Re: [PATCH] Don't iterate the whole /sys/devices just to find drm device

[piliu]

On 3/19/21 6:21 PM, Kairui Song wrote:
>  On some large systems, /sys/devices is huge and it's not a wise
> idea to
>  iterate it. `find` may cause tremendous contention on the kernfs_mutex
>  when there are already stress on /sys, and it will perform very very
>  poorly.
>  
>  Simply check if drm class presents should be good enough.
>  
>  Signed-off-by: Kairui Song <kasong(a)redhat.com&gt;
>  ---
>    dracut-module-setup.sh | 2 +-
>    1 file changed, 1 insertion(+), 1 deletion(-)
>  
>  diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
>  index ac0f196..ce05de7 100755
>  --- a/dracut-module-setup.sh
>  +++ b/dracut-module-setup.sh
>  @@ -58,7 +58,7 @@ depends() {
>            _dep="$_dep znet"
>        fi
>    
>  -    if [ -n "$( find /sys/devices -name drm )" ] || [ -d /sys/module/hyperv_fb
> ]; then
>  +    if [ -n "$( ls -A /sys/class/drm 2>/dev/null )" ] || [ -d
> /sys/module/hyperv_fb ]; then
>            add_opt_module drm
>        fi
>    
>   
Acked-by: Pingfan Liu <piliu(a)redhat.com&gt;