Re: [PATCH] mm/page_alloc: Wait for oom_lock before retrying.

[Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>]

On (12/13/16 18:06), Michal Hocko wrote:
[..]
> What if we lower the loglevel as much as possible to only see KERN_ERR
> should be sufficient to see few oom killer messages while suppressing
> most of the other noise. Unfortunatelly, even messages with level >
> loglevel get stored into the ringbuffer (as I've just learned) so
> console_unlock() has to crawl through them just to drop them (Meh) but
> at least it doesn't have to go to the serial console drivers and spend
> even more time there. An alternative would be to tweak printk to not
> even store those messaes. Something like the below
> 
> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
> index f7a55e9ff2f7..197f2b9fb703 100644
> --- a/kernel/printk/printk.c
> +++ b/kernel/printk/printk.c
> @@ -1865,6 +1865,15 @@ asmlinkage int vprintk_emit(int facility, int level,
>  				lflags |= LOG_CONT;
>  			}
>  
> +			if (suppress_message_printing(kern_level)) {

aren't we supposed to check level here:
				suppress_message_printing(level)?

kern_level is '0' away from actual level:

	kern_level = printk_get_level(text)
	switch (kern_level)
	case '0' ... '7':
		level = kern_level - '0';

	-ss

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