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From: Andy Lutomirski <luto@amacapital.net>
Date: Fri, 27 Jun 2014 11:57:15 -0700
Message-ID: <CALCETrXban-Yk1e95Yy2-fXtudjBmKGFsLMjuB+zPCpxDP3OYg@mail.gmail.com>
Subject: Re: [PATCH v6 02/10] x86, mpx: add MPX specific mmap interface
To: Dave Hansen <dave.hansen@intel.com>
Cc: "Ren, Qiaowei" <qiaowei.ren@intel.com>, "H. Peter Anvin" <hpa@zytor.com>,
        Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
        X86 ML <x86@kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Linux MM <linux-mm@kvack.org>
Content-Type: text/plain; charset=UTF-8
Sender: linux-kernel-owner@vger.kernel.org

On Fri, Jun 27, 2014 at 10:42 AM, Dave Hansen <dave.hansen@intel.com> wrote:
> On 06/27/2014 10:34 AM, Dave Hansen wrote:
>> I'm claiming that we need COW behavior for the bounds tables, at least
>> by default.  If userspace knows enough about the ways that it is using
>> the tables and knows how to share them, let it go to town.  The kernel
>> will permit this kind of usage model, but we simply won't be helping
>> with the management of the tables when userspace creates them.
>
> Actually, this is another reason we need to mark VMAs as being
> MPX-related explicitly instead of inferring it from the tables.  If
> userspace does something really specialized like this, the kernel does
> not want to confuse these VMAs the ones it created.
>

Good point.

--Andy
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