From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751378AbdJRT7z (ORCPT ); Wed, 18 Oct 2017 15:59:55 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:34916 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750853AbdJRT7x (ORCPT ); Wed, 18 Oct 2017 15:59:53 -0400 Date: Wed, 18 Oct 2017 12:59:44 -0700 From: "Paul E. McKenney" To: torvalds@linux-foundation.org Cc: mingo@kernel.org, mathieu.desnoyers@efficios.com, peterz@infradead.org, boqun.feng@gmail.com, ahh@google.com, maged.michael@gmail.com, gromer@google.com, avi@scylladb.com, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, davejwatson@fb.com, stern@rowland.harvard.edu, will.deacon@arm.com, luto@kernel.org, viro@zeniv.linux.org.uk, npiggin@gmail.com, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [GIT PULL urgent-membarrier] membarrier commits for 4.14 Reply-To: paulmck@linux.vnet.ibm.com MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 x-cbid: 17101819-2213-0000-0000-0000022DABA1 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00007915; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000237; SDB=6.00933042; UDB=6.00469921; IPR=6.00713332; BA=6.00005648; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00017596; XFM=3.00000015; UTC=2017-10-18 19:59:49 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17101819-2214-0000-0000-000057E59CFC Message-Id: <20171018195944.GA15331@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-10-18_07:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=1 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1707230000 definitions=main-1710180277 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Linus, This urgent pull request contains five commits that fix a problem that arose when designing requested extensions to sys_membarrier() to allow JITs to efficiently flush old code from instruction caches. Several potential algorithms are much less painful if the user register intent to use this functionality early on, for example, before the process spawns the second thread. Registering at this time removes the need to interrupt each and every thread in that process at the first expedited sys_membarrier() system call. However, if we let the current function out, then user programs might be written without registration, which would make it more difficult to add required registration after the fact. Hence the late-in-merge-window pull request. The last two commits remove unused code from architectures not supporting sys_membarrier() and fix a problem that arises when tasks are created with CLONE_VM but !CLONE_THREAD on powerpc. These have been subject to 0day test robot and -next testing and are available in the git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git membarrier.2017.10.09a for you to fetch changes up to f7399e01ccd0850786bdedbee2fd351651ce99f8: Fix: membarrier: Handle CLONE_VM + !CLONE_THREAD correctly on powerpc (2017-10-09 14:24:49 -0700) ---------------------------------------------------------------- Mathieu Desnoyers (5): membarrier: Provide register expedited private command membarrier: selftest: Test private expedited cmd membarrier: Document scheduler barrier requirements membarrier: Remove unused code for architectures without membarrier hooks Fix: membarrier: Handle CLONE_VM + !CLONE_THREAD correctly on powerpc MAINTAINERS | 2 + arch/powerpc/Kconfig | 1 + arch/powerpc/include/asm/membarrier.h | 26 +++++ arch/powerpc/kernel/Makefile | 2 + arch/powerpc/kernel/membarrier.c | 36 +++++++ arch/powerpc/mm/mmu_context.c | 7 ++ arch/x86/mm/tlb.c | 5 + fs/exec.c | 1 + include/linux/mm_types.h | 3 + include/linux/sched/mm.h | 37 +++++++ include/uapi/linux/membarrier.h | 23 +++-- init/Kconfig | 3 + kernel/sched/core.c | 47 +++++---- kernel/sched/membarrier.c | 35 ++++++- .../testing/selftests/membarrier/membarrier_test.c | 109 ++++++++++++++++++--- 15 files changed, 290 insertions(+), 47 deletions(-) create mode 100644 arch/powerpc/include/asm/membarrier.h create mode 100644 arch/powerpc/kernel/membarrier.c