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Diffstat (limited to 'Documentation/device-mapper/cache.txt')
| -rw-r--r-- | Documentation/device-mapper/cache.txt | 61 |
1 files changed, 35 insertions, 26 deletions
diff --git a/Documentation/device-mapper/cache.txt b/Documentation/device-mapper/cache.txt index 274752f8bdf9..e6b72d355151 100644 --- a/Documentation/device-mapper/cache.txt +++ b/Documentation/device-mapper/cache.txt @@ -217,36 +217,43 @@ the characteristics of a specific policy, always request it by name. Status ------ -<#used metadata blocks>/<#total metadata blocks> <#read hits> <#read misses> -<#write hits> <#write misses> <#demotions> <#promotions> <#blocks in cache> -<#dirty> <#features> <features>* <#core args> <core args>* <#policy args> -<policy args>* - -#used metadata blocks : Number of metadata blocks used -#total metadata blocks : Total number of metadata blocks -#read hits : Number of times a READ bio has been mapped +<metadata block size> <#used metadata blocks>/<#total metadata blocks> +<cache block size> <#used cache blocks>/<#total cache blocks> +<#read hits> <#read misses> <#write hits> <#write misses> +<#demotions> <#promotions> <#dirty> <#features> <features>* +<#core args> <core args>* <policy name> <#policy args> <policy args>* + +metadata block size : Fixed block size for each metadata block in + sectors +#used metadata blocks : Number of metadata blocks used +#total metadata blocks : Total number of metadata blocks +cache block size : Configurable block size for the cache device + in sectors +#used cache blocks : Number of blocks resident in the cache +#total cache blocks : Total number of cache blocks +#read hits : Number of times a READ bio has been mapped to the cache -#read misses : Number of times a READ bio has been mapped +#read misses : Number of times a READ bio has been mapped to the origin -#write hits : Number of times a WRITE bio has been mapped +#write hits : Number of times a WRITE bio has been mapped to the cache -#write misses : Number of times a WRITE bio has been +#write misses : Number of times a WRITE bio has been mapped to the origin -#demotions : Number of times a block has been removed +#demotions : Number of times a block has been removed from the cache -#promotions : Number of times a block has been moved to +#promotions : Number of times a block has been moved to the cache -#blocks in cache : Number of blocks resident in the cache -#dirty : Number of blocks in the cache that differ +#dirty : Number of blocks in the cache that differ from the origin -#feature args : Number of feature args to follow -feature args : 'writethrough' (optional) -#core args : Number of core arguments (must be even) -core args : Key/value pairs for tuning the core +#feature args : Number of feature args to follow +feature args : 'writethrough' (optional) +#core args : Number of core arguments (must be even) +core args : Key/value pairs for tuning the core e.g. migration_threshold -#policy args : Number of policy arguments to follow (must be even) -policy args : Key/value pairs - e.g. 'sequential_threshold 1024 +policy name : Name of the policy +#policy args : Number of policy arguments to follow (must be even) +policy args : Key/value pairs + e.g. sequential_threshold Messages -------- @@ -266,10 +273,12 @@ E.g. Invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the invalidate_cblocks message, which takes an arbitrary number of cblock ranges. Each cblock -must be expressed as a decimal value, in the future a variant message -that takes cblock ranges expressed in hexidecimal may be needed to -better support efficient invalidation of larger caches. The cache must -be in passthrough mode when invalidate_cblocks is used. +range's end value is "one past the end", meaning 5-10 expresses a range +of values from 5 to 9. Each cblock must be expressed as a decimal +value, in the future a variant message that takes cblock ranges +expressed in hexidecimal may be needed to better support efficient +invalidation of larger caches. The cache must be in passthrough mode +when invalidate_cblocks is used. invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]* |