The patch titled
Subject: mm/compaction: fix invalid free_pfn and compact_cached_free_pfn
has been removed from the -mm tree. Its filename was
mm-compaction-fix-invalid-free_pfn-and-compact_cached_free_pfn.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Subject: mm/compaction: fix invalid free_pfn and compact_cached_free_pfn
free_pfn and compact_cached_free_pfn are the pointer that remember restart
position of freepage scanner. When they are reset or invalid, we set them
to zone_end_pfn because freepage scanner works in reverse direction. But,
because zone range is defined as [zone_start_pfn, zone_end_pfn),
zone_end_pfn is invalid to access. Therefore, we should not store it to
free_pfn and compact_cached_free_pfn. Instead, we need to store
zone_end_pfn - 1 to them. There is one more thing we should consider.
Freepage scanner scan reversely by pageblock unit. If free_pfn and
compact_cached_free_pfn are set to middle of pageblock, it regards that
sitiation as that it already scans front part of pageblock so we lose
opportunity to scan there. To fix-up, this patch do round_down() to
guarantee that reset position will be pageblock aligned.
Note that thanks to the current pageblock_pfn_to_page() implementation,
actual access to zone_end_pfn doesn't happen until now. But, following
patch will change pageblock_pfn_to_page() so this patch is needed from now
on.
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Aaron Lu <aaron.lu@xxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/compaction.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff -puN mm/compaction.c~mm-compaction-fix-invalid-free_pfn-and-compact_cached_free_pfn mm/compaction.c
--- a/mm/compaction.c~mm-compaction-fix-invalid-free_pfn-and-compact_cached_free_pfn
+++ a/mm/compaction.c
@@ -200,7 +200,8 @@ static void reset_cached_positions(struc
{
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 = zone_end_pfn(zone);
+ zone->compact_cached_free_pfn =
+ round_down(zone_end_pfn(zone) - 1, pageblock_nr_pages);
}
/*
@@ -1371,11 +1372,11 @@ static int compact_zone(struct zone *zon
*/
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 = end_pfn & ~(pageblock_nr_pages-1);
+ if (cc->free_pfn < start_pfn || cc->free_pfn >= end_pfn) {
+ cc->free_pfn = round_down(end_pfn - 1, pageblock_nr_pages);
zone->compact_cached_free_pfn = cc->free_pfn;
}
- if (cc->migrate_pfn < start_pfn || cc->migrate_pfn > end_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;
_
Patches currently in -mm which might be from iamjoonsoo.kim@xxxxxxx are
mm-vmalloc-query-dynamic-debug_pagealloc-setting.patch
mm-slub-query-dynamic-debug_pagealloc-setting.patch
mm-slub-query-dynamic-debug_pagealloc-setting-v2.patch
sound-query-dynamic-debug_pagealloc-setting.patch
powerpc-query-dynamic-debug_pagealloc-setting.patch
tile-query-dynamic-debug_pagealloc-setting.patch
mm-introduce-page-reference-manipulation-functions.patch
mm-page_ref-add-tracepoint-to-track-down-page-reference-manipulation.patch
mm-page_ref-add-tracepoint-to-track-down-page-reference-manipulation-fix-3.patch
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