97e11ab..9ac82e2 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -107,8 +107,33 @@
* 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(struct zone *zone,
+ enum numa_stat_item item)
+{
+ long x = atomic_long_read(&zone->vm_numa_stat[item]);
+
+ return x;
+}
+#endif /* CONFIG_NUMA */
+
static inline void zone_page_state_add(long x, struct zone *zone,
enum zone_stat_item item)
{
@@ -194,8 +219,10 @@
#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);
+ 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/page_alloc.c b/mm/page_alloc.c
index a9add06..45583cd 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2741,18 +2741,18 @@
static inline void zone_statistics(struct zone *preferred_zone, struct zone *z)
{
#ifdef CONFIG_NUMA
- enum zone_stat_item local_stat = NUMA_LOCAL;
+ enum numa_stat_item local_stat = NUMA_LOCAL;
if (z->node != numa_node_id())
local_stat = NUMA_OTHER;
if (z->node == preferred_zone->node)
- __inc_zone_state(z, NUMA_HIT);
+ __inc_numa_state(z, NUMA_HIT);
else {
- __inc_zone_state(z, NUMA_MISS);
- __inc_zone_state(preferred_zone, NUMA_FOREIGN);
+ __inc_numa_state(z, NUMA_MISS);
+ __inc_numa_state(preferred_zone, NUMA_FOREIGN);
}
- __inc_zone_state(z, local_stat);
+ __inc_numa_state(z, local_stat);
#endif
}
diff --git a/mm/vmstat.c b/mm/vmstat.c
index c7e4b84..daea028 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -87,8 +87,10 @@
* 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
@@ -192,7 +194,10 @@
per_cpu_ptr(zone->pageset, cpu)->stat_threshold
= threshold;
-
+#ifdef CONFIG_NUMA
+ per_cpu_ptr(zone->pageset, cpu)->numa_stat_threshold
+ = threshold;
+#endif
/* Base nodestat threshold on the largest populated zone. */
pgdat_threshold = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold;
per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold
@@ -226,9 +231,14 @@
continue;
threshold = (*calculate_pressure)(zone);
- for_each_online_cpu(cpu)
+ for_each_online_cpu(cpu) {
per_cpu_ptr(zone->pageset, cpu)->stat_threshold
= threshold;
+#ifdef CONFIG_NUMA
+ per_cpu_ptr(zone->pageset, cpu)->numa_stat_threshold
+ = threshold;
+#endif
+ }
}
}
@@ -604,6 +614,32 @@
* 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;
@@ -622,6 +658,7 @@
}
return changes;
}
+#endif /* CONFIG_NUMA */
/*
* Update the zone counters for the current cpu.
@@ -645,6 +682,9 @@
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;
@@ -666,6 +706,18 @@
}
}
#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();
/*
@@ -712,7 +764,12 @@
}
}
+#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;
}
@@ -727,6 +784,9 @@
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) {
@@ -743,6 +803,18 @@
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) {
@@ -761,7 +833,11 @@
}
}
+#ifdef CONFIG_NUMA
+ fold_diff(global_zone_diff, global_numa_diff, global_node_diff);
+#else
fold_diff(global_zone_diff, global_node_diff);
+#endif
}
/*
@@ -779,10 +855,38 @@
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;
+ s8 __percpu *p = pcp->vm_numa_stat_diff + item;
+ s8 v, t;
+
+ v = __this_cpu_inc_return(*p);
+ t = __this_cpu_read(pcp->numa_stat_threshold);
+ if (unlikely(v > t)) {
+ s8 overstep = t >> 1;
+
+ zone_numa_state_add(v + overstep, zone, item);
+ __this_cpu_write(*p, -overstep);
+ }
+}
+
/*
* Determine the per node value of a stat item. This function
* is called frequently in a NUMA machine, so try to be as
@@ -801,6 +905,19 @@
return count;
}
+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(zones + i, item);
+
+ return count;
+}
+
/*
* Determine the per node value of a stat item.
*/
@@ -937,6 +1054,9 @@
#if IS_ENABLED(CONFIG_ZSMALLOC)
"nr_zspages",
#endif
+ "nr_free_cma",
+
+ /* enum numa_stat_item counters */
#ifdef CONFIG_NUMA
"numa_hit",
"numa_miss",
@@ -945,7 +1065,6 @@
"numa_local",
"numa_other",
#endif
- "nr_free_cma",
/* Node-based counters */
"nr_inactive_anon",
@@ -1106,7 +1225,6 @@
};
#endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA */
-
#if (defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)) || \
defined(CONFIG_PROC_FS)
static void *frag_start(struct seq_file *m, loff_t *pos)
@@ -1384,7 +1502,8 @@
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],
+ vmstat_text[i + NR_VM_ZONE_STAT_ITEMS +
+ NR_VM_NUMA_STAT_ITEMS],
node_page_state(pgdat, i));
}
}
@@ -1421,6 +1540,13 @@
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(zone, i));
+#endif
+
seq_printf(m, "\n pagesets");
for_each_online_cpu(i) {
struct per_cpu_pageset *pageset;
@@ -1497,6 +1623,7 @@
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);
@@ -1512,6 +1639,12 @@
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;
@@ -1613,6 +1746,16 @@
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)
@@ -1654,13 +1797,19 @@
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]) != 1);
+#endif
/*
* The fast way of checking if there are any vmstat diffs.
* This works because the diffs are byte sized items.
*/
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;
}