[patch 11/14] powerpc: invoke oom-killer from page fault

[David Rientjes]

On Fri, 23 Apr 2010, npiggin at suse.de wrote:

> As explained in commit 1c0fe6e3bd, we want to call the architecture independent
> oom killer when getting an unexplained OOM from handle_mm_fault, rather than
> simply killing current.
> 
> Cc: linuxppc-dev at ozlabs.org
> Cc: Benjamin Herrenschmidt <benh at kernel.crashing.org>
> Cc: linux-arch at vger.kernel.org
> Signed-off-by: Nick Piggin <npiggin at suse.de>
> ---
> Index: linux-2.6/arch/powerpc/mm/fault.c
> ===================================================================
> --- linux-2.6.orig/arch/powerpc/mm/fault.c
> +++ linux-2.6/arch/powerpc/mm/fault.c
> @@ -359,15 +359,10 @@ bad_area_nosemaphore:
>   */
>  out_of_memory:
>  	up_read(&mm->mmap_sem);
> -	if (is_global_init(current)) {
> -		yield();
> -		down_read(&mm->mmap_sem);
> -		goto survive;
> -	}
> -	printk("VM: killing process %s\n", current->comm);
> -	if (user_mode(regs))
> -		do_group_exit(SIGKILL);
> -	return SIGKILL;
> +	if (!user_mode(regs))
> +		return SIGKILL;
> +	pagefault_out_of_memory();
> +	return 0;

Do we really want to return 0 and indicate that the fault was handled?  It 
seems more consistent to do

	if (user_mode(regs))
		pagefault_out_of_memory();
	return SIGKILL;