Re: [patch 13/20] timer: Switch to a non cascading wheel

From	"George Spelvin" <linux@sciencehorizons.net>
Newsgroups	linux.kernel
Subject	Re: [patch 13/20] timer: Switch to a non cascading wheel
Date	2016-06-14 22:00 +0200
Message-ID	<rK2Fc-Rz-29@gated-at.bofh.it> (permalink)
References	<rJZR0-7rp-45@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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Thomas Gleixner wrote:
> On Tue, 14 Jun 2016, George Spelvin wrote:
>> If you need to shrink TIMER_ARRAYMASK to fit another flag bit,
> 
> We can accomodate wheel with 512 buckets with the current ARRAYMASK and that
> really should be enough.

You're absolutely correct, but I was referring to the possible development
in the future of the need for another flag bit for some purpose *other*
than encoding a bucket number.  There's no need now, but if next year
someone finds and urgent need for another flag bit, there's a way
to proceed.

(Although you could just enlarge "flags"; the removal of "slack" has left
a 32-bit alignment hole.)

> The expiry code uses the pending_map already in patch 13 to avoid looking at
> the bucket if its empty.

My bad, I'm sorry!  I was quickly re-reading it and missed that.
Given the quality of the patch series, I should have expected that and
looked harder.

> Thanks,

Thank *you*.  It really is a pleasure to read.  I can't find anything but the most
insignificant issues to complain about.

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Thread

Re: [patch 13/20] timer: Switch to a non cascading wheel "George Spelvin" <linux@sciencehorizons.net> - 2016-06-14 10:20 +0200
  Re: [patch 13/20] timer: Switch to a non cascading wheel Thomas Gleixner <tglx@linutronix.de> - 2016-06-14 11:00 +0200
    Re: [patch 13/20] timer: Switch to a non cascading wheel "George Spelvin" <linux@sciencehorizons.net> - 2016-06-14 12:20 +0200
  Re: [patch 13/20] timer: Switch to a non cascading wheel Peter Zijlstra <peterz@infradead.org> - 2016-06-14 12:30 +0200
    Re: [patch 13/20] timer: Switch to a non cascading wheel "George Spelvin" <linux@sciencehorizons.net> - 2016-06-14 15:00 +0200
      Re: [patch 13/20] timer: Switch to a non cascading wheel Thomas Gleixner <tglx@linutronix.de> - 2016-06-14 19:00 +0200
        Re: [patch 13/20] timer: Switch to a non cascading wheel "George Spelvin" <linux@sciencehorizons.net> - 2016-06-14 22:00 +0200

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