The patch titled Subject: vmscan: reclaim at order 0 when compaction is enabled has been added to the -mm tree. Its filename is vmscan-reclaim-at-order-0-when-compaction-is-enabled.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: vmscan: reclaim at order 0 when compaction is enabled When built with CONFIG_COMPACTION, kswapd should not try to free contiguous pages, because it is not trying hard enough to have a real chance at being successful, but still disrupts the LRU enough to break other things. Do not do higher order page isolation unless we really are in lumpy reclaim mode. Stop reclaiming pages once we have enough free pages that compaction can deal with things, and we hit the normal order 0 watermarks used by kswapd. Also remove a line of code that increments balanced right before exiting the function. Signed-off-by: Rik van Riel <riel@xxxxxxxxxx> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> Cc: Mel Gorman <mel@xxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Minchan Kim <minchan.kim@xxxxxxxxx> Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> Cc: Hillf Danton <dhillf@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/vmscan.c | 47 ++++++++++++++++++++++++++++++----------------- 1 file changed, 30 insertions(+), 17 deletions(-) diff -puN mm/vmscan.c~vmscan-reclaim-at-order-0-when-compaction-is-enabled mm/vmscan.c --- a/mm/vmscan.c~vmscan-reclaim-at-order-0-when-compaction-is-enabled +++ a/mm/vmscan.c @@ -1138,7 +1138,7 @@ int __isolate_lru_page(struct page *page * @mz: The mem_cgroup_zone to pull pages from. * @dst: The temp list to put pages on to. * @nr_scanned: The number of pages that were scanned. - * @order: The caller's attempted allocation order + * @sc: The scan_control struct for this reclaim session * @mode: One of the LRU isolation modes * @active: True [1] if isolating active pages * @file: True [1] if isolating file [!anon] pages @@ -1147,8 +1147,8 @@ int __isolate_lru_page(struct page *page */ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, struct mem_cgroup_zone *mz, struct list_head *dst, - unsigned long *nr_scanned, int order, isolate_mode_t mode, - int active, int file) + unsigned long *nr_scanned, struct scan_control *sc, + isolate_mode_t mode, int active, int file) { struct lruvec *lruvec; struct list_head *src; @@ -1194,7 +1194,7 @@ static unsigned long isolate_lru_pages(u BUG(); } - if (!order) + if (!sc->order || !(sc->reclaim_mode & RECLAIM_MODE_LUMPYRECLAIM)) continue; /* @@ -1208,8 +1208,8 @@ static unsigned long isolate_lru_pages(u */ zone_id = page_zone_id(page); page_pfn = page_to_pfn(page); - pfn = page_pfn & ~((1 << order) - 1); - end_pfn = pfn + (1 << order); + pfn = page_pfn & ~((1 << sc->order) - 1); + end_pfn = pfn + (1 << sc->order); for (; pfn < end_pfn; pfn++) { struct page *cursor_page; @@ -1275,7 +1275,7 @@ static unsigned long isolate_lru_pages(u *nr_scanned = scan; - trace_mm_vmscan_lru_isolate(order, + trace_mm_vmscan_lru_isolate(sc->order, nr_to_scan, scan, nr_taken, nr_lumpy_taken, nr_lumpy_dirty, nr_lumpy_failed, @@ -1533,9 +1533,8 @@ shrink_inactive_list(unsigned long nr_to spin_lock_irq(&zone->lru_lock); - nr_taken = isolate_lru_pages(nr_to_scan, mz, &page_list, - &nr_scanned, sc->order, - isolate_mode, 0, file); + nr_taken = isolate_lru_pages(nr_to_scan, mz, &page_list, &nr_scanned, + sc, isolate_mode, 0, file); if (global_reclaim(sc)) { zone->pages_scanned += nr_scanned; if (current_is_kswapd()) @@ -1711,8 +1710,7 @@ static void shrink_active_list(unsigned spin_lock_irq(&zone->lru_lock); - nr_taken = isolate_lru_pages(nr_to_scan, mz, &l_hold, - &nr_scanned, sc->order, + nr_taken = isolate_lru_pages(nr_to_scan, mz, &l_hold, &nr_scanned, sc, isolate_mode, 1, file); if (global_reclaim(sc)) zone->pages_scanned += nr_scanned; @@ -2758,7 +2756,7 @@ loop_again: */ for (i = 0; i <= end_zone; i++) { struct zone *zone = pgdat->node_zones + i; - int nr_slab; + int nr_slab, testorder; unsigned long balance_gap; if (!populated_zone(zone)) @@ -2791,7 +2789,20 @@ loop_again: (zone->present_pages + KSWAPD_ZONE_BALANCE_GAP_RATIO-1) / KSWAPD_ZONE_BALANCE_GAP_RATIO); - if (!zone_watermark_ok_safe(zone, order, + /* + * Kswapd reclaims only single pages with compaction + * enabled. Trying too hard to reclaim until contiguous + * free pages have become available can hurt performance + * by evicting too much useful data from memory. + * Do not reclaim more than needed for compaction. + */ + testorder = order; + if (COMPACTION_BUILD && order && + compaction_suitable(zone, order) != + COMPACT_SKIPPED) + testorder = 0; + + if (!zone_watermark_ok_safe(zone, testorder, high_wmark_pages(zone) + balance_gap, end_zone, 0)) { shrink_zone(priority, zone, &sc); @@ -2820,7 +2831,7 @@ loop_again: continue; } - if (!zone_watermark_ok_safe(zone, order, + if (!zone_watermark_ok_safe(zone, testorder, high_wmark_pages(zone), end_zone, 0)) { all_zones_ok = 0; /* @@ -2917,6 +2928,10 @@ out: if (zone->all_unreclaimable && priority != DEF_PRIORITY) continue; + /* Would compaction fail due to lack of free memory? */ + if (compaction_suitable(zone, order) == COMPACT_SKIPPED) + goto loop_again; + /* Confirm the zone is balanced for order-0 */ if (!zone_watermark_ok(zone, 0, high_wmark_pages(zone), 0, 0)) { @@ -2926,8 +2941,6 @@ out: /* If balanced, clear the congested flag */ zone_clear_flag(zone, ZONE_CONGESTED); - if (i <= *classzone_idx) - balanced += zone->present_pages; } } _ Subject: Subject: vmscan: reclaim at order 0 when compaction is enabled Patches currently in -mm which might be from riel@xxxxxxxxxx are origin.patch linux-next.patch mm-vmscanc-cleanup-with-s-reclaim_mode-isolate_mode.patch mm-vmscan-fix-misused-nr_reclaimed-in-shrink_mem_cgroup_zone.patch make-swapin-readahead-skip-over-holes.patch make-swapin-readahead-skip-over-holes-fix.patch vmscan-reclaim-at-order-0-when-compaction-is-enabled.patch vmscan-kswapd-carefully-call-compaction.patch vmscan-kswapd-carefully-call-compaction-fix.patch vmscan-only-defer-compaction-for-failed-order-and-higher.patch mm-fix-page-faults-detection-in-swap-token-logic.patch mm-add-extra-free-kbytes-tunable.patch mm-add-extra-free-kbytes-tunable-update.patch mm-add-extra-free-kbytes-tunable-update-checkpatch-fixes.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