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Diffstat (limited to 'Documentation/sysctl/vm.txt')
| -rw-r--r-- | Documentation/sysctl/vm.txt | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt index 7d73882e2c27..187ce4f599a2 100644 --- a/Documentation/sysctl/vm.txt +++ b/Documentation/sysctl/vm.txt @@ -63,6 +63,7 @@ Currently, these files are in /proc/sys/vm: - swappiness - user_reserve_kbytes - vfs_cache_pressure +- watermark_boost_factor - watermark_scale_factor - zone_reclaim_mode @@ -856,6 +857,26 @@ ten times more freeable objects than there are. ============================================================= +watermark_boost_factor: + +This factor controls the level of reclaim when memory is being fragmented. +It defines the percentage of the high watermark of a zone that will be +reclaimed if pages of different mobility are being mixed within pageblocks. +The intent is that compaction has less work to do in the future and to +increase the success rate of future high-order allocations such as SLUB +allocations, THP and hugetlbfs pages. + +To make it sensible with respect to the watermark_scale_factor parameter, +the unit is in fractions of 10,000. The default value of 15,000 means +that up to 150% of the high watermark will be reclaimed in the event of +a pageblock being mixed due to fragmentation. The level of reclaim is +determined by the number of fragmentation events that occurred in the +recent past. If this value is smaller than a pageblock then a pageblocks +worth of pages will be reclaimed (e.g. 2MB on 64-bit x86). A boost factor +of 0 will disable the feature. + +============================================================= + watermark_scale_factor: This factor controls the aggressiveness of kswapd. It defines the |