Messages in this thread | | | Date | Tue, 5 Sep 2023 13:45:59 +0200 | From | Petr Mladek <> | Subject | Re: [PATCH printk v3 1/7] printk: Add non-BKL (nbcon) console basic infrastructure |
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On Sun 2023-09-03 17:11:33, John Ogness wrote: > From: Thomas Gleixner <tglx@linutronix.de> > > The current console/printk subsystem is protected by a Big Kernel Lock, > (aka console_lock) which has ill defined semantics and is more or less > stateless. This puts severe limitations on the console subsystem and > makes forced takeover and output in emergency and panic situations a > fragile endeavour that is based on try and pray. > > The goal of non-BKL (nbcon) consoles is to break out of the console lock > jail and to provide a new infrastructure that avoids the pitfalls and > also allows console drivers to be gradually converted over. > > The proposed infrastructure aims for the following properties: > > - Per console locking instead of global locking > - Per console state that allows to make informed decisions > - Stateful handover and takeover > > As a first step, state is added to struct console. The per console state > is an atomic_t using a 32bit bit field. > > Reserve state bits, which will be populated later in the series. Wire > it up into the console register/unregister functionality. > > It was decided to use a bitfield because using a plain u32 with > mask/shift operations resulted in uncomprehensible code. > > Co-developed-by: John Ogness <john.ogness@linutronix.de> > Signed-off-by: John Ogness <john.ogness@linutronix.de> > Signed-off-by: Thomas Gleixner (Intel) <tglx@linutronix.de>
Looks good to me:
Reviewed-by: Petr Mladek <pmladek@suse.com>
Best Regards, Petr
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