Re: [GIT pull] printk updates for 4.15

From: Thomas Gleixner <tglx@linutronix.de>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Salyzyn <salyzyn@android.com>,
	Petr Mladek <pmladek@suse.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Ingo Molnar <mingo@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Prarit Bhargava <prarit@redhat.com>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	John Stultz <john.stultz@linaro.org>
Subject: Re: [GIT pull] printk updates for 4.15
Date: Sat, 18 Nov 2017 02:00:35 +0100 (CET)	[thread overview]
Message-ID: <alpine.DEB.2.20.1711180156450.2186@nanos> (raw)
In-Reply-To: <CA+55aFwToNw5cFtD9zwj4COC4tV1n-1gWzvu=rXigKcKFgskjw@mail.gmail.com>

On Fri, 17 Nov 2017, Linus Torvalds wrote:
> On Fri, Nov 17, 2017 at 4:26 PM, Thomas Gleixner <tglx@linutronix.de> wrote:
> >
> > Here you go. It survived suspend resume in a VM.
> 
> That looks almost too small.
> 
> If this were to allow us to basically unify BOOTTIME/MONOTONIC, that
> would be lovely.

I surely missed something. John should figure that out faster than me.

> Should we just try it, with the understanding that we'll quite
> possibly have to just revert?

You've seen the warning in the changelog :)

> Assuming this works, what would the "phase two" patch that actually
> unifies the two (as opposed to make them have the same value) look
> like?
> 
> Is that just basically just removing the dozen or so "offst_boot"
> uses, or are there other possible simplifications?

Pretty much. We can't get rid of CLOCK_BOOTTIME and the handling of it,
though we can remove one hrtimer clock base by mapping boot time to
monotonic. That's about it.

Thanks,

	tglx