From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752481AbeC1Htq (ORCPT ); Wed, 28 Mar 2018 03:49:46 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:45900 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751938AbeC1Hto (ORCPT ); Wed, 28 Mar 2018 03:49:44 -0400 Subject: Re: [PATCH v9 01/24] mm: Introduce CONFIG_SPECULATIVE_PAGE_FAULT To: David Rientjes , Thomas Gleixner Cc: paulmck@linux.vnet.ibm.com, peterz@infradead.org, akpm@linux-foundation.org, kirill@shutemov.name, ak@linux.intel.com, mhocko@kernel.org, dave@stgolabs.net, jack@suse.cz, Matthew Wilcox , benh@kernel.crashing.org, mpe@ellerman.id.au, paulus@samba.org, Ingo Molnar , hpa@zytor.com, Will Deacon , Sergey Senozhatsky , Andrea Arcangeli , Alexei Starovoitov , kemi.wang@intel.com, sergey.senozhatsky.work@gmail.com, Daniel Jordan , linux-kernel@vger.kernel.org, linux-mm@kvack.org, haren@linux.vnet.ibm.com, khandual@linux.vnet.ibm.com, npiggin@gmail.com, bsingharora@gmail.com, Tim Chen , linuxppc-dev@lists.ozlabs.org, x86@kernel.org References: <1520963994-28477-1-git-send-email-ldufour@linux.vnet.ibm.com> <1520963994-28477-2-git-send-email-ldufour@linux.vnet.ibm.com> From: Laurent Dufour Date: Wed, 28 Mar 2018 09:49:29 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 18032807-0008-0000-0000-000004E30EDE X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18032807-0009-0000-0000-00001E764C34 Message-Id: <32c80b6a-28c6-bf63-ed7b-6a042ae18e8f@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-03-28_02:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1803280084 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi David, Thanks a lot for your deep review on this series. On 25/03/2018 23:50, David Rientjes wrote: > On Tue, 13 Mar 2018, Laurent Dufour wrote: > >> This configuration variable will be used to build the code needed to >> handle speculative page fault. >> >> By default it is turned off, and activated depending on architecture >> support. >> >> Suggested-by: Thomas Gleixner >> Signed-off-by: Laurent Dufour >> --- >> mm/Kconfig | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/mm/Kconfig b/mm/Kconfig >> index abefa573bcd8..07c566c88faf 100644 >> --- a/mm/Kconfig >> +++ b/mm/Kconfig >> @@ -759,3 +759,6 @@ config GUP_BENCHMARK >> performance of get_user_pages_fast(). >> >> See tools/testing/selftests/vm/gup_benchmark.c >> + >> +config SPECULATIVE_PAGE_FAULT >> + bool > > Should this be configurable even if the arch supports it? Actually, this is not configurable unless by manually editing the .config file. I made it this way on the Thomas's request : https://lkml.org/lkml/2018/1/15/969 That sounds to be the smarter way to achieve that, isn't it ? Laurent.