[RFC][PATCH 7/7] CGroup API: Update cpusets to use cgroup structured file API

[Li Zefan]

Paul Jackson wrote:
> Ok ... this would (I suspect, just from code reading, no bytes were
> harmed in actual testing of this) have a minor change to how white
> space is handled writing integer flags to cpuset files, and a minor
> inconstency.
> 
>  1) Existing cpuset code lets you set a flag (e.g. cpu_exclusive) by doing:
> 	echo '1 rumplestiltskin' > cpu_exclusive   # same as: echo 1 > cpu_exclusive
>     With this patch, that probably fails, EINVAL.
> 
>  2) With this patch, one can write "1" or "1\n" to cpuset integer files, but one
>     cannot successfully write "1\r\n" or "1 " or "1 \n".  However, for the cpuset
>     control files that take strings, not single integers, one -can- have any mix
>     of trailing white space.
> 
> So far as I know, I have no requirement to write rumplestiltskin to cpuset files ;).
> So I'm content to let the minor change in (1) pass without further comment.
> 
> I'd like to recommend consideration of the following patch, to address the
> minor inconsistency of (2), and to save a few bytes of kernel text space.
> 

For memory controller, we have to do this:
	echo -n 4m > memory.limit_in_bytes
'-n' is necessary. This is another inconsistency..