Re: printk meeting at LPC

[John Ogness]

On 2019-09-18, Sergey Senozhatsky <sergey.senozhatsky.work@xxxxxxxxx> wrote:
>> Each console has its own iterator. This iterators will need to
>> advance, regardless if the message was printed via write() or
>> write_atomic().
>
> Great.
>
> ->atomic_write() path will make sure that kthread is parked or will
> those compete for uart port?

A cpu-lock (probably per-console) will be used to synchronize the
two. Unlike my RFCv1, we want to keep the cpu-lock out of the console
drivers and we want it to be less aggressive (using trylock's instead of
spinning). This should make the cpu-lock less "dangerous". I talked with
PeterZ, Thomas, and PetrM about how this can be implemented, but there
may still be some corner cases.

I would like to put everything together now so that we can run and test
if the decisions made in that meeting hold up for all the cases. I think
it will be easier to identify/add the missing pieces, once we have it
coded.

John Ogness