Re: [patch 3/3] mm, oom: do not emit oom killer warning if chosen thread is already exiting

[Michal Hocko <mhocko@suse.cz>]

On Wed 11-01-12 19:24:28, David Rientjes wrote:
> If a thread is chosen for oom kill and is already PF_EXITING, then the
> oom killer simply sets TIF_MEMDIE and returns.  This allows the thread to
> have access to memory reserves so that it may quickly exit.  This logic
> is preceeded with a comment saying there's no need to alarm the sysadmin.
> This patch adds truth to that statement.
> 
> There's no need to emit any warning about the oom condition if the thread
> is already exiting since it will not be killed.  In this condition, just
> silently return the oom killer since its only giving access to memory
> reserves and is otherwise a no-op.

Definitely

Reviewed-by: Michal Hocko <mhocko@suse.cz>

> 
> Signed-off-by: David Rientjes <rientjes@google.com>
> ---
>  mm/oom_kill.c |    6 +++---
>  1 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> --- a/mm/oom_kill.c
> +++ b/mm/oom_kill.c
> @@ -445,9 +445,6 @@ static void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
>  	struct mm_struct *mm;
>  	unsigned int victim_points = 0;
>  
> -	if (printk_ratelimit())
> -		dump_header(p, gfp_mask, order, mem, nodemask);
> -
>  	/*
>  	 * If the task is already exiting, don't alarm the sysadmin or kill
>  	 * its children or threads, just set TIF_MEMDIE so it can die quickly
> @@ -457,6 +454,9 @@ static void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
>  		return;
>  	}
>  
> +	if (printk_ratelimit())
> +		dump_header(p, gfp_mask, order, mem, nodemask);
> +
>  	task_lock(p);
>  	pr_err("%s: Kill process %d (%s) score %d or sacrifice child\n",
>  		message, task_pid_nr(p), p->comm, points);
> 
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-- 
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9    
Czech Republic

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