Re: [RFC][PATCH 0/7] printk: use alt_printk to handle printk() recursive calls

From: Petr Mladek
Date: Thu Sep 29 2016 - 09:25:14 EST

On Tue 2016-09-27 23:22:30, Sergey Senozhatsky wrote:
> Hello,
> This patch set extends a lock-less NMI per-cpu buffers idea to
> handle recursive printk() calls. The basic mechanism is pretty much the
> same -- at the beginning of a deadlock-prone section we switch to lock-less
> printk callback, and return back to a default printk implementation at the
> end; the messages are getting flushed to a logbuf buffer from a safer
> context.

I was skeptical but I really like this way now.

The switching of the buffers is a bit hairy in this version but I
think that we could make it much better.

Other than that it looks like a big win. It kills a lot of
printk-related pain points. And it will not be that complicated
after all.

Best Regards,