linux-kernel - RE: [PATCH 1/3] x86/mm/pat: Disable preemption around __flush_tlb

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Date:   Wed, 17 Oct 2018 11:45:59 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Sebastian Andrzej Siewior' <bigeasy@...utronix.de>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "x86@...nel.org" <x86@...nel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Borislav Petkov <bp@...en8.de>
Subject: RE: [PATCH 1/3] x86/mm/pat: Disable preemption around
 __flush_tlb_all()

From: 'Sebastian Andrzej Siewior'
> Sent: 17 October 2018 11:39
> On 2018-10-17 09:54:38 [+0000], David Laight wrote:
> > Can it make any sense to flush the tlb with preemption enabled?
> it might. Usually it is disabled for other reasons.

That's what I mean, it should be disabled by the caller.

> > Surely preemption must be disabled over something else as well?
> In this case it is due to the CR3 reload. I don't see anything else.

Right, so it should be disabled before the CR3 reload and enabled after?

	David

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