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From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Ivo Sieben <meltedpianoman@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>,
	linux-kernel@vger.kernel.org, Andi Kleen <andi@firstfloor.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	linux-serial@vger.kernel.org, Alan Cox <alan@linux.intel.com>,
	Greg KH <gregkh@linuxfoundation.org>
Subject: Re: [REPOST-v2] sched: Prevent wakeup to enter critical section needlessly
Date: Wed, 21 Nov 2012 13:47:47 +0000	[thread overview]
Message-ID: <20121121134747.261c426a@pyramind.ukuu.org.uk> (raw)
In-Reply-To: <CAMSQXEGfQE_vcvk9MvP-aJD2jeF7vU+84yx_fEn==v2Jve9w0A@mail.gmail.com>

> But we try to understand your fault scenario: How can the LOAD leak
> into the critical section? As far as we understand the spin_unlock()
> function also contains a memory barrier to prevent such a reordering
> from happening.

It does - it would be very interesting for someone to look at the assembly
if this is making a difference.

Alan

  reply	other threads:[~2012-11-21 13:43 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-09-24 13:06 [PATCH] RFC: " Ivo Sieben
2012-10-09 11:30 ` [REPOST] " Ivo Sieben
2012-10-09 13:37   ` Andi Kleen
2012-10-09 14:15     ` Peter Zijlstra
2012-10-09 15:17       ` Oleg Nesterov
2012-10-10 14:02         ` Andi Kleen
2012-10-18  8:30           ` [PATCH-v2] " Ivo Sieben
2012-10-25 10:12             ` [REPOST-v2] " Ivo Sieben
2012-11-19  7:30               ` Ivo Sieben
2012-11-19 10:20                 ` Preeti U Murthy
2012-11-19 15:10                 ` Oleg Nesterov
2012-11-19 15:34                   ` Ivo Sieben
2012-11-19 15:49                     ` Oleg Nesterov
2012-11-21 13:03                       ` Ivo Sieben
2012-11-21 13:47                         ` Alan Cox [this message]
2012-11-21 13:58                         ` Oleg Nesterov

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