The patch titled
Subject: mm/compaction: fix invalid free_pfn and compact_cached_free_pfn
has been added to the -mm tree. Its filename is
mm-compaction-fix-invalid-free_pfn-and-compact_cached_free_pfn.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-compaction-fix-invalid-free_pfn-and-compact_cached_free_pfn.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-compaction-fix-invalid-free_pfn-and-compact_cached_free_pfn.patch
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------------------------------------------------------
From: Joonsoo Kim <js1304@xxxxxxxxx>
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 js1304@xxxxxxxxx are
mm-slab-fix-stale-code-comment.patch
mm-slab-remove-useless-structure-define.patch
mm-slab-remove-the-checks-for-slab-implementation-bug.patch
mm-slab-activate-debug_pagealloc-in-slab-when-it-is-actually-enabled.patch
mm-slab-use-more-appropriate-condition-check-for-debug_pagealloc.patch
mm-slab-clean-up-debug_pagealloc-processing-code.patch
mm-slab-alternative-implementation-for-debug_slab_leak.patch
mm-slab-remove-object-status-buffer-for-debug_slab_leak.patch
mm-slab-put-the-freelist-at-the-end-of-slab-page.patch
mm-slab-align-cache-size-first-before-determination-of-off_slab-candidate.patch
mm-slab-clean-up-cache-type-determination.patch
mm-slab-do-not-change-cache-size-if-debug-pagealloc-isnt-possible.patch
mm-slab-make-criteria-for-off-slab-determination-robust-and-simple.patch
mm-slab-factor-out-slab-list-fixup-code.patch
mm-slab-factor-out-debugging-initialization-in-cache_init_objs.patch
mm-slab-introduce-new-slab-management-type-objfreelist_slab.patch
mm-compaction-fix-invalid-free_pfn-and-compact_cached_free_pfn.patch
mm-compaction-pass-only-pageblock-aligned-range-to-pageblock_pfn_to_page.patch
mm-compaction-speed-up-pageblock_pfn_to_page-when-zone-is-contiguous.patch
--
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