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authorDmitry Torokhov <dmitry.torokhov@gmail.com>2024-07-15 14:03:44 -0700
committerDmitry Torokhov <dmitry.torokhov@gmail.com>2024-07-15 14:03:44 -0700
commita23e1966932464e1c5226cb9ac4ce1d5fc10ba22 (patch)
treebf5f1b57faa01ca31656bfc48c7d6b6f0bc39189 /mm/compaction.c
parentInput: ads7846 - use spi_device_id table (diff)
parentInput: yealink - simplify locking in sysfs attribute handling (diff)
downloadwireguard-linux-a23e1966932464e1c5226cb9ac4ce1d5fc10ba22.tar.xz
wireguard-linux-a23e1966932464e1c5226cb9ac4ce1d5fc10ba22.zip
Merge branch 'next' into for-linus
Prepare input updates for 6.11 merge window.
Diffstat (limited to 'mm/compaction.c')
-rw-r--r--mm/compaction.c588
1 files changed, 369 insertions, 219 deletions
diff --git a/mm/compaction.c b/mm/compaction.c
index eacca2794e47..807b58e6eb68 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -40,9 +40,22 @@ static inline void count_compact_events(enum vm_event_item item, long delta)
{
count_vm_events(item, delta);
}
+
+/*
+ * order == -1 is expected when compacting proactively via
+ * 1. /proc/sys/vm/compact_memory
+ * 2. /sys/devices/system/node/nodex/compact
+ * 3. /proc/sys/vm/compaction_proactiveness
+ */
+static inline bool is_via_compact_memory(int order)
+{
+ return order == -1;
+}
+
#else
#define count_compact_event(item) do { } while (0)
#define count_compact_events(item, delta) do { } while (0)
+static inline bool is_via_compact_memory(int order) { return false; }
#endif
#if defined CONFIG_COMPACTION || defined CONFIG_CMA
@@ -66,45 +79,56 @@ static inline void count_compact_events(enum vm_event_item item, long delta)
#define COMPACTION_HPAGE_ORDER (PMD_SHIFT - PAGE_SHIFT)
#endif
-static unsigned long release_freepages(struct list_head *freelist)
+static void split_map_pages(struct list_head *freepages)
{
+ unsigned int i, order;
struct page *page, *next;
- unsigned long high_pfn = 0;
+ LIST_HEAD(tmp_list);
- 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;
- }
+ for (order = 0; order < NR_PAGE_ORDERS; order++) {
+ list_for_each_entry_safe(page, next, &freepages[order], lru) {
+ unsigned int nr_pages;
- return high_pfn;
+ list_del(&page->lru);
+
+ 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_init(&tmp_list, &freepages[0]);
+ }
}
-static void split_map_pages(struct list_head *list)
+static unsigned long release_free_list(struct list_head *freepages)
{
- 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);
+ int order;
+ unsigned long high_pfn = 0;
- order = page_private(page);
- nr_pages = 1 << order;
+ for (order = 0; order < NR_PAGE_ORDERS; order++) {
+ struct page *page, *next;
- post_alloc_hook(page, order, __GFP_MOVABLE);
- if (order)
- split_page(page, order);
+ list_for_each_entry_safe(page, next, &freepages[order], lru) {
+ unsigned long pfn = page_to_pfn(page);
- for (i = 0; i < nr_pages; i++) {
- list_add(&page->lru, &tmp_list);
- page++;
+ list_del(&page->lru);
+ /*
+ * Convert free pages into post allocation pages, so
+ * that we can free them via __free_page.
+ */
+ post_alloc_hook(page, order, __GFP_MOVABLE);
+ __free_pages(page, order);
+ if (pfn > high_pfn)
+ high_pfn = pfn;
}
}
-
- list_splice(&tmp_list, list);
+ return high_pfn;
}
#ifdef CONFIG_COMPACTION
@@ -249,11 +273,36 @@ static unsigned long skip_offline_sections(unsigned long start_pfn)
return 0;
}
+
+/*
+ * If the PFN falls into an offline section, return the end PFN of the
+ * next online section in reverse. If the PFN falls into an online section
+ * or if there is no next online section in reverse, return 0.
+ */
+static unsigned long skip_offline_sections_reverse(unsigned long start_pfn)
+{
+ unsigned long start_nr = pfn_to_section_nr(start_pfn);
+
+ if (!start_nr || online_section_nr(start_nr))
+ return 0;
+
+ while (start_nr-- > 0) {
+ if (online_section_nr(start_nr))
+ return section_nr_to_pfn(start_nr) + PAGES_PER_SECTION;
+ }
+
+ return 0;
+}
#else
static unsigned long skip_offline_sections(unsigned long start_pfn)
{
return 0;
}
+
+static unsigned long skip_offline_sections_reverse(unsigned long start_pfn)
+{
+ return 0;
+}
#endif
/*
@@ -357,6 +406,7 @@ static void __reset_isolation_suitable(struct zone *zone)
bool source_set = false;
bool free_set = false;
+ /* Only flush if a full compaction finished recently */
if (!zone->compact_blockskip_flush)
return;
@@ -409,9 +459,7 @@ void reset_isolation_suitable(pg_data_t *pgdat)
if (!populated_zone(zone))
continue;
- /* Only flush if a full compaction finished recently */
- if (zone->compact_blockskip_flush)
- __reset_isolation_suitable(zone);
+ __reset_isolation_suitable(zone);
}
}
@@ -438,12 +486,13 @@ static void update_cached_migrate(struct compact_control *cc, unsigned long pfn)
{
struct zone *zone = cc->zone;
- pfn = pageblock_end_pfn(pfn);
-
/* Set for isolation rather than compaction */
if (cc->no_set_skip_hint)
return;
+ pfn = pageblock_end_pfn(pfn);
+
+ /* Update where async and sync compaction should restart */
if (pfn > zone->compact_cached_migrate_pfn[0])
zone->compact_cached_migrate_pfn[0] = pfn;
if (cc->mode != MIGRATE_ASYNC &&
@@ -465,7 +514,6 @@ static void update_pageblock_skip(struct compact_control *cc,
set_pageblock_skip(page);
- /* Update where async and sync compaction should restart */
if (pfn < zone->compact_cached_free_pfn)
zone->compact_cached_free_pfn = pfn;
}
@@ -564,7 +612,7 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
bool strict)
{
int nr_scanned = 0, total_isolated = 0;
- struct page *cursor;
+ struct page *page;
unsigned long flags = 0;
bool locked = false;
unsigned long blockpfn = *start_pfn;
@@ -574,12 +622,11 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
if (strict)
stride = 1;
- cursor = pfn_to_page(blockpfn);
+ page = pfn_to_page(blockpfn);
/* Isolate free pages. */
- for (; blockpfn < end_pfn; blockpfn += stride, cursor += stride) {
+ for (; blockpfn < end_pfn; blockpfn += stride, page += stride) {
int isolated;
- struct page *page = cursor;
/*
* Periodically drop the lock (if held) regardless of its
@@ -602,11 +649,12 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
if (PageCompound(page)) {
const unsigned int order = compound_order(page);
- if (likely(order <= MAX_ORDER)) {
+ if (blockpfn + (1UL << order) <= end_pfn) {
blockpfn += (1UL << order) - 1;
- cursor += (1UL << order) - 1;
+ page += (1UL << order) - 1;
nr_scanned += (1UL << order) - 1;
}
+
goto isolate_fail;
}
@@ -633,7 +681,7 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
nr_scanned += isolated - 1;
total_isolated += isolated;
cc->nr_freepages += isolated;
- list_add_tail(&page->lru, freelist);
+ list_add_tail(&page->lru, &freelist[order]);
if (!strict && cc->nr_migratepages <= cc->nr_freepages) {
blockpfn += isolated;
@@ -641,14 +689,12 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
}
/* Advance to the end of split page */
blockpfn += isolated - 1;
- cursor += isolated - 1;
+ page += isolated - 1;
continue;
isolate_fail:
if (strict)
break;
- else
- continue;
}
@@ -656,8 +702,7 @@ isolate_fail:
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.
+ * Be careful to not go outside of the pageblock.
*/
if (unlikely(blockpfn > end_pfn))
blockpfn = end_pfn;
@@ -701,7 +746,11 @@ 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);
+ int order;
+ struct list_head tmp_freepages[NR_PAGE_ORDERS];
+
+ for (order = 0; order < NR_PAGE_ORDERS; order++)
+ INIT_LIST_HEAD(&tmp_freepages[order]);
pfn = start_pfn;
block_start_pfn = pageblock_start_pfn(pfn);
@@ -715,8 +764,6 @@ isolate_freepages_range(struct compact_control *cc,
/* 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
@@ -725,15 +772,16 @@ isolate_freepages_range(struct compact_control *cc,
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);
}
+ 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, 0, true);
+ block_end_pfn, tmp_freepages, 0, true);
/*
* In strict mode, isolate_freepages_block() returns 0 if
@@ -750,15 +798,15 @@ isolate_freepages_range(struct compact_control *cc,
*/
}
- /* __isolate_free_page() does not map the pages */
- split_map_pages(&freelist);
-
if (pfn < end_pfn) {
/* Loop terminated early, cleanup. */
- release_freepages(&freelist);
+ release_free_list(tmp_freepages);
return 0;
}
+ /* __isolate_free_page() does not map the pages */
+ split_map_pages(tmp_freepages);
+
/* We don't use freelists for anything. */
return pfn;
}
@@ -797,6 +845,32 @@ static bool too_many_isolated(struct compact_control *cc)
}
/**
+ * skip_isolation_on_order() - determine when to skip folio isolation based on
+ * folio order and compaction target order
+ * @order: to-be-isolated folio order
+ * @target_order: compaction target order
+ *
+ * This avoids unnecessary folio isolations during compaction.
+ */
+static bool skip_isolation_on_order(int order, int target_order)
+{
+ /*
+ * Unless we are performing global compaction (i.e.,
+ * is_via_compact_memory), skip any folios that are larger than the
+ * target order: we wouldn't be here if we'd have a free folio with
+ * the desired target_order, so migrating this folio would likely fail
+ * later.
+ */
+ if (!is_via_compact_memory(target_order) && order >= target_order)
+ return true;
+ /*
+ * We limit memory compaction to pageblocks and won't try
+ * creating free blocks of memory that are larger than that.
+ */
+ return order >= pageblock_order;
+}
+
+/**
* isolate_migratepages_block() - isolate all migrate-able pages within
* a single pageblock
* @cc: Compaction control structure.
@@ -862,6 +936,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
/* Time to isolate some pages for migration */
for (; low_pfn < end_pfn; low_pfn++) {
+ bool is_dirty, is_unevictable;
if (skip_on_failure && low_pfn >= next_skip_pfn) {
/*
@@ -926,7 +1001,22 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
valid_page = page;
}
- if (PageHuge(page) && cc->alloc_contig) {
+ if (PageHuge(page)) {
+ /*
+ * skip hugetlbfs if we are not compacting for pages
+ * bigger than its order. THPs and other compound pages
+ * are handled below.
+ */
+ if (!cc->alloc_contig) {
+ const unsigned int order = compound_order(page);
+
+ if (order <= MAX_PAGE_ORDER) {
+ low_pfn += (1UL << order) - 1;
+ nr_scanned += (1UL << order) - 1;
+ }
+ goto isolate_fail;
+ }
+ /* for alloc_contig case */
if (locked) {
unlock_page_lruvec_irqrestore(locked, flags);
locked = NULL;
@@ -979,7 +1069,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
* 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) {
+ if (freepage_order > 0 && freepage_order <= MAX_PAGE_ORDER) {
low_pfn += (1UL << freepage_order) - 1;
nr_scanned += (1UL << freepage_order) - 1;
}
@@ -987,21 +1077,24 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
}
/*
- * Regardless of being on LRU, compound pages such as THP and
- * hugetlbfs are not to be compacted unless we are attempting
- * an allocation much larger than the huge page size (eg CMA).
- * 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.
+ * Regardless of being on LRU, compound pages such as THP
+ * (hugetlbfs is handled above) are not to be compacted unless
+ * we are attempting an allocation larger than the compound
+ * page size. 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) && !cc->alloc_contig) {
const unsigned int order = compound_order(page);
- if (likely(order <= MAX_ORDER)) {
- low_pfn += (1UL << order) - 1;
- nr_scanned += (1UL << order) - 1;
+ /* Skip based on page order and compaction target order. */
+ if (skip_isolation_on_order(order, cc->order)) {
+ if (order <= MAX_PAGE_ORDER) {
+ low_pfn += (1UL << order) - 1;
+ nr_scanned += (1UL << order) - 1;
+ }
+ goto isolate_fail;
}
- goto isolate_fail;
}
/*
@@ -1059,8 +1152,10 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
if (!folio_test_lru(folio))
goto isolate_fail_put;
+ is_unevictable = folio_test_unevictable(folio);
+
/* Compaction might skip unevictable pages but CMA takes them */
- if (!(mode & ISOLATE_UNEVICTABLE) && folio_test_unevictable(folio))
+ if (!(mode & ISOLATE_UNEVICTABLE) && is_unevictable)
goto isolate_fail_put;
/*
@@ -1072,26 +1167,42 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
if ((mode & ISOLATE_ASYNC_MIGRATE) && folio_test_writeback(folio))
goto isolate_fail_put;
- if ((mode & ISOLATE_ASYNC_MIGRATE) && folio_test_dirty(folio)) {
- bool migrate_dirty;
+ is_dirty = folio_test_dirty(folio);
+
+ if (((mode & ISOLATE_ASYNC_MIGRATE) && is_dirty) ||
+ (mapping && is_unevictable)) {
+ bool migrate_dirty = true;
+ bool is_unmovable;
/*
- * Only pages without mappings or that have a
- * ->migrate_folio callback are possible to migrate
- * without blocking. However, we can be racing with
- * truncation so it's necessary to lock the page
- * to stabilise the mapping as truncation holds
- * the page lock until after the page is removed
- * from the page cache.
+ * Only folios without mappings or that have
+ * a ->migrate_folio callback are possible to migrate
+ * without blocking.
+ *
+ * Folios from unmovable mappings are not migratable.
+ *
+ * However, we can be racing with truncation, which can
+ * free the mapping that we need to check. Truncation
+ * holds the folio lock until after the folio is removed
+ * from the page so holding it ourselves is sufficient.
+ *
+ * To avoid locking the folio just to check unmovable,
+ * assume every unmovable folio is also unevictable,
+ * which is a cheaper test. If our assumption goes
+ * wrong, it's not a correctness bug, just potentially
+ * wasted cycles.
*/
if (!folio_trylock(folio))
goto isolate_fail_put;
mapping = folio_mapping(folio);
- migrate_dirty = !mapping ||
- mapping->a_ops->migrate_folio;
+ if ((mode & ISOLATE_ASYNC_MIGRATE) && is_dirty) {
+ migrate_dirty = !mapping ||
+ mapping->a_ops->migrate_folio;
+ }
+ is_unmovable = mapping && mapping_unmovable(mapping);
folio_unlock(folio);
- if (!migrate_dirty)
+ if (!migrate_dirty || is_unmovable)
goto isolate_fail_put;
}
@@ -1120,15 +1231,17 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
skip_updated = true;
if (test_and_set_skip(cc, valid_page) &&
!cc->finish_pageblock) {
+ low_pfn = end_pfn;
goto isolate_abort;
}
}
/*
- * folio become large since the non-locked check,
- * and it's on LRU.
+ * Check LRU folio order under the lock
*/
- if (unlikely(folio_test_large(folio) && !cc->alloc_contig)) {
+ if (unlikely(skip_isolation_on_order(folio_order(folio),
+ cc->order) &&
+ !cc->alloc_contig)) {
low_pfn += folio_nr_pages(folio) - 1;
nr_scanned += folio_nr_pages(folio) - 1;
folio_set_lru(folio);
@@ -1325,12 +1438,14 @@ static bool suitable_migration_target(struct compact_control *cc,
{
/* If the page is a large free page, then disallow migration */
if (PageBuddy(page)) {
+ int order = cc->order > 0 ? cc->order : pageblock_order;
+
/*
* 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 (buddy_order_unsafe(page) >= pageblock_order)
+ if (buddy_order_unsafe(page) >= order)
return false;
}
@@ -1373,8 +1488,8 @@ move_freelist_head(struct list_head *freelist, struct page *freepage)
{
LIST_HEAD(sublist);
- if (!list_is_last(freelist, &freepage->lru)) {
- list_cut_before(&sublist, freelist, &freepage->lru);
+ if (!list_is_first(&freepage->buddy_list, freelist)) {
+ list_cut_before(&sublist, freelist, &freepage->buddy_list);
list_splice_tail(&sublist, freelist);
}
}
@@ -1390,8 +1505,8 @@ move_freelist_tail(struct list_head *freelist, struct page *freepage)
{
LIST_HEAD(sublist);
- if (!list_is_first(freelist, &freepage->lru)) {
- list_cut_position(&sublist, freelist, &freepage->lru);
+ if (!list_is_last(&freepage->buddy_list, freelist)) {
+ list_cut_position(&sublist, freelist, &freepage->buddy_list);
list_splice_tail(&sublist, freelist);
}
}
@@ -1418,13 +1533,11 @@ fast_isolate_around(struct compact_control *cc, unsigned long pfn)
if (!page)
return;
- isolate_freepages_block(cc, &start_pfn, end_pfn, &cc->freepages, 1, false);
+ isolate_freepages_block(cc, &start_pfn, end_pfn, cc->freepages, 1, false);
/* Skip this pageblock in the future as it's full or nearly full */
- if (start_pfn == end_pfn)
+ if (start_pfn == end_pfn && !cc->no_set_skip_hint)
set_pageblock_skip(page);
-
- return;
}
/* Search orders in round-robin fashion */
@@ -1501,7 +1614,7 @@ static void fast_isolate_freepages(struct compact_control *cc)
spin_lock_irqsave(&cc->zone->lock, flags);
freelist = &area->free_list[MIGRATE_MOVABLE];
- list_for_each_entry_reverse(freepage, freelist, lru) {
+ list_for_each_entry_reverse(freepage, freelist, buddy_list) {
unsigned long pfn;
order_scanned++;
@@ -1530,7 +1643,7 @@ static void fast_isolate_freepages(struct compact_control *cc)
break;
}
- /* Use a minimum pfn if a preferred one was not found */
+ /* Use a maximum candidate pfn if a preferred one was not found */
if (!page && high_pfn) {
page = pfn_to_page(high_pfn);
@@ -1549,7 +1662,7 @@ static void fast_isolate_freepages(struct compact_control *cc)
nr_scanned += nr_isolated - 1;
total_isolated += nr_isolated;
cc->nr_freepages += nr_isolated;
- list_add_tail(&page->lru, &cc->freepages);
+ list_add_tail(&page->lru, &cc->freepages[order]);
count_compact_events(COMPACTISOLATED, nr_isolated);
} else {
/* If isolation fails, abort the search */
@@ -1592,6 +1705,9 @@ static void fast_isolate_freepages(struct compact_control *cc)
min(pageblock_end_pfn(min_pfn),
zone_end_pfn(cc->zone)),
cc->zone);
+ if (page && !suitable_migration_target(cc, page))
+ page = NULL;
+
cc->free_pfn = min_pfn;
}
}
@@ -1623,13 +1739,12 @@ static void isolate_freepages(struct compact_control *cc)
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;
unsigned int stride;
/* Try a small search of the free lists for a candidate */
fast_isolate_freepages(cc);
if (cc->nr_freepages)
- goto splitmap;
+ return;
/*
* Initialise the free scanner. The starting point is where we last
@@ -1669,8 +1784,15 @@ static void isolate_freepages(struct compact_control *cc)
page = pageblock_pfn_to_page(block_start_pfn, block_end_pfn,
zone);
- if (!page)
+ if (!page) {
+ unsigned long next_pfn;
+
+ next_pfn = skip_offline_sections_reverse(block_start_pfn);
+ if (next_pfn)
+ block_start_pfn = max(next_pfn, low_pfn);
+
continue;
+ }
/* Check the block is suitable for migration */
if (!suitable_migration_target(cc, page))
@@ -1682,11 +1804,12 @@ static void isolate_freepages(struct compact_control *cc)
/* Found a block suitable for isolating free pages from. */
nr_isolated = isolate_freepages_block(cc, &isolate_start_pfn,
- block_end_pfn, freelist, stride, false);
+ block_end_pfn, cc->freepages, stride, false);
/* Update the skip hint if the full pageblock was scanned */
if (isolate_start_pfn == block_end_pfn)
- update_pageblock_skip(cc, page, block_start_pfn);
+ update_pageblock_skip(cc, page, block_start_pfn -
+ pageblock_nr_pages);
/* Are enough freepages isolated? */
if (cc->nr_freepages >= cc->nr_migratepages) {
@@ -1722,10 +1845,6 @@ static void isolate_freepages(struct compact_control *cc)
* and the loop terminated due to isolate_start_pfn < low_pfn
*/
cc->free_pfn = isolate_start_pfn;
-
-splitmap:
- /* __isolate_free_page() does not map the pages */
- split_map_pages(freelist);
}
/*
@@ -1736,19 +1855,47 @@ static struct folio *compaction_alloc(struct folio *src, unsigned long data)
{
struct compact_control *cc = (struct compact_control *)data;
struct folio *dst;
+ int order = folio_order(src);
+ bool has_isolated_pages = false;
+ int start_order;
+ struct page *freepage;
+ unsigned long size;
+
+again:
+ for (start_order = order; start_order < NR_PAGE_ORDERS; start_order++)
+ if (!list_empty(&cc->freepages[start_order]))
+ break;
- if (list_empty(&cc->freepages)) {
- isolate_freepages(cc);
-
- if (list_empty(&cc->freepages))
+ /* no free pages in the list */
+ if (start_order == NR_PAGE_ORDERS) {
+ if (has_isolated_pages)
return NULL;
+ isolate_freepages(cc);
+ has_isolated_pages = true;
+ goto again;
}
- dst = list_entry(cc->freepages.next, struct folio, lru);
- list_del(&dst->lru);
- cc->nr_freepages--;
+ freepage = list_first_entry(&cc->freepages[start_order], struct page,
+ lru);
+ size = 1 << start_order;
+
+ list_del(&freepage->lru);
- return dst;
+ while (start_order > order) {
+ start_order--;
+ size >>= 1;
+
+ list_add(&freepage[size].lru, &cc->freepages[start_order]);
+ set_page_private(&freepage[size], start_order);
+ }
+ dst = (struct folio *)freepage;
+
+ post_alloc_hook(&dst->page, order, __GFP_MOVABLE);
+ if (order)
+ prep_compound_page(&dst->page, order);
+ cc->nr_freepages -= 1 << order;
+ cc->nr_migratepages -= 1 << order;
+ return page_rmappable_folio(&dst->page);
}
/*
@@ -1759,9 +1906,19 @@ static struct folio *compaction_alloc(struct folio *src, unsigned long data)
static void compaction_free(struct folio *dst, unsigned long data)
{
struct compact_control *cc = (struct compact_control *)data;
+ int order = folio_order(dst);
+ struct page *page = &dst->page;
- list_add(&dst->lru, &cc->freepages);
- cc->nr_freepages++;
+ if (folio_put_testzero(dst)) {
+ free_pages_prepare(page, order);
+ list_add(&dst->lru, &cc->freepages[order]);
+ cc->nr_freepages += 1 << order;
+ }
+ cc->nr_migratepages += 1 << order;
+ /*
+ * someone else has referenced the page, we cannot take it back to our
+ * free list.
+ */
}
/* possible outcome of isolate_migratepages */
@@ -1884,7 +2041,7 @@ static unsigned long fast_find_migrateblock(struct compact_control *cc)
spin_lock_irqsave(&cc->zone->lock, flags);
freelist = &area->free_list[MIGRATE_MOVABLE];
- list_for_each_entry(freepage, freelist, lru) {
+ list_for_each_entry(freepage, freelist, buddy_list) {
unsigned long free_pfn;
if (nr_scanned++ >= limit) {
@@ -1958,9 +2115,9 @@ static isolate_migrate_t isolate_migratepages(struct compact_control *cc)
block_start_pfn = cc->zone->zone_start_pfn;
/*
- * fast_find_migrateblock marks a pageblock skipped so to avoid
- * the isolation_suitable check below, check whether the fast
- * search was successful.
+ * fast_find_migrateblock() has already ensured the pageblock is not
+ * set with a skipped flag, so to avoid the isolation_suitable check
+ * below again, check whether the fast search was successful.
*/
fast_find_block = low_pfn != cc->migrate_pfn && !cc->fast_search_fail;
@@ -2038,15 +2195,6 @@ static isolate_migrate_t isolate_migratepages(struct compact_control *cc)
}
/*
- * order == -1 is expected when compacting via
- * /proc/sys/vm/compact_memory
- */
-static inline bool is_via_compact_memory(int order)
-{
- return order == -1;
-}
-
-/*
* Determine whether kswapd is (or recently was!) running on this node.
*
* pgdat_kswapd_lock() pins pgdat->kswapd, so a concurrent kswapd_stop() can't
@@ -2114,7 +2262,7 @@ static unsigned int fragmentation_score_node(pg_data_t *pgdat)
return score;
}
-static unsigned int fragmentation_score_wmark(pg_data_t *pgdat, bool low)
+static unsigned int fragmentation_score_wmark(bool low)
{
unsigned int wmark_low;
@@ -2134,7 +2282,7 @@ static bool should_proactive_compact_node(pg_data_t *pgdat)
if (!sysctl_compaction_proactiveness || kswapd_is_running(pgdat))
return false;
- wmark_high = fragmentation_score_wmark(pgdat, false);
+ wmark_high = fragmentation_score_wmark(false);
return fragmentation_score_node(pgdat) > wmark_high;
}
@@ -2173,7 +2321,7 @@ static enum compact_result __compact_finished(struct compact_control *cc)
return COMPACT_PARTIAL_SKIPPED;
score = fragmentation_score_zone(cc->zone);
- wmark_low = fragmentation_score_wmark(pgdat, true);
+ wmark_low = fragmentation_score_wmark(true);
if (score > wmark_low)
ret = COMPACT_CONTINUE;
@@ -2197,7 +2345,7 @@ static enum compact_result __compact_finished(struct compact_control *cc)
/* Direct compactor: Is a suitable page free? */
ret = COMPACT_NO_SUITABLE_PAGE;
- for (order = cc->order; order <= MAX_ORDER; order++) {
+ for (order = cc->order; order < NR_PAGE_ORDERS; order++) {
struct free_area *area = &cc->zone->free_area[order];
bool can_steal;
@@ -2349,6 +2497,30 @@ bool compaction_zonelist_suitable(struct alloc_context *ac, int order,
return false;
}
+/*
+ * Should we do compaction for target allocation order.
+ * Return COMPACT_SUCCESS if allocation for target order can be already
+ * satisfied
+ * Return COMPACT_SKIPPED if compaction for target order is likely to fail
+ * Return COMPACT_CONTINUE if compaction for target order should be ran
+ */
+static enum compact_result
+compaction_suit_allocation_order(struct zone *zone, unsigned int order,
+ int highest_zoneidx, unsigned int alloc_flags)
+{
+ unsigned long watermark;
+
+ watermark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK);
+ if (zone_watermark_ok(zone, order, watermark, highest_zoneidx,
+ alloc_flags))
+ return COMPACT_SUCCESS;
+
+ if (!compaction_suitable(zone, order, highest_zoneidx))
+ return COMPACT_SKIPPED;
+
+ return COMPACT_CONTINUE;
+}
+
static enum compact_result
compact_zone(struct compact_control *cc, struct capture_control *capc)
{
@@ -2358,7 +2530,8 @@ compact_zone(struct compact_control *cc, struct capture_control *capc)
unsigned long last_migrated_pfn;
const bool sync = cc->mode != MIGRATE_ASYNC;
bool update_cached;
- unsigned int nr_succeeded = 0;
+ unsigned int nr_succeeded = 0, nr_migratepages;
+ int order;
/*
* These counters track activities during zone compaction. Initialize
@@ -2368,25 +2541,18 @@ compact_zone(struct compact_control *cc, struct capture_control *capc)
cc->total_free_scanned = 0;
cc->nr_migratepages = 0;
cc->nr_freepages = 0;
- INIT_LIST_HEAD(&cc->freepages);
+ for (order = 0; order < NR_PAGE_ORDERS; order++)
+ INIT_LIST_HEAD(&cc->freepages[order]);
INIT_LIST_HEAD(&cc->migratepages);
cc->migratetype = gfp_migratetype(cc->gfp_mask);
if (!is_via_compact_memory(cc->order)) {
- unsigned long watermark;
-
- /* Allocation can already succeed, nothing to do */
- watermark = wmark_pages(cc->zone,
- cc->alloc_flags & ALLOC_WMARK_MASK);
- if (zone_watermark_ok(cc->zone, cc->order, watermark,
- cc->highest_zoneidx, cc->alloc_flags))
- return COMPACT_SUCCESS;
-
- /* Compaction is likely to fail */
- if (!compaction_suitable(cc->zone, cc->order,
- cc->highest_zoneidx))
- return COMPACT_SKIPPED;
+ ret = compaction_suit_allocation_order(cc->zone, cc->order,
+ cc->highest_zoneidx,
+ cc->alloc_flags);
+ if (ret != COMPACT_CONTINUE)
+ return ret;
}
/*
@@ -2480,14 +2646,21 @@ rescan:
goto check_drain;
case ISOLATE_SUCCESS:
update_cached = false;
- last_migrated_pfn = iteration_start_pfn;
+ last_migrated_pfn = max(cc->zone->zone_start_pfn,
+ pageblock_start_pfn(cc->migrate_pfn - 1));
}
+ /*
+ * Record the number of pages to migrate since the
+ * compaction_alloc/free() will update cc->nr_migratepages
+ * properly.
+ */
+ nr_migratepages = cc->nr_migratepages;
err = migrate_pages(&cc->migratepages, compaction_alloc,
compaction_free, (unsigned long)cc, cc->mode,
MR_COMPACTION, &nr_succeeded);
- trace_mm_compaction_migratepages(cc, nr_succeeded);
+ trace_mm_compaction_migratepages(nr_migratepages, nr_succeeded);
/* All pages were either migrated or will be released */
cc->nr_migratepages = 0;
@@ -2503,7 +2676,7 @@ rescan:
}
/*
* If an ASYNC or SYNC_LIGHT fails to migrate a page
- * within the current order-aligned block and
+ * within the pageblock_order-aligned block and
* fast_find_migrateblock may be used then scan the
* remainder of the pageblock. This will mark the
* pageblock "skip" to avoid rescanning in the near
@@ -2561,7 +2734,7 @@ out:
* 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);
+ unsigned long free_pfn = release_free_list(cc->freepages);
cc->nr_freepages = 0;
VM_BUG_ON(free_pfn == 0);
@@ -2580,7 +2753,6 @@ out:
trace_mm_compaction_end(cc, start_pfn, end_pfn, sync, ret);
- VM_BUG_ON(!list_empty(&cc->freepages));
VM_BUG_ON(!list_empty(&cc->migratepages));
return ret;
@@ -2655,16 +2827,11 @@ 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, struct page **capture)
{
- int may_perform_io = (__force int)(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)
+ if (!gfp_compaction_allowed(gfp_mask))
return COMPACT_SKIPPED;
trace_mm_compaction_try_to_compact_pages(order, gfp_mask, prio);
@@ -2720,25 +2887,27 @@ enum compact_result try_to_compact_pages(gfp_t gfp_mask, unsigned int order,
}
/*
- * Compact all zones within a node till each zone's fragmentation score
- * reaches within proactive compaction thresholds (as determined by the
- * proactiveness tunable).
+ * compact_node() - compact all zones within a node
+ * @pgdat: The node page data
+ * @proactive: Whether the compaction is proactive
*
- * It is possible that the function returns before reaching score targets
- * due to various back-off conditions, such as, contention on per-node or
- * per-zone locks.
+ * For proactive compaction, compact till each zone's fragmentation score
+ * reaches within proactive compaction thresholds (as determined by the
+ * proactiveness tunable), it is possible that the function returns before
+ * reaching score targets due to various back-off conditions, such as,
+ * contention on per-node or per-zone locks.
*/
-static void proactive_compact_node(pg_data_t *pgdat)
+static int compact_node(pg_data_t *pgdat, bool proactive)
{
int zoneid;
struct zone *zone;
struct compact_control cc = {
.order = -1,
- .mode = MIGRATE_SYNC_LIGHT,
+ .mode = proactive ? MIGRATE_SYNC_LIGHT : MIGRATE_SYNC,
.ignore_skip_hint = true,
.whole_zone = true,
.gfp_mask = GFP_KERNEL,
- .proactive_compaction = true,
+ .proactive_compaction = proactive,
};
for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) {
@@ -2746,54 +2915,39 @@ static void proactive_compact_node(pg_data_t *pgdat)
if (!populated_zone(zone))
continue;
+ if (fatal_signal_pending(current))
+ return -EINTR;
+
cc.zone = zone;
compact_zone(&cc, NULL);
- count_compact_events(KCOMPACTD_MIGRATE_SCANNED,
- cc.total_migrate_scanned);
- count_compact_events(KCOMPACTD_FREE_SCANNED,
- cc.total_free_scanned);
+ if (proactive) {
+ count_compact_events(KCOMPACTD_MIGRATE_SCANNED,
+ cc.total_migrate_scanned);
+ count_compact_events(KCOMPACTD_FREE_SCANNED,
+ cc.total_free_scanned);
+ }
}
-}
-
-/* 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,
- .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.zone = zone;
-
- compact_zone(&cc, NULL);
- }
+ return 0;
}
-/* Compact all nodes in the system */
-static void compact_nodes(void)
+/* Compact all zones of all nodes in the system */
+static int compact_nodes(void)
{
- int nid;
+ int ret, nid;
/* Flush pending updates to the LRU lists */
lru_add_drain_all();
- for_each_online_node(nid)
- compact_node(nid);
+ for_each_online_node(nid) {
+ ret = compact_node(NODE_DATA(nid), false);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
}
static int compaction_proactiveness_sysctl_handler(struct ctl_table *table, int write,
@@ -2839,9 +2993,9 @@ static int sysctl_compaction_handler(struct ctl_table *table, int write,
return -EINVAL;
if (write)
- compact_nodes();
+ ret = compact_nodes();
- return 0;
+ return ret;
}
#if defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
@@ -2855,7 +3009,7 @@ static ssize_t compact_store(struct device *dev,
/* Flush pending updates to the LRU lists */
lru_add_drain_all();
- compact_node(nid);
+ compact_node(NODE_DATA(nid), false);
}
return count;
@@ -2869,7 +3023,7 @@ int compaction_register_node(struct node *node)
void compaction_unregister_node(struct node *node)
{
- return device_remove_file(&node->dev, &dev_attr_compact);
+ device_remove_file(&node->dev, &dev_attr_compact);
}
#endif /* CONFIG_SYSFS && CONFIG_NUMA */
@@ -2884,6 +3038,7 @@ static bool kcompactd_node_suitable(pg_data_t *pgdat)
int zoneid;
struct zone *zone;
enum zone_type highest_zoneidx = pgdat->kcompactd_highest_zoneidx;
+ enum compact_result ret;
for (zoneid = 0; zoneid <= highest_zoneidx; zoneid++) {
zone = &pgdat->node_zones[zoneid];
@@ -2891,14 +3046,10 @@ static bool kcompactd_node_suitable(pg_data_t *pgdat)
if (!populated_zone(zone))
continue;
- /* Allocation can already succeed, check other zones */
- if (zone_watermark_ok(zone, pgdat->kcompactd_max_order,
- min_wmark_pages(zone),
- highest_zoneidx, 0))
- continue;
-
- if (compaction_suitable(zone, pgdat->kcompactd_max_order,
- highest_zoneidx))
+ ret = compaction_suit_allocation_order(zone,
+ pgdat->kcompactd_max_order,
+ highest_zoneidx, ALLOC_WMARK_MIN);
+ if (ret == COMPACT_CONTINUE)
return true;
}
@@ -2921,6 +3072,8 @@ static void kcompactd_do_work(pg_data_t *pgdat)
.ignore_skip_hint = false,
.gfp_mask = GFP_KERNEL,
};
+ enum compact_result ret;
+
trace_mm_compaction_kcompactd_wake(pgdat->node_id, cc.order,
cc.highest_zoneidx);
count_compact_event(KCOMPACTD_WAKE);
@@ -2935,12 +3088,9 @@ static void kcompactd_do_work(pg_data_t *pgdat)
if (compaction_deferred(zone, cc.order))
continue;
- /* Allocation can already succeed, nothing to do */
- if (zone_watermark_ok(zone, cc.order,
- min_wmark_pages(zone), zoneid, 0))
- continue;
-
- if (!compaction_suitable(zone, cc.order, zoneid))
+ ret = compaction_suit_allocation_order(zone,
+ cc.order, zoneid, ALLOC_WMARK_MIN);
+ if (ret != COMPACT_CONTINUE)
continue;
if (kthread_should_stop())
@@ -3068,7 +3218,7 @@ static int kcompactd(void *p)
unsigned int prev_score, score;
prev_score = fragmentation_score_node(pgdat);
- proactive_compact_node(pgdat);
+ compact_node(pgdat, true);
score = fragmentation_score_node(pgdat);
/*
* Defer proactive compaction if the fragmentation