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Date: Tue, 2 Feb 2021 12:04:09 +0100
From: Peter Zijlstra <peterz@infradead.org>
Subject: Re: [RFC 11/20] mm/tlb: remove arch-specific tlb_start/end_vma()
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To: Nadav Amit <namit@vmware.com>
Cc: Nicholas Piggin <npiggin@gmail.com>, Andrea Arcangeli <aarcange@redhat.com>, Andrew Morton <akpm@linux-foundation.org>, Dave Hansen <dave.hansen@linux.intel.com>, "linux-csky@vger.kernel.org" <linux-csky@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>, Linux-MM <linux-mm@kvack.org>, linuxppc-dev <linuxppc-dev@lists.ozlabs.org>, linux-s390 <linux-s390@vger.kernel.org>, Andy Lutomirski <luto@kernel.org>, Thomas Gleixner <tglx@linutronix.de>, Will Deacon <will@kernel.org>, X86 ML <x86@kernel.org>, Yu Zhao <yuzhao@google.com>

On Tue, Feb 02, 2021 at 09:54:36AM +0000, Nadav Amit wrote:
> > On Feb 2, 2021, at 1:31 AM, Peter Zijlstra <peterz@infradead.org> wrote:
> > 
> > On Tue, Feb 02, 2021 at 07:20:55AM +0000, Nadav Amit wrote:
> >> Arm does not define tlb_end_vma, and consequently it flushes the TLB after
> >> each VMA. I suspect it is not intentional.
> > 
> > ARM is one of those that look at the VM_EXEC bit to explicitly flush
> > ITLB IIRC, so it has to.
> 
> Hmm… I don’t think Arm is doing that. At least arm64 does not use the
> default tlb_flush(), and it does not seem to consider VM_EXEC (at least in
> this path):
> 

ARM != ARM64. ARM certainly does, but you're right, I don't think ARM64
does this.