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Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/vm/ksm.txt | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/Documentation/vm/ksm.txt b/Documentation/vm/ksm.txt index f34a8ee6f860..0c64a81d6808 100644 --- a/Documentation/vm/ksm.txt +++ b/Documentation/vm/ksm.txt @@ -80,6 +80,20 @@ run - set 0 to stop ksmd from running but keep merged pages, Default: 0 (must be changed to 1 to activate KSM, except if CONFIG_SYSFS is disabled) +use_zero_pages - specifies whether empty pages (i.e. allocated pages + that only contain zeroes) should be treated specially. + When set to 1, empty pages are merged with the kernel + zero page(s) instead of with each other as it would + happen normally. This can improve the performance on + architectures with coloured zero pages, depending on + the workload. Care should be taken when enabling this + setting, as it can potentially degrade the performance + of KSM for some workloads, for example if the checksums + of pages candidate for merging match the checksum of + an empty page. This setting can be changed at any time, + it is only effective for pages merged after the change. + Default: 0 (normal KSM behaviour as in earlier releases) + The effectiveness of KSM and MADV_MERGEABLE is shown in /sys/kernel/mm/ksm/: pages_shared - how many shared pages are being used |