From patchwork Fri Jan 12 17:26:07 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Laurent Dufour X-Patchwork-Id: 860146 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [103.22.144.68]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3zJ9w46j81z9sBW for ; Sat, 13 Jan 2018 05:17:56 +1100 (AEDT) Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 3zJ9w45lk0zF0PS for ; Sat, 13 Jan 2018 05:17:56 +1100 (AEDT) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=linux.vnet.ibm.com (client-ip=148.163.156.1; helo=mx0a-001b2d01.pphosted.com; envelope-from=ldufour@linux.vnet.ibm.com; receiver=) Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3zJ8p40lg3zF0mw for ; Sat, 13 Jan 2018 04:27:39 +1100 (AEDT) Received: from pps.filterd (m0098399.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w0CHPOV8091228 for ; Fri, 12 Jan 2018 12:27:37 -0500 Received: from e06smtp10.uk.ibm.com (e06smtp10.uk.ibm.com [195.75.94.106]) by mx0a-001b2d01.pphosted.com with ESMTP id 2ff0nxak0e-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Fri, 12 Jan 2018 12:27:37 -0500 Received: from localhost by e06smtp10.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Fri, 12 Jan 2018 17:27:28 -0000 Received: from d06av24.portsmouth.uk.ibm.com (mk.ibm.com [9.149.105.60]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w0CHRRjL46989482; Fri, 12 Jan 2018 17:27:27 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 832B942045; Fri, 12 Jan 2018 17:21:00 +0000 (GMT) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 81A6A42042; Fri, 12 Jan 2018 17:20:58 +0000 (GMT) Received: from nimbus.lab.toulouse-stg.fr.ibm.com (unknown [9.145.191.85]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 12 Jan 2018 17:20:58 +0000 (GMT) From: Laurent Dufour To: 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 Subject: [PATCH v6 23/24] x86/mm: Add speculative pagefault handling Date: Fri, 12 Jan 2018 18:26:07 +0100 X-Mailer: git-send-email 2.7.4 In-Reply-To: <1515777968-867-1-git-send-email-ldufour@linux.vnet.ibm.com> References: <1515777968-867-1-git-send-email-ldufour@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18011217-0040-0000-0000-000004041B77 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18011217-0041-0000-0000-000026077DF9 Message-Id: <1515777968-867-24-git-send-email-ldufour@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2018-01-12_09:, , 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=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1801120238 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.24 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev@lists.ozlabs.org, x86@kernel.org, linux-kernel@vger.kernel.org, npiggin@gmail.com, linux-mm@kvack.org, Tim Chen , haren@linux.vnet.ibm.com, khandual@linux.vnet.ibm.com Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" From: Peter Zijlstra Try a speculative fault before acquiring mmap_sem, if it returns with VM_FAULT_RETRY continue with the mmap_sem acquisition and do the traditional fault. Signed-off-by: Peter Zijlstra (Intel) [Clearing of FAULT_FLAG_ALLOW_RETRY is now done in handle_speculative_fault()] [Retry with usual fault path in the case VM_ERROR is returned by handle_speculative_fault(). This allows signal to be delivered] [Don't build SPF call if !CONFIG_SPF] [Try speculative fault path only for multi threaded processes] [Try to the VMA fetch during the speculative path in case of retry] Signed-off-by: Laurent Dufour --- arch/x86/mm/fault.c | 38 +++++++++++++++++++++++++++++++++++++- 1 file changed, 37 insertions(+), 1 deletion(-) diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 06fe3d51d385..8db69a116521 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -1242,6 +1242,9 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code, unsigned long address) { struct vm_area_struct *vma; +#ifdef CONFIG_SPF + struct vm_area_struct *spf_vma = NULL; +#endif struct task_struct *tsk; struct mm_struct *mm; int fault, major = 0; @@ -1339,6 +1342,27 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code, if (error_code & X86_PF_INSTR) flags |= FAULT_FLAG_INSTRUCTION; +#ifdef CONFIG_SPF + if ((error_code & X86_PF_USER) && (atomic_read(&mm->mm_users) > 1)) { + fault = handle_speculative_fault(mm, address, flags, + &spf_vma); + + if (!(fault & VM_FAULT_RETRY)) { + if (!(fault & VM_FAULT_ERROR)) { + perf_sw_event(PERF_COUNT_SW_SPF, 1, + regs, address); + goto done; + } + /* + * In case of error we need the pkey value, but + * can't get it from the spf_vma as it is only returned + * when VM_FAULT_RETRY is returned. So we have to + * retry the page fault with the mmap_sem grabbed. + */ + } + } +#endif /* CONFIG_SPF */ + /* * When running in the kernel we expect faults to occur only to * addresses in user space. All other faults represent errors in @@ -1372,7 +1396,16 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code, might_sleep(); } - vma = find_vma(mm, address); +#ifdef CONFIG_SPF + if (spf_vma) { + if (can_reuse_spf_vma(spf_vma, address)) + vma = spf_vma; + else + vma = find_vma(mm, address); + spf_vma = NULL; + } else +#endif + vma = find_vma(mm, address); if (unlikely(!vma)) { bad_area(regs, error_code, address); return; @@ -1458,6 +1491,9 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code, return; } +#ifdef CONFIG_SPF +done: +#endif /* * Major/minor page fault accounting. If any of the events * returned VM_FAULT_MAJOR, we account it as a major fault.