lvs sync, unusual load (sorry this isn't in the old thread)

[Ryan Cruse]

Hey Horms,

I'm curious if Dean ever got back to you about this fix.  I am seeing 
exactly what Dean saw.  I tried your fix with 2.6.19-1.2911 on Fedora 
Core 6 and
it didn't fix the issue.  After rebooting with the new kernel and 
turning on the connection synchronization daemon the load returns to 1.  
The process is still in the 'D' state:  "D - Uninterruptible sleep 
(usually IO)".  If there is anything else you'd like me to try out or 
any more information about the issue let me know.

Thanks,
-Ryan

> On Fri, Nov 10, 2006 at 03:15:05PM +0900, Horms wrote:
> >/ On Fri, Nov 10, 2006 at 02:54:20PM +1100, Dean Manners wrote:/
> >/ > Horms,/
> >/ > /
> >/ > ip_vs_sync.c: /
> >/ > 885:        __set_current_state(TASK_UNINTERRUPTIBLE);/
> >/ > 886:        add_wait_queue(&stop_sync_wait, &wait);/
> >/ > 887:        set_stop_sync(state, 1);/
> >/ > 888:        ip_vs_sync_state -= state;/
> >/ > 889:        wake_up(&sync_wait);/
> >/ > 890:        schedule();/
> >/ > 891:        __set_current_state(TASK_RUNNING);/
> >/ > 892:        remove_wait_queue(&stop_sync_wait, &wait);/
> >/ > /
> >/ > Seems to have changed? Theres no "schedule_timeout(HZ);" throughout./
> >/ /
> >/ Actually, that is the shutdown code./
> >/ /
> >/ The problem is almost certainly caused inside sync_master_loop()/
> >/ somewhere. Though it is using ssleep(), but perhaps its schemantics have/
> >/ changed somehow.. I can readily reproduce the problem here. I will see/
>
> Is there any chance you could test out the change below to see if it
> helps. It seems to work on my end.
>
> -- 
> Horms
>   H: http://www.vergenet.net/~horms/ <http://www.vergenet.net/%7Ehorms/>
>   W: http://www.valinux.co.jp/en/
>
>
> [IPVS] use msleep_interruptable() instead of ssleep() aka msleep()
>
> Dean Manners notices that when an IPVS synchonisation daemons are
> started the system load slowly climbs up to 1. This seems to be related
> to the call to ssleep(1) (aka msleep(1000) in the main loop. Replacing
> this with a call to msleep_interruptable() seems to make the problem go
> away. Though I'm not sure that it is correct.
>
> Cc: Dean Manners <deanm at xxxxxxxxxxxxx>
> Signed-Off-By: Simon Horman <horms at xxxxxxxxxxxx>
>
> Index: linux-2.6/net/ipv4/ipvs/ip_vs_sync.c
> ===================================================================
> --- linux-2.6.orig/net/ipv4/ipvs/ip_vs_sync.c   2006-11-10 15:33:42.000000000 
> +0900
> +++ linux-2.6/net/ipv4/ipvs/ip_vs_sync.c        2006-11-10 15:33:52.000000000 
> +0900
> @@ -657,7 +657,7 @@
>                 if (stop_master_sync)
>                         break;
>  
> -               ssleep(1);
> +               msleep_interruptible(1000);
>         }
>  
>         /* clean up the sync_buff queue */
>