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From: Waiman Long <waiman.long@hp.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Mikulas Patocka <mpatocka@redhat.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	jejb@parisc-linux.org, deller@gmx.de,
	John David Anglin <dave.anglin@bell.net>,
	linux-parisc@vger.kernel.org, linux-kernel@vger.kernel.org,
	paulmck@linux.vnet.ibm.com, chegu_vinod@hp.com,
	tglx@linutronix.de, riel@redhat.com, akpm@linux-foundation.org,
	davidlohr@hp.com, hpa@zytor.com, andi@firstfloor.org,
	aswin@hp.com, scott.norton@hp.com, Jason Low <jason.low2@hp.com>
Subject: Re: [PATCH v2] introduce atomic_pointer to fix a race condition in cancelable mcs spinlocks
Date: Mon, 02 Jun 2014 13:33:34 -0400	[thread overview]
Message-ID: <538CB56E.5010709@hp.com> (raw)
In-Reply-To: <20140602163032.GI16155@laptop.programming.kicks-ass.net>

On 06/02/2014 12:30 PM, Peter Zijlstra wrote:
> On Mon, Jun 02, 2014 at 06:25:25PM +0200, Peter Zijlstra wrote:
>> I'm almost inclined to just exclude parisc from using opt spinning.
>>
>> That said, this patch still doesn't address the far more interesting
>> problem of actually finding these issues for these few weird archs.
> So why do these archs provide xchg() and cmpxchg() at all? Wouldn't it
> be much simpler if archs that cannot sanely do this, not provide these
> primitives at all?

I believe xchg() and cmpxchg() are used in quite a number of places 
within the generic kernel code. So kernel compilation will fail if those 
APIs aren't provided by an architecture.

-Longman

  parent reply	other threads:[~2014-06-02 17:33 UTC|newest]

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-06-01 17:53 [PATCH] fix a race condition in cancelable mcs spinlocks Mikulas Patocka
2014-06-01 19:20 ` Peter Zijlstra
2014-06-01 20:46   ` John David Anglin
2014-06-01 21:30     ` Peter Zijlstra
2014-06-01 21:46       ` Paul E. McKenney
2014-06-02  9:19       ` Mikulas Patocka
2014-06-02 13:24         ` Paul E. McKenney
2014-06-02 15:57           ` Mikulas Patocka
2014-06-02 16:39             ` Paul E. McKenney
2014-06-02 19:56       ` James Bottomley
2014-06-03  7:56         ` Peter Zijlstra
2014-06-04 12:53           ` Mikulas Patocka
2014-06-02 13:58     ` Mikulas Patocka
2014-06-02 14:02       ` Mikulas Patocka
2014-06-02 15:39         ` John David Anglin
2014-06-02 10:34   ` Mikulas Patocka
2014-06-02 14:14 ` Waiman Long
2014-06-02 15:27   ` Jason Low
2014-06-02 16:00 ` [PATCH v2] introduce atomic_pointer to " Mikulas Patocka
2014-06-02 16:25   ` Peter Zijlstra
2014-06-02 16:30     ` Peter Zijlstra
2014-06-02 16:46       ` Paul E. McKenney
2014-06-02 17:33       ` Waiman Long [this message]
2014-06-02 20:05         ` Peter Zijlstra
2014-06-02 20:22           ` Linus Torvalds
2014-06-02 21:02             ` Paul E. McKenney
2014-06-02 21:12               ` Linus Torvalds
2014-06-02 22:08                 ` Paul E. McKenney
2014-06-02 22:44                   ` Eric Dumazet
2014-06-02 23:17                     ` Paul E. McKenney
2014-06-02 23:53                       ` Eric Dumazet
2014-06-03  0:28                         ` Paul E. McKenney
2014-06-02 22:55                   ` Linus Torvalds
2014-06-03 16:48                     ` Paul E. McKenney
2014-06-03  7:54             ` Peter Zijlstra
2014-06-02 20:24           ` James Bottomley
2014-06-02 16:43     ` Paul E. McKenney
2014-06-02 17:14       ` James Bottomley
2014-06-02 17:29       ` Waiman Long
2014-06-02 17:09     ` Linus Torvalds
2014-06-02 17:12       ` Davidlohr Bueso
2014-06-02 17:42         ` Waiman Long
2014-06-02 20:46       ` Mikulas Patocka
2014-06-02 20:53         ` Linus Torvalds
2014-06-02 21:12           ` Mikulas Patocka
2014-06-03  7:36             ` Peter Zijlstra
2014-06-03 11:14               ` Mikulas Patocka
2014-06-03 13:24                 ` Peter Zijlstra
2014-06-03 14:18                   ` Mikulas Patocka
2014-06-03 14:07               ` Paul E. McKenney
2014-06-03 15:09                 ` Peter Zijlstra
2014-06-03 15:56                   ` Paul E. McKenney
2014-06-03  7:20         ` Peter Zijlstra
2014-06-02 21:03       ` Paul E. McKenney
2014-06-06 15:06       ` Peter Zijlstra
2014-06-06 15:15         ` Paul E. McKenney
2014-06-06 15:42         ` Davidlohr Bueso
2014-06-02 16:50   ` Jason Low
2014-06-02 17:03     ` Paul E. McKenney
2014-06-02 17:25     ` Waiman Long
2014-06-02 17:38       ` H. Peter Anvin

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