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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	LKML <linux-kernel@vger.kernel.org>,
	Prarit Bhargava <prarit@redhat.com>,
	Mark Salyzyn <salyzyn@android.com>,
	Petr Mladek <pmladek@suse.com>, Ingo Molnar <mingo@kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Joe Perches <joe@perches.com>
Subject: Re: [RFC patch 4/7] timekeeping: Add NMI safe accessor to mono/boot/real clocks
Date: Fri, 17 Nov 2017 15:12:33 -0800	[thread overview]
Message-ID: <CA+55aFzFnQ9n=kfLCnq_mmDD3aqb+Uy_BHy9234UxCYTPPqBig@mail.gmail.com> (raw)
In-Reply-To: <20171117180034.30413b64@gandalf.local.home>

On Fri, Nov 17, 2017 at 3:00 PM, Steven Rostedt <rostedt@goodmis.org> wrote:
>
> Could you indent this better. It looks like timekeeping_delta_to_ns()
> takes 4 arguments, when it really only takes two.

Actually, even better would be to simply not have that ugly three-line
expression from hell.

Maybe it could even be a helper inline function, somethin glike

   static inline u64 tk_delta_ns(struct tk_read_base *tkr)
   {
        u64 cycle = tk_clock_read(tkr);
        u64 delta= clocksource_delta(cycle, tkr->cycle_last, tkr->mask);
        return timekeeping_delta_to_ns(tkr, cycle);
    }

and that whole thing would just become

        now += tk_delta_ns(tkr);

which looks a whole lot more legible. And shouldn't generate any worse code.

(I might have screwed up something, I wrote that in the email client,
maybe I got something wrong.

And my name choice is probably garbage. But you get the idea.

            Linus

  reply	other threads:[~2017-11-17 23:12 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-15 18:15 [RFC patch 0/7] printk: Switch to CLOCK_MONOTONIC and store extra time stamps Thomas Gleixner
2017-11-15 18:15 ` [RFC patch 1/7] timekeeping: Do not unconditionally suspend NMI safe timekeepers Thomas Gleixner
2017-11-15 18:15 ` [RFC patch 2/7] x86/tsc: Set clocksource CLOCK_SOURCE_SUSPEND_ACCESS_OK Thomas Gleixner
2017-11-15 18:15 ` [RFC patch 3/7] printk: Use clock MONOTONIC for timestamps Thomas Gleixner
2017-11-16  7:58   ` Sergey Senozhatsky
2017-11-15 18:15 ` [RFC patch 4/7] timekeeping: Add NMI safe accessor to mono/boot/real clocks Thomas Gleixner
2017-11-17 23:00   ` Steven Rostedt
2017-11-17 23:12     ` Linus Torvalds [this message]
2017-11-17 23:43       ` Thomas Gleixner
2017-11-15 18:15 ` [RFC patch 5/7] crash: Add VMCOREINFO_FIELD_AND_OFFSET() Thomas Gleixner
2017-11-23 12:46   ` Petr Mladek
2017-11-15 18:15 ` [RFC patch 6/7] printk: Store mono/boot/real time timestamps Thomas Gleixner
2017-11-23 13:36   ` Petr Mladek
2017-11-15 18:15 ` [RFC patch 7/7] timekeeping: Hack to use fine grained timestamps during boot Thomas Gleixner
2017-11-23 12:58   ` Petr Mladek
2017-11-28 18:43     ` Prarit Bhargava
2017-11-28 18:47       ` Thomas Gleixner
2017-12-08 11:23         ` Petr Mladek
2017-12-08 19:51           ` Thomas Gleixner
2017-11-28 19:10       ` Mark Salyzyn
2017-11-28 19:45         ` Steven Rostedt
2017-11-28 20:29           ` Mark Salyzyn
2017-11-28 20:38             ` Peter Zijlstra

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