Re: [PATCH] net/skbuff: silence warnings under memory pressure

From: Sergey Senozhatsky
Date: Wed Sep 04 2019 - 03:00:49 EST

On (09/04/19 15:41), Sergey Senozhatsky wrote:
> But the thing is different in case of dump_stack() + show_mem() +
> some other output. Because now we ratelimit not a single printk() line,
> but hundreds of them. The ratelimit becomes - 10 * $$$ lines in 5 seconds
> (IOW, now we talk about thousands of lines).

And on devices with slow serial consoles this can be somewhat close to
"no ratelimit". *Suppose* that warn_alloc() adds 700 lines each time.
Within 5 seconds we can call warn_alloc() 10 times, which will add 7000
lines to the logbuf. If printk() can evict only 6000 lines in 5 seconds
then we have a growing number of pending logbuf messages.