From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1753413AbdFVSKd (ORCPT <rfc822;w@1wt.eu>);
        Thu, 22 Jun 2017 14:10:33 -0400
Received: from mail.kernel.org ([198.145.29.99]:56714 "EHLO mail.kernel.org"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1751224AbdFVSKc (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Thu, 22 Jun 2017 14:10:32 -0400
DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6D27D22B66
Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org
Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=luto@kernel.org
MIME-Version: 1.0
In-Reply-To: <E43BCF62-8688-4238-80F6-FE6F0040FD25@gmail.com>
References: <cover.1498022414.git.luto@kernel.org> <a8cdfbbb17785aed10980d24692745f68615a584.1498022414.git.luto@kernel.org>
 <E43BCF62-8688-4238-80F6-FE6F0040FD25@gmail.com>
From: Andy Lutomirski <luto@kernel.org>
Date: Thu, 22 Jun 2017 11:10:10 -0700
X-Gmail-Original-Message-ID: <CALCETrXcTG2JBnX7kwP2iM=dngk1NRf-3deSgU3BDA5rz1GuSQ@mail.gmail.com>
Message-ID: <CALCETrXcTG2JBnX7kwP2iM=dngk1NRf-3deSgU3BDA5rz1GuSQ@mail.gmail.com>
Subject: Re: [PATCH v3 11/11] x86/mm: Try to preserve old TLB entries using PCID
To: Nadav Amit <nadav.amit@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>, X86 ML <x86@kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Borislav Petkov <bp@alien8.de>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Mel Gorman <mgorman@suse.de>,
        "linux-mm@kvack.org" <linux-mm@kvack.org>,
        Rik van Riel <riel@redhat.com>, Dave Hansen <dave.hansen@intel.com>,
        Arjan van de Ven <arjan@linux.intel.com>,
        Peter Zijlstra <peterz@infradead.org>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Thu, Jun 22, 2017 at 9:09 AM, Nadav Amit <nadav.amit@gmail.com> wrote:
> Andy Lutomirski <luto@kernel.org> wrote:
>
>>
>> --- a/arch/x86/mm/init.c
>> +++ b/arch/x86/mm/init.c
>> @@ -812,6 +812,7 @@ void __init zone_sizes_init(void)
>>
>> DEFINE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate) = {
>>       .loaded_mm = &init_mm,
>> +     .next_asid = 1,
>
> I think this is a remainder from previous version of the patches, no? It
> does not seem necessary and may be confusing (ctx_id 0 is reserved, but not
> asid 0).

Hmm.  It's no longer needed for correctness, but init_mm still lands
in slot 0, and it seems friendly to avoid immediately stomping it.
Admittedly, this won't make any practical difference since it'll only
happen once per cpu.

>
> Other than that, if you want, you can put for the entire series:
>
> Reviewed-by: Nadav Amit <nadav.amit@gmail.com>
>

Thanks!