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| author | Joel Becker <joel.becker@oracle.com> | 2010-10-15 13:03:09 -0700 |
|---|---|---|
| committer | Joel Becker <joel.becker@oracle.com> | 2010-10-15 13:03:09 -0700 |
| commit | fc3718918f13ad72827d62d36ea0f5fb55090644 (patch) | |
| tree | 4f9551256e02d08be37bab137f3d94182a67504c /mm/mmzone.c | |
| parent | 7bdb0d18bfd381cc5491eb95973ec5604b356c7e (diff) | |
| parent | d4396eafe402b710a8535137b3bf2abe6c059a15 (diff) | |
Merge branch 'globalheartbeat-2' of git://oss.oracle.com/git/smushran/linux-2.6 into ocfs2-merge-window
Conflicts:
fs/ocfs2/ocfs2.h
Diffstat (limited to 'mm/mmzone.c')
| -rw-r--r-- | mm/mmzone.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/mm/mmzone.c b/mm/mmzone.c index f5b7d1760213..e35bfb82c855 100644 --- a/mm/mmzone.c +++ b/mm/mmzone.c @@ -87,3 +87,24 @@ int memmap_valid_within(unsigned long pfn, return 1; } #endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */ + +#ifdef CONFIG_SMP +/* Called when a more accurate view of NR_FREE_PAGES is needed */ +unsigned long zone_nr_free_pages(struct zone *zone) +{ + unsigned long nr_free_pages = zone_page_state(zone, NR_FREE_PAGES); + + /* + * While kswapd is awake, it is considered the zone is under some + * memory pressure. Under pressure, there is a risk that + * per-cpu-counter-drift will allow the min watermark to be breached + * potentially causing a live-lock. While kswapd is awake and + * free pages are low, get a better estimate for free pages + */ + if (nr_free_pages < zone->percpu_drift_mark && + !waitqueue_active(&zone->zone_pgdat->kswapd_wait)) + return zone_page_state_snapshot(zone, NR_FREE_PAGES); + + return nr_free_pages; +} +#endif /* CONFIG_SMP */ |