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From: Michal Hocko <mhocko@suse.cz>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: David Rientjes <rientjes@google.com>,
	Konstantin Khlebnikov <khlebnikov@openvz.org>,
	Oleg Nesterov <oleg@redhat.com>,
	KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
	"Rafael J. Wysocki" <rjw@sisk.pl>, Tejun Heo <htejun@gmail.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 1/2] lguest: move process freezing before pending signals check
Date: Wed, 12 Oct 2011 08:55:04 +0200	[thread overview]
Message-ID: <20111012065504.GC31570@tiehlicka.suse.cz> (raw)
In-Reply-To: <e213ea00900cba783f228eb4234ad929a05d4359.1317110948.git.mhocko@suse.cz>

Hi Rusty,
what is the current state of this patch? Are you planning to push it for
3.2?

Thanks

On Tue 27-09-11 08:56:03, Michal Hocko wrote:
> run_guest tries to freeze the current process after it has handled
> pending interrupts and before it calls lguest_arch_run_guest.
> This doesn't work nicely if the task has been killed while being frozen
> and when we want to handle that signal as soon as possible.
> Let's move try_to_freeze before we check for pending signal so that we
> can get out of the loop as soon as possible.
> 
> Signed-off-by: Michal Hocko <mhocko@suse.cz>
> Acked-by: Rusty Russell <rusty@rustcorp.com.au>
> ---
>  drivers/lguest/core.c |   14 +++++++-------
>  1 files changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/lguest/core.c b/drivers/lguest/core.c
> index 2535933..e7dda91 100644
> --- a/drivers/lguest/core.c
> +++ b/drivers/lguest/core.c
> @@ -232,6 +232,13 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user)
>  			}
>  		}
>  
> +		/*
> +		 * All long-lived kernel loops need to check with this horrible
> +		 * thing called the freezer.  If the Host is trying to suspend,
> +		 * it stops us.
> +		 */
> +		try_to_freeze();
> +
>  		/* Check for signals */
>  		if (signal_pending(current))
>  			return -ERESTARTSYS;
> @@ -246,13 +253,6 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user)
>  			try_deliver_interrupt(cpu, irq, more);
>  
>  		/*
> -		 * All long-lived kernel loops need to check with this horrible
> -		 * thing called the freezer.  If the Host is trying to suspend,
> -		 * it stops us.
> -		 */
> -		try_to_freeze();
> -
> -		/*
>  		 * Just make absolutely sure the Guest is still alive.  One of
>  		 * those hypercalls could have been fatal, for example.
>  		 */
> -- 
> 1.7.5.4
> 

-- 
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9    
Czech Republic

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  reply	other threads:[~2011-10-12  6:55 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-27  8:09 [PATCH 0/2] oom: fix livelock when frozen task is selected Michal Hocko
2011-09-27  6:56 ` [PATCH 1/2] lguest: move process freezing before pending signals check Michal Hocko
2011-10-12  6:55   ` Michal Hocko [this message]
2011-10-12 23:57     ` Rusty Russell
2011-10-13  5:48       ` Michal Hocko
2011-09-27  8:01 ` [PATCH 2/2] oom: do not live lock on frozen tasks Michal Hocko
2011-09-27 18:35   ` [patch] oom: thaw threads if oom killed thread is frozen before deferring David Rientjes
2011-09-28 10:44     ` Michal Hocko
2011-09-29 11:51       ` Michal Hocko
2011-09-29 12:05         ` Oleg Nesterov
2011-09-29 13:02           ` Michal Hocko
2011-09-29 16:32             ` Michal Hocko
2011-09-29 16:37             ` Oleg Nesterov
2011-09-29 18:00               ` Michal Hocko
2011-09-30  1:51                 ` Tejun Heo
2011-09-30  7:41                   ` Michal Hocko
2011-09-30  7:46                     ` Tejun Heo
2011-09-30  8:04                       ` Michal Hocko
2011-09-30 15:30                 ` Oleg Nesterov
2011-10-28 22:23   ` [PATCH 2/2] oom: do not live lock on frozen tasks Andrew Morton
2011-10-29  9:01     ` Michal Hocko

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