From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934264AbeCEKui (ORCPT ); Mon, 5 Mar 2018 05:50:38 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:34678 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S933579AbeCEKug (ORCPT ); Mon, 5 Mar 2018 05:50:36 -0500 Subject: Re: [PATCH v8 18/24] mm: Provide speculative fault infrastructure To: Daniel Jordan , 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, Thomas Gleixner , Ingo Molnar , hpa@zytor.com, Will Deacon , Sergey Senozhatsky , Andrea Arcangeli , Alexei Starovoitov , kemi.wang@intel.com, sergey.senozhatsky.work@gmail.com Cc: 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: <1518794738-4186-1-git-send-email-ldufour@linux.vnet.ibm.com> <1518794738-4186-19-git-send-email-ldufour@linux.vnet.ibm.com> <5b16d6ce-6b62-e4ca-2d78-c25bb008e27e@oracle.com> From: Laurent Dufour Date: Mon, 5 Mar 2018 11:50:21 +0100 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: <5b16d6ce-6b62-e4ca-2d78-c25bb008e27e@oracle.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 18030510-0040-0000-0000-0000043ADA72 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18030510-0041-0000-0000-000020DDEB85 Message-Id: <1d6c1ea9-6488-5e25-68b7-6f4aa07d1945@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-03-05_04:,, 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-1803050130 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jordan, Thanks for reporting this. On 26/02/2018 18:16, Daniel Jordan wrote: > Hi Laurent, > > This series doesn't build for me[*] when CONFIG_TRANSPARENT_HUGEPAGE is unset. > > The problem seems to be that the BUILD_BUG() version of pmd_same is called in > pte_map_lock: > > On 02/16/2018 10:25 AM, Laurent Dufour wrote: >> +static bool pte_map_lock(struct vm_fault *vmf) >> +{ > ...snip... >> +    if (!pmd_same(pmdval, vmf->orig_pmd)) >> +        goto out; > > Since SPF can now call pmd_same without THP, maybe the way to fix it is just > > diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h > index 2cfa3075d148..e130692db24a 100644 > --- a/include/asm-generic/pgtable.h > +++ b/include/asm-generic/pgtable.h > @@ -375,7 +375,8 @@ static inline int pte_unused(pte_t pte) >  #endif >   >  #ifndef __HAVE_ARCH_PMD_SAME > -#ifdef CONFIG_TRANSPARENT_HUGEPAGE > +#if defined(CONFIG_TRANSPARENT_HUGEPAGE) || \ > +    defined(CONFIG_SPECULATIVE_PAGE_FAULT) >  static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b) >  { >         return pmd_val(pmd_a) == pmd_val(pmd_b); We can't fix that this way because some architectures define their own pmd_same() function (like ppc64), thus forcing the define here will be useless since __HAVE_ARCH_PMD_SAME is set in that case. The right way to fix that is to _not check_ for the PMD value in pte_spinlock() when CONFIG_TRANSPARENT_HUGEPAGE is not set since there is no risk of collapsing operation in our back if THP are disabled. I'll fix that in the next version. Laurent. > ? > > Daniel > > > [*]  The errors are: > > In file included from /home/dmjordan/src/linux/include/linux/kernel.h:10:0, >                  from /home/dmjordan/src/linux/include/linux/list.h:9, >                  from /home/dmjordan/src/linux/include/linux/smp.h:12, >                  from /home/dmjordan/src/linux/include/linux/kernel_stat.h:5, >                  from /home/dmjordan/src/linux/mm/memory.c:41: > In function ‘pmd_same.isra.104’, >     inlined from ‘pte_map_lock’ at /home/dmjordan/src/linux/mm/memory.c:2380:7: > /home/dmjordan/src/linux/include/linux/compiler.h:324:38: error: call to > ‘__compiletime_assert_391’ declared with attribute error: BUILD_BUG failed >   _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) >                                       ^ > /home/dmjordan/src/linux/include/linux/compiler.h:304:4: note: in definition of > macro ‘__compiletime_assert’ >     prefix ## suffix();    \ >     ^~~~~~ > /home/dmjordan/src/linux/include/linux/compiler.h:324:2: note: in expansion of > macro ‘_compiletime_assert’ >   _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) >   ^~~~~~~~~~~~~~~~~~~ > /home/dmjordan/src/linux/include/linux/build_bug.h:45:37: note: in expansion of > macro ‘compiletime_assert’ >  #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) >                                      ^~~~~~~~~~~~~~~~~~ > /home/dmjordan/src/linux/include/linux/build_bug.h:79:21: note: in expansion of > macro ‘BUILD_BUG_ON_MSG’ >  #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed") >                      ^~~~~~~~~~~~~~~~ > /home/dmjordan/src/linux/include/asm-generic/pgtable.h:391:2: note: in > expansion of macro ‘BUILD_BUG’ >   BUILD_BUG(); >   ^~~~~~~~~ >   CC      block/elevator.o >   CC      crypto/crypto_wq.o > In function ‘pmd_same.isra.104’, >     inlined from ‘pte_spinlock’ at /home/dmjordan/src/linux/mm/memory.c:2326:7, >     inlined from ‘handle_pte_fault’ at > /home/dmjordan/src/linux/mm/memory.c:4181:7: > /home/dmjordan/src/linux/include/linux/compiler.h:324:38: error: call to > ‘__compiletime_assert_391’ declared with attribute error: BUILD_BUG failed >   _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) >                                       ^ > /home/dmjordan/src/linux/include/linux/compiler.h:304:4: note: in definition of > macro ‘__compiletime_assert’ >     prefix ## suffix();    \ >     ^~~~~~ > /home/dmjordan/src/linux/include/linux/compiler.h:324:2: note: in expansion of > macro ‘_compiletime_assert’ >   _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) >   ^~~~~~~~~~~~~~~~~~~ > /home/dmjordan/src/linux/include/linux/build_bug.h:45:37: note: in expansion of > macro ‘compiletime_assert’ >  #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) >                                      ^~~~~~~~~~~~~~~~~~ > /home/dmjordan/src/linux/include/linux/build_bug.h:79:21: note: in expansion of > macro ‘BUILD_BUG_ON_MSG’ >  #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed") >                      ^~~~~~~~~~~~~~~~ > /home/dmjordan/src/linux/include/asm-generic/pgtable.h:391:2: note: in > expansion of macro ‘BUILD_BUG’ >   BUILD_BUG(); >   ^~~~~~~~~ > ... > make[2]: *** [/home/dmjordan/src/linux/scripts/Makefile.build:316: mm/memory.o] > Error 1 > make[1]: *** [/home/dmjordan/src/linux/Makefile:1047: mm] Error 2 >