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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Andy Lutomirski <luto@amacapital.net>
Cc: "linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	X86 ML <x86@kernel.org>, Borislav Petkov <bp@suse.de>,
	Andy Lutomirski <luto@kernel.org>, Rik van Riel <riel@redhat.com>,
	Mel Gorman <mgorman@suse.de>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [PATCH] x86/mm: disable preemption during CR3 read+write
Date: Fri, 5 Aug 2016 17:52:38 +0200	[thread overview]
Message-ID: <c0a89331-e6f1-5c71-b513-2ff55de392d4@linutronix.de> (raw)
In-Reply-To: <CALCETrV9n=-Zi2KBT7i-WLrYGffXy1ha+M=_PhvnuOiG7pim8A@mail.gmail.com>

On 08/05/2016 05:42 PM, Andy Lutomirski wrote:
> 
> This should affect kernel threads too, right?

I don't think so because they don't have a MM in the first place so
they don't shouldn't need to flush a TLB. But then there is iounmap()
and vfree() for instance which does

vmap_debug_free_range()
{
   if (debug_pagealloc_enabled()) {
         vunmap_page_range(start, end);
         flush_tlb_kernel_range(start, end);
   }
}

so it looks like a candidate.

> Acked-by: Andy Lutomirski <luto@kernel.org>

Sebastian

WARNING: multiple messages have this Message-ID (diff)
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Andy Lutomirski <luto@amacapital.net>
Cc: "linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	X86 ML <x86@kernel.org>, Borislav Petkov <bp@suse.de>,
	Andy Lutomirski <luto@kernel.org>, Rik van Riel <riel@redhat.com>,
	Mel Gorman <mgorman@suse.de>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [PATCH] x86/mm: disable preemption during CR3 read+write
Date: Fri, 5 Aug 2016 17:52:38 +0200	[thread overview]
Message-ID: <c0a89331-e6f1-5c71-b513-2ff55de392d4@linutronix.de> (raw)
In-Reply-To: <CALCETrV9n=-Zi2KBT7i-WLrYGffXy1ha+M=_PhvnuOiG7pim8A@mail.gmail.com>

On 08/05/2016 05:42 PM, Andy Lutomirski wrote:
> 
> This should affect kernel threads too, right?

I don't think so because they don't have a MM in the first place so
they don't shouldn't need to flush a TLB. But then there is iounmap()
and vfree() for instance which does

vmap_debug_free_range()
{
   if (debug_pagealloc_enabled()) {
         vunmap_page_range(start, end);
         flush_tlb_kernel_range(start, end);
   }
}

so it looks like a candidate.

> Acked-by: Andy Lutomirski <luto@kernel.org>

Sebastian

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  reply	other threads:[~2016-08-05 15:52 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-05 13:37 [PATCH] x86/mm: disable preemption during CR3 read+write Sebastian Andrzej Siewior
2016-08-05 13:37 ` Sebastian Andrzej Siewior
2016-08-05 13:53 ` Peter Zijlstra
2016-08-05 13:53   ` Peter Zijlstra
2016-08-05 14:38 ` Rik van Riel
2016-08-05 15:42 ` Andy Lutomirski
2016-08-05 15:42   ` Andy Lutomirski
2016-08-05 15:52   ` Sebastian Andrzej Siewior [this message]
2016-08-05 15:52     ` Sebastian Andrzej Siewior
2016-08-10 18:10 ` [tip:x86/urgent] x86/mm: Disable " tip-bot for Sebastian Andrzej Siewior
2017-10-17 15:57 [PATCH] " Sebastian Andrzej Siewior
2017-10-18 15:01 ` Bernhard Kaindl
2017-10-18 16:51   ` Greg KH

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