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Diffstat (limited to 'Documentation/sysctl/vm.txt')
| -rw-r--r-- | Documentation/sysctl/vm.txt | 38 |
1 files changed, 37 insertions, 1 deletions
diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt index 2f1aae32a5d9..391dd64363e7 100644 --- a/Documentation/sysctl/vm.txt +++ b/Documentation/sysctl/vm.txt @@ -26,12 +26,14 @@ Currently, these files are in /proc/sys/vm: - min_free_kbytes - laptop_mode - block_dump +- drop-caches +- zone_reclaim_mode ============================================================== dirty_ratio, dirty_background_ratio, dirty_expire_centisecs, dirty_writeback_centisecs, vfs_cache_pressure, laptop_mode, -block_dump, swap_token_timeout: +block_dump, swap_token_timeout, drop-caches: See Documentation/filesystems/proc.txt @@ -102,3 +104,37 @@ This is used to force the Linux VM to keep a minimum number of kilobytes free. The VM uses this number to compute a pages_min value for each lowmem zone in the system. Each lowmem zone gets a number of reserved free pages based proportionally on its size. + +============================================================== + +percpu_pagelist_fraction + +This is the fraction of pages at most (high mark pcp->high) in each zone that +are allocated for each per cpu page list. The min value for this is 8. It +means that we don't allow more than 1/8th of pages in each zone to be +allocated in any single per_cpu_pagelist. This entry only changes the value +of hot per cpu pagelists. User can specify a number like 100 to allocate +1/100th of each zone to each per cpu page list. + +The batch value of each per cpu pagelist is also updated as a result. It is +set to pcp->high/4. The upper limit of batch is (PAGE_SHIFT * 8) + +The initial value is zero. Kernel does not use this value at boot time to set +the high water marks for each per cpu page list. + +=============================================================== + +zone_reclaim_mode: + +This is set during bootup to 1 if it is determined that pages from +remote zones will cause a significant performance reduction. The +page allocator will then reclaim easily reusable pages (those page +cache pages that are currently not used) before going off node. + +The user can override this setting. It may be beneficial to switch +off zone reclaim if the system is used for a file server and all +of memory should be used for caching files from disk. + +It may be beneficial to switch this on if one wants to do zone +reclaim regardless of the numa distances in the system. + |