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-rw-r--r--mm/compaction.c142
1 files changed, 119 insertions, 23 deletions
diff --git a/mm/compaction.c b/mm/compaction.c
index da7d35ea510..840ee288e29 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -235,7 +235,7 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
*/
while (unlikely(too_many_isolated(zone))) {
/* async migration should just abort */
- if (!cc->sync)
+ if (cc->mode != COMPACT_SYNC)
return 0;
congestion_wait(BLK_RW_ASYNC, HZ/10);
@@ -303,7 +303,8 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
* satisfies the allocation
*/
pageblock_nr = low_pfn >> pageblock_order;
- if (!cc->sync && last_pageblock_nr != pageblock_nr &&
+ if (cc->mode != COMPACT_SYNC &&
+ last_pageblock_nr != pageblock_nr &&
!migrate_async_suitable(get_pageblock_migratetype(page))) {
low_pfn += pageblock_nr_pages;
low_pfn = ALIGN(low_pfn, pageblock_nr_pages) - 1;
@@ -324,7 +325,7 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
continue;
}
- if (!cc->sync)
+ if (cc->mode != COMPACT_SYNC)
mode |= ISOLATE_ASYNC_MIGRATE;
/* Try isolate the page */
@@ -357,27 +358,90 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
#endif /* CONFIG_COMPACTION || CONFIG_CMA */
#ifdef CONFIG_COMPACTION
+/*
+ * Returns true if MIGRATE_UNMOVABLE pageblock was successfully
+ * converted to MIGRATE_MOVABLE type, false otherwise.
+ */
+static bool rescue_unmovable_pageblock(struct page *page)
+{
+ unsigned long pfn, start_pfn, end_pfn;
+ struct page *start_page, *end_page;
+
+ pfn = page_to_pfn(page);
+ start_pfn = pfn & ~(pageblock_nr_pages - 1);
+ end_pfn = start_pfn + pageblock_nr_pages;
+
+ start_page = pfn_to_page(start_pfn);
+ end_page = pfn_to_page(end_pfn);
+
+ /* Do not deal with pageblocks that overlap zones */
+ if (page_zone(start_page) != page_zone(end_page))
+ return false;
+
+ for (page = start_page, pfn = start_pfn; page < end_page; pfn++,
+ page++) {
+ if (!pfn_valid_within(pfn))
+ continue;
+
+ if (PageBuddy(page)) {
+ int order = page_order(page);
+
+ pfn += (1 << order) - 1;
+ page += (1 << order) - 1;
+
+ continue;
+ } else if (page_count(page) == 0 || PageLRU(page))
+ continue;
+
+ return false;
+ }
+
+ set_pageblock_migratetype(page, MIGRATE_MOVABLE);
+ move_freepages_block(page_zone(page), page, MIGRATE_MOVABLE);
+ return true;
+}
-/* Returns true if the page is within a block suitable for migration to */
-static bool suitable_migration_target(struct page *page)
+enum smt_result {
+ GOOD_AS_MIGRATION_TARGET,
+ FAIL_UNMOVABLE_TARGET,
+ FAIL_BAD_TARGET,
+};
+
+/*
+ * Returns GOOD_AS_MIGRATION_TARGET if the page is within a block
+ * suitable for migration to, FAIL_UNMOVABLE_TARGET if the page
+ * is within a MIGRATE_UNMOVABLE block, FAIL_BAD_TARGET otherwise.
+ */
+static enum smt_result suitable_migration_target(struct page *page,
+ struct compact_control *cc)
{
int migratetype = get_pageblock_migratetype(page);
/* Don't interfere with memory hot-remove or the min_free_kbytes blocks */
if (migratetype == MIGRATE_ISOLATE || migratetype == MIGRATE_RESERVE)
- return false;
+ return FAIL_BAD_TARGET;
/* If the page is a large free page, then allow migration */
if (PageBuddy(page) && page_order(page) >= pageblock_order)
- return true;
+ return GOOD_AS_MIGRATION_TARGET;
/* If the block is MIGRATE_MOVABLE or MIGRATE_CMA, allow migration */
- if (migrate_async_suitable(migratetype))
- return true;
+ if (cc->mode != COMPACT_ASYNC_UNMOVABLE &&
+ migrate_async_suitable(migratetype))
+ return GOOD_AS_MIGRATION_TARGET;
+
+ if (cc->mode == COMPACT_ASYNC_MOVABLE &&
+ migratetype == MIGRATE_UNMOVABLE)
+ return FAIL_UNMOVABLE_TARGET;
+
+ if (cc->mode != COMPACT_ASYNC_MOVABLE &&
+ migratetype == MIGRATE_UNMOVABLE &&
+ rescue_unmovable_pageblock(page))
+ return GOOD_AS_MIGRATION_TARGET;
/* Otherwise skip the block */
- return false;
+ return FAIL_BAD_TARGET;
}
/*
@@ -411,6 +475,13 @@ static void isolate_freepages(struct zone *zone,
zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
/*
+ * isolate_freepages() may be called more than once during
+ * compact_zone_order() run and we want only the most recent
+ * count.
+ */
+ cc->nr_pageblocks_skipped = 0;
+
+ /*
* 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.
@@ -418,6 +489,7 @@ static void isolate_freepages(struct zone *zone,
for (; pfn > low_pfn && cc->nr_migratepages > nr_freepages;
pfn -= pageblock_nr_pages) {
unsigned long isolated;
+ enum smt_result ret;
if (!pfn_valid(pfn))
continue;
@@ -434,9 +506,12 @@ static void isolate_freepages(struct zone *zone,
continue;
/* Check the block is suitable for migration */
- if (!suitable_migration_target(page))
+ ret = suitable_migration_target(page, cc);
+ if (ret != GOOD_AS_MIGRATION_TARGET) {
+ if (ret == FAIL_UNMOVABLE_TARGET)
+ cc->nr_pageblocks_skipped++;
continue;
-
+ }
/*
* Found a block suitable for isolating free pages from. Now
* we disabled interrupts, double check things are ok and
@@ -445,12 +520,14 @@ static void isolate_freepages(struct zone *zone,
*/
isolated = 0;
spin_lock_irqsave(&zone->lock, flags);
- if (suitable_migration_target(page)) {
+ ret = suitable_migration_target(page, cc);
+ if (ret == GOOD_AS_MIGRATION_TARGET) {
end_pfn = min(pfn + pageblock_nr_pages, zone_end_pfn);
isolated = isolate_freepages_block(pfn, end_pfn,
freelist, false);
nr_freepages += isolated;
- }
+ } else if (ret == FAIL_UNMOVABLE_TARGET)
+ cc->nr_pageblocks_skipped++;
spin_unlock_irqrestore(&zone->lock, flags);
/*
@@ -682,8 +759,9 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
nr_migrate = cc->nr_migratepages;
err = migrate_pages(&cc->migratepages, compaction_alloc,
- (unsigned long)cc, false,
- cc->sync ? MIGRATE_SYNC_LIGHT : MIGRATE_ASYNC);
+ (unsigned long)&cc->freepages, false,
+ (cc->mode == COMPACT_SYNC) ? MIGRATE_SYNC_LIGHT
+ : MIGRATE_ASYNC);
update_nr_listpages(cc);
nr_remaining = cc->nr_migratepages;
@@ -712,7 +790,8 @@ out:
static unsigned long compact_zone_order(struct zone *zone,
int order, gfp_t gfp_mask,
- bool sync)
+ enum compact_mode mode,
+ unsigned long *nr_pageblocks_skipped)
{
struct compact_control cc = {
.nr_freepages = 0,
@@ -720,12 +799,17 @@ static unsigned long compact_zone_order(struct zone *zone,
.order = order,
.migratetype = allocflags_to_migratetype(gfp_mask),
.zone = zone,
- .sync = sync,
+ .mode = mode,
};
+ unsigned long rc;
+
INIT_LIST_HEAD(&cc.freepages);
INIT_LIST_HEAD(&cc.migratepages);
- return compact_zone(zone, &cc);
+ rc = compact_zone(zone, &cc);
+ *nr_pageblocks_skipped = cc.nr_pageblocks_skipped;
+
+ return rc;
}
int sysctl_extfrag_threshold = 500;
@@ -750,6 +834,8 @@ unsigned long try_to_compact_pages(struct zonelist *zonelist,
struct zoneref *z;
struct zone *zone;
int rc = COMPACT_SKIPPED;
+ unsigned long nr_pageblocks_skipped;
+ enum compact_mode mode;
/*
* Check whether it is worth even starting compaction. The order check is
@@ -766,12 +852,22 @@ unsigned long try_to_compact_pages(struct zonelist *zonelist,
nodemask) {
int status;
- status = compact_zone_order(zone, order, gfp_mask, sync);
+ mode = sync ? COMPACT_SYNC : COMPACT_ASYNC_MOVABLE;
+retry:
+ status = compact_zone_order(zone, order, gfp_mask, mode,
+ &nr_pageblocks_skipped);
rc = max(status, rc);
/* If a normal allocation would succeed, stop compacting */
if (zone_watermark_ok(zone, order, low_wmark_pages(zone), 0, 0))
break;
+
+ if (rc == COMPACT_COMPLETE && mode == COMPACT_ASYNC_MOVABLE) {
+ if (nr_pageblocks_skipped) {
+ mode = COMPACT_ASYNC_UNMOVABLE;
+ goto retry;
+ }
+ }
}
return rc;
@@ -805,7 +901,7 @@ static int __compact_pgdat(pg_data_t *pgdat, struct compact_control *cc)
if (ok && cc->order > zone->compact_order_failed)
zone->compact_order_failed = cc->order + 1;
/* Currently async compaction is never deferred. */
- else if (!ok && cc->sync)
+ else if (!ok && cc->mode == COMPACT_SYNC)
defer_compaction(zone, cc->order);
}
@@ -820,7 +916,7 @@ int compact_pgdat(pg_data_t *pgdat, int order)
{
struct compact_control cc = {
.order = order,
- .sync = false,
+ .mode = COMPACT_ASYNC_MOVABLE,
};
return __compact_pgdat(pgdat, &cc);
@@ -830,7 +926,7 @@ static int compact_node(int nid)
{
struct compact_control cc = {
.order = -1,
- .sync = true,
+ .mode = COMPACT_SYNC,
};
return __compact_pgdat(NODE_DATA(nid), &cc);