From: Frederic Weisbecker <fweisbec@gmail.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 2/3] nohz: Convert tick dependency mask to atomic_t
Date: Fri, 25 Mar 2016 15:56:13 +0100 [thread overview]
Message-ID: <20160325145612.GB16488@lerouge> (raw)
In-Reply-To: <20160325085202.GB15235@gmail.com>
On Fri, Mar 25, 2016 at 09:52:02AM +0100, Ingo Molnar wrote:
> > diff --git a/kernel/time/tick-sched.h b/kernel/time/tick-sched.h
> > index eb4e325..bf38226 100644
> > --- a/kernel/time/tick-sched.h
> > +++ b/kernel/time/tick-sched.h
> > @@ -60,7 +60,7 @@ struct tick_sched {
> > u64 next_timer;
> > ktime_t idle_expires;
> > int do_timer_last;
> > - unsigned long tick_dep_mask;
> > + atomic_t tick_dep_mask;
> > };
> >
> > extern struct tick_sched *tick_get_tick_sched(int cpu);
>
> Yeah, so I really like this interface, because it makes it really, really obvious
> that only atomic_t-compatible operations can be used on the value. It's a common
> bug to have a long, operated on atomically via bitops - and then occasionally
> operated on in a non-atomic fashion, or used without taking ordering into account.
> Such bugs are quite hard to find.
>
> This change also shrinks the mask from long to int, which is an another bonus, and
> which addresses the other objection Linus had.
Thanks, I much prefer it that way too!
Should I do a pull request or can I let you apply these?
next prev parent reply other threads:[~2016-03-25 14:56 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-24 14:37 [PATCH 0/3] nohz: Convert tick dependency mask to atomic_t Frederic Weisbecker
2016-03-24 14:37 ` [PATCH 1/3] atomic: Introduce atomic_fetch_or Frederic Weisbecker
2016-03-29 10:36 ` [tip:core/urgent] locking/atomic: Introduce atomic_fetch_or() tip-bot for Frederic Weisbecker
2016-03-24 14:38 ` [PATCH 2/3] nohz: Convert tick dependency mask to atomic_t Frederic Weisbecker
2016-03-25 8:52 ` Ingo Molnar
2016-03-25 14:56 ` Frederic Weisbecker [this message]
2016-03-29 10:37 ` [tip:core/urgent] timers/nohz: " tip-bot for Frederic Weisbecker
2016-03-24 14:38 ` [PATCH 3/3] Revert "atomic: Export fetch_or()" Frederic Weisbecker
2016-03-29 10:37 ` [tip:core/urgent] locking/atomic, sched: Unexport fetch_or() tip-bot for Frederic Weisbecker
2016-03-25 8:48 ` [PATCH 0/3] nohz: Convert tick dependency mask to atomic_t Ingo Molnar
2016-03-25 13:17 ` Frederic Weisbecker
2016-03-29 9:44 ` Ingo Molnar
2016-03-29 12:23 ` Linus Torvalds
2016-03-29 12:59 ` Ingo Molnar
2016-03-29 13:05 ` Ingo Molnar
2016-03-29 13:08 ` Frederic Weisbecker
2016-03-31 6:54 ` Ingo Molnar
2016-03-31 9:20 ` Peter Zijlstra
2016-03-31 13:18 ` Ingo Molnar
2016-03-29 13:14 ` Ingo Molnar
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