Release 4.11 mm/compaction.c
/*
* linux/mm/compaction.c
*
* Memory compaction for the reduction of external fragmentation. Note that
* this heavily depends upon page migration to do all the real heavy
* lifting
*
* Copyright IBM Corp. 2007-2010 Mel Gorman <mel@csn.ul.ie>
*/
#include <linux/cpu.h>
#include <linux/swap.h>
#include <linux/migrate.h>
#include <linux/compaction.h>
#include <linux/mm_inline.h>
#include <linux/sched/signal.h>
#include <linux/backing-dev.h>
#include <linux/sysctl.h>
#include <linux/sysfs.h>
#include <linux/page-isolation.h>
#include <linux/kasan.h>
#include <linux/kthread.h>
#include <linux/freezer.h>
#include <linux/page_owner.h>
#include "internal.h"
#ifdef CONFIG_COMPACTION
static inline void count_compact_event(enum vm_event_item item)
{
count_vm_event(item);
}
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static inline void count_compact_events(enum vm_event_item item, long delta)
{
count_vm_events(item, delta);
}
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#else
#define count_compact_event(item) do { } while (0)
#define count_compact_events(item, delta) do { } while (0)
#endif
#if defined CONFIG_COMPACTION || defined CONFIG_CMA
#define CREATE_TRACE_POINTS
#include <trace/events/compaction.h>
#define block_start_pfn(pfn, order) round_down(pfn, 1UL << (order))
#define block_end_pfn(pfn, order) ALIGN((pfn) + 1, 1UL << (order))
#define pageblock_start_pfn(pfn) block_start_pfn(pfn, pageblock_order)
#define pageblock_end_pfn(pfn) block_end_pfn(pfn, pageblock_order)
static unsigned long release_freepages(struct list_head *freelist)
{
struct page *page, *next;
unsigned long high_pfn = 0;
list_for_each_entry_safe(page, next, freelist, lru) {
unsigned long pfn = page_to_pfn(page);
list_del(&page->lru);
__free_page(page);
if (pfn > high_pfn)
high_pfn = pfn;
}
return high_pfn;
}
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static void map_pages(struct list_head *list)
{
unsigned int i, order, nr_pages;
struct page *page, *next;
LIST_HEAD(tmp_list);
list_for_each_entry_safe(page, next, list, lru) {
list_del(&page->lru);
order = page_private(page);
nr_pages = 1 << order;
post_alloc_hook(page, order, __GFP_MOVABLE);
if (order)
split_page(page, order);
for (i = 0; i < nr_pages; i++) {
list_add(&page->lru, &tmp_list);
page++;
}
}
list_splice(&tmp_list, list);
}
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| Total | 122 | 100.00% | 5 | 100.00% |
static inline bool migrate_async_suitable(int migratetype)
{
return is_migrate_cma(migratetype) || migratetype == MIGRATE_MOVABLE;
}
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#ifdef CONFIG_COMPACTION
int PageMovable(struct page *page)
{
struct address_space *mapping;
VM_BUG_ON_PAGE(!PageLocked(page), page);
if (!__PageMovable(page))
return 0;
mapping = page_mapping(page);
if (mapping && mapping->a_ops && mapping->a_ops->isolate_page)
return 1;
return 0;
}
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EXPORT_SYMBOL(PageMovable);
void __SetPageMovable(struct page *page, struct address_space *mapping)
{
VM_BUG_ON_PAGE(!PageLocked(page), page);
VM_BUG_ON_PAGE((unsigned long)mapping & PAGE_MAPPING_MOVABLE, page);
page->mapping = (void *)((unsigned long)mapping | PAGE_MAPPING_MOVABLE);
}
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EXPORT_SYMBOL(__SetPageMovable);
void __ClearPageMovable(struct page *page)
{
VM_BUG_ON_PAGE(!PageLocked(page), page);
VM_BUG_ON_PAGE(!PageMovable(page), page);
/*
* Clear registered address_space val with keeping PAGE_MAPPING_MOVABLE
* flag so that VM can catch up released page by driver after isolation.
* With it, VM migration doesn't try to put it back.
*/
page->mapping = (void *)((unsigned long)page->mapping &
PAGE_MAPPING_MOVABLE);
}
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EXPORT_SYMBOL(__ClearPageMovable);
/* Do not skip compaction more than 64 times */
#define COMPACT_MAX_DEFER_SHIFT 6
/*
* Compaction is deferred when compaction fails to result in a page
* allocation success. 1 << compact_defer_limit compactions are skipped up
* to a limit of 1 << COMPACT_MAX_DEFER_SHIFT
*/
void defer_compaction(struct zone *zone, int order)
{
zone->compact_considered = 0;
zone->compact_defer_shift++;
if (order < zone->compact_order_failed)
zone->compact_order_failed = order;
if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT)
zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT;
trace_mm_compaction_defer_compaction(zone, order);
}
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/* Returns true if compaction should be skipped this time */
bool compaction_deferred(struct zone *zone, int order)
{
unsigned long defer_limit = 1UL << zone->compact_defer_shift;
if (order < zone->compact_order_failed)
return false;
/* Avoid possible overflow */
if (++zone->compact_considered > defer_limit)
zone->compact_considered = defer_limit;
if (zone->compact_considered >= defer_limit)
return false;
trace_mm_compaction_deferred(zone, order);
return true;
}
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/*
* Update defer tracking counters after successful compaction of given order,
* which means an allocation either succeeded (alloc_success == true) or is
* expected to succeed.
*/
void compaction_defer_reset(struct zone *zone, int order,
bool alloc_success)
{
if (alloc_success) {
zone->compact_considered = 0;
zone->compact_defer_shift = 0;
}
if (order >= zone->compact_order_failed)
zone->compact_order_failed = order + 1;
trace_mm_compaction_defer_reset(zone, order);
}
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/* Returns true if restarting compaction after many failures */
bool compaction_restarting(struct zone *zone, int order)
{
if (order < zone->compact_order_failed)
return false;
return zone->compact_defer_shift == COMPACT_MAX_DEFER_SHIFT &&
zone->compact_considered >= 1UL << zone->compact_defer_shift;
}
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/* Returns true if the pageblock should be scanned for pages to isolate. */
static inline bool isolation_suitable(struct compact_control *cc,
struct page *page)
{
if (cc->ignore_skip_hint)
return true;
return !get_pageblock_skip(page);
}
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static void reset_cached_positions(struct zone *zone)
{
zone->compact_cached_migrate_pfn[0] = zone->zone_start_pfn;
zone->compact_cached_migrate_pfn[1] = zone->zone_start_pfn;
zone->compact_cached_free_pfn =
pageblock_start_pfn(zone_end_pfn(zone) - 1);
}
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| Total | 47 | 100.00% | 3 | 100.00% |
/*
* This function is called to clear all cached information on pageblocks that
* should be skipped for page isolation when the migrate and free page scanner
* meet.
*/
static void __reset_isolation_suitable(struct zone *zone)
{
unsigned long start_pfn = zone->zone_start_pfn;
unsigned long end_pfn = zone_end_pfn(zone);
unsigned long pfn;
zone->compact_blockskip_flush = false;
/* Walk the zone and mark every pageblock as suitable for isolation */
for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
struct page *page;
cond_resched();
if (!pfn_valid(pfn))
continue;
page = pfn_to_page(pfn);
if (zone != page_zone(page))
continue;
clear_pageblock_skip(page);
}
reset_cached_positions(zone);
}
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| Cody P Schafer | 3 | 3.03% | 1 | 25.00% |
| Total | 99 | 100.00% | 4 | 100.00% |
void reset_isolation_suitable(pg_data_t *pgdat)
{
int zoneid;
for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) {
struct zone *zone = &pgdat->node_zones[zoneid];
if (!populated_zone(zone))
continue;
/* Only flush if a full compaction finished recently */
if (zone->compact_blockskip_flush)
__reset_isolation_suitable(zone);
}
}
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| Mel Gorman | 61 | 100.00% | 1 | 100.00% |
| Total | 61 | 100.00% | 1 | 100.00% |
/*
* If no pages were isolated then mark this pageblock to be skipped in the
* future. The information is later cleared by __reset_isolation_suitable().
*/
static void update_pageblock_skip(struct compact_control *cc,
struct page *page, unsigned long nr_isolated,
bool migrate_scanner)
{
struct zone *zone = cc->zone;
unsigned long pfn;
if (cc->ignore_skip_hint)
return;
if (!page)
return;
if (nr_isolated)
return;
set_pageblock_skip(page);
pfn = page_to_pfn(page);
/* Update where async and sync compaction should restart */
if (migrate_scanner) {
if (pfn > zone->compact_cached_migrate_pfn[0])
zone->compact_cached_migrate_pfn[0] = pfn;
if (cc->mode != MIGRATE_ASYNC &&
pfn > zone->compact_cached_migrate_pfn[1])
zone->compact_cached_migrate_pfn[1] = pfn;
} else {
if (pfn < zone->compact_cached_free_pfn)
zone->compact_cached_free_pfn = pfn;
}
}
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| Mel Gorman | 87 | 63.97% | 2 | 40.00% |
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| JoonSoo Kim | 7 | 5.15% | 1 | 20.00% |
| Total | 136 | 100.00% | 5 | 100.00% |
#else
static inline bool isolation_suitable(struct compact_control *cc,
struct page *page)
{
return true;
}
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static void update_pageblock_skip(struct compact_control *cc,
struct page *page, unsigned long nr_isolated,
bool migrate_scanner)
{
}
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| Total | 22 | 100.00% | 2 | 100.00% |
#endif /* CONFIG_COMPACTION */
/*
* Compaction requires the taking of some coarse locks that are potentially
* very heavily contended. For async compaction, back out if the lock cannot
* be taken immediately. For sync compaction, spin on the lock if needed.
*
* Returns true if the lock is held
* Returns false if the lock is not held and compaction should abort
*/
static bool compact_trylock_irqsave(spinlock_t *lock, unsigned long *flags,
struct compact_control *cc)
{
if (cc->mode == MIGRATE_ASYNC) {
if (!spin_trylock_irqsave(lock, *flags)) {
cc->contended = true;
return false;
}
} else {
spin_lock_irqsave(lock, *flags);
}
return true;
}
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| Vlastimil Babka | 54 | 81.82% | 3 | 75.00% |
| Mel Gorman | 12 | 18.18% | 1 | 25.00% |
| Total | 66 | 100.00% | 4 | 100.00% |
/*
* Compaction requires the taking of some coarse locks that are potentially
* very heavily contended. The lock should be periodically unlocked to avoid
* having disabled IRQs for a long time, even when there is nobody waiting on
* the lock. It might also be that allowing the IRQs will result in
* need_resched() becoming true. If scheduling is needed, async compaction
* aborts. Sync compaction schedules.
* Either compaction type will also abort if a fatal signal is pending.
* In either case if the lock was locked, it is dropped and not regained.
*
* Returns true if compaction should abort due to fatal signal pending, or
* async compaction due to need_resched()
* Returns false when compaction can continue (sync compaction might have
* scheduled)
*/
static bool compact_unlock_should_abort(spinlock_t *lock,
unsigned long flags, bool *locked, struct compact_control *cc)
{
if (*locked) {
spin_unlock_irqrestore(lock, flags);
*locked = false;
}
if (fatal_signal_pending(current)) {
cc->contended = true;
return true;
}
if (need_resched()) {
if (cc->mode == MIGRATE_ASYNC) {
cc->contended = true;
return true;
}
cond_resched();
}
return false;
}
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| Person | Tokens | Prop | Commits | CommitProp |
| Mel Gorman | 58 | 63.04% | 1 | 25.00% |
| Vlastimil Babka | 31 | 33.70% | 2 | 50.00% |
| David Rientjes | 3 | 3.26% | 1 | 25.00% |
| Total | 92 | 100.00% | 4 | 100.00% |
/*
* Aside from avoiding lock contention, compaction also periodically checks
* need_resched() and either schedules in sync compaction or aborts async
* compaction. This is similar to what compact_unlock_should_abort() does, but
* is used where no lock is concerned.
*
* Returns false when no scheduling was needed, or sync compaction scheduled.
* Returns true when async compaction should abort.
*/
static inline bool compact_should_abort(struct compact_control *cc)
{
/* async compaction aborts if contended */
if (need_resched()) {
if (cc->mode == MIGRATE_ASYNC) {
cc->contended = true;
return true;
}
cond_resched();
}
return false;
}
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| Person | Tokens | Prop | Commits | CommitProp |
| Vlastimil Babka | 45 | 100.00% | 2 | 100.00% |
| Total | 45 | 100.00% | 2 | 100.00% |
/*
* Isolate free pages onto a private freelist. If @strict is true, will abort
* returning 0 on any invalid PFNs or non-free pages inside of the pageblock
* (even though it may still end up isolating some pages).
*/
static unsigned long isolate_freepages_block(struct compact_control *cc,
unsigned long *start_pfn,
unsigned long end_pfn,
struct list_head *freelist,
bool strict)
{
int nr_scanned = 0, total_isolated = 0;
struct page *cursor, *valid_page = NULL;
unsigned long flags = 0;
bool locked = false;
unsigned long blockpfn = *start_pfn;
unsigned int order;
cursor = pfn_to_page(blockpfn);
/* Isolate free pages. */
for (; blockpfn < end_pfn; blockpfn++, cursor++) {
int isolated;
struct page *page = cursor;
/*
* Periodically drop the lock (if held) regardless of its
* contention, to give chance to IRQs. Abort if fatal signal
* pending or async compaction detects need_resched()
*/
if (!(blockpfn % SWAP_CLUSTER_MAX)
&& compact_unlock_should_abort(&cc->zone->lock, flags,
&locked, cc))
break;
nr_scanned++;
if (!pfn_valid_within(blockpfn))
goto isolate_fail;
if (!valid_page)
valid_page = page;
/*
* For compound pages such as THP and hugetlbfs, we can save
* potentially a lot of iterations if we skip them at once.
* The check is racy, but we can consider only valid values
* and the only danger is skipping too much.
*/
if (PageCompound(page)) {
unsigned int comp_order = compound_order(page);
if (likely(comp_order < MAX_ORDER)) {
blockpfn += (1UL << comp_order) - 1;
cursor += (1UL << comp_order) - 1;
}
goto isolate_fail;
}
if (!PageBuddy(page))
goto isolate_fail;
/*
* If we already hold the lock, we can skip some rechecking.
* Note that if we hold the lock now, checked_pageblock was
* already set in some previous iteration (or strict is true),
* so it is correct to skip the suitable migration target
* recheck as well.
*/
if (!locked) {
/*
* The zone lock must be held to isolate freepages.
* Unfortunately this is a very coarse lock and can be
* heavily contended if there are parallel allocations
* or parallel compactions. For async compaction do not
* spin on the lock and we acquire the lock as late as
* possible.
*/
locked = compact_trylock_irqsave(&cc->zone->lock,
&flags, cc);
if (!locked)
break;
/* Recheck this is a buddy page under lock */
if (!PageBuddy(page))
goto isolate_fail;
}
/* Found a free page, will break it into order-0 pages */
order = page_order(page);
isolated = __isolate_free_page(page, order);
if (!isolated)
break;
set_page_private(page, order);
total_isolated += isolated;
cc->nr_freepages += isolated;
list_add_tail(&page->lru, freelist);
if (!strict && cc->nr_migratepages <= cc->nr_freepages) {
blockpfn += isolated;
break;
}
/* Advance to the end of split page */
blockpfn += isolated - 1;
cursor += isolated - 1;
continue;
isolate_fail:
if (strict)
break;
else
continue;
}
if (locked)
spin_unlock_irqrestore(&cc->zone->lock, flags);
/*
* There is a tiny chance that we have read bogus compound_order(),
* so be careful to not go outside of the pageblock.
*/
if (unlikely(blockpfn > end_pfn))
blockpfn = end_pfn;
trace_mm_compaction_isolate_freepages(*start_pfn, blockpfn,
nr_scanned, total_isolated);
/* Record how far we have got within the block */
*start_pfn = blockpfn;
/*
* If strict isolation is requested by CMA then check that all the
* pages requested were isolated. If there were any failures, 0 is
* returned and CMA will fail.
*/
if (strict && blockpfn < end_pfn)
total_isolated = 0;
/* Update the pageblock-skip if the whole pageblock was scanned */
if (blockpfn == end_pfn)
update_pageblock_skip(cc, valid_page, total_isolated, false);
cc->total_free_scanned += nr_scanned;
if (total_isolated)
count_compact_events(COMPACTISOLATED, total_isolated);
return total_isolated;
}
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| Person | Tokens | Prop | Commits | CommitProp |
| Mel Gorman | 213 | 46.92% | 6 | 31.58% |
| Vlastimil Babka | 117 | 25.77% | 4 | 21.05% |
| JoonSoo Kim | 53 | 11.67% | 3 | 15.79% |
| David Rientjes | 33 | 7.27% | 2 | 10.53% |
| Laura Abbott | 22 | 4.85% | 1 | 5.26% |
| Michal Nazarewicz | 13 | 2.86% | 1 | 5.26% |
| Xiubo Li | 2 | 0.44% | 1 | 5.26% |
| MinChan Kim | 1 | 0.22% | 1 | 5.26% |
| Total | 454 | 100.00% | 19 | 100.00% |
/**
* isolate_freepages_range() - isolate free pages.
* @start_pfn: The first PFN to start isolating.
* @end_pfn: The one-past-last PFN.
*
* Non-free pages, invalid PFNs, or zone boundaries within the
* [start_pfn, end_pfn) range are considered errors, cause function to
* undo its actions and return zero.
*
* Otherwise, function returns one-past-the-last PFN of isolated page
* (which may be greater then end_pfn if end fell in a middle of
* a free page).
*/
unsigned long
isolate_freepages_range(struct compact_control *cc,
unsigned long start_pfn, unsigned long end_pfn)
{
unsigned long isolated, pfn, block_start_pfn, block_end_pfn;
LIST_HEAD(freelist);
pfn = start_pfn;
block_start_pfn = pageblock_start_pfn(pfn);
if (block_start_pfn < cc->zone->zone_start_pfn)
block_start_pfn = cc->zone->zone_start_pfn;
block_end_pfn = pageblock_end_pfn(pfn);
for (; pfn < end_pfn; pfn += isolated,
block_start_pfn = block_end_pfn,
block_end_pfn += pageblock_nr_pages) {
/* Protect pfn from changing by isolate_freepages_block */
unsigned long isolate_start_pfn = pfn;
block_end_pfn = min(block_end_pfn, end_pfn);
/*
* pfn could pass the block_end_pfn if isolated freepage
* is more than pageblock order. In this case, we adjust
* scanning range to right one.
*/
if (pfn >= block_end_pfn) {
block_start_pfn = pageblock_start_pfn(pfn);
block_end_pfn = pageblock_end_pfn(pfn);
block_end_pfn = min(block_end_pfn, end_pfn);
}
if (!pageblock_pfn_to_page(block_start_pfn,
block_end_pfn, cc->zone))
break;
isolated = isolate_freepages_block(cc, &isolate_start_pfn,
block_end_pfn, &freelist, true);
/*
* In strict mode, isolate_freepages_block() returns 0 if
* there are any holes in the block (ie. invalid PFNs or
* non-free pages).
*/
if (!isolated)
break;
/*
* If we managed to isolate pages, it is always (1 << n) *
* pageblock_nr_pages for some non-negative n. (Max order
* page may span two pageblocks).
*/
}
/* __isolate_free_page() does not map the pages */
map_pages(&freelist);
if (pfn < end_pfn) {
/* Loop terminated early, cleanup. */
release_freepages(&freelist);
return 0;
}
/* We don't use freelists for anything. */
return pfn;
}
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| Michal Nazarewicz | 96 | 46.15% | 2 | 18.18% |
| JoonSoo Kim | 58 | 27.88% | 3 | 27.27% |
| Vlastimil Babka | 43 | 20.67% | 3 | 27.27% |
| Mel Gorman | 11 | 5.29% | 3 | 27.27% |
| Total | 208 | 100.00% | 11 | 100.00% |
/* Similar to reclaim, but different enough that they don't share logic */
static bool too_many_isolated(struct zone *zone)
{
unsigned long active, inactive, isolated;
inactive = node_page_state(zone->zone_pgdat, NR_INACTIVE_FILE) +
node_page_state(zone->zone_pgdat, NR_INACTIVE_ANON);
active = node_page_state(zone->zone_pgdat, NR_ACTIVE_FILE) +
node_page_state(zone->zone_pgdat, NR_ACTIVE_ANON);
isolated = node_page_state(zone->zone_pgdat, NR_ISOLATED_FILE) +
node_page_state(zone->zone_pgdat, NR_ISOLATED_ANON);
return isolated > (inactive + active) / 2;
}
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| Mel Gorman | 68 | 75.56% | 2 | 66.67% |
| MinChan Kim | 22 | 24.44% | 1 | 33.33% |
| Total | 90 | 100.00% | 3 | 100.00% |
/**
* isolate_migratepages_block() - isolate all migrate-able pages within
* a single pageblock
* @cc: Compaction control structure.
* @low_pfn: The first PFN to isolate
* @end_pfn: The one-past-the-last PFN to isolate, within same pageblock
* @isolate_mode: Isolation mode to be used.
*
* Isolate all pages that can be migrated from the range specified by
* [low_pfn, end_pfn). The range is expected to be within same pageblock.
* Returns zero if there is a fatal signal pending, otherwise PFN of the
* first page that was not scanned (which may be both less, equal to or more
* than end_pfn).
*
* The pages are isolated on cc->migratepages list (not required to be empty),
* and cc->nr_migratepages is updated accordingly. The cc->migrate_pfn field
* is neither read nor updated.
*/
static unsigned long
isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
unsigned long end_pfn, isolate_mode_t isolate_mode)
{
struct zone *zone = cc->zone;
unsigned long nr_scanned = 0, nr_isolated = 0;
struct lruvec *lruvec;
unsigned long flags = 0;
bool locked = false;
struct page *page = NULL, *valid_page = NULL;
unsigned long start_pfn = low_pfn;
bool skip_on_failure = false;
unsigned long next_skip_pfn = 0;
/*
* Ensure that there are not too many pages isolated from the LRU
* list by either parallel reclaimers or compaction. If there are,
* delay for some time until fewer pages are isolated
*/
while (unlikely(too_many_isolated(zone))) {
/* async migration should just abort */
if (cc->mode == MIGRATE_ASYNC)
return 0;
congestion_wait(BLK_RW_ASYNC, HZ/10);
if (fatal_signal_pending(current))
return 0;
}
if (compact_should_abort(cc))
return 0;
if (cc->direct_compaction && (cc->mode == MIGRATE_ASYNC)) {
skip_on_failure = true;
next_skip_pfn = block_end_pfn(low_pfn, cc->order);
}
/* Time to isolate some pages for migration */
for (; low_pfn < end_pfn; low_pfn++) {
if (skip_on_failure && low_pfn >= next_skip_pfn) {
/*
* We have isolated all migration candidates in the
* previous order-aligned block, and did not skip it due
* to failure. We should migrate the pages now and
* hopefully succeed compaction.
*/
if (nr_isolated)
break;
/*
* We failed to isolate in the previous order-aligned
* block. Set the new boundary to the end of the
* current block. Note we can't simply increase
* next_skip_pfn by 1 << order, as low_pfn might have
* been incremented by a higher number due to skipping
* a compound or a high-order buddy page in the
* previous loop iteration.
*/
next_skip_pfn = block_end_pfn(low_pfn, cc->order);
}
/*
* Periodically drop the lock (if held) regardless of its
* contention, to give chance to IRQs. Abort async compaction
* if contended.
*/
if (!(low_pfn % SWAP_CLUSTER_MAX)
&& compact_unlock_should_abort(zone_lru_lock(zone), flags,
&locked, cc))
break;
if (!pfn_valid_within(low_pfn))
goto isolate_fail;
nr_scanned++;
page = pfn_to_page(low_pfn);
if (!valid_page)
valid_page = page;
/*
* Skip if free. We read page order here without zone lock
* which is generally unsafe, but the race window is small and
* the worst thing that can happen is that we skip some
* potential isolation targets.
*/
if (PageBuddy(page)) {
unsigned long freepage_order = page_order_unsafe(page);
/*
* Without lock, we cannot be sure that what we got is
* a valid page order. Consider only values in the
* valid order range to prevent low_pfn overflow.
*/
if (freepage_order > 0 && freepage_order < MAX_ORDER)
low_pfn += (1UL << freepage_order) - 1;
continue;
}
/*
* Regardless of being on LRU, compound pages such as THP and
* hugetlbfs are not to be compacted. We can potentially save
* a lot of iterations if we skip them at once. The check is
* racy, but we can consider only valid values and the only
* danger is skipping too much.
*/
if (PageCompound(page)) {
unsigned int comp_order = compound_order(page);
if (likely(comp_order < MAX_ORDER))
low_pfn += (1UL << comp_order) - 1;
goto isolate_fail;
}
/*
* Check may be lockless but that's ok as we recheck later.
* It's possible to migrate LRU and non-lru movable pages.
* Skip any other type of page
*/
if (!PageLRU(page)) {
/*
* __PageMovable can return false positive so we need
* to verify it under page_lock.
*/
if (unlikely(__PageMovable(page)) &&
!PageIsolated(page)) {
if (locked) {
spin_unlock_irqrestore(zone_lru_lock(zone),
flags);
locked = false;
}
if (!isolate_movable_page(page, isolate_mode))
goto isolate_success;
}
goto isolate_fail;
}
/*
* Migration will fail if an anonymous page is pinned in memory,
* so avoid taking lru_lock and isolating it unnecessarily in an
* admittedly racy check.
*/
if (!page_mapping(page) &&
page_count(page) > page_mapcount(page))
goto isolate_fail;
/*
* Only allow to migrate anonymous pages in GFP_NOFS context
* because those do not depend on fs locks.
*/
if (!(cc->gfp_mask & __GFP_FS) && page_mapping(page))
goto isolate_fail;
/* If we already hold the lock, we can skip some rechecking */
if (!locked) {
locked = compact_trylock_irqsave(zone_lru_lock(zone),
&flags, cc);
if (!locked)
break;
/* Recheck PageLRU and PageCompound under lock */
if (!PageLRU(page))
goto isolate_fail;
/*
* Page become compound since the non-locked check,
* and it's on LRU. It can only be a THP so the order
* is safe to read and it's 0 for tail pages.
*/
if (unlikely(PageCompound(page))) {
low_pfn += (1UL << compound_order(page)) - 1;
goto isolate_fail;
}
}
lruvec = mem_cgroup_page_lruvec(page, zone->zone_pgdat);
/* Try isolate the page */
if (__isolate_lru_page(page, isolate_mode) != 0)
goto isolate_fail;
VM_BUG_ON_PAGE(PageCompound(page), page);
/* Successfully isolated */
del_page_from_lru_list(page, lruvec, page_lru(page));
inc_node_page_state(page,
NR_ISOLATED_ANON + page_is_file_cache(page));
isolate_success:
list_add(&page->lru, &cc->migratepages);
cc->nr_migratepages++;
nr_isolated++;
/*
* Record where we could have freed pages by migration and not
* yet flushed them to buddy allocator.
* - this is the lowest page that was isolated and likely be
* then freed by migration.
*/
if (!cc->last_migrated_pfn)
cc->last_migrated_pfn = low_pfn;
/* Avoid isolating too much */
if (cc->nr_migratepages == COMPACT_CLUSTER_MAX) {
++low_pfn;
break;
}
continue;
isolate_fail:
if (!skip_on_failure)
continue;
/*
* We have isolated some pages, but then failed. Release them
* instead of migrating, as we cannot form the cc->order buddy
* page anyway.
*/
if (nr_isolated) {
if (locked) {
spin_unlock_irqrestore(zone_lru_lock(zone), flags);
locked = false;
}
putback_movable_pages(&cc->migratepages);
cc->nr_migratepages = 0;
cc->last_migrated_pfn = 0;
nr_isolated = 0;
}
if (low_pfn < next_skip_pfn) {
low_pfn = next_skip_pfn - 1;
/*
* The check near the loop beginning would have updated
* next_skip_pfn too, but this is a bit simpler.
*/
next_skip_pfn += 1UL << cc->order;
}
}
/*
* The PageBuddy() check could have potentially brought us outside
* the range to be scanned.
*/
if (unlikely(low_pfn > end_pfn))
low_pfn = end_pfn;
if (locked)
spin_unlock_irqrestore(zone_lru_lock(zone), flags);
/*
* Update the pageblock-skip information and cached scanner pfn,
* if the whole pageblock was scanned without isolating any page.
*/
if (low_pfn == end_pfn)
update_pageblock_skip(cc, valid_page, nr_isolated, true);
trace_mm_compaction_isolate_migratepages(start_pfn, low_pfn,
nr_scanned, nr_isolated);
cc->total_migrate_scanned += nr_scanned;
if (nr_isolated)
count_compact_events(COMPACTISOLATED, nr_isolated);
return low_pfn;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Vlastimil Babka | 287 | 35.79% | 8 | 19.51% |
| Mel Gorman | 259 | 32.29% | 11 | 26.83% |
| MinChan Kim | 76 | 9.48% | 3 | 7.32% |
| Andrea Arcangeli | 45 | 5.61% | 2 | 4.88% |
| David Rientjes | 35 | 4.36% | 5 | 12.20% |
| Michal Nazarewicz | 21 | 2.62% | 1 | 2.44% |
| Michal Hocko | 20 | 2.49% | 1 | 2.44% |
| JoonSoo Kim | 20 | 2.49% | 3 | 7.32% |
| Hugh Dickins | 15 | 1.87% | 1 | 2.44% |
| Lin Ming | 12 | 1.50% | 1 | 2.44% |
| Hillf Danton | 5 | 0.62% | 1 | 2.44% |
| Sasha Levin | 3 | 0.37% | 1 | 2.44% |
| Xiubo Li | 2 | 0.25% | 1 | 2.44% |
| Yisheng Xie | 1 | 0.12% | 1 | 2.44% |
| Rafael Aquini | 1 | 0.12% | 1 | 2.44% |
| Total | 802 | 100.00% | 41 | 100.00% |
/**
* isolate_migratepages_range() - isolate migrate-able pages in a PFN range
* @cc: Compaction control structure.
* @start_pfn: The first PFN to start isolating.
* @end_pfn: The one-past-last PFN.
*
* Returns zero if isolation fails fatally due to e.g. pending signal.
* Otherwise, function returns one-past-the-last PFN of isolated page
* (which may be greater than end_pfn if end fell in a middle of a THP page).
*/
unsigned long
isolate_migratepages_range(struct compact_control *cc, unsigned long start_pfn,
unsigned long end_pfn)
{
unsigned long pfn, block_start_pfn, block_end_pfn;
/* Scan block by block. First and last block may be incomplete */
pfn = start_pfn;
block_start_pfn = pageblock_start_pfn(pfn);
if (block_start_pfn < cc->zone->zone_start_pfn)
block_start_pfn = cc->zone->zone_start_pfn;
block_end_pfn = pageblock_end_pfn(pfn);
for (; pfn < end_pfn; pfn = block_end_pfn,
block_start_pfn = block_end_pfn,
block_end_pfn += pageblock_nr_pages) {
block_end_pfn = min(block_end_pfn, end_pfn);
if (!pageblock_pfn_to_page(block_start_pfn,
block_end_pfn, cc->zone))
continue;
pfn = isolate_migratepages_block(cc, pfn, block_end_pfn,
ISOLATE_UNEVICTABLE);
if (!pfn)
break;
if (cc->nr_migratepages == COMPACT_CLUSTER_MAX)
break;
}
return pfn;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Vlastimil Babka | 102 | 72.86% | 3 | 60.00% |
| JoonSoo Kim | 38 | 27.14% | 2 | 40.00% |
| Total | 140 | 100.00% | 5 | 100.00% |
#endif /* CONFIG_COMPACTION || CONFIG_CMA */
#ifdef CONFIG_COMPACTION
/* Returns true if the page is within a block suitable for migration to */
static bool suitable_migration_target(struct compact_control *cc,
struct page *page)
{
if (cc->ignore_block_suitable)
return true;
/* If the page is a large free page, then disallow migration */
if (PageBuddy(page)) {
/*
* We are checking page_order without zone->lock taken. But
* the only small danger is that we skip a potentially suitable
* pageblock, so it's not worth to check order for valid range.
*/
if (page_order_unsafe(page) >= pageblock_order)
return false;
}
/* If the block is MIGRATE_MOVABLE or MIGRATE_CMA, allow migration */
if (migrate_async_suitable(get_pageblock_migratetype(page)))
return true;
/* Otherwise skip the block */
return false;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Andrew Morton | 52 | 78.79% | 1 | 50.00% |
| Vlastimil Babka | 14 | 21.21% | 1 | 50.00% |
| Total | 66 | 100.00% | 2 | 100.00% |
/*
* Test whether the free scanner has reached the same or lower pageblock than
* the migration scanner, and compaction should thus terminate.
*/
static inline bool compact_scanners_met(struct compact_control *cc)
{
return (cc->free_pfn >> pageblock_order)
<= (cc->migrate_pfn >> pageblock_order);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Vlastimil Babka | 29 | 100.00% | 1 | 100.00% |
| Total | 29 | 100.00% | 1 | 100.00% |
/*
* Based on information in the current compact_control, find blocks
* suitable for isolating free pages from and then isolate them.
*/
static void isolate_freepages(struct compact_control *cc)
{
struct zone *zone = cc->zone;
struct page *page;
unsigned long block_start_pfn; /* start of current pageblock */
unsigned long isolate_start_pfn; /* exact pfn we start at */
unsigned long block_end_pfn; /* end of current pageblock */
unsigned long low_pfn; /* lowest pfn scanner is able to scan */
struct list_head *freelist = &cc->freepages;
/*
* Initialise the free scanner. The starting point is where we last
* successfully isolated from, zone-cached value, or the end of the
* zone when isolating for the first time. For looping we also need
* this pfn aligned down to the pageblock boundary, because we do
* block_start_pfn -= pageblock_nr_pages in the for loop.
* For ending point, take care when isolating in last pageblock of a
* a zone which ends in the middle of a pageblock.
* The low boundary is the end of the pageblock the migration scanner
* is using.
*/
isolate_start_pfn = cc->free_pfn;
block_start_pfn = pageblock_start_pfn(cc->free_pfn);
block_end_pfn = min(block_start_pfn + pageblock_nr_pages,
zone_end_pfn(zone));
low_pfn = pageblock_end_pfn(cc->migrate_pfn);
/*
* Isolate free pages until enough are available to migrate the
* pages on cc->migratepages. We stop searching if the migrate
* and free page scanners meet or enough free pages are isolated.
*/
for (; block_start_pfn >= low_pfn;
block_end_pfn = block_start_pfn,
block_start_pfn -= pageblock_nr_pages,
isolate_start_pfn = block_start_pfn) {
/*
* This can iterate a massively long zone without finding any
* suitable migration targets, so periodically check if we need
* to schedule, or even abort async compaction.
*/
if (!(block_start_pfn % (SWAP_CLUSTER_MAX * pageblock_nr_pages))
&& compact_should_abort(cc))
break;
page = pageblock_pfn_to_page(block_start_pfn, block_end_pfn,
zone);
if (!page)
continue;
/* Check the block is suitable for migration */
if (!suitable_migration_target(cc, page))
continue;
/* If isolation recently failed, do not retry */
if (!isolation_suitable(cc, page))
continue;
/* Found a block suitable for isolating free pages from. */
isolate_freepages_block(cc, &isolate_start_pfn, block_end_pfn,
freelist, false);
/*
* If we isolated enough freepages, or aborted due to lock
* contention, terminate.
*/
if ((cc->nr_freepages >= cc->nr_migratepages)
|| cc->contended) {
if (isolate_start_pfn >= block_end_pfn) {
/*
* Restart at previous pageblock if more
* freepages can be isolated next time.
*/
isolate_start_pfn =
block_start_pfn - pageblock_nr_pages;
}
break;
} else if (isolate_start_pfn < block_end_pfn) {
/*
* If isolation failed early, do not continue
* needlessly.
*/
break;
}
}
/* __isolate_free_page() does not map the pages */
map_pages(freelist);
/*
* Record where the free scanner will restart next time. Either we
* broke from the loop and set isolate_start_pfn based on the last
* call to isolate_freepages_block(), or we met the migration scanner
* and the loop terminated due to isolate_start_pfn < low_pfn
*/
cc->free_pfn = isolate_start_pfn;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Vlastimil Babka | 134 | 53.39% | 9 | 50.00% |
| Michal Nazarewicz | 86 | 34.26% | 2 | 11.11% |
| Mel Gorman | 16 | 6.37% | 4 | 22.22% |
| David Rientjes | 11 | 4.38% | 1 | 5.56% |
| Linus Torvalds | 3 | 1.20% | 1 | 5.56% |
| JoonSoo Kim | 1 | 0.40% | 1 | 5.56% |
| Total | 251 | 100.00% | 18 | 100.00% |
/*
* This is a migrate-callback that "allocates" freepages by taking pages
* from the isolated freelists in the block we are migrating to.
*/
static struct page *compaction_alloc(struct page *migratepage,
unsigned long data,
int **result)
{
struct compact_control *cc = (struct compact_control *)data;
struct page *freepage;
/*
* Isolate free pages if necessary, and if we are not aborting due to
* contention.
*/
if (list_empty(&cc->freepages)) {
if (!cc->contended)
isolate_freepages(cc);
if (list_empty(&cc->freepages))
return NULL;
}
freepage = list_entry(cc->freepages.next, struct page, lru);
list_del(&freepage->lru);
cc->nr_freepages--;
return freepage;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Mel Gorman | 101 | 92.66% | 1 | 50.00% |
| Vlastimil Babka | 8 | 7.34% | 1 | 50.00% |
| Total | 109 | 100.00% | 2 | 100.00% |
/*
* This is a migrate-callback that "frees" freepages back to the isolated
* freelist. All pages on the freelist are from the same zone, so there is no
* special handling needed for NUMA.
*/
static void compaction_free(struct page *page, unsigned long data)
{
struct compact_control *cc = (struct compact_control *)data;
list_add(&page->lru, &cc->freepages);
cc->nr_freepages++;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| David Rientjes | 45 | 100.00% | 1 | 100.00% |
| Total | 45 | 100.00% | 1 | 100.00% |
/* possible outcome of isolate_migratepages */
typedef enum {
ISOLATE_ABORT, /* Abort compaction now */
ISOLATE_NONE, /* No pages isolated, continue scanning */
ISOLATE_SUCCESS, /* Pages isolated, migrate */
}
isolate_migrate_t;
/*
* Allow userspace to control policy on scanning the unevictable LRU for
* compactable pages.
*/
int sysctl_compact_unevictable_allowed __read_mostly = 1;
/*
* Isolate all pages that can be migrated from the first suitable block,
* starting at the block pointed to by the migrate scanner pfn within
* compact_control.
*/
static isolate_migrate_t isolate_migratepages(struct zone *zone,
struct compact_control *cc)
{
unsigned long block_start_pfn;
unsigned long block_end_pfn;
unsigned long low_pfn;
struct page *page;
const isolate_mode_t isolate_mode =
(sysctl_compact_unevictable_allowed ? ISOLATE_UNEVICTABLE : 0) |
(cc->mode != MIGRATE_SYNC ? ISOLATE_ASYNC_MIGRATE : 0);
/*
* Start at where we last stopped, or beginning of the zone as
* initialized by compact_zone()
*/
low_pfn = cc->migrate_pfn;
block_start_pfn = pageblock_start_pfn(low_pfn);
if (block_start_pfn < zone->zone_start_pfn)
block_start_pfn = zone->zone_start_pfn;
/* Only scan within a pageblock boundary */
block_end_pfn = pageblock_end_pfn(low_pfn);
/*
* Iterate over whole pageblocks until we find the first suitable.
* Do not cross the free scanner.
*/
for (; block_end_pfn <= cc->free_pfn;
low_pfn = block_end_pfn,
block_start_pfn = block_end_pfn,
block_end_pfn += pageblock_nr_pages) {
/*
* This can potentially iterate a massively long zone with
* many pageblocks unsuitable, so periodically check if we
* need to schedule, or even abort async compaction.
*/
if (!(low_pfn % (SWAP_CLUSTER_MAX * pageblock_nr_pages))
&& compact_should_abort(cc))
break;
page = pageblock_pfn_to_page(block_start_pfn, block_end_pfn,
zone);
if (!page)
continue;
/* If isolation recently failed, do not retry */
if (!isolation_suitable(cc, page))
continue;
/*
* For async compaction, also only scan in MOVABLE blocks.
* Async compaction is optimistic to see if the minimum amount
* of work satisfies the allocation.
*/
if (cc->mode == MIGRATE_ASYNC &&
!migrate_async_suitable(get_pageblock_migratetype(page)))
continue;
/* Perform the isolation */
low_pfn = isolate_migratepages_block(cc, low_pfn,
block_end_pfn, isolate_mode);
if (!low_pfn || cc->contended)
return ISOLATE_ABORT;
/*
* Either we isolated something and proceed with migration. Or
* we failed and compact_zone should decide if we should
* continue or not.
*/
break;
}
/* Record where migration scanner will be restarted. */
cc->migrate_pfn = low_pfn;
return cc->nr_migratepages ? ISOLATE_SUCCESS : ISOLATE_NONE;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Vlastimil Babka | 114 | 49.78% | 4 | 40.00% |
| Michal Nazarewicz | 64 | 27.95% | 1 | 10.00% |
| JoonSoo Kim | 36 | 15.72% | 1 | 10.00% |
| Eric B Munson | 8 | 3.49% | 1 | 10.00% |
| Shaohua Li | 4 | 1.75% | 1 | 10.00% |
| Hugh Dickins | 2 | 0.87% | 1 | 10.00% |
| MinChan Kim | 1 | 0.44% | 1 | 10.00% |
| Total | 229 | 100.00% | 10 | 100.00% |
/*
* order == -1 is expected when compacting via
* /proc/sys/vm/compact_memory
*/
static inline bool is_via_compact_memory(int order)
{
return order == -1;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Yaowei Bai | 16 | 100.00% | 1 | 100.00% |
| Total | 16 | 100.00% | 1 | 100.00% |
static enum compact_result __compact_finished(struct zone *zone, struct compact_control *cc,
const int migratetype)
{
unsigned int order;
unsigned long watermark;
if (cc->contended || fatal_signal_pending(current))
return COMPACT_CONTENDED;
/* Compaction run completes if the migrate and free scanner meet */
if (compact_scanners_met(cc)) {
/* Let the next compaction start anew. */
reset_cached_positions(zone);
/*
* Mark that the PG_migrate_skip information should be cleared
* by kswapd when it goes to sleep. kcompactd does not set the
* flag itself as the decision to be clear should be directly
* based on an allocation request.
*/
if (cc->direct_compaction)
zone->compact_blockskip_flush = true;
if (cc->whole_zone)
return COMPACT_COMPLETE;
else
return COMPACT_PARTIAL_SKIPPED;
}
if (is_via_compact_memory(cc->order))
return COMPACT_CONTINUE;
/* Compaction run is not finished if the watermark is not met */
watermark = zone->watermark[cc->alloc_flags & ALLOC_WMARK_MASK];
if (!zone_watermark_ok(zone, cc->order, watermark, cc->classzone_idx,
cc->alloc_flags))
return COMPACT_CONTINUE;
/* Direct compactor: Is a suitable page free? */
for (order = cc->order; order < MAX_ORDER; order++) {
struct free_area *area = &zone->free_area[order];
bool can_steal;
/* Job done if page is free of the right migratetype */
if (!list_empty(&area->free_list[migratetype]))
return COMPACT_SUCCESS;
#ifdef CONFIG_CMA
/* MIGRATE_MOVABLE can fallback on MIGRATE_CMA */
if (migratetype == MIGRATE_MOVABLE &&
!list_empty(&area->free_list[MIGRATE_CMA]))
return COMPACT_SUCCESS;
#endif
/*
* Job done if allocation would steal freepages from
* other migratetype buddy lists.
*/
if (find_suitable_fallback(area, order, migratetype,
true, &can_steal) != -1)
return COMPACT_SUCCESS;
}
return COMPACT_NO_SUITABLE_PAGE;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Mel Gorman | 124 | 51.45% | 7 | 29.17% |
| JoonSoo Kim | 47 | 19.50% | 2 | 8.33% |
| Vlastimil Babka | 36 | 14.94% | 9 | 37.50% |
| Michal Hocko | 21 | 8.71% | 3 | 12.50% |
| Andrea Arcangeli | 6 | 2.49% | 1 | 4.17% |
| David Rientjes | 4 | 1.66% | 1 | 4.17% |
| Yaowei Bai | 3 | 1.24% | 1 | 4.17% |
| Total | 241 | 100.00% | 24 | 100.00% |
static enum compact_result compact_finished(struct zone *zone,
struct compact_control *cc,
const int migratetype)
{
int ret;
ret = __compact_finished(zone, cc, migratetype);
trace_mm_compaction_finished(zone, cc->order, ret);
if (ret == COMPACT_NO_SUITABLE_PAGE)
ret = COMPACT_CONTINUE;
return ret;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| JoonSoo Kim | 54 | 91.53% | 1 | 33.33% |
| Mel Gorman | 3 | 5.08% | 1 | 33.33% |
| Michal Hocko | 2 | 3.39% | 1 | 33.33% |
| Total | 59 | 100.00% | 3 | 100.00% |
/*
* compaction_suitable: Is this suitable to run compaction on this zone now?
* Returns
* COMPACT_SKIPPED - If there are too few free pages for compaction
* COMPACT_SUCCESS - If the allocation would succeed without compaction
* COMPACT_CONTINUE - If compaction should run now
*/
static enum compact_result __compaction_suitable(struct zone *zone, int order,
unsigned int alloc_flags,
int classzone_idx,
unsigned long wmark_target)
{
unsigned long watermark;
if (is_via_compact_memory(order))
return COMPACT_CONTINUE;
watermark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK];
/*
* If watermarks for high-order allocation are already met, there
* should be no need for compaction at all.
*/
if (zone_watermark_ok(zone, order, watermark, classzone_idx,
alloc_flags))
return COMPACT_SUCCESS;
/*
* Watermarks for order-0 must be met for compaction to be able to
* isolate free pages for migration targets. This means that the
* watermark and alloc_flags have to match, or be more pessimistic than
* the check in __isolate_free_page(). We don't use the direct
* compactor's alloc_flags, as they are not relevant for freepage
* isolation. We however do use the direct compactor's classzone_idx to
* skip over zones where lowmem reserves would prevent allocation even
* if compaction succeeds.
* For costly orders, we require low watermark instead of min for
* compaction to proceed to increase its chances.
* ALLOC_CMA is used, as pages in CMA pageblocks are considered
* suitable migration targets
*/
watermark = (order > PAGE_ALLOC_COSTLY_ORDER) ?
low_wmark_pages(zone) : min_wmark_pages(zone);
watermark += compact_gap(order);
if (!__zone_watermark_ok(zone, 0, watermark, classzone_idx,
ALLOC_CMA, wmark_target))
return COMPACT_SKIPPED;
return COMPACT_CONTINUE;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Vlastimil Babka | 59 | 49.17% | 6 | 46.15% |
| Mel Gorman | 40 | 33.33% | 2 | 15.38% |
| Michal Hocko | 16 | 13.33% | 3 | 23.08% |
| Yaowei Bai | 3 | 2.50% | 1 | 7.69% |
| JoonSoo Kim | 2 | 1.67% | 1 | 7.69% |
| Total | 120 | 100.00% | 13 | 100.00% |
enum compact_result compaction_suitable(struct zone *zone, int order,
unsigned int alloc_flags,
int classzone_idx)
{
enum compact_result ret;
int fragindex;
ret = __compaction_suitable(zone, order, alloc_flags, classzone_idx,
zone_page_state(zone, NR_FREE_PAGES));
/*
* fragmentation index determines if allocation failures are due to
* low memory or external fragmentation
*
* index of -1000 would imply allocations might succeed depending on
* watermarks, but we already failed the high-order watermark check
* index towards 0 implies failure is due to lack of memory
* index towards 1000 implies failure is due to fragmentation
*
* Only compact if a failure would be due to fragmentation. Also
* ignore fragindex for non-costly orders where the alternative to
* a successful reclaim/compaction is OOM. Fragindex and the
* vm.extfrag_threshold sysctl is meant as a heuristic to prevent
* excessive compaction for costly orders, but it should not be at the
* expense of system stability.
*/
if (ret == COMPACT_CONTINUE && (order > PAGE_ALLOC_COSTLY_ORDER)) {
fragindex = fragmentation_index(zone, order);
if (fragindex >= 0 && fragindex <= sysctl_extfrag_threshold)
ret = COMPACT_NOT_SUITABLE_ZONE;
}
trace_mm_compaction_suitable(zone, order, ret);
if (ret == COMPACT_NOT_SUITABLE_ZONE)
ret = COMPACT_SKIPPED;
return ret;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| JoonSoo Kim | 55 | 50.93% | 1 | 16.67% |
| Vlastimil Babka | 41 | 37.96% | 2 | 33.33% |
| Michal Hocko | 11 | 10.19% | 2 | 33.33% |
| Mel Gorman | 1 | 0.93% | 1 | 16.67% |
| Total | 108 | 100.00% | 6 | 100.00% |
bool compaction_zonelist_suitable(struct alloc_context *ac, int order,
int alloc_flags)
{
struct zone *zone;
struct zoneref *z;
/*
* Make sure at least one zone would pass __compaction_suitable if we continue
* retrying the reclaim.
*/
for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->high_zoneidx,
ac->nodemask) {
unsigned long available;
enum compact_result compact_result;
/*
* Do not consider all the reclaimable memory because we do not
* want to trash just for a single high order allocation which
* is even not guaranteed to appear even if __compaction_suitable
* is happy about the watermark check.
*/
available = zone_reclaimable_pages(zone) / order;
available += zone_page_state_snapshot(zone, NR_FREE_PAGES);
compact_result = __compaction_suitable(zone, order, alloc_flags,
ac_classzone_idx(ac), available);
if (compact_result != COMPACT_SKIPPED)
return true;
}
return false;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Michal Hocko | 96 | 97.96% | 1 | 50.00% |
| Mel Gorman | 2 | 2.04% | 1 | 50.00% |
| Total | 98 | 100.00% | 2 | 100.00% |
static enum compact_result compact_zone(struct zone *zone, struct compact_control *cc)
{
enum compact_result ret;
unsigned long start_pfn = zone->zone_start_pfn;
unsigned long end_pfn = zone_end_pfn(zone);
const int migratetype = gfpflags_to_migratetype(cc->gfp_mask);
const bool sync = cc->mode != MIGRATE_ASYNC;
ret = compaction_suitable(zone, cc->order, cc->alloc_flags,
cc->classzone_idx);
/* Compaction is likely to fail */
if (ret == COMPACT_SUCCESS || ret == COMPACT_SKIPPED)
return ret;
/* huh, compaction_suitable is returning something unexpected */
VM_BUG_ON(ret != COMPACT_CONTINUE);
/*
* Clear pageblock skip if there were failures recently and compaction
* is about to be retried after being deferred.
*/
if (compaction_restarting(zone, cc->order))
__reset_isolation_suitable(zone);
/*
* Setup to move all movable pages to the end of the zone. Used cached
* information on where the scanners should start (unless we explicitly
* want to compact the whole zone), but check that it is initialised
* by ensuring the values are within zone boundaries.
*/
if (cc->whole_zone) {
cc->migrate_pfn = start_pfn;
cc->free_pfn = pageblock_start_pfn(end_pfn - 1);
} else {
cc->migrate_pfn = zone->compact_cached_migrate_pfn[sync];
cc->free_pfn = zone->compact_cached_free_pfn;
if (cc->free_pfn < start_pfn || cc->free_pfn >= end_pfn) {
cc->free_pfn = pageblock_start_pfn(end_pfn - 1);
zone->compact_cached_free_pfn = cc->free_pfn;
}
if (cc->migrate_pfn < start_pfn || cc->migrate_pfn >= end_pfn) {
cc->migrate_pfn = start_pfn;
zone->compact_cached_migrate_pfn[0] = cc->migrate_pfn;
zone->compact_cached_migrate_pfn[1] = cc->migrate_pfn;
}
if (cc->migrate_pfn == start_pfn)
cc->whole_zone = true;
}
cc->last_migrated_pfn = 0;
trace_mm_compaction_begin(start_pfn, cc->migrate_pfn,
cc->free_pfn, end_pfn, sync);
migrate_prep_local();
while ((ret = compact_finished(zone, cc, migratetype)) ==
COMPACT_CONTINUE) {
int err;
switch (isolate_migratepages(zone, cc)) {
case ISOLATE_ABORT:
ret = COMPACT_CONTENDED;
putback_movable_pages(&cc->migratepages);
cc->nr_migratepages = 0;
goto out;
case ISOLATE_NONE:
/*
* We haven't isolated and migrated anything, but
* there might still be unflushed migrations from
* previous cc->order aligned block.
*/
goto check_drain;
case ISOLATE_SUCCESS:
;
}
err = migrate_pages(&cc->migratepages, compaction_alloc,
compaction_free, (unsigned long)cc, cc->mode,
MR_COMPACTION);
trace_mm_compaction_migratepages(cc->nr_migratepages, err,
&cc->migratepages);
/* All pages were either migrated or will be released */
cc->nr_migratepages = 0;
if (err) {
putback_movable_pages(&cc->migratepages);
/*
* migrate_pages() may return -ENOMEM when scanners meet
* and we want compact_finished() to detect it
*/
if (err == -ENOMEM && !compact_scanners_met(cc)) {
ret = COMPACT_CONTENDED;
goto out;
}
/*
* We failed to migrate at least one page in the current
* order-aligned block, so skip the rest of it.
*/
if (cc->direct_compaction &&
(cc->mode == MIGRATE_ASYNC)) {
cc->migrate_pfn = block_end_pfn(
cc->migrate_pfn - 1, cc->order);
/* Draining pcplists is useless in this case */
cc->last_migrated_pfn = 0;
}
}
check_drain:
/*
* Has the migration scanner moved away from the previous
* cc->order aligned block where we migrated from? If yes,
* flush the pages that were freed, so that they can merge and
* compact_finished() can detect immediately if allocation
* would succeed.
*/
if (cc->order > 0 && cc->last_migrated_pfn) {
int cpu;
unsigned long current_block_start =
block_start_pfn(cc->migrate_pfn, cc->order);
if (cc->last_migrated_pfn < current_block_start) {
cpu = get_cpu();
lru_add_drain_cpu(cpu);
drain_local_pages(zone);
put_cpu();
/* No more flushing until we migrate again */
cc->last_migrated_pfn = 0;
}
}
}
out:
/*
* Release free pages and update where the free scanner should restart,
* so we don't leave any returned pages behind in the next attempt.
*/
if (cc->nr_freepages > 0) {
unsigned long free_pfn = release_freepages(&cc->freepages);
cc->nr_freepages = 0;
VM_BUG_ON(free_pfn == 0);
/* The cached pfn is always the first in a pageblock */
free_pfn = pageblock_start_pfn(free_pfn);
/*
* Only go back, not forward. The cached pfn might have been
* already reset to zone end in compact_finished()
*/
if (free_pfn > zone->compact_cached_free_pfn)
zone->compact_cached_free_pfn = free_pfn;
}
count_compact_events(COMPACTMIGRATE_SCANNED, cc->total_migrate_scanned);
count_compact_events(COMPACTFREE_SCANNED, cc->total_free_scanned);
trace_mm_compaction_end(start_pfn, cc->migrate_pfn,
cc->free_pfn, end_pfn, sync, ret);
return ret;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Mel Gorman | 254 | 39.20% | 8 | 21.05% |
| Vlastimil Babka | 230 | 35.49% | 13 | 34.21% |
| David Rientjes | 76 | 11.73% | 7 | 18.42% |
| JoonSoo Kim | 32 | 4.94% | 3 | 7.89% |
| Michal Hocko | 32 | 4.94% | 3 | 7.89% |
| Shaohua Li | 13 | 2.01% | 1 | 2.63% |
| MinChan Kim | 6 | 0.93% | 1 | 2.63% |
| Cody P Schafer | 3 | 0.46% | 1 | 2.63% |
| Rafael Aquini | 2 | 0.31% | 1 | 2.63% |
| Total | 648 | 100.00% | 38 | 100.00% |
static enum compact_result compact_zone_order(struct zone *zone, int order,
gfp_t gfp_mask, enum compact_priority prio,
unsigned int alloc_flags, int classzone_idx)
{
enum compact_result ret;
struct compact_control cc = {
.nr_freepages = 0,
.nr_migratepages = 0,
.total_migrate_scanned = 0,
.total_free_scanned = 0,
.order = order,
.gfp_mask = gfp_mask,
.zone = zone,
.mode = (prio == COMPACT_PRIO_ASYNC) ?
MIGRATE_ASYNC : MIGRATE_SYNC_LIGHT,
.alloc_flags = alloc_flags,
.classzone_idx = classzone_idx,
.direct_compaction = true,
.whole_zone = (prio == MIN_COMPACT_PRIORITY),
.ignore_skip_hint = (prio == MIN_COMPACT_PRIORITY),
.ignore_block_suitable = (prio == MIN_COMPACT_PRIORITY)
};
INIT_LIST_HEAD(&cc.freepages);
INIT_LIST_HEAD(&cc.migratepages);
ret = compact_zone(zone, &cc);
VM_BUG_ON(!list_empty(&cc.freepages));
VM_BUG_ON(!list_empty(&cc.migratepages));
return ret;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Mel Gorman | 74 | 40.66% | 4 | 26.67% |
| Vlastimil Babka | 59 | 32.42% | 5 | 33.33% |
| Shaohua Li | 31 | 17.03% | 1 | 6.67% |
| David Rientjes | 13 | 7.14% | 3 | 20.00% |
| Michal Hocko | 4 | 2.20% | 1 | 6.67% |
| Kyungmin Park | 1 | 0.55% | 1 | 6.67% |
| Total | 182 | 100.00% | 15 | 100.00% |
int sysctl_extfrag_threshold = 500;
/**
* try_to_compact_pages - Direct compact to satisfy a high-order allocation
* @gfp_mask: The GFP mask of the current allocation
* @order: The order of the current allocation
* @alloc_flags: The allocation flags of the current allocation
* @ac: The context of current allocation
* @mode: The migration mode for async, sync light, or sync migration
*
* This is the main entry point for direct page compaction.
*/
enum compact_result try_to_compact_pages(gfp_t gfp_mask, unsigned int order,
unsigned int alloc_flags, const struct alloc_context *ac,
enum compact_priority prio)
{
int may_perform_io = gfp_mask & __GFP_IO;
struct zoneref *z;
struct zone *zone;
enum compact_result rc = COMPACT_SKIPPED;
/*
* Check if the GFP flags allow compaction - GFP_NOIO is really
* tricky context because the migration might require IO
*/
if (!may_perform_io)
return COMPACT_SKIPPED;
trace_mm_compaction_try_to_compact_pages(order, gfp_mask, prio);
/* Compact each zone in the list */
for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->high_zoneidx,
ac->nodemask) {
enum compact_result status;
if (prio > MIN_COMPACT_PRIORITY
&& compaction_deferred(zone, order)) {
rc = max_t(enum compact_result, COMPACT_DEFERRED, rc);
continue;
}
status = compact_zone_order(zone, order, gfp_mask, prio,
alloc_flags, ac_classzone_idx(ac));
rc = max(status, rc);
/* The allocation should succeed, stop compacting */
if (status == COMPACT_SUCCESS) {
/*
* We think the allocation will succeed in this zone,
* but it is not certain, hence the false. The caller
* will repeat this with true if allocation indeed
* succeeds in this zone.
*/
compaction_defer_reset(zone, order, false);
break;
}
if (prio != COMPACT_PRIO_ASYNC && (status == COMPACT_COMPLETE ||
status == COMPACT_PARTIAL_SKIPPED))
/*
* We think that allocation won't succeed in this zone
* so we defer compaction there. If it ends up
* succeeding after all, it will be reset.
*/
defer_compaction(zone, order);
/*
* We might have stopped compacting due to need_resched() in
* async compaction, or due to a fatal signal detected. In that
* case do not try further zones
*/
if ((prio == COMPACT_PRIO_ASYNC && need_resched())
|| fatal_signal_pending(current))
break;
}
return rc;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Vlastimil Babka | 87 | 41.63% | 9 | 42.86% |
| Mel Gorman | 84 | 40.19% | 5 | 23.81% |
| Michal Hocko | 28 | 13.40% | 4 | 19.05% |
| JoonSoo Kim | 8 | 3.83% | 1 | 4.76% |
| David Rientjes | 1 | 0.48% | 1 | 4.76% |
| Andrea Arcangeli | 1 | 0.48% | 1 | 4.76% |
| Total | 209 | 100.00% | 21 | 100.00% |
/* Compact all zones within a node */
static void compact_node(int nid)
{
pg_data_t *pgdat = NODE_DATA(nid);
int zoneid;
struct zone *zone;
struct compact_control cc = {
.order = -1,
.total_migrate_scanned = 0,
.total_free_scanned = 0,
.mode = MIGRATE_SYNC,
.ignore_skip_hint = true,
.whole_zone = true,
.gfp_mask = GFP_KERNEL,
};
for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) {
zone = &pgdat->node_zones[zoneid];
if (!populated_zone(zone))
continue;
cc.nr_freepages = 0;
cc.nr_migratepages = 0;
cc.zone = zone;
INIT_LIST_HEAD(&cc.freepages);
INIT_LIST_HEAD(&cc.migratepages);
compact_zone(zone, &cc);
VM_BUG_ON(!list_empty(&cc.freepages));
VM_BUG_ON(!list_empty(&cc.migratepages));
}
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Mel Gorman | 69 | 41.07% | 1 | 14.29% |
| Vlastimil Babka | 46 | 27.38% | 1 | 14.29% |
| JoonSoo Kim | 22 | 13.10% | 1 | 14.29% |
| Rik Van Riel | 15 | 8.93% | 1 | 14.29% |
| David Rientjes | 10 | 5.95% | 1 | 14.29% |
| Michal Hocko | 5 | 2.98% | 1 | 14.29% |
| Andrew Morton | 1 | 0.60% | 1 | 14.29% |
| Total | 168 | 100.00% | 7 | 100.00% |
/* Compact all nodes in the system */
static void compact_nodes(void)
{
int nid;
/* Flush pending updates to the LRU lists */
lru_add_drain_all();
for_each_online_node(nid)
compact_node(nid);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Mel Gorman | 19 | 79.17% | 1 | 33.33% |
| Hugh Dickins | 4 | 16.67% | 1 | 33.33% |
| Jason Liu | 1 | 4.17% | 1 | 33.33% |
| Total | 24 | 100.00% | 3 | 100.00% |
/* The written value is actually unused, all memory is compacted */
int sysctl_compact_memory;
/*
* This is the entry point for compacting all nodes via
* /proc/sys/vm/compact_memory
*/
int sysctl_compaction_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *length, loff_t *ppos)
{
if (write)
compact_nodes();
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Mel Gorman | 35 | 97.22% | 1 | 50.00% |
| Jason Liu | 1 | 2.78% | 1 | 50.00% |
| Total | 36 | 100.00% | 2 | 100.00% |
int sysctl_extfrag_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *length, loff_t *ppos)
{
proc_dointvec_minmax(table, write, buffer, length, ppos);
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Mel Gorman | 42 | 100.00% | 1 | 100.00% |
| Total | 42 | 100.00% | 1 | 100.00% |
#if defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
static ssize_t sysfs_compact_node(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
int nid = dev->id;
if (nid >= 0 && nid < nr_node_ids && node_online(nid)) {
/* Flush pending updates to the LRU lists */
lru_add_drain_all();
compact_node(nid);
}
return count;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Mel Gorman | 29 | 48.33% | 1 | 25.00% |
| Hugh Dickins | 28 | 46.67% | 1 | 25.00% |
| Kay Sievers | 2 | 3.33% | 1 | 25.00% |
| Rashika Kheria | 1 | 1.67% | 1 | 25.00% |
| Total | 60 | 100.00% | 4 | 100.00% |
static DEVICE_ATTR(compact, S_IWUSR, NULL, sysfs_compact_node);
int compaction_register_node(struct node *node)
{
return device_create_file(&node->dev, &dev_attr_compact);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Mel Gorman | 19 | 86.36% | 1 | 50.00% |
| Kay Sievers | 3 | 13.64% | 1 | 50.00% |
| Total | 22 | 100.00% | 2 | 100.00% |
void compaction_unregister_node(struct node *node)
{
return device_remove_file(&node->dev, &dev_attr_compact);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Mel Gorman | 19 | 86.36% | 1 | 50.00% |
| Kay Sievers | 3 | 13.64% | 1 | 50.00% |
| Total | 22 | 100.00% | 2 | 100.00% |
#endif /* CONFIG_SYSFS && CONFIG_NUMA */
static inline bool kcompactd_work_requested(pg_data_t *pgdat)
{
return pgdat->kcompactd_max_order > 0 || kthread_should_stop();
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Vlastimil Babka | 21 | 100.00% | 2 | 100.00% |
| Total | 21 | 100.00% | 2 | 100.00% |
static bool kcompactd_node_suitable(pg_data_t *pgdat)
{
int zoneid;
struct zone *zone;
enum zone_type classzone_idx = pgdat->kcompactd_classzone_idx;
for (zoneid = 0; zoneid <= classzone_idx; zoneid++) {
zone = &pgdat->node_zones[zoneid];
if (!populated_zone(zone))
continue;
if (compaction_suitable(zone, pgdat->kcompactd_max_order, 0,
classzone_idx) == COMPACT_CONTINUE)
return true;
}
return false;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Vlastimil Babka | 82 | 98.80% | 1 | 50.00% |
| Chen Feng | 1 | 1.20% | 1 | 50.00% |
| Total | 83 | 100.00% | 2 | 100.00% |
static void kcompactd_do_work(pg_data_t *pgdat)
{
/*
* With no special task, compact all zones so that a page of requested
* order is allocatable.
*/
int zoneid;
struct zone *zone;
struct compact_control cc = {
.order = pgdat->kcompactd_max_order,
.total_migrate_scanned = 0,
.total_free_scanned = 0,
.classzone_idx = pgdat->kcompactd_classzone_idx,
.mode = MIGRATE_SYNC_LIGHT,
.ignore_skip_hint = true,
.gfp_mask = GFP_KERNEL,
};
trace_mm_compaction_kcompactd_wake(pgdat->node_id, cc.order,
cc.classzone_idx);
count_compact_event(KCOMPACTD_WAKE);
for (zoneid = 0; zoneid <= cc.classzone_idx; zoneid++) {
int status;
zone = &pgdat->node_zones[zoneid];
if (!populated_zone(zone))
continue;
if (compaction_deferred(zone, cc.order))
continue;
if (compaction_suitable(zone, cc.order, 0, zoneid) !=
COMPACT_CONTINUE)
continue;
cc.nr_freepages = 0;
cc.nr_migratepages = 0;
cc.total_migrate_scanned = 0;
cc.total_free_scanned = 0;
cc.zone = zone;
INIT_LIST_HEAD(&cc.freepages);
INIT_LIST_HEAD(&cc.migratepages);
if (kthread_should_stop())
return;
status = compact_zone(zone, &cc);
if (status == COMPACT_SUCCESS) {
compaction_defer_reset(zone, cc.order, false);
} else if (status == COMPACT_PARTIAL_SKIPPED || status == COMPACT_COMPLETE) {
/*
* We use sync migration mode here, so we defer like
* sync direct compaction does.
*/
defer_compaction(zone, cc.order);
}
count_compact_events(KCOMPACTD_MIGRATE_SCANNED,
cc.total_migrate_scanned);
count_compact_events(KCOMPACTD_FREE_SCANNED,
cc.total_free_scanned);
VM_BUG_ON(!list_empty(&cc.freepages));
VM_BUG_ON(!list_empty(&cc.migratepages));
}
/*
* Regardless of success, we are done until woken up next. But remember
* the requested order/classzone_idx in case it was higher/tighter than
* our current ones
*/
if (pgdat->kcompactd_max_order <= cc.order)
pgdat->kcompactd_max_order = 0;
if (pgdat->kcompactd_classzone_idx >= cc.classzone_idx)
pgdat->kcompactd_classzone_idx = pgdat->nr_zones - 1;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Vlastimil Babka | 285 | 84.82% | 3 | 42.86% |
| David Rientjes | 41 | 12.20% | 1 | 14.29% |
| Michal Hocko | 9 | 2.68% | 2 | 28.57% |
| Chen Feng | 1 | 0.30% | 1 | 14.29% |
| Total | 336 | 100.00% | 7 | 100.00% |
void wakeup_kcompactd(pg_data_t *pgdat, int order, int classzone_idx)
{
if (!order)
return;
if (pgdat->kcompactd_max_order < order)
pgdat->kcompactd_max_order = order;
/*
* Pairs with implicit barrier in wait_event_freezable()
* such that wakeups are not missed in the lockless
* waitqueue_active() call.
*/
smp_acquire__after_ctrl_dep();
if (pgdat->kcompactd_classzone_idx > classzone_idx)
pgdat->kcompactd_classzone_idx = classzone_idx;
if (!waitqueue_active(&pgdat->kcompactd_wait))
return;
if (!kcompactd_node_suitable(pgdat))
return;
trace_mm_compaction_wakeup_kcompactd(pgdat->node_id, order,
classzone_idx);
wake_up_interruptible(&pgdat->kcompactd_wait);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Vlastimil Babka | 89 | 95.70% | 1 | 50.00% |
| Davidlohr Bueso A | 4 | 4.30% | 1 | 50.00% |
| Total | 93 | 100.00% | 2 | 100.00% |
/*
* The background compaction daemon, started as a kernel thread
* from the init process.
*/
static int kcompactd(void *p)
{
pg_data_t *pgdat = (pg_data_t*)p;
struct task_struct *tsk = current;
const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id);
if (!cpumask_empty(cpumask))
set_cpus_allowed_ptr(tsk, cpumask);
set_freezable();
pgdat->kcompactd_max_order = 0;
pgdat->kcompactd_classzone_idx = pgdat->nr_zones - 1;
while (!kthread_should_stop()) {
trace_mm_compaction_kcompactd_sleep(pgdat->node_id);
wait_event_freezable(pgdat->kcompactd_wait,
kcompactd_work_requested(pgdat));
kcompactd_do_work(pgdat);
}
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Vlastimil Babka | 109 | 100.00% | 1 | 100.00% |
| Total | 109 | 100.00% | 1 | 100.00% |
/*
* This kcompactd start function will be called by init and node-hot-add.
* On node-hot-add, kcompactd will moved to proper cpus if cpus are hot-added.
*/
int kcompactd_run(int nid)
{
pg_data_t *pgdat = NODE_DATA(nid);
int ret = 0;
if (pgdat->kcompactd)
return 0;
pgdat->kcompactd = kthread_run(kcompactd, pgdat, "kcompactd%d", nid);
if (IS_ERR(pgdat->kcompactd)) {
pr_err("Failed to start kcompactd on node %d\n", nid);
ret = PTR_ERR(pgdat->kcompactd);
pgdat->kcompactd = NULL;
}
return ret;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Vlastimil Babka | 82 | 100.00% | 1 | 100.00% |
| Total | 82 | 100.00% | 1 | 100.00% |
/*
* Called by memory hotplug when all memory in a node is offlined. Caller must
* hold mem_hotplug_begin/end().
*/
void kcompactd_stop(int nid)
{
struct task_struct *kcompactd = NODE_DATA(nid)->kcompactd;
if (kcompactd) {
kthread_stop(kcompactd);
NODE_DATA(nid)->kcompactd = NULL;
}
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Vlastimil Babka | 40 | 100.00% | 1 | 100.00% |
| Total | 40 | 100.00% | 1 | 100.00% |
/*
* It's optimal to keep kcompactd on the same CPUs as their memory, but
* not required for correctness. So if the last cpu in a node goes
* away, we get changed to run anywhere: as the first one comes back,
* restore their cpu bindings.
*/
static int kcompactd_cpu_online(unsigned int cpu)
{
int nid;
for_each_node_state(nid, N_MEMORY) {
pg_data_t *pgdat = NODE_DATA(nid);
const struct cpumask *mask;
mask = cpumask_of_node(pgdat->node_id);
if (cpumask_any_and(cpu_online_mask, mask) < nr_cpu_ids)
/* One of our CPUs online: restore mask */
set_cpus_allowed_ptr(pgdat->kcompactd, mask);
}
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Vlastimil Babka | 65 | 94.20% | 1 | 50.00% |
| Anna-Maria Gleixner | 4 | 5.80% | 1 | 50.00% |
| Total | 69 | 100.00% | 2 | 100.00% |
static int __init kcompactd_init(void)
{
int nid;
int ret;
ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
"mm/compaction:online",
kcompactd_cpu_online, NULL);
if (ret < 0) {
pr_err("kcompactd: failed to register hotplug callbacks.\n");
return ret;
}
for_each_node_state(nid, N_MEMORY)
kcompactd_run(nid);
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Anna-Maria Gleixner | 32 | 55.17% | 1 | 50.00% |
| Vlastimil Babka | 26 | 44.83% | 1 | 50.00% |
| Total | 58 | 100.00% | 2 | 100.00% |
subsys_initcall(kcompactd_init)
#endif /* CONFIG_COMPACTION */
Overall Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Vlastimil Babka | 2461 | 35.73% | 45 | 29.61% |
| Mel Gorman | 1999 | 29.02% | 27 | 17.76% |
| JoonSoo Kim | 771 | 11.19% | 18 | 11.84% |
| Michal Nazarewicz | 359 | 5.21% | 4 | 2.63% |
| MinChan Kim | 358 | 5.20% | 6 | 3.95% |
| David Rientjes | 315 | 4.57% | 11 | 7.24% |
| Michal Hocko | 244 | 3.54% | 7 | 4.61% |
| Andrew Morton | 54 | 0.78% | 2 | 1.32% |
| Andrea Arcangeli | 52 | 0.75% | 4 | 2.63% |
| Hugh Dickins | 49 | 0.71% | 3 | 1.97% |
| Shaohua Li | 48 | 0.70% | 1 | 0.66% |
| Anna-Maria Gleixner | 36 | 0.52% | 1 | 0.66% |
| Yaowei Bai | 24 | 0.35% | 2 | 1.32% |
| Laura Abbott | 22 | 0.32% | 1 | 0.66% |
| Eric B Munson | 15 | 0.22% | 1 | 0.66% |
| Rik Van Riel | 15 | 0.22% | 1 | 0.66% |
| Lin Ming | 12 | 0.17% | 1 | 0.66% |
| Kay Sievers | 9 | 0.13% | 1 | 0.66% |
| Cody P Schafer | 6 | 0.09% | 1 | 0.66% |
| Andrey Ryabinin | 6 | 0.09% | 1 | 0.66% |
| Hillf Danton | 5 | 0.07% | 1 | 0.66% |
| Xiubo Li | 4 | 0.06% | 1 | 0.66% |
| Davidlohr Bueso A | 4 | 0.06% | 1 | 0.66% |
| Sasha Levin | 3 | 0.04% | 1 | 0.66% |
| Rafael Aquini | 3 | 0.04% | 2 | 1.32% |
| Linus Torvalds | 3 | 0.04% | 1 | 0.66% |
| Ingo Molnar | 3 | 0.04% | 1 | 0.66% |
| Jason Liu | 2 | 0.03% | 1 | 0.66% |
| Chen Feng | 2 | 0.03% | 1 | 0.66% |
| Kyungmin Park | 1 | 0.01% | 1 | 0.66% |
| Rashika Kheria | 1 | 0.01% | 1 | 0.66% |
| Yisheng Xie | 1 | 0.01% | 1 | 0.66% |
| Jerome Marchand | 1 | 0.01% | 1 | 0.66% |
| Total | 6888 | 100.00% | 152 | 100.00% |
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