From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <owner-linux-mm@kvack.org>
Received: from psmtp.com (na3sys010amx158.postini.com [74.125.245.158])
	by kanga.kvack.org (Postfix) with SMTP id 5F2A56B00A4
	for <linux-mm@kvack.org>; Mon, 16 Sep 2013 08:12:09 -0400 (EDT)
From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
In-Reply-To: <20130916114404.GC9326@twins.programming.kicks-ass.net>
References: <1379330740-5602-1-git-send-email-kirill.shutemov@linux.intel.com>
 <20130916114404.GC9326@twins.programming.kicks-ass.net>
Subject: Re: [PATCHv2 0/9] split page table lock for PMD tables
Content-Transfer-Encoding: 7bit
Message-Id: <20130916121154.3525EE0090@blue.fi.intel.com>
Date: Mon, 16 Sep 2013 15:11:54 +0300 (EEST)
Sender: owner-linux-mm@kvack.org
List-ID: <linux-mm.kvack.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>, Alex Thorlton <athorlton@sgi.com>, Ingo Molnar <mingo@redhat.com>, Andrew Morton <akpm@linux-foundation.org>, Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>, "Eric W . Biederman" <ebiederm@xmission.com>, "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>, Al Viro <viro@zeniv.linux.org.uk>, Andi Kleen <ak@linux.intel.com>, Andrea Arcangeli <aarcange@redhat.com>, Dave Hansen <dave.hansen@intel.com>, Dave Jones <davej@redhat.com>, David Howells <dhowells@redhat.com>, Frederic Weisbecker <fweisbec@gmail.com>, Johannes Weiner <hannes@cmpxchg.org>, Kees Cook <keescook@chromium.org>, Mel Gorman <mgorman@suse.de>, Michael Kerrisk <mtk.manpages@gmail.com>, Oleg Nesterov <oleg@redhat.com>, Rik van Riel <riel@redhat.com>, Robin Holt <robinmholt@gmail.com>, Sedat Dilek <sedat.dilek@gmail.com>, Srikar Dronamraju <srikar@linux.vnet.ibm.com>, Thomas Gleixner <tglx@linutronix.de>, linux-kernel@vger.kernel.org, linux-mm@kvack.org

Peter Zijlstra wrote:
> >   - reuse CONFIG_SPLIT_PTLOCK_CPUS for PMD split lock;
> 
> So why is there still CONFIG_SPLIT_PTE_PTLOCK and
> CONFIG_SPLIT_PMD_PTLOCK in the series?

There is not.

We have USE_SPLIT_{PTE,PMD}_PTLOCK. We can't use split pmd lock everywhere
split pte lock is available: it requires separate enabling on arch side
and will not work on all hardware (i.e. with 2-level page table
configuration).

-- 
 Kirill A. Shutemov

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>