Commit e3a7b455 authored by Leonid Bloch's avatar Leonid Bloch Committed by Kevin Wolf
Browse files

qcow2: Fix cache-clean-interval documentation 



Fixing cache-clean-interval documentation following the recent change to
a default of 600 seconds on supported plarforms (only Linux currently).

Signed-off-by: default avatarLeonid Bloch <lbloch@janustech.com>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent cb53460b

docs/qcow2-cache.txt

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@@ -202,18 +202,18 @@ Reducing the memory usage 
It is possible to clean unused cache entries in order to reduce the

memory usage during periods of low I/O activity.



The parameter "cache-clean-interval" defines an interval (in seconds).

All cache entries that haven't been accessed during that interval are

removed from memory.

The parameter "cache-clean-interval" defines an interval (in seconds),

after which all the cache entries that haven't been accessed during the

interval are removed from memory. Setting this parameter to 0 disables this

feature.



This example removes all unused cache entries every 15 minutes:

The following example removes all unused cache entries every 15 minutes:



   -drive file=hd.qcow2,cache-clean-interval=900



If unset, the default value for this parameter is 600. Setting it to 0

disables this feature.

If unset, the default value for this parameter is 600 on platforms which

support this functionality, and is 0 (disabled) on other platforms.



Note that this functionality currently relies on the MADV_DONTNEED

argument for madvise() to actually free the memory. This is a

Linux-specific feature, so cache-clean-interval is not supported in

other systems.
 
This functionality currently relies on the MADV_DONTNEED argument for

madvise() to actually free the memory. This is a Linux-specific feature,

so cache-clean-interval is not supported on other systems.

qapi/block-core.json

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@@ -2895,7 +2895,8 @@ 
#

# @cache-clean-interval:  clean unused entries in the L2 and refcount

#                         caches. The interval is in seconds. The default value

#                         is 600, and 0 disables this feature. (since 2.5)

#                         is 600 on supporting platforms, and 0 on other

#                         platforms. 0 disables this feature. (since 2.5)

#

# @encrypt:               Image decryption options. Mandatory for

#                         encrypted images, except when doing a metadata-only

qemu-options.hx

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@@ -747,7 +747,8 @@ it which is not used for the L2 cache) 


@item cache-clean-interval

Clean unused entries in the L2 and refcount caches. The interval is in seconds.

The default value is 600. Setting it to 0 disables this feature.

The default value is 600 on supporting platforms, and 0 on other platforms.

Setting it to 0 disables this feature.



@item pass-discard-request

Whether discard requests to the qcow2 device should be forwarded to the data