This is a note to let you know that I've just added the patch titled mm: vmscan: convert global reclaim to per-memcg LRU lists
to the 3.0-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mm-vmscan-convert-global-reclaim-to-per-memcg-lru-lists.patch and it can be found in the queue-3.0 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@vger.kernel.org> know about it. >From b95a2f2d486d0d768a92879c023a03757b9c7e58 Mon Sep 17 00:00:00 2001 From: Johannes Weiner <jwei...@redhat.com> Date: Thu, 12 Jan 2012 17:18:06 -0800 Subject: mm: vmscan: convert global reclaim to per-memcg LRU lists From: Johannes Weiner <jwei...@redhat.com> commit b95a2f2d486d0d768a92879c023a03757b9c7e58 upstream - WARNING: this is a substitute patch. Stable note: Not tracked in Bugzilla. This is a partial backport of an upstream commit addressing a completely different issue that accidentally contained an important fix. The workload this patch helps was memcached when IO is started in the background. memcached should stay resident but without this patch it gets swapped. Sometimes this manifests as a drop in throughput but mostly it was observed through /proc/vmstat. Commit [246e87a9: memcg: fix get_scan_count() for small targets] was meant to fix a problem whereby small scan targets on memcg were ignored causing priority to raise too sharply. It forced scanning to take place if the target was small, memcg or kswapd. >From the time it was introduced it caused excessive reclaim by kswapd with workloads being pushed to swap that previously would have stayed resident. This was accidentally fixed in commit [b95a2f2d: mm: vmscan: convert global reclaim to per-memcg LRU lists] by making it harder for kswapd to force scan small targets but that patchset is not suitable for backporting. This was later changed again by commit [90126375: mm/vmscan: push lruvec pointer into get_scan_count()] into a format that looks like it would be a straight-forward backport but there is a subtle difference due to the use of lruvecs. The impact of the accidental fix is to make it harder for kswapd to force scan small targets by taking zone->all_unreclaimable into account. This patch is the closest equivalent available based on what is backported. --- mm/vmscan.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1850,7 +1850,8 @@ static void get_scan_count(struct zone * unsigned long nr_force_scan[2]; /* kswapd does zone balancing and needs to scan this zone */ - if (scanning_global_lru(sc) && current_is_kswapd()) + if (scanning_global_lru(sc) && current_is_kswapd() && + zone->all_unreclaimable) force_scan = true; /* memcg may have small limit and need to avoid priority drop */ if (!scanning_global_lru(sc)) Patches currently in stable-queue which might be from jwei...@redhat.com are queue-3.0/mm-vmscan-when-reclaiming-for-compaction-ensure-there-are-sufficient-free-pages-available.patch queue-3.0/mm-compaction-allow-compaction-to-isolate-dirty-pages.patch queue-3.0/mm-page-allocator-do-not-call-direct-reclaim-for-thp-allocations-while-compaction-is-deferred.patch queue-3.0/mm-vmscan-check-if-reclaim-should-really-abort-even-if-compaction_ready-is-true-for-one-zone.patch queue-3.0/mm-vmscan-convert-global-reclaim-to-per-memcg-lru-lists.patch queue-3.0/mm-compaction-introduce-sync-light-migration-for-use-by-compaction.patch queue-3.0/mm-vmscan.c-consider-swap-space-when-deciding-whether-to-continue-reclaim.patch queue-3.0/mm-vmscan-do-not-oom-if-aborting-reclaim-to-start-compaction.patch queue-3.0/mm-compaction-make-isolate_lru_page-filter-aware-again.patch queue-3.0/mm-compaction-determine-if-dirty-pages-can-be-migrated-without-blocking-within-migratepage.patch queue-3.0/vmscan-limit-direct-reclaim-for-higher-order-allocations.patch queue-3.0/mm-vmscan-fix-force-scanning-small-targets-without-swap.patch queue-3.0/vmscan-abort-reclaim-compaction-if-compaction-can-proceed.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html