The patch titled
mm: compaction: various fixes to the patch 'Memory compaction core'
has been added to the -mm tree. Its filename is
mm-compaction-memory-compaction-core-fix.patch
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out what to do about this
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------------------------------------------------------
Subject: mm: compaction: various fixes to the patch 'Memory compaction core'
From: Mel Gorman <mel@xxxxxxxxx>
o Use unsigned long instead of int for page counters
o Simplify logic in isolate_freepages_block() and isolate_migratepages()
o Optimise isolate_freepages_block to use a cursor
o Use bool instead of int for true/false
o Clarify some comments
o Improve control flow in isolate_migratepages()
o Add newlines for clarity
o Simply loop in compact_zones
Signed-off-by: Mel Gorman <mel@xxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Minchan Kim <minchan.kim@xxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/compaction.c | 81 ++++++++++++++++++++++++++--------------------
mm/page_alloc.c | 2 -
2 files changed, 47 insertions(+), 36 deletions(-)
diff -puN mm/Kconfig~mm-compaction-memory-compaction-core-fix mm/Kconfig
diff -puN mm/compaction.c~mm-compaction-memory-compaction-core-fix mm/compaction.c
--- a/mm/compaction.c~mm-compaction-memory-compaction-core-fix
+++ a/mm/compaction.c
@@ -36,10 +36,10 @@ struct compact_control {
struct zone *zone;
};
-static int release_freepages(struct list_head *freelist)
+static unsigned long release_freepages(struct list_head *freelist)
{
struct page *page, *next;
- int count = 0;
+ unsigned long count = 0;
list_for_each_entry_safe(page, next, freelist, lru) {
list_del(&page->lru);
@@ -51,28 +51,33 @@ static int release_freepages(struct list
}
/* Isolate free pages onto a private freelist. Must hold zone->lock */
-static int isolate_freepages_block(struct zone *zone,
+static unsigned long isolate_freepages_block(struct zone *zone,
unsigned long blockpfn,
struct list_head *freelist)
{
unsigned long zone_end_pfn, end_pfn;
int total_isolated = 0;
+ struct page *cursor;
/* Get the last PFN we should scan for free pages at */
zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
- end_pfn = blockpfn + pageblock_nr_pages;
- if (end_pfn > zone_end_pfn)
- end_pfn = zone_end_pfn;
+ end_pfn = min(blockpfn + pageblock_nr_pages, zone_end_pfn);
- /* Isolate free pages. This assumes the block is valid */
+ /* Find the first usable PFN in the block to initialse page cursor */
for (; blockpfn < end_pfn; blockpfn++) {
- struct page *page;
+ if (pfn_valid_within(blockpfn))
+ break;
+ }
+ cursor = pfn_to_page(blockpfn);
+
+ /* Isolate free pages. This assumes the block is valid */
+ for (; blockpfn < end_pfn; blockpfn++, cursor++) {
int isolated, i;
+ struct page *page = cursor;
if (!pfn_valid_within(blockpfn))
continue;
- page = pfn_to_page(blockpfn);
if (!PageBuddy(page))
continue;
@@ -85,38 +90,40 @@ static int isolate_freepages_block(struc
}
/* If a page was split, advance to the end of it */
- if (isolated)
+ if (isolated) {
blockpfn += isolated - 1;
+ cursor += isolated - 1;
+ }
}
return total_isolated;
}
-/* Returns 1 if the page is within a block suitable for migration to */
-static int suitable_migration_target(struct page *page)
+/* Returns true if the page is within a block suitable for migration to */
+static bool suitable_migration_target(struct page *page)
{
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 0;
+ return false;
/* If the page is a large free page, then allow migration */
if (PageBuddy(page) && page_order(page) >= pageblock_order)
- return 1;
+ return true;
/* If the block is MIGRATE_MOVABLE, allow migration */
if (migratetype == MIGRATE_MOVABLE)
- return 1;
+ return true;
/* Otherwise skip the block */
- return 0;
+ return false;
}
/*
* Based on information in the current compact_control, find blocks
- * suitable for isolating free pages from
+ * suitable for isolating free pages from and then isolate them.
*/
static void isolate_freepages(struct zone *zone,
struct compact_control *cc)
@@ -139,7 +146,7 @@ static void isolate_freepages(struct zon
spin_lock_irqsave(&zone->lock, flags);
for (; pfn > low_pfn && cc->nr_migratepages > nr_freepages;
pfn -= pageblock_nr_pages) {
- int isolated;
+ unsigned long isolated;
if (!pfn_valid(pfn))
continue;
@@ -195,7 +202,7 @@ static void acct_isolated(struct zone *z
}
/* Similar to reclaim, but different enough that they don't share logic */
-static int too_many_isolated(struct zone *zone)
+static bool too_many_isolated(struct zone *zone)
{
unsigned long inactive, isolated;
@@ -216,16 +223,12 @@ static unsigned long isolate_migratepage
struct compact_control *cc)
{
unsigned long low_pfn, end_pfn;
- struct list_head *migratelist;
-
- low_pfn = cc->migrate_pfn;
- migratelist = &cc->migratepages;
+ struct list_head *migratelist = &cc->migratepages;
/* Do not scan outside zone boundaries */
- if (low_pfn < zone->zone_start_pfn)
- low_pfn = zone->zone_start_pfn;
+ low_pfn = max(cc->migrate_pfn, zone->zone_start_pfn);
- /* Setup to scan one block but not past where we are migrating to */
+ /* Only scan within a pageblock boundary */
end_pfn = ALIGN(low_pfn + pageblock_nr_pages, pageblock_nr_pages);
/* Do not cross the free scanner or scan within a memory hole */
@@ -234,7 +237,11 @@ static unsigned long isolate_migratepage
return 0;
}
- /* Do not isolate the world */
+ /*
+ * 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))) {
congestion_wait(BLK_RW_ASYNC, HZ/10);
@@ -257,12 +264,14 @@ static unsigned long isolate_migratepage
}
/* Try isolate the page */
- if (__isolate_lru_page(page, ISOLATE_BOTH, 0) == 0) {
- del_page_from_lru_list(zone, page, page_lru(page));
- list_add(&page->lru, migratelist);
- mem_cgroup_del_lru(page);
- cc->nr_migratepages++;
- }
+ if (__isolate_lru_page(page, ISOLATE_BOTH, 0) != 0)
+ continue;
+
+ /* Successfully isolated */
+ del_page_from_lru_list(zone, page, page_lru(page));
+ list_add(&page->lru, migratelist);
+ mem_cgroup_del_lru(page);
+ cc->nr_migratepages++;
/* Avoid isolating too much */
if (cc->nr_migratepages == COMPACT_CLUSTER_MAX)
@@ -313,6 +322,7 @@ static void update_nr_listpages(struct c
int nr_migratepages = 0;
int nr_freepages = 0;
struct page *page;
+
list_for_each_entry(page, &cc->migratepages, lru)
nr_migratepages++;
list_for_each_entry(page, &cc->freepages, lru)
@@ -337,7 +347,7 @@ static inline int compact_finished(struc
static int compact_zone(struct zone *zone, struct compact_control *cc)
{
- int ret = COMPACT_INCOMPLETE;
+ int ret;
/* Setup to move all movable pages to the end of the zone */
cc->migrate_pfn = zone->zone_start_pfn;
@@ -346,8 +356,9 @@ static int compact_zone(struct zone *zon
migrate_prep();
- for (; ret == COMPACT_INCOMPLETE; ret = compact_finished(zone, cc)) {
+ while ((ret = compact_finished(zone, cc)) == COMPACT_INCOMPLETE) {
unsigned long nr_migrate, nr_remaining;
+
if (!isolate_migratepages(zone, cc))
continue;
diff -puN mm/page_alloc.c~mm-compaction-memory-compaction-core-fix mm/page_alloc.c
--- a/mm/page_alloc.c~mm-compaction-memory-compaction-core-fix
+++ a/mm/page_alloc.c
@@ -1222,7 +1222,7 @@ int split_free_page(struct page *page)
zone = page_zone(page);
order = page_order(page);
- /* Obey watermarks or the system could deadlock */
+ /* Obey watermarks as if the page was being allocated */
watermark = low_wmark_pages(zone) + (1 << order);
if (!zone_watermark_ok(zone, 0, watermark, 0, 0))
return 0;
_
Patches currently in -mm which might be from mel@xxxxxxxxx are
page-allocator-reduce-fragmentation-in-buddy-allocator-by-adding-buddies-that-are-merging-to-the-tail-of-the-free-lists.patch
mempolicy-remove-redundant-code.patch
mm-default-to-node-zonelist-ordering-when-nodes-have-only-lowmem.patch
mm-migration-take-a-reference-to-the-anon_vma-before-migrating.patch
mm-migration-do-not-try-to-migrate-unmapped-anonymous-pages.patch
mm-share-the-anon_vma-ref-counts-between-ksm-and-page-migration.patch
mm-allow-config_migration-to-be-set-without-config_numa-or-memory-hot-remove.patch
mm-allow-config_migration-to-be-set-without-config_numa-or-memory-hot-remove-fix.patch
mm-export-unusable-free-space-index-via-proc-unusable_index.patch
mm-export-fragmentation-index-via-proc-extfrag_index.patch
mm-move-definition-for-lru-isolation-modes-to-a-header.patch
mm-compaction-memory-compaction-core.patch
mm-compaction-memory-compaction-core-fix.patch
mm-compaction-add-proc-trigger-for-memory-compaction.patch
mm-compaction-add-sys-trigger-for-per-node-memory-compaction.patch
mm-compaction-direct-compact-when-a-high-order-allocation-fails.patch
mm-compaction-add-a-tunable-that-decides-when-memory-should-be-compacted-and-when-it-should-be-reclaimed.patch
mm-compaction-do-not-compact-within-a-preferred-zone-after-a-compaction-failure.patch
mm-migration-allow-the-migration-of-pageswapcache-pages.patch
delay-accounting-re-implement-c-for-getdelaysc-to-report-information-on-a-target-command.patch
delay-accounting-re-implement-c-for-getdelaysc-to-report-information-on-a-target-command-checkpatch-fixes.patch
add-debugging-aid-for-memory-initialisation-problems.patch
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