linux-kernel - Re: Do we need to disable preemption in flush_tlb

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Message-ID: <5a5c67c1-9f45-f908-2c8d-0914cd616a18@synopsys.com>
Date:   Wed, 14 Mar 2018 13:19:01 -0700
From:   Vineet Gupta <Vineet.Gupta1@...opsys.com>
To:     Alexey Brodkin <Alexey.Brodkin@...opsys.com>
CC:     Peter Zijlstra <peterz@...radead.org>,
        "linux-arch@...r.kernel.org" <linux-arch@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-snps-arc@...ts.infradead.org" 
        <linux-snps-arc@...ts.infradead.org>
Subject: Re: Do we need to disable preemption in flush_tlb_range()?

+CC Peter since we have his attention ;-)

On 03/01/2018 07:13 AM, Alexey Brodkin wrote:
> Hi Vineet,
> 
> Just noticed that in comments for smp_call_function_many() it is said that
> preemption must be disabled during its execution. And that function gets executed
> among other ways like that:
> -------------------------->8-----------------------
>    flush_tlb_range()
>      -> on_each_cpu_mask()
>           -> smp_call_function_many()
> -------------------------->8-----------------------

In general I prefer not to - Peter what say you ?

> 
> I'm not seeing right now any real problem with current implementation but
> some architectures do that thus the question.
> 
> -Alexey
>