[ovs-dev] [PATCH] ovs-lib: Wait for a longer time after SIGKILL.

[Ben Pfaff]

On Wed, Mar 27, 2013 at 02:30:05PM -0700, Gurucharan Shetty wrote:
> Currently, when we stop a daemon, we first send it SIGTERM.
> If SIGTERM did not work within ~5 seconds, we send a SIGKILL.
> After sending SIGKILL, we wait only for 4 seconds, before giving
> up.
> 
> If the system is exteremely busy, there is a chance that a
> process is not killed by the kernel within 4 seconds. In such
> a case, when we try to start the daemon immediately, we see that
> the pid inside the pid-file is valid and assume that the daemon
> is still running. This leaves us in a state, where the daemon is
> actually not running.
> 
> This patch increases the time waiting for the kernel to kill the
> process to 60 seconds.
> 
> Bug #15404.
> Signed-off-by: Gurucharan Shetty <gshetty at nicira.com>

I see why you changed the FAIL case, but I think that it might instead
be better to do something like the following, to avoid duplicating the
pid_exists call in two places:

diff --git a/utilities/ovs-lib.in b/utilities/ovs-lib.in
index d010abf..b44ab37 100644
--- a/utilities/ovs-lib.in
+++ b/utilities/ovs-lib.in
@@ -173,6 +173,9 @@ stop_daemon () {
     if test -e "$rundir/$1.pid"; then
         if pid=`cat "$rundir/$1.pid"`; then
             for action in TERM .1 .25 .65 1 1 1 1 KILL 1 1 1 1 FAIL; do
+                if pid_exists $pid >/dev/null 2>&1; then :; else
+                    return 0
+                fi
                 case $action in
                     TERM)
                         action "Killing $1 ($pid)" kill $pid
@@ -185,11 +188,7 @@ stop_daemon () {
                         return 1
                         ;;
                     *)
-                        if pid_exists $pid >/dev/null 2>&1; then
-                            sleep $action
-                        else
-                            return 0
-                        fi
+                        sleep $action
                         ;;
                 esac
             done