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From: "H. Peter Anvin" <hpa@zytor.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andi Kleen <andi@firstfloor.org>,
	Suresh Siddha <suresh.b.siddha@intel.com>,
	Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
	LKML <linux-kernel@vger.kernel.org>,
	"Mallick, Asit K" <asit.k.mallick@intel.com>
Subject: Re: [patch] x86, mm: avoid stale tlb entries by clearing prev mm_cpumask after switching mm
Date: Wed, 02 Feb 2011 20:22:52 -0800	[thread overview]
Message-ID: <4D4A2D9C.2040803@zytor.com> (raw)
In-Reply-To: <AANLkTi=+VQGKDcMmpCLT87NEpMU99i7iW8cOFzyHFpmn@mail.gmail.com>

On 02/02/2011 08:12 PM, Linus Torvalds wrote:
> 
> So right now, we pretty much depend on "asm volatile" (a) not being
> re-ordered wrt other asm volatiles and (b) having that dependency on
> memory.
> 
> Iirc, the gcc people even agreed on this. Peter may remember details better..
> 

Yes, IIRC an "asm volatile" is assumed to be a universal consumer of
memory (it is only a universal producer if the "memory" clobber is
used), as well as being ordered with respect to other volatile operations.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.


  reply	other threads:[~2011-02-03  4:23 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-02-02 20:07 [patch] x86, mm: avoid stale tlb entries by clearing prev mm_cpumask after switching mm Suresh Siddha
2011-02-03  1:23 ` Andi Kleen
2011-02-03  1:55   ` Suresh Siddha
2011-02-03  2:15     ` Andi Kleen
2011-02-03  4:12       ` Linus Torvalds
2011-02-03  4:22         ` H. Peter Anvin [this message]
2011-02-03  1:55 ` Linus Torvalds
2011-02-03  4:03   ` Linus Torvalds
2011-02-03 18:27     ` Suresh Siddha
2011-02-03 19:13       ` Linus Torvalds
2011-02-03 19:34         ` Suresh Siddha
2011-02-03 19:48           ` Linus Torvalds
2011-02-03 20:20             ` Suresh Siddha
2011-02-03 21:06               ` Ingo Molnar
2011-02-03 21:33                 ` Linus Torvalds
2011-02-03 21:39                   ` Ingo Molnar
     [not found] <BLU157-w495F35A445E063E33DC9E8DAAC0@phx.gbl>
     [not found] ` <BLU157-w41A610FD3413183801060CDAAC0@phx.gbl>
     [not found]   ` <BLU157-w548B9D2F8EDD8CA9DB6CD3DAAC0@phx.gbl>
2011-04-15 11:58     ` MaoXiaoyun

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