Re: [Qemu-devel] [PATCH 2/3] qcow2: add option to clean unused cache entries after some time

[Kevin Wolf <kwolf@redhat.com>]

Am 29.05.2015 um 11:24 hat Alberto Garcia geschrieben:
> This adds a new 'cache-clean-interval' option that cleans all qcow2
> cache entries that haven't been used in a certain interval, given in
> seconds.
> 
> This allows setting a large L2 cache size so it can handle scenarios
> with lots of I/O and at the same time use little memory during periods
> of inactivity.
> 
> This feature currently relies on MADV_DONTNEED to free that memory, so
> it is not useful in systems that don't follow that behavior.
> 
> Signed-off-by: Alberto Garcia <berto@igalia.com>
> Reviewed-by: Max Reitz <mreitz@redhat.com>

> diff --git a/qapi/block-core.json b/qapi/block-core.json
> index 863ffea..f42338d 100644
> --- a/qapi/block-core.json
> +++ b/qapi/block-core.json
> @@ -1538,6 +1538,9 @@
>  # @refcount-cache-size:   #optional the maximum size of the refcount block cache
>  #                         in bytes (since 2.2)
>  #
> +# @cache-clean-interval:  #optional clean unused entries in the L2 and refcount
> +#                         caches. The interval is in seconds (since 2.4)

Should add that 0 means disabling the cleaning, and 0 is the default.

Kevin