From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756593Ab2JZNJA (ORCPT ); Fri, 26 Oct 2012 09:09:00 -0400 Received: from casper.infradead.org ([85.118.1.10]:42789 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753338Ab2JZNI7 convert rfc822-to-8bit (ORCPT ); Fri, 26 Oct 2012 09:08:59 -0400 Message-ID: <1351256885.16863.62.camel@twins> Subject: Re: [PATCH 1/2] numa, mm: drop redundant check in do_huge_pmd_numa_page() From: Peter Zijlstra To: "Kirill A. Shutemov" Cc: linux-mm@kvack.org, Will Deacon , Andrew Morton , Andrea Arcangeli , Xiao Guangrong , Ingo Molnar , linux-kernel@vger.kernel.org Date: Fri, 26 Oct 2012 15:08:05 +0200 In-Reply-To: <1351256077-1594-1-git-send-email-kirill.shutemov@linux.intel.com> References: <1351256077-1594-1-git-send-email-kirill.shutemov@linux.intel.com> Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-Mailer: Evolution 3.2.2- Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2012-10-26 at 15:54 +0300, Kirill A. Shutemov wrote: > From: "Kirill A. Shutemov" > > We check if the pmd entry is the same as on pmd_trans_huge() in > handle_mm_fault(). That's enough. > > Signed-off-by: Kirill A. Shutemov Ah indeed, Will mentioned something like this on IRC as well, I hadn't gotten around to looking at it -- now have, thanks! Acked-by: Peter Zijlstra That said, where in handle_mm_fault() do we wait for a split to complete? We have a pmd_trans_huge() && !pmd_trans_splitting(), so a fault on a currently splitting pmd will fall through. Is it the return from the fault on unlikely(pmd_trans_huge()) ? I'm probably missing something obvious..