The patch titled Subject: mm: fix zone_watermark_ok_safe() accounting of isolated pages has been added to the -mm tree. Its filename is mm-fix-zone_watermark_ok_safe-accounting-of-isolated-pages.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: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx> Subject: mm: fix zone_watermark_ok_safe() accounting of isolated pages In kernel v3.6 commit 702d1a6e07 ("memory-hotplug: fix kswapd looping forever problem") added isolated pageblocks counter (nr_pageblock_isolate in struct zone) and used it to adjust free pages counter in zone_watermark_ok_safe() to prevent kswapd looping forever problem. In kernel v3.7 commit 2139cbe627b8 ("cma: fix counting of isolated pages") fixed accounting of isolated pages in global free pages counter. It made previous zone_watermark_ok_safe() fix unnecessary and potentially harmful (cause now isolated pages may be accounted twice making free pages counter incorrect). This patch removes special isolated pageblocks counter altogether which fixes zone_watermark_ok_safe() free pages check. Reported-by: Tomasz Stanislawski <t.stanislaws@xxxxxxxxxxx> Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx> Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx> Cc: Minchan Kim <minchan@xxxxxxxxxx> Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> Cc: Aaditya Kumar <aaditya.kumar.30@xxxxxxxxx> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Cc: Mel Gorman <mgorman@xxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxx> Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> Cc: Michal Nazarewicz <mina86@xxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/mmzone.h | 8 -------- mm/page_alloc.c | 27 --------------------------- mm/page_isolation.c | 26 ++------------------------ 3 files changed, 2 insertions(+), 59 deletions(-) diff -puN include/linux/mmzone.h~mm-fix-zone_watermark_ok_safe-accounting-of-isolated-pages include/linux/mmzone.h --- a/include/linux/mmzone.h~mm-fix-zone_watermark_ok_safe-accounting-of-isolated-pages +++ a/include/linux/mmzone.h @@ -503,14 +503,6 @@ struct zone { * rarely used fields: */ const char *name; -#ifdef CONFIG_MEMORY_ISOLATION - /* - * the number of MIGRATE_ISOLATE *pageblock*. - * We need this for free page counting. Look at zone_watermark_ok_safe. - * It's protected by zone->lock - */ - int nr_pageblock_isolate; -#endif } ____cacheline_internodealigned_in_smp; typedef enum { diff -puN mm/page_alloc.c~mm-fix-zone_watermark_ok_safe-accounting-of-isolated-pages mm/page_alloc.c --- a/mm/page_alloc.c~mm-fix-zone_watermark_ok_safe-accounting-of-isolated-pages +++ a/mm/page_alloc.c @@ -221,11 +221,6 @@ EXPORT_SYMBOL(nr_online_nodes); int page_group_by_mobility_disabled __read_mostly; -/* - * NOTE: - * Don't use set_pageblock_migratetype(page, MIGRATE_ISOLATE) directly. - * Instead, use {un}set_pageblock_isolate. - */ void set_pageblock_migratetype(struct page *page, int migratetype) { @@ -1655,20 +1650,6 @@ static bool __zone_watermark_ok(struct z return true; } -#ifdef CONFIG_MEMORY_ISOLATION -static inline unsigned long nr_zone_isolate_freepages(struct zone *zone) -{ - if (unlikely(zone->nr_pageblock_isolate)) - return zone->nr_pageblock_isolate * pageblock_nr_pages; - return 0; -} -#else -static inline unsigned long nr_zone_isolate_freepages(struct zone *zone) -{ - return 0; -} -#endif - bool zone_watermark_ok(struct zone *z, int order, unsigned long mark, int classzone_idx, int alloc_flags) { @@ -1684,14 +1665,6 @@ bool zone_watermark_ok_safe(struct zone if (z->percpu_drift_mark && free_pages < z->percpu_drift_mark) free_pages = zone_page_state_snapshot(z, NR_FREE_PAGES); - /* - * If the zone has MIGRATE_ISOLATE type free pages, we should consider - * it. nr_zone_isolate_freepages is never accurate so kswapd might not - * sleep although it could do so. But this is more desirable for memory - * hotplug than sleeping which can cause a livelock in the direct - * reclaim path. - */ - free_pages -= nr_zone_isolate_freepages(z); return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags, free_pages); } diff -puN mm/page_isolation.c~mm-fix-zone_watermark_ok_safe-accounting-of-isolated-pages mm/page_isolation.c --- a/mm/page_isolation.c~mm-fix-zone_watermark_ok_safe-accounting-of-isolated-pages +++ a/mm/page_isolation.c @@ -8,28 +8,6 @@ #include <linux/memory.h> #include "internal.h" -/* called while holding zone->lock */ -static void set_pageblock_isolate(struct page *page) -{ - if (get_pageblock_migratetype(page) == MIGRATE_ISOLATE) - return; - - set_pageblock_migratetype(page, MIGRATE_ISOLATE); - page_zone(page)->nr_pageblock_isolate++; -} - -/* called while holding zone->lock */ -static void restore_pageblock_isolate(struct page *page, int migratetype) -{ - struct zone *zone = page_zone(page); - if (WARN_ON(get_pageblock_migratetype(page) != MIGRATE_ISOLATE)) - return; - - BUG_ON(zone->nr_pageblock_isolate <= 0); - set_pageblock_migratetype(page, migratetype); - zone->nr_pageblock_isolate--; -} - int set_migratetype_isolate(struct page *page, bool skip_hwpoisoned_pages) { struct zone *zone; @@ -80,7 +58,7 @@ out: unsigned long nr_pages; int migratetype = get_pageblock_migratetype(page); - set_pageblock_isolate(page); + set_pageblock_migratetype(page, MIGRATE_ISOLATE); nr_pages = move_freepages_block(zone, page, MIGRATE_ISOLATE); __mod_zone_freepage_state(zone, -nr_pages, migratetype); @@ -103,7 +81,7 @@ void unset_migratetype_isolate(struct pa goto out; nr_pages = move_freepages_block(zone, page, migratetype); __mod_zone_freepage_state(zone, nr_pages, migratetype); - restore_pageblock_isolate(page, migratetype); + set_pageblock_migratetype(page, migratetype); out: spin_unlock_irqrestore(&zone->lock, flags); } _ Patches currently in -mm which might be from b.zolnierkie@xxxxxxxxxxx are origin.patch mm-fix-zone_watermark_ok_safe-accounting-of-isolated-pages.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