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-rw-r--r--mm/compaction.c157
1 files changed, 109 insertions, 48 deletions
diff --git a/mm/compaction.c b/mm/compaction.c
index ec74cf0123e..546e571e9d6 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -41,15 +41,17 @@ static inline void count_compact_events(enum vm_event_item item, long delta)
static unsigned long release_freepages(struct list_head *freelist)
{
struct page *page, *next;
- unsigned long count = 0;
+ 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);
- count++;
+ if (pfn > high_pfn)
+ high_pfn = pfn;
}
- return count;
+ return high_pfn;
}
static void map_pages(struct list_head *list)
@@ -195,16 +197,12 @@ static void update_pageblock_skip(struct compact_control *cc,
/* Update where async and sync compaction should restart */
if (migrate_scanner) {
- if (cc->finished_update_migrate)
- return;
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 (cc->finished_update_free)
- return;
if (pfn < zone->compact_cached_free_pfn)
zone->compact_cached_free_pfn = pfn;
}
@@ -479,6 +477,16 @@ isolate_freepages_range(struct compact_control *cc,
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_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
+ block_end_pfn = min(block_end_pfn, end_pfn);
+ }
+
if (!pageblock_pfn_to_page(pfn, block_end_pfn, cc->zone))
break;
@@ -705,7 +713,6 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
del_page_from_lru_list(page, lruvec, page_lru(page));
isolate_success:
- cc->finished_update_migrate = true;
list_add(&page->lru, migratelist);
cc->nr_migratepages++;
nr_isolated++;
@@ -879,15 +886,6 @@ static void isolate_freepages(struct compact_control *cc)
block_start_pfn - pageblock_nr_pages;
/*
- * Set a flag that we successfully isolated in this pageblock.
- * In the next loop iteration, zone->compact_cached_free_pfn
- * will not be updated and thus it will effectively contain the
- * highest pageblock we isolated pages from.
- */
- if (isolated)
- cc->finished_update_free = true;
-
- /*
* isolate_freepages_block() might have aborted due to async
* compaction being contended
*/
@@ -1029,8 +1027,12 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone,
}
acct_isolated(zone, cc);
- /* Record where migration scanner will be restarted */
- cc->migrate_pfn = low_pfn;
+ /*
+ * Record where migration scanner will be restarted. If we end up in
+ * the same pageblock as the free scanner, make the scanners fully
+ * meet so that compact_finished() terminates compaction.
+ */
+ cc->migrate_pfn = (end_pfn <= cc->free_pfn) ? low_pfn : cc->free_pfn;
return cc->nr_migratepages ? ISOLATE_SUCCESS : ISOLATE_NONE;
}
@@ -1072,9 +1074,9 @@ static int compact_finished(struct zone *zone, struct compact_control *cc,
/* Compaction run is not finished if the watermark is not met */
watermark = low_wmark_pages(zone);
- watermark += (1 << cc->order);
- if (!zone_watermark_ok(zone, cc->order, watermark, 0, 0))
+ if (!zone_watermark_ok(zone, cc->order, watermark, cc->classzone_idx,
+ cc->alloc_flags))
return COMPACT_CONTINUE;
/* Direct compactor: Is a suitable page free? */
@@ -1100,7 +1102,8 @@ static int compact_finished(struct zone *zone, struct compact_control *cc,
* COMPACT_PARTIAL - If the allocation would succeed without compaction
* COMPACT_CONTINUE - If compaction should run now
*/
-unsigned long compaction_suitable(struct zone *zone, int order)
+unsigned long compaction_suitable(struct zone *zone, int order,
+ int alloc_flags, int classzone_idx)
{
int fragindex;
unsigned long watermark;
@@ -1112,21 +1115,30 @@ unsigned long compaction_suitable(struct zone *zone, int order)
if (order == -1)
return COMPACT_CONTINUE;
+ watermark = low_wmark_pages(zone);
+ /*
+ * 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_PARTIAL;
+
/*
* Watermarks for order-0 must be met for compaction. Note the 2UL.
* This is because during migration, copies of pages need to be
* allocated and for a short time, the footprint is higher
*/
- watermark = low_wmark_pages(zone) + (2UL << order);
- if (!zone_watermark_ok(zone, 0, watermark, 0, 0))
+ watermark += (2UL << order);
+ if (!zone_watermark_ok(zone, 0, watermark, classzone_idx, alloc_flags))
return COMPACT_SKIPPED;
/*
* fragmentation index determines if allocation failures are due to
* low memory or external fragmentation
*
- * index of -1000 implies allocations might succeed depending on
- * watermarks
+ * 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
*
@@ -1136,10 +1148,6 @@ unsigned long compaction_suitable(struct zone *zone, int order)
if (fragindex >= 0 && fragindex <= sysctl_extfrag_threshold)
return COMPACT_SKIPPED;
- if (fragindex == -1000 && zone_watermark_ok(zone, order, watermark,
- 0, 0))
- return COMPACT_PARTIAL;
-
return COMPACT_CONTINUE;
}
@@ -1150,8 +1158,10 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
unsigned long end_pfn = zone_end_pfn(zone);
const int migratetype = gfpflags_to_migratetype(cc->gfp_mask);
const bool sync = cc->mode != MIGRATE_ASYNC;
+ unsigned long last_migrated_pfn = 0;
- ret = compaction_suitable(zone, cc->order);
+ ret = compaction_suitable(zone, cc->order, cc->alloc_flags,
+ cc->classzone_idx);
switch (ret) {
case COMPACT_PARTIAL:
case COMPACT_SKIPPED:
@@ -1194,6 +1204,7 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
while ((ret = compact_finished(zone, cc, migratetype)) ==
COMPACT_CONTINUE) {
int err;
+ unsigned long isolate_start_pfn = cc->migrate_pfn;
switch (isolate_migratepages(zone, cc)) {
case ISOLATE_ABORT:
@@ -1202,7 +1213,12 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
cc->nr_migratepages = 0;
goto out;
case ISOLATE_NONE:
- continue;
+ /*
+ * 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:
;
}
@@ -1227,12 +1243,61 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
goto out;
}
}
+
+ /*
+ * Record where we could have freed pages by migration and not
+ * yet flushed them to buddy allocator. We use the pfn that
+ * isolate_migratepages() started from in this loop iteration
+ * - this is the lowest page that could have been isolated and
+ * then freed by migration.
+ */
+ if (!last_migrated_pfn)
+ last_migrated_pfn = isolate_start_pfn;
+
+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 && last_migrated_pfn) {
+ int cpu;
+ unsigned long current_block_start =
+ cc->migrate_pfn & ~((1UL << cc->order) - 1);
+
+ if (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 */
+ last_migrated_pfn = 0;
+ }
+ }
+
}
out:
- /* Release free pages and check accounting */
- cc->nr_freepages -= release_freepages(&cc->freepages);
- VM_BUG_ON(cc->nr_freepages != 0);
+ /*
+ * 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_nr_pages-1);
+ /*
+ * 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;
+ }
trace_mm_compaction_end(ret);
@@ -1240,7 +1305,8 @@ out:
}
static unsigned long compact_zone_order(struct zone *zone, int order,
- gfp_t gfp_mask, enum migrate_mode mode, int *contended)
+ gfp_t gfp_mask, enum migrate_mode mode, int *contended,
+ int alloc_flags, int classzone_idx)
{
unsigned long ret;
struct compact_control cc = {
@@ -1250,6 +1316,8 @@ static unsigned long compact_zone_order(struct zone *zone, int order,
.gfp_mask = gfp_mask,
.zone = zone,
.mode = mode,
+ .alloc_flags = alloc_flags,
+ .classzone_idx = classzone_idx,
};
INIT_LIST_HEAD(&cc.freepages);
INIT_LIST_HEAD(&cc.migratepages);
@@ -1274,14 +1342,13 @@ int sysctl_extfrag_threshold = 500;
* @mode: The migration mode for async, sync light, or sync migration
* @contended: Return value that determines if compaction was aborted due to
* need_resched() or lock contention
- * @candidate_zone: Return the zone where we think allocation should succeed
*
* This is the main entry point for direct page compaction.
*/
unsigned long try_to_compact_pages(struct zonelist *zonelist,
int order, gfp_t gfp_mask, nodemask_t *nodemask,
enum migrate_mode mode, int *contended,
- struct zone **candidate_zone)
+ int alloc_flags, int classzone_idx)
{
enum zone_type high_zoneidx = gfp_zone(gfp_mask);
int may_enter_fs = gfp_mask & __GFP_FS;
@@ -1289,7 +1356,6 @@ unsigned long try_to_compact_pages(struct zonelist *zonelist,
struct zoneref *z;
struct zone *zone;
int rc = COMPACT_DEFERRED;
- int alloc_flags = 0;
int all_zones_contended = COMPACT_CONTENDED_LOCK; /* init for &= op */
*contended = COMPACT_CONTENDED_NONE;
@@ -1298,10 +1364,6 @@ unsigned long try_to_compact_pages(struct zonelist *zonelist,
if (!order || !may_enter_fs || !may_perform_io)
return COMPACT_SKIPPED;
-#ifdef CONFIG_CMA
- if (gfpflags_to_migratetype(gfp_mask) == MIGRATE_MOVABLE)
- alloc_flags |= ALLOC_CMA;
-#endif
/* Compact each zone in the list */
for_each_zone_zonelist_nodemask(zone, z, zonelist, high_zoneidx,
nodemask) {
@@ -1312,7 +1374,7 @@ unsigned long try_to_compact_pages(struct zonelist *zonelist,
continue;
status = compact_zone_order(zone, order, gfp_mask, mode,
- &zone_contended);
+ &zone_contended, alloc_flags, classzone_idx);
rc = max(status, rc);
/*
* It takes at least one zone that wasn't lock contended
@@ -1321,9 +1383,8 @@ unsigned long try_to_compact_pages(struct zonelist *zonelist,
all_zones_contended &= zone_contended;
/* If a normal allocation would succeed, stop compacting */
- if (zone_watermark_ok(zone, order, low_wmark_pages(zone), 0,
- alloc_flags)) {
- *candidate_zone = zone;
+ if (zone_watermark_ok(zone, order, low_wmark_pages(zone),
+ classzone_idx, alloc_flags)) {
/*
* We think the allocation will succeed in this zone,
* but it is not certain, hence the false. The caller
@@ -1345,7 +1406,7 @@ unsigned long try_to_compact_pages(struct zonelist *zonelist,
goto break_loop;
}
- if (mode != MIGRATE_ASYNC) {
+ if (mode != MIGRATE_ASYNC && status == COMPACT_COMPLETE) {
/*
* We think that allocation won't succeed in this zone
* so we defer compaction there. If it ends up
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-26 21:50:46 +0000