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OpenCloudOS-Kernel/mm/vmstat.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/mm/vmstat.c
*
* Manages VM statistics
* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
*
* zoned VM statistics
* Copyright (C) 2006 Silicon Graphics, Inc.,
* Christoph Lameter <christoph@lameter.com>
* Copyright (C) 2008-2014 Christoph Lameter
*/
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/cpu.h>
#include <linux/cpumask.h>
#include <linux/vmstat.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/debugfs.h>
#include <linux/sched.h>
#include <linux/math64.h>
#include <linux/writeback.h>
#include <linux/compaction.h>
#include <linux/mm_inline.h>
#include <linux/page_ext.h>
#include <linux/page_owner.h>
#include "internal.h"
#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)
{
int item, cpu;
for (item = 0; item < NR_VM_NUMA_EVENT_ITEMS; item++) {
atomic_long_set(&zone->vm_numa_event[item], 0);
for_each_online_cpu(cpu) {
per_cpu_ptr(zone->per_cpu_zonestats, cpu)->vm_numa_event[item]
= 0;
}
}
}
/* zero numa counters of all the populated zones */
static void zero_zones_numa_counters(void)
{
struct zone *zone;
for_each_populated_zone(zone)
zero_zone_numa_counters(zone);
}
/* zero global numa counters */
static void zero_global_numa_counters(void)
{
int item;
for (item = 0; item < NR_VM_NUMA_EVENT_ITEMS; item++)
atomic_long_set(&vm_numa_event[item], 0);
}
static void invalid_numa_statistics(void)
{
zero_zones_numa_counters();
zero_global_numa_counters();
}
static DEFINE_MUTEX(vm_numa_stat_lock);
int sysctl_vm_numa_stat_handler(struct ctl_table *table, int write,
void *buffer, size_t *length, loff_t *ppos)
{
int ret, oldval;
mutex_lock(&vm_numa_stat_lock);
if (write)
oldval = sysctl_vm_numa_stat;
ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
if (ret || !write)
goto out;
if (oldval == sysctl_vm_numa_stat)
goto out;
else if (sysctl_vm_numa_stat == ENABLE_NUMA_STAT) {
static_branch_enable(&vm_numa_stat_key);
pr_info("enable numa statistics\n");
} else {
static_branch_disable(&vm_numa_stat_key);
invalid_numa_statistics();
pr_info("disable numa statistics, and clear numa counters\n");
}
out:
mutex_unlock(&vm_numa_stat_lock);
return ret;
}
#endif
#ifdef CONFIG_VM_EVENT_COUNTERS
DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}};
EXPORT_PER_CPU_SYMBOL(vm_event_states);
static void sum_vm_events(unsigned long *ret)
{
int cpu;
int i;
memset(ret, 0, NR_VM_EVENT_ITEMS * sizeof(unsigned long));
for_each_online_cpu(cpu) {
struct vm_event_state *this = &per_cpu(vm_event_states, cpu);
for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
ret[i] += this->event[i];
}
}
/*
* Accumulate the vm event counters across all CPUs.
* The result is unavoidably approximate - it can change
* during and after execution of this function.
*/
void all_vm_events(unsigned long *ret)
{
cpus_read_lock();
sum_vm_events(ret);
cpus_read_unlock();
}
EXPORT_SYMBOL_GPL(all_vm_events);
/*
* Fold the foreign cpu events into our own.
*
* This is adding to the events on one processor
* but keeps the global counts constant.
*/
void vm_events_fold_cpu(int cpu)
{
struct vm_event_state *fold_state = &per_cpu(vm_event_states, cpu);
int i;
for (i = 0; i < NR_VM_EVENT_ITEMS; i++) {
count_vm_events(i, fold_state->event[i]);
fold_state->event[i] = 0;
}
}
#endif /* CONFIG_VM_EVENT_COUNTERS */
/*
* Manage combined zone based / global counters
*
* 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_node_stat[NR_VM_NODE_STAT_ITEMS] __cacheline_aligned_in_smp;
atomic_long_t vm_numa_event[NR_VM_NUMA_EVENT_ITEMS] __cacheline_aligned_in_smp;
EXPORT_SYMBOL(vm_zone_stat);
EXPORT_SYMBOL(vm_node_stat);
#ifdef CONFIG_NUMA
static void fold_vm_zone_numa_events(struct zone *zone)
{
unsigned long zone_numa_events[NR_VM_NUMA_EVENT_ITEMS] = { 0, };
int cpu;
enum numa_stat_item item;
for_each_online_cpu(cpu) {
struct per_cpu_zonestat *pzstats;
pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
for (item = 0; item < NR_VM_NUMA_EVENT_ITEMS; item++)
zone_numa_events[item] += xchg(&pzstats->vm_numa_event[item], 0);
}
for (item = 0; item < NR_VM_NUMA_EVENT_ITEMS; item++)
zone_numa_event_add(zone_numa_events[item], zone, item);
}
void fold_vm_numa_events(void)
{
struct zone *zone;
for_each_populated_zone(zone)
fold_vm_zone_numa_events(zone);
}
#endif
#ifdef CONFIG_SMP
int calculate_pressure_threshold(struct zone *zone)
{
int threshold;
int watermark_distance;
/*
* As vmstats are not up to date, there is drift between the estimated
* and real values. For high thresholds and a high number of CPUs, it
* is possible for the min watermark to be breached while the estimated
* value looks fine. The pressure threshold is a reduced value such
* that even the maximum amount of drift will not accidentally breach
* the min watermark
*/
watermark_distance = low_wmark_pages(zone) - min_wmark_pages(zone);
threshold = max(1, (int)(watermark_distance / num_online_cpus()));
/*
* Maximum threshold is 125
*/
threshold = min(125, threshold);
return threshold;
}
int calculate_normal_threshold(struct zone *zone)
{
int threshold;
int mem; /* memory in 128 MB units */
/*
* The threshold scales with the number of processors and the amount
* of memory per zone. More memory means that we can defer updates for
* longer, more processors could lead to more contention.
* fls() is used to have a cheap way of logarithmic scaling.
*
* Some sample thresholds:
*
* Threshold Processors (fls) Zonesize fls(mem)+1
* ------------------------------------------------------------------
* 8 1 1 0.9-1 GB 4
* 16 2 2 0.9-1 GB 4
* 20 2 2 1-2 GB 5
* 24 2 2 2-4 GB 6
* 28 2 2 4-8 GB 7
* 32 2 2 8-16 GB 8
* 4 2 2 <128M 1
* 30 4 3 2-4 GB 5
* 48 4 3 8-16 GB 8
* 32 8 4 1-2 GB 4
* 32 8 4 0.9-1GB 4
* 10 16 5 <128M 1
* 40 16 5 900M 4
* 70 64 7 2-4 GB 5
* 84 64 7 4-8 GB 6
* 108 512 9 4-8 GB 6
* 125 1024 10 8-16 GB 8
* 125 1024 10 16-32 GB 9
*/
mem = zone_managed_pages(zone) >> (27 - PAGE_SHIFT);
threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem));
/*
* Maximum threshold is 125
*/
threshold = min(125, threshold);
return threshold;
}
/*
* Refresh the thresholds for each zone.
*/
void refresh_zone_stat_thresholds(void)
{
struct pglist_data *pgdat;
struct zone *zone;
int cpu;
int threshold;
/* Zero current pgdat thresholds */
for_each_online_pgdat(pgdat) {
for_each_online_cpu(cpu) {
per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold = 0;
}
}
for_each_populated_zone(zone) {
struct pglist_data *pgdat = zone->zone_pgdat;
unsigned long max_drift, tolerate_drift;
threshold = calculate_normal_threshold(zone);
for_each_online_cpu(cpu) {
int pgdat_threshold;
per_cpu_ptr(zone->per_cpu_zonestats, cpu)->stat_threshold
= threshold;
/* 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
= max(threshold, pgdat_threshold);
}
/*
* Only set percpu_drift_mark if there is a danger that
* NR_FREE_PAGES reports the low watermark is ok when in fact
* the min watermark could be breached by an allocation
*/
tolerate_drift = low_wmark_pages(zone) - min_wmark_pages(zone);
max_drift = num_online_cpus() * threshold;
if (max_drift > tolerate_drift)
zone->percpu_drift_mark = high_wmark_pages(zone) +
max_drift;
}
}
void set_pgdat_percpu_threshold(pg_data_t *pgdat,
int (*calculate_pressure)(struct zone *))
{
struct zone *zone;
int cpu;
int threshold;
int i;
for (i = 0; i < pgdat->nr_zones; i++) {
zone = &pgdat->node_zones[i];
if (!zone->percpu_drift_mark)
continue;
threshold = (*calculate_pressure)(zone);
for_each_online_cpu(cpu)
per_cpu_ptr(zone->per_cpu_zonestats, cpu)->stat_threshold
= threshold;
}
}
/*
* For use when we know that interrupts are disabled,
* or when we know that preemption is disabled and that
* particular counter cannot be updated from interrupt context.
*/
void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
long delta)
{
struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
s8 __percpu *p = pcp->vm_stat_diff + item;
long x;
long t;
/*
* Accurate vmstat updates require a RMW. On !PREEMPT_RT kernels,
* atomicity is provided by IRQs being disabled -- either explicitly
* or via local_lock_irq. On PREEMPT_RT, local_lock_irq only disables
* CPU migrations and preemption potentially corrupts a counter so
* disable preemption.
*/
preempt_disable_nested();
x = delta + __this_cpu_read(*p);
t = __this_cpu_read(pcp->stat_threshold);
if (unlikely(abs(x) > t)) {
zone_page_state_add(x, zone, item);
x = 0;
}
__this_cpu_write(*p, x);
preempt_enable_nested();
}
EXPORT_SYMBOL(__mod_zone_page_state);
void __mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
long delta)
{
struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
s8 __percpu *p = pcp->vm_node_stat_diff + item;
long x;
long t;
if (vmstat_item_in_bytes(item)) {
/*
* Only cgroups use subpage accounting right now; at
* the global level, these items still change in
* multiples of whole pages. Store them as pages
* internally to keep the per-cpu counters compact.
*/
VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1));
delta >>= PAGE_SHIFT;
}
/* See __mod_node_page_state */
preempt_disable_nested();
x = delta + __this_cpu_read(*p);
t = __this_cpu_read(pcp->stat_threshold);
if (unlikely(abs(x) > t)) {
node_page_state_add(x, pgdat, item);
x = 0;
}
__this_cpu_write(*p, x);
preempt_enable_nested();
}
EXPORT_SYMBOL(__mod_node_page_state);
/*
* Optimized increment and decrement functions.
*
* These are only for a single page and therefore can take a struct page *
* argument instead of struct zone *. This allows the inclusion of the code
* generated for page_zone(page) into the optimized functions.
*
* No overflow check is necessary and therefore the differential can be
* incremented or decremented in place which may allow the compilers to
* generate better code.
* The increment or decrement is known and therefore one boundary check can
* be omitted.
*
* NOTE: These functions are very performance sensitive. Change only
* with care.
*
* Some processors have inc/dec instructions that are atomic vs an interrupt.
* However, the code must first determine the differential location in a zone
* based on the processor number and then inc/dec the counter. There is no
* guarantee without disabling preemption that the processor will not change
* in between and therefore the atomicity vs. interrupt cannot be exploited
* in a useful way here.
*/
void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
{
struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
s8 __percpu *p = pcp->vm_stat_diff + item;
s8 v, t;
/* See __mod_node_page_state */
preempt_disable_nested();
v = __this_cpu_inc_return(*p);
t = __this_cpu_read(pcp->stat_threshold);
if (unlikely(v > t)) {
s8 overstep = t >> 1;
zone_page_state_add(v + overstep, zone, item);
__this_cpu_write(*p, -overstep);
}
preempt_enable_nested();
}
void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
{
struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
s8 __percpu *p = pcp->vm_node_stat_diff + item;
s8 v, t;
VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
/* See __mod_node_page_state */
preempt_disable_nested();
v = __this_cpu_inc_return(*p);
t = __this_cpu_read(pcp->stat_threshold);
if (unlikely(v > t)) {
s8 overstep = t >> 1;
node_page_state_add(v + overstep, pgdat, item);
__this_cpu_write(*p, -overstep);
}
preempt_enable_nested();
}
void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
{
__inc_zone_state(page_zone(page), item);
}
EXPORT_SYMBOL(__inc_zone_page_state);
void __inc_node_page_state(struct page *page, enum node_stat_item item)
{
__inc_node_state(page_pgdat(page), item);
}
EXPORT_SYMBOL(__inc_node_page_state);
void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
{
struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
s8 __percpu *p = pcp->vm_stat_diff + item;
s8 v, t;
/* See __mod_node_page_state */
preempt_disable_nested();
v = __this_cpu_dec_return(*p);
t = __this_cpu_read(pcp->stat_threshold);
if (unlikely(v < - t)) {
s8 overstep = t >> 1;
zone_page_state_add(v - overstep, zone, item);
__this_cpu_write(*p, overstep);
}
preempt_enable_nested();
}
void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item)
{
struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
s8 __percpu *p = pcp->vm_node_stat_diff + item;
s8 v, t;
VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
/* See __mod_node_page_state */
preempt_disable_nested();
v = __this_cpu_dec_return(*p);
t = __this_cpu_read(pcp->stat_threshold);
if (unlikely(v < - t)) {
s8 overstep = t >> 1;
node_page_state_add(v - overstep, pgdat, item);
__this_cpu_write(*p, overstep);
}
preempt_enable_nested();
}
void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
{
__dec_zone_state(page_zone(page), item);
}
EXPORT_SYMBOL(__dec_zone_page_state);
void __dec_node_page_state(struct page *page, enum node_stat_item item)
{
__dec_node_state(page_pgdat(page), item);
}
EXPORT_SYMBOL(__dec_node_page_state);
#ifdef CONFIG_HAVE_CMPXCHG_LOCAL
/*
* If we have cmpxchg_local support then we do not need to incur the overhead
* that comes with local_irq_save/restore if we use this_cpu_cmpxchg.
*
* mod_state() modifies the zone counter state through atomic per cpu
* operations.
*
* Overstep mode specifies how overstep should handled:
* 0 No overstepping
* 1 Overstepping half of threshold
* -1 Overstepping minus half of threshold
*/
static inline void mod_zone_state(struct zone *zone,
enum zone_stat_item item, long delta, int overstep_mode)
{
struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
s8 __percpu *p = pcp->vm_stat_diff + item;
long o, n, t, z;
do {
z = 0; /* overflow to zone counters */
/*
* The fetching of the stat_threshold is racy. We may apply
* a counter threshold to the wrong the cpu if we get
* rescheduled while executing here. However, the next
* counter update will apply the threshold again and
* therefore bring the counter under the threshold again.
*
* Most of the time the thresholds are the same anyways
* for all cpus in a zone.
*/
t = this_cpu_read(pcp->stat_threshold);
o = this_cpu_read(*p);
n = delta + o;
if (abs(n) > t) {
int os = overstep_mode * (t >> 1) ;
/* Overflow must be added to zone counters */
z = n + os;
n = -os;
}
} while (this_cpu_cmpxchg(*p, o, n) != o);
if (z)
zone_page_state_add(z, zone, item);
}
void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
long delta)
{
mod_zone_state(zone, item, delta, 0);
}
EXPORT_SYMBOL(mod_zone_page_state);
void inc_zone_page_state(struct page *page, enum zone_stat_item item)
{
mod_zone_state(page_zone(page), item, 1, 1);
}
EXPORT_SYMBOL(inc_zone_page_state);
void dec_zone_page_state(struct page *page, enum zone_stat_item item)
{
mod_zone_state(page_zone(page), item, -1, -1);
}
EXPORT_SYMBOL(dec_zone_page_state);
static inline void mod_node_state(struct pglist_data *pgdat,
enum node_stat_item item, int delta, int overstep_mode)
{
struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
s8 __percpu *p = pcp->vm_node_stat_diff + item;
long o, n, t, z;
if (vmstat_item_in_bytes(item)) {
/*
* Only cgroups use subpage accounting right now; at
* the global level, these items still change in
* multiples of whole pages. Store them as pages
* internally to keep the per-cpu counters compact.
*/
VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1));
delta >>= PAGE_SHIFT;
}
do {
z = 0; /* overflow to node counters */
/*
* The fetching of the stat_threshold is racy. We may apply
* a counter threshold to the wrong the cpu if we get
* rescheduled while executing here. However, the next
* counter update will apply the threshold again and
* therefore bring the counter under the threshold again.
*
* Most of the time the thresholds are the same anyways
* for all cpus in a node.
*/
t = this_cpu_read(pcp->stat_threshold);
o = this_cpu_read(*p);
n = delta + o;
if (abs(n) > t) {
int os = overstep_mode * (t >> 1) ;
/* Overflow must be added to node counters */
z = n + os;
n = -os;
}
} while (this_cpu_cmpxchg(*p, o, n) != o);
if (z)
node_page_state_add(z, pgdat, item);
}
void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
long delta)
{
mod_node_state(pgdat, item, delta, 0);
}
EXPORT_SYMBOL(mod_node_page_state);
void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
{
mod_node_state(pgdat, item, 1, 1);
}
void inc_node_page_state(struct page *page, enum node_stat_item item)
{
mod_node_state(page_pgdat(page), item, 1, 1);
}
EXPORT_SYMBOL(inc_node_page_state);
void dec_node_page_state(struct page *page, enum node_stat_item item)
{
mod_node_state(page_pgdat(page), item, -1, -1);
}
EXPORT_SYMBOL(dec_node_page_state);
#else
/*
* Use interrupt disable to serialize counter updates
*/
void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
long delta)
{
unsigned long flags;
local_irq_save(flags);
__mod_zone_page_state(zone, item, delta);
local_irq_restore(flags);
}
EXPORT_SYMBOL(mod_zone_page_state);
void inc_zone_page_state(struct page *page, enum zone_stat_item item)
{
unsigned long flags;
struct zone *zone;
zone = page_zone(page);
local_irq_save(flags);
__inc_zone_state(zone, item);
local_irq_restore(flags);
}
EXPORT_SYMBOL(inc_zone_page_state);
void dec_zone_page_state(struct page *page, enum zone_stat_item item)
{
unsigned long flags;
local_irq_save(flags);
__dec_zone_page_state(page, item);
local_irq_restore(flags);
}
EXPORT_SYMBOL(dec_zone_page_state);
void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
{
unsigned long flags;
local_irq_save(flags);
__inc_node_state(pgdat, item);
local_irq_restore(flags);
}
EXPORT_SYMBOL(inc_node_state);
void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
long delta)
{
unsigned long flags;
local_irq_save(flags);
__mod_node_page_state(pgdat, item, delta);
local_irq_restore(flags);
}
EXPORT_SYMBOL(mod_node_page_state);
void inc_node_page_state(struct page *page, enum node_stat_item item)
{
unsigned long flags;
struct pglist_data *pgdat;
pgdat = page_pgdat(page);
local_irq_save(flags);
__inc_node_state(pgdat, item);
local_irq_restore(flags);
}
EXPORT_SYMBOL(inc_node_page_state);
void dec_node_page_state(struct page *page, enum node_stat_item item)
{
unsigned long flags;
local_irq_save(flags);
__dec_node_page_state(page, item);
local_irq_restore(flags);
}
EXPORT_SYMBOL(dec_node_page_state);
#endif
/*
* Fold a differential into the global counters.
* Returns the number of counters updated.
*/
static int fold_diff(int *zone_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_NODE_STAT_ITEMS; i++)
if (node_diff[i]) {
atomic_long_add(node_diff[i], &vm_node_stat[i]);
changes++;
}
return changes;
}
/*
* Update the zone counters for the current cpu.
*
* Note that refresh_cpu_vm_stats strives to only access
* node local memory. The per cpu pagesets on remote zones are placed
* in the memory local to the processor using that pageset. So the
* loop over all zones will access a series of cachelines local to
* the processor.
*
* The call to zone_page_state_add updates the cachelines with the
* statistics in the remote zone struct as well as the global cachelines
* with the global counters. These could cause remote node cache line
* bouncing and will have to be only done when necessary.
*
* The function returns the number of global counters updated.
*/
static int refresh_cpu_vm_stats(bool do_pagesets)
{
struct pglist_data *pgdat;
struct zone *zone;
int i;
int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
int changes = 0;
for_each_populated_zone(zone) {
struct per_cpu_zonestat __percpu *pzstats = zone->per_cpu_zonestats;
#ifdef CONFIG_NUMA
struct per_cpu_pages __percpu *pcp = zone->per_cpu_pageset;
#endif
for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
int v;
v = this_cpu_xchg(pzstats->vm_stat_diff[i], 0);
if (v) {
atomic_long_add(v, &zone->vm_stat[i]);
global_zone_diff[i] += v;
#ifdef CONFIG_NUMA
/* 3 seconds idle till flush */
__this_cpu_write(pcp->expire, 3);
#endif
}
}
#ifdef CONFIG_NUMA
if (do_pagesets) {
cond_resched();
/*
* Deal with draining the remote pageset of this
* processor
*
* Check if there are pages remaining in this pageset
* if not then there is nothing to expire.
*/
if (!__this_cpu_read(pcp->expire) ||
!__this_cpu_read(pcp->count))
continue;
/*
* We never drain zones local to this processor.
*/
if (zone_to_nid(zone) == numa_node_id()) {
__this_cpu_write(pcp->expire, 0);
continue;
}
if (__this_cpu_dec_return(pcp->expire))
continue;
if (__this_cpu_read(pcp->count)) {
drain_zone_pages(zone, this_cpu_ptr(pcp));
changes++;
}
}
#endif
}
for_each_online_pgdat(pgdat) {
struct per_cpu_nodestat __percpu *p = pgdat->per_cpu_nodestats;
for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
int v;
v = this_cpu_xchg(p->vm_node_stat_diff[i], 0);
if (v) {
atomic_long_add(v, &pgdat->vm_stat[i]);
global_node_diff[i] += v;
}
}
}
changes += fold_diff(global_zone_diff, global_node_diff);
return changes;
}
/*
* Fold the data for an offline cpu into the global array.
* There cannot be any access by the offline cpu and therefore
* synchronization is simplified.
*/
void cpu_vm_stats_fold(int cpu)
{
struct pglist_data *pgdat;
struct zone *zone;
int i;
int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
for_each_populated_zone(zone) {
struct per_cpu_zonestat *pzstats;
pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
if (pzstats->vm_stat_diff[i]) {
int v;
v = pzstats->vm_stat_diff[i];
pzstats->vm_stat_diff[i] = 0;
atomic_long_add(v, &zone->vm_stat[i]);
global_zone_diff[i] += v;
}
}
#ifdef CONFIG_NUMA
for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++) {
if (pzstats->vm_numa_event[i]) {
unsigned long v;
v = pzstats->vm_numa_event[i];
pzstats->vm_numa_event[i] = 0;
zone_numa_event_add(v, zone, i);
}
}
#endif
}
for_each_online_pgdat(pgdat) {
struct per_cpu_nodestat *p;
p = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu);
for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
if (p->vm_node_stat_diff[i]) {
int v;
v = p->vm_node_stat_diff[i];
p->vm_node_stat_diff[i] = 0;
atomic_long_add(v, &pgdat->vm_stat[i]);
global_node_diff[i] += v;
}
}
fold_diff(global_zone_diff, global_node_diff);
}
/*
* this is only called if !populated_zone(zone), which implies no other users of
* pset->vm_stat_diff[] exist.
*/
void drain_zonestat(struct zone *zone, struct per_cpu_zonestat *pzstats)
{
unsigned long v;
int i;
for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
if (pzstats->vm_stat_diff[i]) {
v = pzstats->vm_stat_diff[i];
pzstats->vm_stat_diff[i] = 0;
zone_page_state_add(v, zone, i);
}
}
#ifdef CONFIG_NUMA
for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++) {
if (pzstats->vm_numa_event[i]) {
v = pzstats->vm_numa_event[i];
pzstats->vm_numa_event[i] = 0;
zone_numa_event_add(v, zone, i);
}
}
#endif
}
#endif
#ifdef CONFIG_NUMA
/*
* Determine the per node value of a stat item. This function
* is called frequently in a NUMA machine, so try to be as
* frugal as possible.
*/
unsigned long sum_zone_node_page_state(int node,
enum zone_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_page_state(zones + i, item);
return count;
}
/* Determine the per node value of a numa stat item. */
unsigned long sum_zone_numa_event_state(int node,
enum numa_stat_item item)
{
struct zone *zones = NODE_DATA(node)->node_zones;
unsigned long count = 0;
int i;
for (i = 0; i < MAX_NR_ZONES; i++)
count += zone_numa_event_state(zones + i, item);
return count;
}
/*
* Determine the per node value of a stat item.
*/
unsigned long node_page_state_pages(struct pglist_data *pgdat,
enum node_stat_item item)
{
long x = atomic_long_read(&pgdat->vm_stat[item]);
#ifdef CONFIG_SMP
if (x < 0)
x = 0;
#endif
return x;
}
unsigned long node_page_state(struct pglist_data *pgdat,
enum node_stat_item item)
{
VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
return node_page_state_pages(pgdat, item);
}
#endif
#ifdef CONFIG_COMPACTION
struct contig_page_info {
unsigned long free_pages;
unsigned long free_blocks_total;
unsigned long free_blocks_suitable;
};
/*
* Calculate the number of free pages in a zone, how many contiguous
* pages are free and how many are large enough to satisfy an allocation of
* the target size. Note that this function makes no attempt to estimate
* how many suitable free blocks there *might* be if MOVABLE pages were
* migrated. Calculating that is possible, but expensive and can be
* figured out from userspace
*/
static void fill_contig_page_info(struct zone *zone,
unsigned int suitable_order,
struct contig_page_info *info)
{
unsigned int order;
info->free_pages = 0;
info->free_blocks_total = 0;
info->free_blocks_suitable = 0;
for (order = 0; order <= MAX_ORDER; order++) {
unsigned long blocks;
/*
* Count number of free blocks.
*
* Access to nr_free is lockless as nr_free is used only for
* diagnostic purposes. Use data_race to avoid KCSAN warning.
*/
blocks = data_race(zone->free_area[order].nr_free);
info->free_blocks_total += blocks;
/* Count free base pages */
info->free_pages += blocks << order;
/* Count the suitable free blocks */
if (order >= suitable_order)
info->free_blocks_suitable += blocks <<
(order - suitable_order);
}
}
/*
* A fragmentation index only makes sense if an allocation of a requested
* size would fail. If that is true, the fragmentation index indicates
* whether external fragmentation or a lack of memory was the problem.
* The value can be used to determine if page reclaim or compaction
* should be used
*/
static int __fragmentation_index(unsigned int order, struct contig_page_info *info)
{
unsigned long requested = 1UL << order;
if (WARN_ON_ONCE(order > MAX_ORDER))
return 0;
if (!info->free_blocks_total)
return 0;
/* Fragmentation index only makes sense when a request would fail */
if (info->free_blocks_suitable)
return -1000;
/*
* Index is between 0 and 1 so return within 3 decimal places
*
* 0 => allocation would fail due to lack of memory
* 1 => allocation would fail due to fragmentation
*/
return 1000 - div_u64( (1000+(div_u64(info->free_pages * 1000ULL, requested))), info->free_blocks_total);
}
/*
* Calculates external fragmentation within a zone wrt the given order.
* It is defined as the percentage of pages found in blocks of size
* less than 1 << order. It returns values in range [0, 100].
*/
unsigned int extfrag_for_order(struct zone *zone, unsigned int order)
{
struct contig_page_info info;
fill_contig_page_info(zone, order, &info);
if (info.free_pages == 0)
return 0;
return div_u64((info.free_pages -
(info.free_blocks_suitable << order)) * 100,
info.free_pages);
}
/* Same as __fragmentation index but allocs contig_page_info on stack */
int fragmentation_index(struct zone *zone, unsigned int order)
{
struct contig_page_info info;
fill_contig_page_info(zone, order, &info);
return __fragmentation_index(order, &info);
}
#endif
#if defined(CONFIG_PROC_FS) || defined(CONFIG_SYSFS) || \
defined(CONFIG_NUMA) || defined(CONFIG_MEMCG)
#ifdef CONFIG_ZONE_DMA
#define TEXT_FOR_DMA(xx) xx "_dma",
#else
#define TEXT_FOR_DMA(xx)
#endif
#ifdef CONFIG_ZONE_DMA32
#define TEXT_FOR_DMA32(xx) xx "_dma32",
#else
#define TEXT_FOR_DMA32(xx)
#endif
#ifdef CONFIG_HIGHMEM
#define TEXT_FOR_HIGHMEM(xx) xx "_high",
#else
#define TEXT_FOR_HIGHMEM(xx)
#endif
#ifdef CONFIG_ZONE_DEVICE
#define TEXT_FOR_DEVICE(xx) xx "_device",
#else
#define TEXT_FOR_DEVICE(xx)
#endif
#define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
TEXT_FOR_HIGHMEM(xx) xx "_movable", \
TEXT_FOR_DEVICE(xx)
const char * const vmstat_text[] = {
/* enum zone_stat_item counters */
"nr_free_pages",
"nr_zone_inactive_anon",
"nr_zone_active_anon",
"nr_zone_inactive_file",
"nr_zone_active_file",
"nr_zone_unevictable",
"nr_zone_write_pending",
"nr_mlock",
"nr_bounce",
#if IS_ENABLED(CONFIG_ZSMALLOC)
"nr_zspages",
#endif
"nr_free_cma",
/* enum numa_stat_item counters */
#ifdef CONFIG_NUMA
"numa_hit",
"numa_miss",
"numa_foreign",
"numa_interleave",
"numa_local",
"numa_other",
#endif
/* enum node_stat_item counters */
"nr_inactive_anon",
"nr_active_anon",
"nr_inactive_file",
"nr_active_file",
"nr_unevictable",
"nr_slab_reclaimable",
"nr_slab_unreclaimable",
"nr_isolated_anon",
"nr_isolated_file",
"workingset_nodes",
"workingset_refault_anon",
"workingset_refault_file",
"workingset_activate_anon",
"workingset_activate_file",
"workingset_restore_anon",
"workingset_restore_file",
"workingset_nodereclaim",
"nr_anon_pages",
"nr_mapped",
"nr_file_pages",
"nr_dirty",
"nr_writeback",
"nr_writeback_temp",
"nr_shmem",
"nr_shmem_hugepages",
"nr_shmem_pmdmapped",
"nr_file_hugepages",
"nr_file_pmdmapped",
"nr_anon_transparent_hugepages",
"nr_vmscan_write",
"nr_vmscan_immediate_reclaim",
"nr_dirtied",
"nr_written",
"nr_throttled_written",
"nr_kernel_misc_reclaimable",
"nr_foll_pin_acquired",
"nr_foll_pin_released",
"nr_kernel_stack",
#if IS_ENABLED(CONFIG_SHADOW_CALL_STACK)
"nr_shadow_call_stack",
#endif
"nr_page_table_pages",
"nr_sec_page_table_pages",
#ifdef CONFIG_SWAP
"nr_swapcached",
#endif
#ifdef CONFIG_NUMA_BALANCING
"pgpromote_success",
"pgpromote_candidate",
#endif
/* enum writeback_stat_item counters */
"nr_dirty_threshold",
"nr_dirty_background_threshold",
#if defined(CONFIG_VM_EVENT_COUNTERS) || defined(CONFIG_MEMCG)
/* enum vm_event_item counters */
"pgpgin",
"pgpgout",
"pswpin",
"pswpout",
TEXTS_FOR_ZONES("pgalloc")
TEXTS_FOR_ZONES("allocstall")
TEXTS_FOR_ZONES("pgskip")
"pgfree",
"pgactivate",
"pgdeactivate",
"pglazyfree",
"pgfault",
"pgmajfault",
"pglazyfreed",
"pgrefill",
"pgreuse",
"pgsteal_kswapd",
"pgsteal_direct",
"pgsteal_khugepaged",
"pgdemote_kswapd",
"pgdemote_direct",
"pgdemote_khugepaged",
"pgscan_kswapd",
"pgscan_direct",
"pgscan_khugepaged",
"pgscan_direct_throttle",
"pgscan_anon",
"pgscan_file",
"pgsteal_anon",
"pgsteal_file",
#ifdef CONFIG_NUMA
"zone_reclaim_failed",
#endif
"pginodesteal",
"slabs_scanned",
"kswapd_inodesteal",
"kswapd_low_wmark_hit_quickly",
"kswapd_high_wmark_hit_quickly",
"pageoutrun",
"pgrotated",
"drop_pagecache",
"drop_slab",
"oom_kill",
#ifdef CONFIG_NUMA_BALANCING
"numa_pte_updates",
"numa_huge_pte_updates",
"numa_hint_faults",
"numa_hint_faults_local",
"numa_pages_migrated",
#endif
#ifdef CONFIG_MIGRATION
"pgmigrate_success",
"pgmigrate_fail",
"thp_migration_success",
"thp_migration_fail",
"thp_migration_split",
#endif
#ifdef CONFIG_COMPACTION
"compact_migrate_scanned",
"compact_free_scanned",
"compact_isolated",
"compact_stall",
"compact_fail",
"compact_success",
"compact_daemon_wake",
"compact_daemon_migrate_scanned",
"compact_daemon_free_scanned",
#endif
#ifdef CONFIG_HUGETLB_PAGE
"htlb_buddy_alloc_success",
"htlb_buddy_alloc_fail",
#endif
#ifdef CONFIG_CMA
"cma_alloc_success",
"cma_alloc_fail",
#endif
"unevictable_pgs_culled",
"unevictable_pgs_scanned",
"unevictable_pgs_rescued",
"unevictable_pgs_mlocked",
"unevictable_pgs_munlocked",
"unevictable_pgs_cleared",
"unevictable_pgs_stranded",
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
"thp_fault_alloc",
"thp_fault_fallback",
"thp_fault_fallback_charge",
"thp_collapse_alloc",
"thp_collapse_alloc_failed",
"thp_file_alloc",
"thp_file_fallback",
"thp_file_fallback_charge",
"thp_file_mapped",
"thp_split_page",
"thp_split_page_failed",
"thp_deferred_split_page",
"thp_split_pmd",
"thp_scan_exceed_none_pte",
"thp_scan_exceed_swap_pte",
"thp_scan_exceed_share_pte",
#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
"thp_split_pud",
#endif
"thp_zero_page_alloc",
"thp_zero_page_alloc_failed",
"thp_swpout",
"thp_swpout_fallback",
#endif
#ifdef CONFIG_MEMORY_BALLOON
"balloon_inflate",
"balloon_deflate",
#ifdef CONFIG_BALLOON_COMPACTION
"balloon_migrate",
#endif
#endif /* CONFIG_MEMORY_BALLOON */
#ifdef CONFIG_DEBUG_TLBFLUSH
"nr_tlb_remote_flush",
"nr_tlb_remote_flush_received",
"nr_tlb_local_flush_all",
"nr_tlb_local_flush_one",
#endif /* CONFIG_DEBUG_TLBFLUSH */
#ifdef CONFIG_SWAP
"swap_ra",
"swap_ra_hit",
#ifdef CONFIG_KSM
"ksm_swpin_copy",
#endif
#endif
#ifdef CONFIG_KSM
"cow_ksm",
#endif
#ifdef CONFIG_ZSWAP
"zswpin",
"zswpout",
#endif
#ifdef CONFIG_X86
"direct_map_level2_splits",
"direct_map_level3_splits",
#endif
#ifdef CONFIG_PER_VMA_LOCK_STATS
"vma_lock_success",
"vma_lock_abort",
"vma_lock_retry",
"vma_lock_miss",
#endif
#endif /* CONFIG_VM_EVENT_COUNTERS || CONFIG_MEMCG */
};
#endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA || CONFIG_MEMCG */
#if (defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)) || \
defined(CONFIG_PROC_FS)
static void *frag_start(struct seq_file *m, loff_t *pos)
{
pg_data_t *pgdat;
loff_t node = *pos;
for (pgdat = first_online_pgdat();
pgdat && node;
pgdat = next_online_pgdat(pgdat))
--node;
return pgdat;
}
static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
{
pg_data_t *pgdat = (pg_data_t *)arg;
(*pos)++;
return next_online_pgdat(pgdat);
}
static void frag_stop(struct seq_file *m, void *arg)
{
}
/*
* Walk zones in a node and print using a callback.
* If @assert_populated is true, only use callback for zones that are populated.
*/
static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
bool assert_populated, bool nolock,
void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
{
struct zone *zone;
struct zone *node_zones = pgdat->node_zones;
unsigned long flags;
for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
if (assert_populated && !populated_zone(zone))
continue;
if (!nolock)
spin_lock_irqsave(&zone->lock, flags);
print(m, pgdat, zone);
if (!nolock)
spin_unlock_irqrestore(&zone->lock, flags);
}
}
#endif
#ifdef CONFIG_PROC_FS
static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
struct zone *zone)
{
int order;
seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
for (order = 0; order <= MAX_ORDER; ++order)
/*
* Access to nr_free is lockless as nr_free is used only for
* printing purposes. Use data_race to avoid KCSAN warning.
*/
seq_printf(m, "%6lu ", data_race(zone->free_area[order].nr_free));
seq_putc(m, '\n');
}
/*
* This walks the free areas for each zone.
*/
static int frag_show(struct seq_file *m, void *arg)
{
pg_data_t *pgdat = (pg_data_t *)arg;
walk_zones_in_node(m, pgdat, true, false, frag_show_print);
return 0;
}
static void pagetypeinfo_showfree_print(struct seq_file *m,
pg_data_t *pgdat, struct zone *zone)
{
int order, mtype;
for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
seq_printf(m, "Node %4d, zone %8s, type %12s ",
pgdat->node_id,
zone->name,
migratetype_names[mtype]);
for (order = 0; order <= MAX_ORDER; ++order) {
unsigned long freecount = 0;
struct free_area *area;
struct list_head *curr;
bool overflow = false;
area = &(zone->free_area[order]);
list_for_each(curr, &area->free_list[mtype]) {
/*
* Cap the free_list iteration because it might
* be really large and we are under a spinlock
* so a long time spent here could trigger a
* hard lockup detector. Anyway this is a
* debugging tool so knowing there is a handful
* of pages of this order should be more than
* sufficient.
*/
if (++freecount >= 100000) {
overflow = true;
break;
}
}
seq_printf(m, "%s%6lu ", overflow ? ">" : "", freecount);
spin_unlock_irq(&zone->lock);
cond_resched();
spin_lock_irq(&zone->lock);
}
seq_putc(m, '\n');
}
}
/* Print out the free pages at each order for each migatetype */
static void pagetypeinfo_showfree(struct seq_file *m, void *arg)
{
int order;
pg_data_t *pgdat = (pg_data_t *)arg;
/* Print header */
seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
for (order = 0; order <= MAX_ORDER; ++order)
seq_printf(m, "%6d ", order);
seq_putc(m, '\n');
walk_zones_in_node(m, pgdat, true, false, pagetypeinfo_showfree_print);
}
static void pagetypeinfo_showblockcount_print(struct seq_file *m,
pg_data_t *pgdat, struct zone *zone)
{
int mtype;
unsigned long pfn;
unsigned long start_pfn = zone->zone_start_pfn;
unsigned long end_pfn = zone_end_pfn(zone);
unsigned long count[MIGRATE_TYPES] = { 0, };
for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
struct page *page;
page = pfn_to_online_page(pfn);
if (!page)
continue;
if (page_zone(page) != zone)
continue;
mtype = get_pageblock_migratetype(page);
if (mtype < MIGRATE_TYPES)
count[mtype]++;
}
/* Print counts */
seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
seq_printf(m, "%12lu ", count[mtype]);
seq_putc(m, '\n');
}
/* Print out the number of pageblocks for each migratetype */
static void pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
{
int mtype;
pg_data_t *pgdat = (pg_data_t *)arg;
seq_printf(m, "\n%-23s", "Number of blocks type ");
for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
seq_printf(m, "%12s ", migratetype_names[mtype]);
seq_putc(m, '\n');
walk_zones_in_node(m, pgdat, true, false,
pagetypeinfo_showblockcount_print);
}
/*
* Print out the number of pageblocks for each migratetype that contain pages
* of other types. This gives an indication of how well fallbacks are being
* contained by rmqueue_fallback(). It requires information from PAGE_OWNER
* to determine what is going on
*/
static void pagetypeinfo_showmixedcount(struct seq_file *m, pg_data_t *pgdat)
{
#ifdef CONFIG_PAGE_OWNER
int mtype;
if (!static_branch_unlikely(&page_owner_inited))
return;
drain_all_pages(NULL);
seq_printf(m, "\n%-23s", "Number of mixed blocks ");
for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
seq_printf(m, "%12s ", migratetype_names[mtype]);
seq_putc(m, '\n');
walk_zones_in_node(m, pgdat, true, true,
pagetypeinfo_showmixedcount_print);
#endif /* CONFIG_PAGE_OWNER */
}
/*
* This prints out statistics in relation to grouping pages by mobility.
* It is expensive to collect so do not constantly read the file.
*/
static int pagetypeinfo_show(struct seq_file *m, void *arg)
{
pg_data_t *pgdat = (pg_data_t *)arg;
/* check memoryless node */
if (!node_state(pgdat->node_id, N_MEMORY))
return 0;
seq_printf(m, "Page block order: %d\n", pageblock_order);
seq_printf(m, "Pages per block: %lu\n", pageblock_nr_pages);
seq_putc(m, '\n');
pagetypeinfo_showfree(m, pgdat);
pagetypeinfo_showblockcount(m, pgdat);
pagetypeinfo_showmixedcount(m, pgdat);
return 0;
}
static const struct seq_operations fragmentation_op = {
.start = frag_start,
.next = frag_next,
.stop = frag_stop,
.show = frag_show,
};
static const struct seq_operations pagetypeinfo_op = {
.start = frag_start,
.next = frag_next,
.stop = frag_stop,
.show = pagetypeinfo_show,
};
static bool is_zone_first_populated(pg_data_t *pgdat, struct zone *zone)
{
int zid;
for (zid = 0; zid < MAX_NR_ZONES; zid++) {
struct zone *compare = &pgdat->node_zones[zid];
if (populated_zone(compare))
return zone == compare;
}
return false;
}
static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
struct zone *zone)
{
int i;
seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
if (is_zone_first_populated(pgdat, zone)) {
seq_printf(m, "\n per-node stats");
for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
unsigned long pages = node_page_state_pages(pgdat, i);
if (vmstat_item_print_in_thp(i))
pages /= HPAGE_PMD_NR;
seq_printf(m, "\n %-12s %lu", node_stat_name(i),
pages);
}
}
seq_printf(m,
"\n pages free %lu"
"\n boost %lu"
"\n min %lu"
"\n low %lu"
"\n high %lu"
"\n spanned %lu"
"\n present %lu"
"\n managed %lu"
"\n cma %lu",
zone_page_state(zone, NR_FREE_PAGES),
zone->watermark_boost,
min_wmark_pages(zone),
low_wmark_pages(zone),
high_wmark_pages(zone),
zone->spanned_pages,
zone->present_pages,
zone_managed_pages(zone),
zone_cma_pages(zone));
seq_printf(m,
"\n protection: (%ld",
zone->lowmem_reserve[0]);
for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
seq_printf(m, ", %ld", zone->lowmem_reserve[i]);
seq_putc(m, ')');
/* If unpopulated, no other information is useful */
if (!populated_zone(zone)) {
seq_putc(m, '\n');
return;
}
for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
seq_printf(m, "\n %-12s %lu", zone_stat_name(i),
zone_page_state(zone, i));
#ifdef CONFIG_NUMA
for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++)
seq_printf(m, "\n %-12s %lu", numa_stat_name(i),
zone_numa_event_state(zone, i));
#endif
seq_printf(m, "\n pagesets");
for_each_online_cpu(i) {
struct per_cpu_pages *pcp;
struct per_cpu_zonestat __maybe_unused *pzstats;
pcp = per_cpu_ptr(zone->per_cpu_pageset, i);
seq_printf(m,
"\n cpu: %i"
"\n count: %i"
"\n high: %i"
"\n batch: %i",
i,
pcp->count,
pcp->high,
pcp->batch);
#ifdef CONFIG_SMP
pzstats = per_cpu_ptr(zone->per_cpu_zonestats, i);
seq_printf(m, "\n vm stats threshold: %d",
pzstats->stat_threshold);
#endif
}
seq_printf(m,
"\n node_unreclaimable: %u"
"\n start_pfn: %lu",
pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES,
zone->zone_start_pfn);
seq_putc(m, '\n');
}
/*
* Output information about zones in @pgdat. All zones are printed regardless
* of whether they are populated or not: lowmem_reserve_ratio operates on the
* set of all zones and userspace would not be aware of such zones if they are
* suppressed here (zoneinfo displays the effect of lowmem_reserve_ratio).
*/
static int zoneinfo_show(struct seq_file *m, void *arg)
{
pg_data_t *pgdat = (pg_data_t *)arg;
walk_zones_in_node(m, pgdat, false, false, zoneinfo_show_print);
return 0;
}
static const struct seq_operations zoneinfo_op = {
.start = frag_start, /* iterate over all zones. The same as in
* fragmentation. */
.next = frag_next,
.stop = frag_stop,
.show = zoneinfo_show,
};
#define NR_VMSTAT_ITEMS (NR_VM_ZONE_STAT_ITEMS + \
NR_VM_NUMA_EVENT_ITEMS + \
NR_VM_NODE_STAT_ITEMS + \
NR_VM_WRITEBACK_STAT_ITEMS + \
(IS_ENABLED(CONFIG_VM_EVENT_COUNTERS) ? \
NR_VM_EVENT_ITEMS : 0))
static void *vmstat_start(struct seq_file *m, loff_t *pos)
{
unsigned long *v;
int i;
if (*pos >= NR_VMSTAT_ITEMS)
return NULL;
BUILD_BUG_ON(ARRAY_SIZE(vmstat_text) < NR_VMSTAT_ITEMS);
fold_vm_numa_events();
v = kmalloc_array(NR_VMSTAT_ITEMS, sizeof(unsigned long), GFP_KERNEL);
m->private = v;
if (!v)
return ERR_PTR(-ENOMEM);
for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
v[i] = global_zone_page_state(i);
v += NR_VM_ZONE_STAT_ITEMS;
#ifdef CONFIG_NUMA
for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++)
v[i] = global_numa_event_state(i);
v += NR_VM_NUMA_EVENT_ITEMS;
#endif
for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
v[i] = global_node_page_state_pages(i);
if (vmstat_item_print_in_thp(i))
v[i] /= HPAGE_PMD_NR;
}
v += NR_VM_NODE_STAT_ITEMS;
global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
v + NR_DIRTY_THRESHOLD);
v += NR_VM_WRITEBACK_STAT_ITEMS;
#ifdef CONFIG_VM_EVENT_COUNTERS
all_vm_events(v);
v[PGPGIN] /= 2; /* sectors -> kbytes */
v[PGPGOUT] /= 2;
#endif
return (unsigned long *)m->private + *pos;
}
static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
{
(*pos)++;
if (*pos >= NR_VMSTAT_ITEMS)
return NULL;
return (unsigned long *)m->private + *pos;
}
static int vmstat_show(struct seq_file *m, void *arg)
{
unsigned long *l = arg;
unsigned long off = l - (unsigned long *)m->private;
seq_puts(m, vmstat_text[off]);
seq_put_decimal_ull(m, " ", *l);
seq_putc(m, '\n');
if (off == NR_VMSTAT_ITEMS - 1) {
/*
* We've come to the end - add any deprecated counters to avoid
* breaking userspace which might depend on them being present.
*/
seq_puts(m, "nr_unstable 0\n");
}
return 0;
}
static void vmstat_stop(struct seq_file *m, void *arg)
{
kfree(m->private);
m->private = NULL;
}
static const struct seq_operations vmstat_op = {
.start = vmstat_start,
.next = vmstat_next,
.stop = vmstat_stop,
.show = vmstat_show,
};
#endif /* CONFIG_PROC_FS */
#ifdef CONFIG_SMP
static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
int sysctl_stat_interval __read_mostly = HZ;
#ifdef CONFIG_PROC_FS
static void refresh_vm_stats(struct work_struct *work)
{
refresh_cpu_vm_stats(true);
}
int vmstat_refresh(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
long val;
int err;
int i;
/*
* The regular update, every sysctl_stat_interval, may come later
* than expected: leaving a significant amount in per_cpu buckets.
* This is particularly misleading when checking a quantity of HUGE
* pages, immediately after running a test. /proc/sys/vm/stat_refresh,
* which can equally be echo'ed to or cat'ted from (by root),
* can be used to update the stats just before reading them.
*
* Oh, and since global_zone_page_state() etc. are so careful to hide
* transiently negative values, report an error here if any of
* the stats is negative, so we know to go looking for imbalance.
*/
err = schedule_on_each_cpu(refresh_vm_stats);
if (err)
return err;
for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
/*
* Skip checking stats known to go negative occasionally.
*/
switch (i) {
case NR_ZONE_WRITE_PENDING:
case NR_FREE_CMA_PAGES:
continue;
}
val = atomic_long_read(&vm_zone_stat[i]);
if (val < 0) {
pr_warn("%s: %s %ld\n",
__func__, zone_stat_name(i), val);
}
}
for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
/*
* Skip checking stats known to go negative occasionally.
*/
switch (i) {
case NR_WRITEBACK:
continue;
}
val = atomic_long_read(&vm_node_stat[i]);
if (val < 0) {
pr_warn("%s: %s %ld\n",
__func__, node_stat_name(i), val);
}
}
if (write)
*ppos += *lenp;
else
*lenp = 0;
return 0;
}
#endif /* CONFIG_PROC_FS */
static void vmstat_update(struct work_struct *w)
{
if (refresh_cpu_vm_stats(true)) {
/*
* Counters were updated so we expect more updates
* to occur in the future. Keep on running the
* update worker thread.
*/
queue_delayed_work_on(smp_processor_id(), mm_percpu_wq,
this_cpu_ptr(&vmstat_work),
round_jiffies_relative(sysctl_stat_interval));
}
}
/*
* Check if the diffs for a certain cpu indicate that
* an update is needed.
*/
static bool need_update(int cpu)
{
pg_data_t *last_pgdat = NULL;
struct zone *zone;
for_each_populated_zone(zone) {
struct per_cpu_zonestat *pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
struct per_cpu_nodestat *n;
/*
* The fast way of checking if there are any vmstat diffs.
*/
if (memchr_inv(pzstats->vm_stat_diff, 0, sizeof(pzstats->vm_stat_diff)))
return true;
if (last_pgdat == zone->zone_pgdat)
continue;
last_pgdat = zone->zone_pgdat;
n = per_cpu_ptr(zone->zone_pgdat->per_cpu_nodestats, cpu);
if (memchr_inv(n->vm_node_stat_diff, 0, sizeof(n->vm_node_stat_diff)))
return true;
}
return false;
}
/*
* Switch off vmstat processing and then fold all the remaining differentials
* until the diffs stay at zero. The function is used by NOHZ and can only be
* invoked when tick processing is not active.
*/
void quiet_vmstat(void)
{
if (system_state != SYSTEM_RUNNING)
return;
if (!delayed_work_pending(this_cpu_ptr(&vmstat_work)))
return;
if (!need_update(smp_processor_id()))
return;
/*
* Just refresh counters and do not care about the pending delayed
* vmstat_update. It doesn't fire that often to matter and canceling
* it would be too expensive from this path.
* vmstat_shepherd will take care about that for us.
*/
refresh_cpu_vm_stats(false);
}
/*
* Shepherd worker thread that checks the
* differentials of processors that have their worker
* threads for vm statistics updates disabled because of
* inactivity.
*/
static void vmstat_shepherd(struct work_struct *w);
static DECLARE_DEFERRABLE_WORK(shepherd, vmstat_shepherd);
static void vmstat_shepherd(struct work_struct *w)
{
int cpu;
cpus_read_lock();
/* Check processors whose vmstat worker threads have been disabled */
for_each_online_cpu(cpu) {
struct delayed_work *dw = &per_cpu(vmstat_work, cpu);
if (!delayed_work_pending(dw) && need_update(cpu))
queue_delayed_work_on(cpu, mm_percpu_wq, dw, 0);
cond_resched();
}
cpus_read_unlock();
schedule_delayed_work(&shepherd,
round_jiffies_relative(sysctl_stat_interval));
}
static void __init start_shepherd_timer(void)
{
int cpu;
for_each_possible_cpu(cpu)
INIT_DEFERRABLE_WORK(per_cpu_ptr(&vmstat_work, cpu),
vmstat_update);
schedule_delayed_work(&shepherd,
round_jiffies_relative(sysctl_stat_interval));
}
static void __init init_cpu_node_state(void)
{
int node;
for_each_online_node(node) {
if (!cpumask_empty(cpumask_of_node(node)))
node_set_state(node, N_CPU);
}
}
static int vmstat_cpu_online(unsigned int cpu)
{
refresh_zone_stat_thresholds();
if (!node_state(cpu_to_node(cpu), N_CPU)) {
node_set_state(cpu_to_node(cpu), N_CPU);
}
return 0;
}
static int vmstat_cpu_down_prep(unsigned int cpu)
{
cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
return 0;
}
static int vmstat_cpu_dead(unsigned int cpu)
{
const struct cpumask *node_cpus;
int node;
node = cpu_to_node(cpu);
refresh_zone_stat_thresholds();
node_cpus = cpumask_of_node(node);
if (!cpumask_empty(node_cpus))
return 0;
node_clear_state(node, N_CPU);
return 0;
}
#endif
struct workqueue_struct *mm_percpu_wq;
void __init init_mm_internals(void)
{
int ret __maybe_unused;
mm_percpu_wq = alloc_workqueue("mm_percpu_wq", WQ_MEM_RECLAIM, 0);
#ifdef CONFIG_SMP
ret = cpuhp_setup_state_nocalls(CPUHP_MM_VMSTAT_DEAD, "mm/vmstat:dead",
NULL, vmstat_cpu_dead);
if (ret < 0)
pr_err("vmstat: failed to register 'dead' hotplug state\n");
ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "mm/vmstat:online",
vmstat_cpu_online,
vmstat_cpu_down_prep);
if (ret < 0)
pr_err("vmstat: failed to register 'online' hotplug state\n");
cpus_read_lock();
init_cpu_node_state();
cpus_read_unlock();
start_shepherd_timer();
#endif
#ifdef CONFIG_PROC_FS
proc_create_seq("buddyinfo", 0444, NULL, &fragmentation_op);
proc_create_seq("pagetypeinfo", 0400, NULL, &pagetypeinfo_op);
proc_create_seq("vmstat", 0444, NULL, &vmstat_op);
proc_create_seq("zoneinfo", 0444, NULL, &zoneinfo_op);
#endif
}
#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)
/*
* Return an index indicating how much of the available free memory is
* unusable for an allocation of the requested size.
*/
static int unusable_free_index(unsigned int order,
struct contig_page_info *info)
{
/* No free memory is interpreted as all free memory is unusable */
if (info->free_pages == 0)
return 1000;
/*
* Index should be a value between 0 and 1. Return a value to 3
* decimal places.
*
* 0 => no fragmentation
* 1 => high fragmentation
*/
return div_u64((info->free_pages - (info->free_blocks_suitable << order)) * 1000ULL, info->free_pages);
}
static void unusable_show_print(struct seq_file *m,
pg_data_t *pgdat, struct zone *zone)
{
unsigned int order;
int index;
struct contig_page_info info;
seq_printf(m, "Node %d, zone %8s ",
pgdat->node_id,
zone->name);
for (order = 0; order <= MAX_ORDER; ++order) {
fill_contig_page_info(zone, order, &info);
index = unusable_free_index(order, &info);
seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
}
seq_putc(m, '\n');
}
/*
* Display unusable free space index
*
* The unusable free space index measures how much of the available free
* memory cannot be used to satisfy an allocation of a given size and is a
* value between 0 and 1. The higher the value, the more of free memory is
* unusable and by implication, the worse the external fragmentation is. This
* can be expressed as a percentage by multiplying by 100.
*/
static int unusable_show(struct seq_file *m, void *arg)
{
pg_data_t *pgdat = (pg_data_t *)arg;
/* check memoryless node */
if (!node_state(pgdat->node_id, N_MEMORY))
return 0;
walk_zones_in_node(m, pgdat, true, false, unusable_show_print);
return 0;
}
static const struct seq_operations unusable_sops = {
.start = frag_start,
.next = frag_next,
.stop = frag_stop,
.show = unusable_show,
};
DEFINE_SEQ_ATTRIBUTE(unusable);
static void extfrag_show_print(struct seq_file *m,
pg_data_t *pgdat, struct zone *zone)
{
unsigned int order;
int index;
/* Alloc on stack as interrupts are disabled for zone walk */
struct contig_page_info info;
seq_printf(m, "Node %d, zone %8s ",
pgdat->node_id,
zone->name);
for (order = 0; order <= MAX_ORDER; ++order) {
fill_contig_page_info(zone, order, &info);
index = __fragmentation_index(order, &info);
seq_printf(m, "%2d.%03d ", index / 1000, index % 1000);
}
seq_putc(m, '\n');
}
/*
* Display fragmentation index for orders that allocations would fail for
*/
static int extfrag_show(struct seq_file *m, void *arg)
{
pg_data_t *pgdat = (pg_data_t *)arg;
walk_zones_in_node(m, pgdat, true, false, extfrag_show_print);
return 0;
}
static const struct seq_operations extfrag_sops = {
.start = frag_start,
.next = frag_next,
.stop = frag_stop,
.show = extfrag_show,
};
DEFINE_SEQ_ATTRIBUTE(extfrag);
static int __init extfrag_debug_init(void)
{
struct dentry *extfrag_debug_root;
extfrag_debug_root = debugfs_create_dir("extfrag", NULL);
debugfs_create_file("unusable_index", 0444, extfrag_debug_root, NULL,
&unusable_fops);
debugfs_create_file("extfrag_index", 0444, extfrag_debug_root, NULL,
&extfrag_fops);
return 0;
}
module_init(extfrag_debug_init);
#endif
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