Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754150AbdGSU7a (ORCPT ); Wed, 19 Jul 2017 16:59:30 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:49590 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753580AbdGSU73 (ORCPT ); Wed, 19 Jul 2017 16:59:29 -0400 Date: Wed, 19 Jul 2017 13:59:27 -0700 From: Andrew Morton To: "Zi Yan" Cc: "kbuild test robot" , kbuild-all@01.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, kirill.shutemov@linux.intel.com, minchan@kernel.org, vbabka@suse.cz, mgorman@techsingularity.net, mhocko@kernel.org, khandual@linux.vnet.ibm.com, dnellans@nvidia.com, dave.hansen@intel.com, n-horiguchi@ah.jp.nec.com Subject: Re: [PATCH v9 05/10] mm: thp: enable thp migration in generic path Message-Id: <20170719135927.d553f5afe893ca43d70cbdc5@linux-foundation.org> In-Reply-To: References: <201707191504.G4xCE7El%fengguang.wu@intel.com> X-Mailer: Sylpheed 3.4.1 (GTK+ 2.24.23; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2758 Lines: 64 On Wed, 19 Jul 2017 14:39:43 -0400 "Zi Yan" wrote: > On 19 Jul 2017, at 4:04, kbuild test robot wrote: > > > Hi Zi, > > > > [auto build test WARNING on mmotm/master] > > [also build test WARNING on v4.13-rc1 next-20170718] > > [if your patch is applied to the wrong git tree, please drop us a note to help improve the system] > > > > url: https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2F0day-ci%2Flinux%2Fcommits%2FZi-Yan%2Fmm-page-migration-enhancement-for-thp%2F20170718-095519&data=02%7C01%7Czi.yan%40cs.rutgers.edu%7Ca711ac47d4c0436ef66f08d4ce7cf30c%7Cb92d2b234d35447093ff69aca6632ffe%7C1%7C0%7C636360483431631457&sdata=NpxRpWbxe6o56xDJYpw1K6wgQo11IPCAbG2tE8l%2BU6E%3D&reserved=0 > > base: git://git.cmpxchg.org/linux-mmotm.git master > > config: xtensa-common_defconfig (attached as .config) > > compiler: xtensa-linux-gcc (GCC) 4.9.0 > > reproduce: > > wget https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fraw.githubusercontent.com%2F01org%2Flkp-tests%2Fmaster%2Fsbin%2Fmake.cross&data=02%7C01%7Czi.yan%40cs.rutgers.edu%7Ca711ac47d4c0436ef66f08d4ce7cf30c%7Cb92d2b234d35447093ff69aca6632ffe%7C1%7C0%7C636360483431631457&sdata=rBCfu0xUg3v%2B8r%2Be2tsiqRcqw%2FEZSTa4OtF0hU%2FqMbc%3D&reserved=0 -O ~/bin/make.cross > > chmod +x ~/bin/make.cross > > # save the attached .config to linux build tree > > make.cross ARCH=xtensa > > > > All warnings (new ones prefixed by >>): > > > > In file included from mm/vmscan.c:55:0: > > include/linux/swapops.h: In function 'swp_entry_to_pmd': > >>> include/linux/swapops.h:220:2: warning: missing braces around initializer [-Wmissing-braces] > > return (pmd_t){ 0 }; > > ^ > > include/linux/swapops.h:220:2: warning: (near initialization for '(anonymous).pud') [-Wmissing-braces] > > > > vim +220 include/linux/swapops.h > > > > 217 > > 218 static inline pmd_t swp_entry_to_pmd(swp_entry_t entry) > > 219 { > >> 220 return (pmd_t){ 0 }; > > 221 } > > 222 > > It is a GCC 4.9.0 bug: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53119 > > Upgrading GCC can get rid of this warning. I think there was a workaround for this, but I don't recall what it was. This suppressed the warning: --- a/include/linux/swapops.h~a +++ a/include/linux/swapops.h @@ -217,7 +217,7 @@ static inline swp_entry_t pmd_to_swp_ent static inline pmd_t swp_entry_to_pmd(swp_entry_t entry) { - return (pmd_t){ 0 }; + return (pmd_t){}; } static inline int is_pmd_migration_entry(pmd_t pmd) But I don't know if this is the approved workaround and I don't know what it will do at runtime! But we should fix this. Expecting zillions of people to update their compiler version isn't nice.