linux-kernel - Re: [PATCH 1/3] [PATCH i386] during VM oom condition, kill all threads in process group

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Date:	Thu, 7 Jun 2007 15:34:59 -0700
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	Will Schmidt <will_schmidt@...t.ibm.com>
Cc:	linux-kernel@...r.kernel.org, anton@...ba.org,
	liuxppc-dev@...abs.org
Subject: Re: [PATCH 1/3] [PATCH i386] during VM oom condition, kill all
 threads in process group

On Tue, 05 Jun 2007 12:48:32 -0500
Will Schmidt <will_schmidt@...t.ibm.com> wrote:

> 
> When we get into a state where VM has ran out of memory, and it's time to
> thwack a process, we should take out the entire process group, rather than 
> just one thread.
> 
> Tested on i386
> 
> Signed-off-by: Will Schmidt <will_schmidt@...t.ibm.com>
> ---
> 
>  arch/i386/mm/fault.c |    4 +++-
>  1 files changed, 3 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/i386/mm/fault.c b/arch/i386/mm/fault.c
> index b8c4e25..82aec0e 100644
> --- a/arch/i386/mm/fault.c
> +++ b/arch/i386/mm/fault.c
> @@ -567,8 +567,10 @@ out_of_memory:
>  		goto survive;
>  	}
>  	printk("VM: killing process %s\n", tsk->comm);
> -	if (error_code & 4)
> +	if (error_code & 4) {
> +		zap_other_threads(tsk);
>  		do_exit(SIGKILL);
> +	}
>  	goto no_context;
>  

zap_other_threads() requires tasklist_lock.

If we're going to do this then we should probably create some new function
(with a better name) which takes tasklsit_lock and then calls
zap_other_threads().

Does this patch fix any observed-in-the-real-world problem?  If so, please
describe it.
-
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