Re: [dpdk-dev] [PATCH] usertools: add huge page setup script

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 9/4/2020 7:35 PM, Stephen Hemminger wrote:
> This is an improved version of the setup of huge pages
> bases on earlier DPDK setup. Differences are:
>    * it autodetects NUMA vs non NUMA
>    * it allows setting different page sizes
>      recent kernels support multiple sizes.
>    * it accepts a parameter in bytes (not pages).
> 
> If necessary the steps of clearing old settings and mounting/umounting
> can be done individually.

Very handy, thanks.

> 
> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
> ---
> v3 -- incorporate review feedback
>       add missing SPDX and env header
>       overengineer the memory prefix string code
>       add numa node argument
>       fix some pylint warnings
> 
> v2 -- convert to python3
> 

<...>

> +def is_numa():
> +    '''Test if NUMA is necessary on this system'''
> +    return exists('/sys/devices/numa/node')

 -    return exists('/sys/devices/numa/node')
 +    return exists('/sys/devices/system/node')

<...>

> +def clear_numa_pages():
> +    for path in glob.glob(
> +            '/sys/devices/system/node/node*/hugepages/hugepages-*'):
> +        with open(path + '/nr_hugepages', 'w') as f:
> +            f.write('\n0')

 -            f.write('\n0')
 +            f.write('0\n')

<...>

> +def mount_huge(pagesize):> +    cmd = "mount -t hugetlbfs"
> +    if pagesize:
> +        cmd += ' -o pagesize={}'.format(pagesize)
> +    cmd += ' nodev {}'.format(HUGEDIR)
> +    os.system(cmd)

What do you thing checking if mount point exist before 'cmd'?

 +    if not exists(HUGEDIR):
 +        os.system('mkdir -p ' + HUGEDIR)


<...>

> +def do_arg_actions():
> +    '''do the actual action requested by the user'''
> +    global hugepagesize_kb
> +
> +    if clear_flag:
> +        clear_pages()
> +    if unmount_flag:
> +        os.system("umount " + HUGEDIR)

What do you think umount only if it is mounted, (to get rid of warning for
--setup after -u), something like:

 +        if not os.system("mount | grep -q " + HUGEDIR):
 +            os.system("umount " + HUGEDIR)