From: Ingo Molnar <mingo@elte.hu>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Valdis.Kletnieks@vt.edu,
Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: 2.6.39-rc6-mmotm0506 - lockdep splat in RCU code on page fault
Date: Tue, 10 May 2011 10:57:46 +0200 [thread overview]
Message-ID: <20110510085746.GG27426@elte.hu> (raw)
In-Reply-To: <20110510082029.GF2258@linux.vnet.ibm.com>
* Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote:
> - raw_spin_lock_irqsave(&rnp->lock, flags);
> - rnp->wakemask |= rdp->grpmask;
> - raw_spin_unlock_irqrestore(&rnp->lock, flags);
> + do {
> + old = rnp->wakemask;
> + new = old | rdp->grpmask;
> + } while (cmpxchg(&rnp->wakemask, old, new) != old);
Hm, isnt this an inferior version of atomic_or_long() in essence?
Note that atomic_or_long() is x86 only, so a generic one would have to be
offered too i suspect, atomic_cmpxchg() driven or so - which would look like
the above loop.
Most architectures could offer atomic_or_long() i suspect.
Thanks,
Ingo
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next prev parent reply other threads:[~2011-05-10 8:57 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-10 1:04 2.6.39-rc6-mmotm0506 - lockdep splat in RCU code on page fault Valdis.Kletnieks
2011-05-10 8:20 ` Paul E. McKenney
2011-05-10 8:57 ` Ingo Molnar [this message]
2011-05-10 16:21 ` Paul E. McKenney
2011-05-10 20:44 ` Ingo Molnar
2011-05-11 7:44 ` Paul E. McKenney
2011-05-11 23:11 ` Valdis.Kletnieks
2011-05-12 9:47 ` Paul E. McKenney
2011-05-12 16:05 ` Valdis.Kletnieks
2011-05-13 7:18 ` Paul E. McKenney
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