Re: [GIT PULL] dlm fix for 2.6.38

[Steven Whitehouse <swhiteho@redhat.com>]

Hi,

On Fri, 2011-02-11 at 18:38 -0500, David Teigland wrote:
> Linus,
> 
> Please pull this fix for a dlm regression from:
> 
> git://git.kernel.org/pub/scm/linux/kernel/git/teigland/dlm.git for-linus
> 
> Thanks,
> Dave
> 
> Author: David Teigland <teigland@redhat.com>
> Date:   Fri Feb 11 16:44:31 2011 -0600
> 
>     dlm: use single thread workqueues
>     
>     The recent commit to use cmwq for send and recv threads
>     dcce240ead802d42b1e45ad2fcb2ed4a399cb255 introduced problems,
>     apparently due to multiple workqueue threads.  Single threads
>     make the problems go away, so return to that until we fully
>     understand the concurrency issues with multiple threads.
>     
>     Signed-off-by: David Teigland <teigland@redhat.com>
> 
> diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
> index 9c64ae9..2d8c87b 100644
> --- a/fs/dlm/lowcomms.c
> +++ b/fs/dlm/lowcomms.c
> @@ -1468,15 +1468,13 @@ static void work_stop(void)
>  
>  static int work_start(void)
>  {
> -	recv_workqueue = alloc_workqueue("dlm_recv", WQ_MEM_RECLAIM |
> -					 WQ_HIGHPRI | WQ_FREEZEABLE, 0);
> +	recv_workqueue = create_singlethread_workqueue("dlm_recv");
>  	if (!recv_workqueue) {
>  		log_print("can't start dlm_recv");
>  		return -ENOMEM;
>  	}
>  
> -	send_workqueue = alloc_workqueue("dlm_send", WQ_MEM_RECLAIM |
> -					 WQ_HIGHPRI | WQ_FREEZEABLE, 0);
> +	send_workqueue = create_singlethread_workqueue("dlm_send");
>  	if (!send_workqueue) {
>  		log_print("can't start dlm_send");
>  		destroy_workqueue(recv_workqueue);
> 
> 

What is the issue here? If there is a problem with the workqueues then
we should ask Tejun about it,

Steve.