[PATCH] Add checking num-threads of makedumpfile

[Minfei Huang]

On 08/25/15 at 12:51pm, Zhou Wenjian wrote:
> A new feature that doing compressing and writing by multi-threads
> has been added in makedumpfile. The thread num is specified by
> "--num-threads NUM". According to its implementation, there will
> be performance degradation if the threads are more than cpus.
> So we should check it.
> 
> Signed-off-by: Zhou wenjian <zhouwj-fnst at cn.fujitsu.com>
> ---
>  kdumpctl |   16 ++++++++++++++++
>  1 files changed, 16 insertions(+), 0 deletions(-)
> 
> diff --git a/kdumpctl b/kdumpctl
> index b504734..a4b4681 100755
> --- a/kdumpctl
> +++ b/kdumpctl
> @@ -259,6 +259,22 @@ check_config()
>  		esac
>  	done < $KDUMP_CONFIG_FILE
>  
> +	grep -v "^#" $KDUMP_CONFIG_FILE | grep -q "num-threads"

This filter cannot handle the all of the corner cases, like the
following.

 # grep -v "^#" /etc/kdump.conf  | grep "num-threads"
 ext4 /dev/mapper/num-threads

So it is better to use the exact regular expression to filter out the
string. Maybe you can use $core_collector to filter out the string
--num_threads.

> +	if [ $? -eq 0 ];then
> +		local nr_cpus=1
> +		local num_threads=0
> +		local core_collector=`grep -v "^#" $KDUMP_CONFIG_FILE | grep "^core_collector"`
> +
> +		num_threads=`echo ${core_collector#*--num-threads} | awk '{print $1}'`
> +		nr_cpus=`echo ${KDUMP_COMMANDLINE_APPEND#*nr_cpus=} | awk '{print $1}'`
> +
> +		test $num_threads -ge $nr_cpus &> /dev/null
> +		if [ $? -eq 0 ];then

To keep the style, it is better to use "if [ $a -ge $b ]".

Thanks
Minfei