[arch-projects] [initscripts] [PATCH 09/11] functions: Speed up reboot/shutdown by recognizing killall5 exit code 2

[Dave Reisner]

On Sat, Jul 02, 2011 at 08:44:27PM +0200, Kurt J. Bosch wrote:
> killall5 returns 2 if it didn't kill any processes. Using this avoids sleeping longer than needed. This saves another up to six seconds of reboot/shutdown/go-single time.
> ---
>  functions |   16 ++++++++++++----
>  1 files changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/functions b/functions
> index 69f06eb..401e323 100644
> --- a/functions
> +++ b/functions
> @@ -293,13 +293,21 @@ kill_everything() {
> 
>  	# Terminate all processes
>  	stat_busy "Sending SIGTERM To Processes"
> -		killall5 -15 ${omit_pids[@]/#/-o } &>/dev/null
> -		sleep 5
> +		local i
> +		for (( i=0; i<500; i+=25 )); do
> +			killall5 -15 ${omit_pids[@]/#/-o } &>/dev/null
> +			(( $? == 2 )) && break
> +			sleep .25
> +		done

In the context of killall5, 'killed' means a signal was sent. This will
cause a zombie process to hang shutdown for 2 minutes.

>  	stat_done
> 
>  	stat_busy "Sending SIGKILL To Processes"
> -		killall5 -9 ${omit_pids[@]/#/-o } &>/dev/null
> -		sleep 1
> +		local i
> +		for (( i=0; i<100; i+=25 )); do
> +			killall5 -9 ${omit_pids[@]/#/-o } &>/dev/null
> +			(( $? == 2 )) && break
> +			sleep .25
> +		done

Ideally, this never kills anything, because all our processes exited
nicely in the loop above. However, if it does successfully send a signal
to a process, then we just spent the past 125 seconds waiting on the
above SIGTERM spam to time out. When it does time out, we're going to
spend another 25 seconds here waiting for the same process to be spammed
with SIGKILL.

>  	stat_done
> 
>  	run_hook "$1_postkillall"
> --
> 1.7.1
> 

There's probably a handful of programs who don't appreciate receiving
SIGTERM every 1/4 of a second.

dave