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From: Peter Zijlstra <peterz@infradead.org>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>,
	linux-kernel@vger.kernel.org, linux-next@vger.kernel.org,
	"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@elte.hu>,
	ppc-dev <linuxppc-dev@lists.ozlabs.org>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: linux-next: PowerPC WARN_ON_ONCE() after merge of the final tree (tip related)
Date: Fri, 16 Apr 2010 12:38:43 +0200	[thread overview]
Message-ID: <1271414323.4807.1931.camel@twins> (raw)
In-Reply-To: <20100415171551.GA5069@nowhere>

On Thu, 2010-04-15 at 19:15 +0200, Frederic Weisbecker wrote:
> > that looks rather ugly. Why not do a raw:
> >=20
> >       this_cpu_inc(lockdep_stats.redundant_hardirqs_on);
> >=20
> > which basically open-codes debug_atomic_inc(), but without the warning?
>=20
>=20
> Because that would open a race against interrupts that might
> touch lockdep_stats.redundant_hardirqs_on too.


How so, its a pure per-cpu variable right? so either the increment
happens before the interrupts hits, or after, in either case there
should not be a race with interrupts.

  reply	other threads:[~2010-04-16 10:38 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-04-15  6:12 linux-next: boot failure after merge of the final tree (tip related) Stephen Rothwell
2010-04-15  6:48 ` Benjamin Herrenschmidt
2010-04-15  6:49 ` linux-next: PowerPC WARN_ON_ONCE() " Ingo Molnar
2010-04-15  6:55   ` David Miller
2010-04-15  7:32     ` Ingo Molnar
2010-04-16  1:51       ` Benjamin Herrenschmidt
2010-04-16  1:56     ` Benjamin Herrenschmidt
2010-04-15 10:04   ` Stephen Rothwell
2010-04-15 13:00   ` Frederic Weisbecker
2010-04-15 14:03     ` Ingo Molnar
2010-04-15 17:15       ` Frederic Weisbecker
2010-04-16 10:38         ` Peter Zijlstra [this message]
2010-04-16 12:32           ` Frederic Weisbecker
2010-04-15 17:24       ` Frederic Weisbecker
2010-04-15 17:39         ` Ingo Molnar

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