RE: [Xen-devel] [PATCH][Take 2] Sysfs Interface for balloon driver

Ian Pratt
2006-09-25T12:10:54Z

> This patch provides a sysfs interface for the balloon driver (Take 2).
> Example outputs of the sysfs interface of the balloon driver are as
> follows:
>
>  Example 1.  Show each information
>
>   [root@Dom0 ~]# ls /sys/devices/system/memory/memory0/
>   balloon_high  current_pages  hard_limit
>   balloon_low   driver_pages   target_pages

These names are a bit misleading, confusing pages and KB.

Perhaps go for everything in KB, and have a ''_KB'' post fix to
all the
names e.g. ''current_KB''.

Does anyone actually use balloon_low and _high? At the very least they
should be renamed, possibly put under an info sub directory.

Something that would be good to export via sysfs is the maximum amount
of memory the guest could have (for guests that can''t expand their page
array i.e. all current guests).

Since linux currently doesn''t know the hard limit, perhaps best to
remove this node.

Thanks,
Ian

>   [root@Dom0 ~]# cat /sys/devices/system/memory/memory0/current_pages
>     262144
>   [root@Dom0 ~]# cat /sys/devices/system/memory/memory0/target_pages
>     262144
>   [root@Dom0 ~]# cat /sys/devices/system/memory/memory0/balloon_high
>          0
>   [root@Dom0 ~]# cat /sys/devices/system/memory/memory0/balloon_low
>     509952
>   [root@Dom0 ~]# cat /sys/devices/system/memory/memory0/hard_limit
>   ???
>   [root@Dom0 ~]# cat /sys/devices/system/memory/memory0/driver_pages
>       1024
>
>  Example 2. Set memory size of a domain
>
>   [root@Dom0 ~]# echo 1024M >
> /sys/devices/system/memory/memory0/target_pages
>   [root@Dom0 ~]# cat /sys/devices/system/memory/memory0/target_pages
>    1048576
>   [root@Dom0 ~]# cat /sys/devices/system/memory/memory0/current_pages
>     758192
>   [root@Dom0 ~]# cat /sys/devices/system/memory/memory0/hard_limit
>     758192
>   [root@Dom0 ~]# cat /sys/devices/system/memory/memory0/driver_pages
>       1024
>
>
> Regards
> Satoshi UCHIDA
>    NEC Corporation, Japan