From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH 4/6] x86/kasan: Prepare clear_pgds() to switch to
 <asm-generic/pgtable-nop4d.h>
Date: Fri, 24 Mar 2017 11:58:14 +0100
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To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>, "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>, Linus Torvalds <torvalds@linux-foundation.org>, Andrew Morton <akpm@linux-foundation.org>, x86@kernel.org, Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, Arnd Bergmann <arnd@arndb.de>, "H. Peter Anvin" <hpa@zytor.com>, Andi Kleen <ak@linux.intel.com>, Dave Hansen <dave.hansen@intel.com>, Andy Lutomirski <luto@amacapital.net>, Michal Hocko <mhocko@suse.com>, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Dmitry Vyukov <dvyukov@google.com>


* Kirill A. Shutemov <kirill@shutemov.name> wrote:

> On Wed, Mar 22, 2017 at 08:31:36AM +0100, Ingo Molnar wrote:
> > * Andrey Ryabinin <aryabinin@virtuozzo.com> wrote:
> > > On 03/17/2017 09:55 PM, Kirill A. Shutemov wrote:
> > > > With folded p4d, pgd_clear() is nop. Change clear_pgds() to use
> > > > p4d_clear() instead.
> > > > 
> > > 
> > > You could probably just use set_pgd(pgd_offset_k(start), __pgd(0)); instead of pgd_clear()
> > > as we already do in arm64.
> > > It's basically pgd_clear() except it's not a nop wih p4d folded.
> > 
> > Makes sense. Kirill, if you agree, mind spinning a v2 patch?
> 
> I can re-spin, if you want. But honestly, I don't think such constructs
> help readability.

Good point - I'll keep it as-is unless convinced otherwise.

Thanks,

	Ingo