+ mm-zone_page_state-regularize-up-and-smp-behavior.patch added to -mm tree

+ mm-zone_page_state-regularize-up-and-smp-behavior.patch added to -mm tree

[akpm]

The patch titled
     Subject: mm: zone_page_state(): regularize UP and SMP behavior
has been added to the -mm tree.  Its filename is
     mm-zone_page_state-regularize-up-and-smp-behavior.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/mm-zone_page_state-regularize-up-and-smp-behavior.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/mm-zone_page_state-regularize-up-and-smp-behavior.patch

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------------------------------------------------------
From: Mel Gorman <mgorman@suse.de>
Subject: mm: zone_page_state(): regularize UP and SMP behavior

zone_page_state is an API hazard because of the difference in behaviour
between SMP and UP is very surprising.  There is a good reason to allow
NR_ALLOC_BATCH to go negative -- when the counter is reset the negative
value takes recent activity into account.  This patch makes
zone_page_state behave the same on SMP and UP as saving one branch on UP
is not likely to make a measurable performance difference.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Reported-by: Vlastimil Babka <vbabka@suse.cz>
Reported-by: Leon Romanovsky <leon@leon.nu>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/vmstat.h |    2 --
 1 file changed, 2 deletions(-)

diff -puN include/linux/vmstat.h~mm-zone_page_state-regularize-up-and-smp-behavior include/linux/vmstat.h
--- a/include/linux/vmstat.h~mm-zone_page_state-regularize-up-and-smp-behavior
+++ a/include/linux/vmstat.h
@@ -131,10 +131,8 @@ static inline unsigned long zone_page_st
 					enum zone_stat_item item)
 {
 	long x = atomic_long_read(&zone->vm_stat[item]);
-#ifdef CONFIG_SMP
 	if (x < 0)
 		x = 0;
-#endif
 	return x;
 }
 
_

Patches currently in -mm which might be from mgorman@suse.de are

mm-page_alloc-fix-zone-allocation-fairness-on-up.patch
mm-remove-misleading-arch_uses_numa_prot_none.patch
mm-page_alloc-determine-migratetype-only-once.patch
mm-thp-dont-hold-mmap_sem-in-khugepaged-when-allocating-thp.patch
mm-compaction-defer-each-zone-individually-instead-of-preferred-zone.patch
mm-compaction-defer-each-zone-individually-instead-of-preferred-zone-fix.patch
mm-compaction-do-not-count-compact_stall-if-all-zones-skipped-compaction.patch
mm-compaction-do-not-recheck-suitable_migration_target-under-lock.patch
mm-compaction-move-pageblock-checks-up-from-isolate_migratepages_range.patch
mm-compaction-reduce-zone-checking-frequency-in-the-migration-scanner.patch
mm-compaction-khugepaged-should-not-give-up-due-to-need_resched.patch
mm-compaction-khugepaged-should-not-give-up-due-to-need_resched-fix.patch
mm-compaction-periodically-drop-lock-and-restore-irqs-in-scanners.patch
mm-compaction-skip-rechecks-when-lock-was-already-held.patch
mm-compaction-remember-position-within-pageblock-in-free-pages-scanner.patch
mm-compaction-skip-buddy-pages-by-their-order-in-the-migrate-scanner.patch
mm-rename-allocflags_to_migratetype-for-clarity.patch
mm-compaction-pass-gfp-mask-to-compact_control.patch
introduce-dump_vma.patch
introduce-dump_vma-fix.patch
introduce-vm_bug_on_vma.patch
convert-a-few-vm_bug_on-callers-to-vm_bug_on_vma.patch
mm-page_alloc-avoid-wakeup-kswapd-on-the-unintended-node.patch
mm-clean-up-zone-flags.patch
mm-zone_page_state-regularize-up-and-smp-behavior.patch
mm-introduce-do_shared_fault-and-drop-do_fault-fix-fix.patch
do_shared_fault-check-that-mmap_sem-is-held.patch
x86-optimize-resource-lookups-for-ioremap.patch
x86-optimize-resource-lookups-for-ioremap-fix.patch
x86-use-optimized-ioresource-lookup-in-ioremap-function.patch
linux-next.patch