From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Andi Kleen <ak@suse.de>
Cc: Benjamin LaHaise <bcrl@kvack.org>, Ingo Molnar <mingo@elte.hu>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: What protects cpu_tlbstate?
Date: Thu, 05 Apr 2007 14:00:22 -0700 [thread overview]
Message-ID: <46156366.70206@goop.org> (raw)
In-Reply-To: <200704052228.36590.ak@suse.de>
Andi Kleen wrote:
> The interrupts can only happen when the other CPU is already lazy
> and enter_lazy_tlb would be a nop then. The flushers itself are
> synchronized by the page_table_lock or the mm semaphore.
>
> Against switch_mm it tries to protect with ordering.
>
> wmb()s are not needed on x86 (ok minus errata on ppro and
> VIA magic mode but which is UP only). That would leave some rmb()s,
> but I don't see any place they would be needed.
>
Hm, I was more wondering about simple compiler reordering. Does the
relative order of setting and reading cpu_tlbstate.state, active_mm and
the mm->cpu_vm_mask matter?
J
next prev parent reply other threads:[~2007-04-05 21:00 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-05 19:44 What protects cpu_tlbstate? Jeremy Fitzhardinge
2007-04-05 20:28 ` Andi Kleen
2007-04-05 21:00 ` Jeremy Fitzhardinge [this message]
2007-04-05 21:03 ` Andi Kleen
2007-04-05 21:08 ` Jeremy Fitzhardinge
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