The patch titled Subject: mm: have order > 0 compaction start off where it left has been added to the -mm tree. Its filename is mm-have-order-0-compaction-start-off-where-it-left-v3.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Rik van Riel <riel@xxxxxxxxxx> Subject: mm: have order > 0 compaction start off where it left This patch makes the comment for cc->wrapped longer, explaining what is really going on. It also incorporates the comment fix pointed out by Minchan. Additionally, Minchan found that, when no pages get isolated, high_pte could be a value that is much lower than desired, which might potentially cause compaction to skip a range of pages. Only assign zone->compact_cache_free_pfn if we actually isolated free pages for compaction. Split out the calculation to get the start of the last page block in a zone into its own, commented function. Signed-off-by: Rik van Riel <riel@xxxxxxxxxx> Cc: Jim Schutt <jaschut@xxxxxxxxxx> Cc: Minchan Kim <minchan.kim@xxxxxxxxx> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Cc: Mel Gorman <mel@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/mmzone.h | 2 +- mm/compaction.c | 30 ++++++++++++++++++++++-------- mm/internal.h | 6 +++++- 3 files changed, 28 insertions(+), 10 deletions(-) diff -puN include/linux/mmzone.h~mm-have-order-0-compaction-start-off-where-it-left-v3 include/linux/mmzone.h --- a/include/linux/mmzone.h~mm-have-order-0-compaction-start-off-where-it-left-v3 +++ a/include/linux/mmzone.h @@ -368,7 +368,7 @@ struct zone { spinlock_t lock; int all_unreclaimable; /* All pages pinned */ #if defined CONFIG_COMPACTION || defined CONFIG_CMA - /* pfn where the last order > 0 compaction isolated free pages */ + /* pfn where the last incremental compaction isolated free pages */ unsigned long compact_cached_free_pfn; #endif #ifdef CONFIG_MEMORY_HOTPLUG diff -puN mm/compaction.c~mm-have-order-0-compaction-start-off-where-it-left-v3 mm/compaction.c --- a/mm/compaction.c~mm-have-order-0-compaction-start-off-where-it-left-v3 +++ a/mm/compaction.c @@ -472,10 +472,11 @@ static void isolate_freepages(struct zon * looking for free pages, the search will restart here as * page migration may have returned some pages to the allocator */ - if (isolated) + if (isolated) { high_pfn = max(high_pfn, pfn); - if (cc->order > 0) - zone->compact_cached_free_pfn = high_pfn; + if (cc->order > 0) + zone->compact_cached_free_pfn = high_pfn; + } } /* split_free_page does not map the pages */ @@ -569,6 +570,21 @@ static isolate_migrate_t isolate_migrate return ISOLATE_SUCCESS; } +/* + * Returns the start pfn of the laste page block in a zone. + * This is the starting point for full compaction of a zone. + * Compaction searches for free pages from the end of each zone, + * while isolate_freepages_block scans forward inside each page + * block. + */ +static unsigned long start_free_pfn(struct zone *zone) +{ + unsigned long free_pfn; + free_pfn = zone->zone_start_pfn + zone->spanned_pages; + free_pfn &= ~(pageblock_nr_pages-1); + return free_pfn; +} + static int compact_finished(struct zone *zone, struct compact_control *cc) { @@ -587,10 +603,9 @@ static int compact_finished(struct zone if (cc->free_pfn <= cc->migrate_pfn) { if (cc->order > 0 && !cc->wrapped) { /* We started partway through; restart at the end. */ - unsigned long free_pfn; - free_pfn = zone->zone_start_pfn + zone->spanned_pages; - free_pfn &= ~(pageblock_nr_pages-1); + unsigned long free_pfn = start_free_pfn(zone); zone->compact_cached_free_pfn = free_pfn; + cc->free_pfn = free_pfn; cc->wrapped = 1; return COMPACT_CONTINUE; } @@ -703,8 +718,7 @@ static int compact_zone(struct zone *zon cc->start_free_pfn = cc->free_pfn; } else { /* Order == -1 starts at the end of the zone. */ - cc->free_pfn = cc->migrate_pfn + zone->spanned_pages; - cc->free_pfn &= ~(pageblock_nr_pages-1); + cc->free_pfn = start_free_pfn(zone); } migrate_prep_local(); diff -puN mm/internal.h~mm-have-order-0-compaction-start-off-where-it-left-v3 mm/internal.h --- a/mm/internal.h~mm-have-order-0-compaction-start-off-where-it-left-v3 +++ a/mm/internal.h @@ -121,7 +121,11 @@ struct compact_control { unsigned long start_free_pfn; /* where we started the search */ unsigned long migrate_pfn; /* isolate_migratepages search base */ bool sync; /* Synchronous migration */ - bool wrapped; /* Last round for order>0 compaction */ + bool wrapped; /* Order > 0 compactions are + incremental, once free_pfn + and migrate_pfn meet, we restart + from the top of the zone; + remember we wrapped around. */ int order; /* order a direct compactor needs */ int migratetype; /* MOVABLE, RECLAIMABLE etc */ _ Subject: Subject: mm: have order > 0 compaction start off where it left Patches currently in -mm which might be from riel@xxxxxxxxxx are mm-thp-abort-compaction-if-migration-page-cannot-be-charged-to-memcg.patch linux-next.patch swap-allow-swap-readahead-to-be-merged.patch memcg-prevent-oom-with-too-many-dirty-pages.patch mm-clear-pages_scanned-only-if-draining-a-pcp-adds-pages-to-the-buddy-allocator-again.patch mm-remove-unused-lru_all_evictable.patch mm-have-order-0-compaction-start-off-where-it-left.patch mm-have-order-0-compaction-start-off-where-it-left-checkpatch-fixes.patch mm-have-order-0-compaction-start-off-where-it-left-v3.patch tmpfs-implement-numa-node-interleaving.patch tmpfs-implement-numa-node-interleaving-fix.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html