// 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 * Copyright (C) 2008-2014 Christoph Lameter */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #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) { int item, cpu; for (item = 0; item < NR_VM_NUMA_STAT_ITEMS; item++) { atomic_long_set(&zone->vm_numa_stat[item], 0); for_each_online_cpu(cpu) per_cpu_ptr(zone->pageset, cpu)->vm_numa_stat_diff[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_STAT_ITEMS; item++) atomic_long_set(&vm_numa_stat[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 __user *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) { get_online_cpus(); sum_vm_events(ret); put_online_cpus(); } 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_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 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->pageset, 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->pageset, 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_pageset __percpu *pcp = zone->pageset; s8 __percpu *p = pcp->vm_stat_diff + item; long x; long t; x = delta + __this_cpu_read(*p); t = __this_cpu_read(pcp->stat_threshold); if (unlikely(x > t || x < -t)) { zone_page_state_add(x, zone, item); x = 0; } __this_cpu_write(*p, x); } 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; x = delta + __this_cpu_read(*p); t = __this_cpu_read(pcp->stat_threshold); if (unlikely(x > t || x < -t)) { node_page_state_add(x, pgdat, item); x = 0; } __this_cpu_write(*p, x); } 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_pageset __percpu *pcp = zone->pageset; s8 __percpu *p = pcp->vm_stat_diff + item; s8 v, t; 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); } } 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; 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); } } 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_pageset __percpu *pcp = zone->pageset; s8 __percpu *p = pcp->vm_stat_diff + item; s8 v, t; 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); } } 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; 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); } } 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_pageset __percpu *pcp = zone->pageset; 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 (n > t || 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; 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 (n > t || 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. */ #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; 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; } #endif /* CONFIG_NUMA */ /* * 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, }; #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; for_each_populated_zone(zone) { struct per_cpu_pageset __percpu *p = zone->pageset; for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) { int v; v = this_cpu_xchg(p->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(p->expire, 3); #endif } } #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(); /* * 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(p->expire) || !__this_cpu_read(p->pcp.count)) continue; /* * We never drain zones local to this processor. */ if (zone_to_nid(zone) == numa_node_id()) { __this_cpu_write(p->expire, 0); continue; } if (__this_cpu_dec_return(p->expire)) continue; if (__this_cpu_read(p->pcp.count)) { drain_zone_pages(zone, this_cpu_ptr(&p->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; } } } #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; } /* * 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, }; #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) { struct per_cpu_pageset *p; p = per_cpu_ptr(zone->pageset, cpu); for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) if (p->vm_stat_diff[i]) { int v; v = p->vm_stat_diff[i]; p->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_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) { 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; } } #ifdef CONFIG_NUMA fold_diff(global_zone_diff, global_numa_diff, global_node_diff); #else fold_diff(global_zone_diff, global_node_diff); #endif } /* * this is only called if !populated_zone(zone), which implies no other users of * pset->vm_stat_diff[] exsist. */ void drain_zonestat(struct zone *zone, struct per_cpu_pageset *pset) { int i; for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) if (pset->vm_stat_diff[i]) { int v = pset->vm_stat_diff[i]; pset->vm_stat_diff[i] = 0; 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 * 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. 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, 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; } #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 */ blocks = 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); } /* 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) #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 #define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \ TEXT_FOR_HIGHMEM(xx) xx "_movable", const char * const vmstat_text[] = { /* enum zone_stat_item countes */ "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_page_table_pages", "nr_kernel_stack", "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 /* Node-based 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", "workingset_activate", "workingset_restore", "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_unstable", "nr_vmscan_write", "nr_vmscan_immediate_reclaim", "nr_dirtied", "nr_written", "nr_kernel_misc_reclaimable", /* enum writeback_stat_item counters */ "nr_dirty_threshold", "nr_dirty_background_threshold", #ifdef CONFIG_VM_EVENT_COUNTERS /* 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", "pgsteal_kswapd", "pgsteal_direct", "pgscan_kswapd", "pgscan_direct", "pgscan_direct_throttle", #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", #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 "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_collapse_alloc", "thp_collapse_alloc_failed", "thp_file_alloc", "thp_file_mapped", "thp_split_page", "thp_split_page_failed", "thp_deferred_split_page", "thp_split_pmd", #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_DEBUG_VM_VMACACHE "vmacache_find_calls", "vmacache_find_hits", #endif #ifdef CONFIG_SWAP "swap_ra", "swap_ra_hit", #endif #endif /* CONFIG_VM_EVENTS_COUNTERS */ }; #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) { 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) seq_printf(m, "%6lu ", 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; area = &(zone->free_area[order]); list_for_each(curr, &area->free_list[mtype]) freecount++; seq_printf(m, "%6lu ", freecount); } seq_putc(m, '\n'); } } /* Print out the free pages at each order for each migatetype */ static int 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); return 0; } 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; /* Watch for unexpected holes punched in the memmap */ if (!memmap_valid_within(pfn, page, zone)) 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 int 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); return 0; } /* * 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++) { seq_printf(m, "\n %-12s %lu", vmstat_text[i + NR_VM_ZONE_STAT_ITEMS + NR_VM_NUMA_STAT_ITEMS], node_page_state(pgdat, i)); } } seq_printf(m, "\n pages free %lu" "\n min %lu" "\n low %lu" "\n high %lu" "\n spanned %lu" "\n present %lu" "\n managed %lu", zone_page_state(zone, NR_FREE_PAGES), min_wmark_pages(zone), low_wmark_pages(zone), high_wmark_pages(zone), zone->spanned_pages, zone->present_pages, zone_managed_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", 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; pageset = per_cpu_ptr(zone->pageset, i); seq_printf(m, "\n cpu: %i" "\n count: %i" "\n high: %i" "\n batch: %i", i, pageset->pcp.count, pageset->pcp.high, pageset->pcp.batch); #ifdef CONFIG_SMP seq_printf(m, "\n vm stats threshold: %d", pageset->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, }; enum writeback_stat_item { NR_DIRTY_THRESHOLD, NR_DIRTY_BG_THRESHOLD, NR_VM_WRITEBACK_STAT_ITEMS, }; static void *vmstat_start(struct seq_file *m, loff_t *pos) { unsigned long *v; int i, stat_items_size; 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); #ifdef CONFIG_VM_EVENT_COUNTERS stat_items_size += sizeof(struct vm_event_state); #endif BUILD_BUG_ON(stat_items_size != ARRAY_SIZE(vmstat_text) * sizeof(unsigned long)); v = kmalloc(stat_items_size, 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_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; 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 >= ARRAY_SIZE(vmstat_text)) 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'); 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 __user *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++) { val = atomic_long_read(&vm_zone_stat[i]); if (val < 0) { pr_warn("%s: %s %ld\n", __func__, vmstat_text[i], val); 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) *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)); } } /* * 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. */ /* * Check if the diffs for a certain cpu indicate that * an update is needed. */ static bool need_update(int cpu) { struct zone *zone; for_each_populated_zone(zone) { 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. */ if (memchr_inv(p->vm_stat_diff, 0, NR_VM_ZONE_STAT_ITEMS * sizeof(p->vm_stat_diff[0]))) return true; #ifdef CONFIG_NUMA if (memchr_inv(p->vm_numa_stat_diff, 0, NR_VM_NUMA_STAT_ITEMS * sizeof(p->vm_numa_stat_diff[0]))) return true; #endif } 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; get_online_cpus(); /* 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); } put_online_cpus(); 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_weight(cpumask_of_node(node)) > 0) node_set_state(node, N_CPU); } } static int vmstat_cpu_online(unsigned int cpu) { refresh_zone_stat_thresholds(); 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_weight(node_cpus) > 0) 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"); get_online_cpus(); init_cpu_node_state(); put_online_cpus(); 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_op = { .start = frag_start, .next = frag_next, .stop = frag_stop, .show = unusable_show, }; static int unusable_open(struct inode *inode, struct file *file) { return seq_open(file, &unusable_op); } static const struct file_operations unusable_file_ops = { .open = unusable_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release, }; 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, "%d.%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_op = { .start = frag_start, .next = frag_next, .stop = frag_stop, .show = extfrag_show, }; static int extfrag_open(struct inode *inode, struct file *file) { return seq_open(file, &extfrag_op); } static const struct file_operations extfrag_file_ops = { .open = extfrag_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release, }; 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_file_ops); debugfs_create_file("extfrag_index", 0444, extfrag_debug_root, NULL, &extfrag_file_ops); return 0; } module_init(extfrag_debug_init); #endif