diff options
Diffstat (limited to 'mm/compaction.c')
| -rw-r--r-- | mm/compaction.c | 32 |
1 files changed, 26 insertions, 6 deletions
diff --git a/mm/compaction.c b/mm/compaction.c index 6d42ea126242..00a5126b6548 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -949,8 +949,11 @@ isolate_success: cc->nr_migratepages++; nr_isolated++; - /* Avoid isolating too much */ - if (cc->nr_migratepages == COMPACT_CLUSTER_MAX) { + /* + * Avoid isolating too much unless this block is being + * rescanned (e.g. dirty/writeback pages, parallel allocation). + */ + if (cc->nr_migratepages == COMPACT_CLUSTER_MAX && !cc->rescan) { ++low_pfn; break; } @@ -997,11 +1000,14 @@ isolate_abort: spin_unlock_irqrestore(zone_lru_lock(zone), flags); /* - * Updated the cached scanner pfn if the pageblock was scanned - * without isolating a page. The pageblock may not be marked - * skipped already if there were no LRU pages in the block. + * Updated the cached scanner pfn once the pageblock has been scanned + * Pages will either be migrated in which case there is no point + * scanning in the near future or migration failed in which case the + * failure reason may persist. The block is marked for skipping if + * there were no pages isolated in the block or if the block is + * rescanned twice in a row. */ - if (low_pfn == end_pfn && !nr_isolated) { + if (low_pfn == end_pfn && (!nr_isolated || cc->rescan)) { if (valid_page && !skip_updated) set_pageblock_skip(valid_page); update_cached_migrate(cc, low_pfn); @@ -2035,6 +2041,20 @@ static enum compact_result compact_zone(struct compact_control *cc) int err; unsigned long start_pfn = cc->migrate_pfn; + /* + * Avoid multiple rescans which can happen if a page cannot be + * isolated (dirty/writeback in async mode) or if the migrated + * pages are being allocated before the pageblock is cleared. + * The first rescan will capture the entire pageblock for + * migration. If it fails, it'll be marked skip and scanning + * will proceed as normal. + */ + cc->rescan = false; + if (pageblock_start_pfn(last_migrated_pfn) == + pageblock_start_pfn(start_pfn)) { + cc->rescan = true; + } + switch (isolate_migratepages(cc->zone, cc)) { case ISOLATE_ABORT: ret = COMPACT_CONTENDED; |