linux/mm/vmstat.c
Michael Rubin 79da826aee writeback: report dirty thresholds in /proc/vmstat
The kernel already exposes the user desired thresholds in /proc/sys/vm
with dirty_background_ratio and background_ratio.  But the kernel may
alter the number requested without giving the user any indication that is
the case.

Knowing the actual ratios the kernel is honoring can help app developers
understand how their buffered IO will be sent to the disk.

        $ grep threshold /proc/vmstat
        nr_dirty_threshold 409111
        nr_dirty_background_threshold 818223

Signed-off-by: Michael Rubin <mrubin@google.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:06 -07:00

1234 lines
29 KiB
C

/*
* 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>
*/
#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/vmstat.h>
#include <linux/sched.h>
#include <linux/math64.h>
#include <linux/writeback.h>
#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);
#ifdef CONFIG_HOTPLUG
/*
* 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_HOTPLUG */
#endif /* CONFIG_VM_EVENT_COUNTERS */
/*
* Manage combined zone based / global counters
*
* vm_stat contains the global counters
*/
atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS];
EXPORT_SYMBOL(vm_stat);
#ifdef CONFIG_SMP
static int calculate_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->present_pages >> (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.
*/
static void refresh_zone_stat_thresholds(void)
{
struct zone *zone;
int cpu;
int threshold;
for_each_populated_zone(zone) {
unsigned long max_drift, tolerate_drift;
threshold = calculate_threshold(zone);
for_each_online_cpu(cpu)
per_cpu_ptr(zone->pageset, cpu)->stat_threshold
= 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;
}
}
/*
* For use when we know that interrupts are disabled.
*/
void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
int delta)
{
struct per_cpu_pageset *pcp = this_cpu_ptr(zone->pageset);
s8 *p = pcp->vm_stat_diff + item;
long x;
x = delta + *p;
if (unlikely(x > pcp->stat_threshold || x < -pcp->stat_threshold)) {
zone_page_state_add(x, zone, item);
x = 0;
}
*p = x;
}
EXPORT_SYMBOL(__mod_zone_page_state);
/*
* For an unknown interrupt state
*/
void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
int 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);
/*
* 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 *pcp = this_cpu_ptr(zone->pageset);
s8 *p = pcp->vm_stat_diff + item;
(*p)++;
if (unlikely(*p > pcp->stat_threshold)) {
int overstep = pcp->stat_threshold / 2;
zone_page_state_add(*p + overstep, zone, item);
*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 __dec_zone_state(struct zone *zone, enum zone_stat_item item)
{
struct per_cpu_pageset *pcp = this_cpu_ptr(zone->pageset);
s8 *p = pcp->vm_stat_diff + item;
(*p)--;
if (unlikely(*p < - pcp->stat_threshold)) {
int overstep = pcp->stat_threshold / 2;
zone_page_state_add(*p - overstep, zone, item);
*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 inc_zone_state(struct zone *zone, enum zone_stat_item item)
{
unsigned long flags;
local_irq_save(flags);
__inc_zone_state(zone, item);
local_irq_restore(flags);
}
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);
/*
* Update the zone counters for one cpu.
*
* The cpu specified must be either the current cpu or a processor that
* is not online. If it is the current cpu then the execution thread must
* be pinned to 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.
*/
void refresh_cpu_vm_stats(int cpu)
{
struct zone *zone;
int i;
int global_diff[NR_VM_ZONE_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]) {
unsigned long flags;
int v;
local_irq_save(flags);
v = p->vm_stat_diff[i];
p->vm_stat_diff[i] = 0;
local_irq_restore(flags);
atomic_long_add(v, &zone->vm_stat[i]);
global_diff[i] += v;
#ifdef CONFIG_NUMA
/* 3 seconds idle till flush */
p->expire = 3;
#endif
}
cond_resched();
#ifdef CONFIG_NUMA
/*
* 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 (!p->expire || !p->pcp.count)
continue;
/*
* We never drain zones local to this processor.
*/
if (zone_to_nid(zone) == numa_node_id()) {
p->expire = 0;
continue;
}
p->expire--;
if (p->expire)
continue;
if (p->pcp.count)
drain_zone_pages(zone, &p->pcp);
#endif
}
for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
if (global_diff[i])
atomic_long_add(global_diff[i], &vm_stat[i]);
}
#endif
#ifdef CONFIG_NUMA
/*
* zonelist = the list of zones passed to the allocator
* z = the zone from which the allocation occurred.
*
* Must be called with interrupts disabled.
*/
void zone_statistics(struct zone *preferred_zone, struct zone *z)
{
if (z->zone_pgdat == preferred_zone->zone_pgdat) {
__inc_zone_state(z, NUMA_HIT);
} else {
__inc_zone_state(z, NUMA_MISS);
__inc_zone_state(preferred_zone, NUMA_FOREIGN);
}
if (z->node == numa_node_id())
__inc_zone_state(z, NUMA_LOCAL);
else
__inc_zone_state(z, NUMA_OTHER);
}
#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 (!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_COMPACTION)
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
static char * const migratetype_names[MIGRATE_TYPES] = {
"Unmovable",
"Reclaimable",
"Movable",
"Reserve",
"Isolate",
};
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 all the zones in a node and print using a callback */
static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
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 (!populated_zone(zone))
continue;
spin_lock_irqsave(&zone->lock, flags);
print(m, pgdat, zone);
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, 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, 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 = start_pfn + zone->spanned_pages;
unsigned long count[MIGRATE_TYPES] = { 0, };
for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
struct page *page;
if (!pfn_valid(pfn))
continue;
page = pfn_to_page(pfn);
/* Watch for unexpected holes punched in the memmap */
if (!memmap_valid_within(pfn, 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 free pages at each order 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, pagetypeinfo_showblockcount_print);
return 0;
}
/*
* 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_HIGH_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);
return 0;
}
static const struct seq_operations fragmentation_op = {
.start = frag_start,
.next = frag_next,
.stop = frag_stop,
.show = frag_show,
};
static int fragmentation_open(struct inode *inode, struct file *file)
{
return seq_open(file, &fragmentation_op);
}
static const struct file_operations fragmentation_file_operations = {
.open = fragmentation_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static const struct seq_operations pagetypeinfo_op = {
.start = frag_start,
.next = frag_next,
.stop = frag_stop,
.show = pagetypeinfo_show,
};
static int pagetypeinfo_open(struct inode *inode, struct file *file)
{
return seq_open(file, &pagetypeinfo_op);
}
static const struct file_operations pagetypeinfo_file_ops = {
.open = pagetypeinfo_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
#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",
static const char * const vmstat_text[] = {
/* Zoned VM counters */
"nr_free_pages",
"nr_inactive_anon",
"nr_active_anon",
"nr_inactive_file",
"nr_active_file",
"nr_unevictable",
"nr_mlock",
"nr_anon_pages",
"nr_mapped",
"nr_file_pages",
"nr_dirty",
"nr_writeback",
"nr_slab_reclaimable",
"nr_slab_unreclaimable",
"nr_page_table_pages",
"nr_kernel_stack",
"nr_unstable",
"nr_bounce",
"nr_vmscan_write",
"nr_writeback_temp",
"nr_isolated_anon",
"nr_isolated_file",
"nr_shmem",
"nr_dirtied",
"nr_written",
"nr_dirty_threshold",
"nr_dirty_background_threshold",
#ifdef CONFIG_NUMA
"numa_hit",
"numa_miss",
"numa_foreign",
"numa_interleave",
"numa_local",
"numa_other",
#endif
#ifdef CONFIG_VM_EVENT_COUNTERS
"pgpgin",
"pgpgout",
"pswpin",
"pswpout",
TEXTS_FOR_ZONES("pgalloc")
"pgfree",
"pgactivate",
"pgdeactivate",
"pgfault",
"pgmajfault",
TEXTS_FOR_ZONES("pgrefill")
TEXTS_FOR_ZONES("pgsteal")
TEXTS_FOR_ZONES("pgscan_kswapd")
TEXTS_FOR_ZONES("pgscan_direct")
#ifdef CONFIG_NUMA
"zone_reclaim_failed",
#endif
"pginodesteal",
"slabs_scanned",
"kswapd_steal",
"kswapd_inodesteal",
"kswapd_low_wmark_hit_quickly",
"kswapd_high_wmark_hit_quickly",
"kswapd_skip_congestion_wait",
"pageoutrun",
"allocstall",
"pgrotated",
#ifdef CONFIG_COMPACTION
"compact_blocks_moved",
"compact_pages_moved",
"compact_pagemigrate_failed",
"compact_stall",
"compact_fail",
"compact_success",
#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",
"unevictable_pgs_mlockfreed",
#endif
};
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);
seq_printf(m,
"\n pages free %lu"
"\n min %lu"
"\n low %lu"
"\n high %lu"
"\n scanned %lu"
"\n spanned %lu"
"\n present %lu",
zone_nr_free_pages(zone),
min_wmark_pages(zone),
low_wmark_pages(zone),
high_wmark_pages(zone),
zone->pages_scanned,
zone->spanned_pages,
zone->present_pages);
for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
seq_printf(m, "\n %-12s %lu", vmstat_text[i],
zone_page_state(zone, i));
seq_printf(m,
"\n protection: (%lu",
zone->lowmem_reserve[0]);
for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
seq_printf(m, ", %lu", zone->lowmem_reserve[i]);
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 all_unreclaimable: %u"
"\n start_pfn: %lu"
"\n inactive_ratio: %u",
zone->all_unreclaimable,
zone->zone_start_pfn,
zone->inactive_ratio);
seq_putc(m, '\n');
}
/*
* Output information about zones in @pgdat.
*/
static int zoneinfo_show(struct seq_file *m, void *arg)
{
pg_data_t *pgdat = (pg_data_t *)arg;
walk_zones_in_node(m, pgdat, 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,
};
static int zoneinfo_open(struct inode *inode, struct file *file)
{
return seq_open(file, &zoneinfo_op);
}
static const struct file_operations proc_zoneinfo_file_operations = {
.open = zoneinfo_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
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_WRITEBACK_STAT_ITEMS * sizeof(unsigned long);
#ifdef CONFIG_VM_EVENT_COUNTERS
stat_items_size += sizeof(struct vm_event_state);
#endif
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_page_state(i);
v += NR_VM_ZONE_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 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_printf(m, "%s %lu\n", vmstat_text[off], *l);
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,
};
static int vmstat_open(struct inode *inode, struct file *file)
{
return seq_open(file, &vmstat_op);
}
static const struct file_operations proc_vmstat_file_operations = {
.open = vmstat_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
#endif /* CONFIG_PROC_FS */
#ifdef CONFIG_SMP
static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
int sysctl_stat_interval __read_mostly = HZ;
static void vmstat_update(struct work_struct *w)
{
refresh_cpu_vm_stats(smp_processor_id());
schedule_delayed_work(&__get_cpu_var(vmstat_work),
round_jiffies_relative(sysctl_stat_interval));
}
static void __cpuinit start_cpu_timer(int cpu)
{
struct delayed_work *work = &per_cpu(vmstat_work, cpu);
INIT_DELAYED_WORK_DEFERRABLE(work, vmstat_update);
schedule_delayed_work_on(cpu, work, __round_jiffies_relative(HZ, cpu));
}
/*
* Use the cpu notifier to insure that the thresholds are recalculated
* when necessary.
*/
static int __cpuinit vmstat_cpuup_callback(struct notifier_block *nfb,
unsigned long action,
void *hcpu)
{
long cpu = (long)hcpu;
switch (action) {
case CPU_ONLINE:
case CPU_ONLINE_FROZEN:
refresh_zone_stat_thresholds();
start_cpu_timer(cpu);
node_set_state(cpu_to_node(cpu), N_CPU);
break;
case CPU_DOWN_PREPARE:
case CPU_DOWN_PREPARE_FROZEN:
cancel_rearming_delayed_work(&per_cpu(vmstat_work, cpu));
per_cpu(vmstat_work, cpu).work.func = NULL;
break;
case CPU_DOWN_FAILED:
case CPU_DOWN_FAILED_FROZEN:
start_cpu_timer(cpu);
break;
case CPU_DEAD:
case CPU_DEAD_FROZEN:
refresh_zone_stat_thresholds();
break;
default:
break;
}
return NOTIFY_OK;
}
static struct notifier_block __cpuinitdata vmstat_notifier =
{ &vmstat_cpuup_callback, NULL, 0 };
#endif
static int __init setup_vmstat(void)
{
#ifdef CONFIG_SMP
int cpu;
refresh_zone_stat_thresholds();
register_cpu_notifier(&vmstat_notifier);
for_each_online_cpu(cpu)
start_cpu_timer(cpu);
#endif
#ifdef CONFIG_PROC_FS
proc_create("buddyinfo", S_IRUGO, NULL, &fragmentation_file_operations);
proc_create("pagetypeinfo", S_IRUGO, NULL, &pagetypeinfo_file_ops);
proc_create("vmstat", S_IRUGO, NULL, &proc_vmstat_file_operations);
proc_create("zoneinfo", S_IRUGO, NULL, &proc_zoneinfo_file_operations);
#endif
return 0;
}
module_init(setup_vmstat)
#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)
#include <linux/debugfs.h>
static struct dentry *extfrag_debug_root;
/*
* 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_HIGH_MEMORY))
return 0;
walk_zones_in_node(m, pgdat, 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, 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)
{
extfrag_debug_root = debugfs_create_dir("extfrag", NULL);
if (!extfrag_debug_root)
return -ENOMEM;
if (!debugfs_create_file("unusable_index", 0444,
extfrag_debug_root, NULL, &unusable_file_ops))
return -ENOMEM;
if (!debugfs_create_file("extfrag_index", 0444,
extfrag_debug_root, NULL, &extfrag_file_ops))
return -ENOMEM;
return 0;
}
module_init(extfrag_debug_init);
#endif