diff options
| -rw-r--r-- | mm/compaction.c | 35 |
1 files changed, 20 insertions, 15 deletions
diff --git a/mm/compaction.c b/mm/compaction.c index 7077b81a4893..2c1e1ff321bf 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -943,8 +943,7 @@ static void isolate_freepages(struct compact_control *cc) * pages on cc->migratepages. We stop searching if the migrate * and free page scanners meet or enough free pages are isolated. */ - for (; block_start_pfn >= low_pfn && - cc->nr_migratepages > cc->nr_freepages; + for (; block_start_pfn >= low_pfn; block_end_pfn = block_start_pfn, block_start_pfn -= pageblock_nr_pages, isolate_start_pfn = block_start_pfn) { @@ -976,6 +975,8 @@ static void isolate_freepages(struct compact_control *cc) block_end_pfn, freelist, false); /* + * If we isolated enough freepages, or aborted due to async + * compaction being contended, terminate the loop. * Remember where the free scanner should restart next time, * which is where isolate_freepages_block() left off. * But if it scanned the whole pageblock, isolate_start_pfn @@ -984,27 +985,31 @@ static void isolate_freepages(struct compact_control *cc) * In that case we will however want to restart at the start * of the previous pageblock. */ - cc->free_pfn = (isolate_start_pfn < block_end_pfn) ? - isolate_start_pfn : - block_start_pfn - pageblock_nr_pages; - - /* - * isolate_freepages_block() might have aborted due to async - * compaction being contended - */ - if (cc->contended) + if ((cc->nr_freepages >= cc->nr_migratepages) + || cc->contended) { + if (isolate_start_pfn >= block_end_pfn) + isolate_start_pfn = + block_start_pfn - pageblock_nr_pages; break; + } else { + /* + * isolate_freepages_block() should not terminate + * prematurely unless contended, or isolated enough + */ + VM_BUG_ON(isolate_start_pfn < block_end_pfn); + } } /* split_free_page does not map the pages */ map_pages(freelist); /* - * If we crossed the migrate scanner, we want to keep it that way - * so that compact_finished() may detect this + * Record where the free scanner will restart next time. Either we + * broke from the loop and set isolate_start_pfn based on the last + * call to isolate_freepages_block(), or we met the migration scanner + * and the loop terminated due to isolate_start_pfn < low_pfn */ - if (block_start_pfn < low_pfn) - cc->free_pfn = cc->migrate_pfn; + cc->free_pfn = isolate_start_pfn; } /* |