Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752732AbdI3UDS (ORCPT ); Sat, 30 Sep 2017 16:03:18 -0400 Received: from omzsmtpe03.verizonbusiness.com ([199.249.25.208]:19423 "EHLO omzsmtpe03.verizonbusiness.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751141AbdI3UDR (ORCPT ); Sat, 30 Sep 2017 16:03:17 -0400 From: "Levin, Alexander (Sasha Levin)" X-Host: discovery.odc.vzwcorp.com To: Vegard Nossum CC: Steven Rostedt , Michal Hocko , "akpm@linux-foundation.org" , "linux-kernel@vger.kernel.org" , "David S . Miller" , Alexander Potapenko , Andrey Ryabinin , Dmitry Vyukov Subject: Re: [PATCH] mm: kill kmemcheck again Thread-Topic: [PATCH] mm: kill kmemcheck again Thread-Index: AQHTOicSVtH0DJBhY0uJkPsuuXSPwA== Date: Sat, 30 Sep 2017 20:02:41 +0000 Message-ID: <20170930200239.ngcyp2tcpuidpctv@sasha-lappy> References: <20170927112723.16862-1-alexander.levin@verizon.com> <20170927150207.swmcarc4lqlklohr@dhcp22.suse.cz> <20170930054815.0e2c182f@vmware.local.home> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: user-agent: NeoMutt/20170113 (1.7.2) x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.144.60.250] Content-Type: text/plain; charset="us-ascii" Content-ID: <9483A02BA60D0142942DBAFE2731A0F3@vzwcorp.com> MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id v8UK3Y0O012966 Content-Length: 1288 Lines: 29 On Sat, Sep 30, 2017 at 03:57:27PM +0200, Vegard Nossum wrote: >On 30 September 2017 at 11:48, Steven Rostedt wrote: >> On Wed, 27 Sep 2017 17:02:07 +0200 >> Michal Hocko wrote: >> >>> > Now that 2 years have passed, and all distros provide gcc that supports >>> > KASAN, kill kmemcheck again for the very same reasons. >>> >>> This is just too large to review manually. How have you generated the >>> patch? >> >> I agree. This needs to be taken out piece by piece, not in one go, >> where there could be unexpected fallout. > >I have a patch from earlier this year that starts by removing the core >code and defining all the helpers/flags as no-ops so they can be >removed bit by bit at a later time. See the attachment. Pekka signed >off on it too. >e >I never actually submitted this because I was waiting for MSAN to be I'm not sure how much value there is in doing it this way. I agree that the patch is big, but most of it is simply removing code under arch/x86/mm/kmemcheck. The difference between Vegard's patch and mine is about 300 lines (out of 2800+), where those 300 lines are simply removing calls to kmemcheck. There are no logic changes. (so something very similar to 's/*kmemcheck*//g' would do the trick). -- Thanks, Sasha