From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Paul E. McKenney" Subject: [GIT PULL urgent-membarrier] membarrier commits for 4.14 Date: Wed, 18 Oct 2017 12:59:44 -0700 Message-ID: <20171018195944.GA15331@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:51100 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750880AbdJRT7x (ORCPT ); Wed, 18 Oct 2017 15:59:53 -0400 Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v9IJwkVJ061808 for ; Wed, 18 Oct 2017 15:59:53 -0400 Received: from e11.ny.us.ibm.com (e11.ny.us.ibm.com [129.33.205.201]) by mx0a-001b2d01.pphosted.com with ESMTP id 2dp9p4we0j-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 18 Oct 2017 15:59:53 -0400 Received: from localhost by e11.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 18 Oct 2017 15:59:51 -0400 Content-Disposition: inline Sender: linux-arch-owner@vger.kernel.org List-ID: 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 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