From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f199.google.com (mail-pf0-f199.google.com [209.85.192.199]) by kanga.kvack.org (Postfix) with ESMTP id D375483293 for ; Fri, 16 Jun 2017 13:53:09 -0400 (EDT) Received: by mail-pf0-f199.google.com with SMTP id o74so43070097pfi.6 for ; Fri, 16 Jun 2017 10:53:09 -0700 (PDT) Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com. [148.163.156.1]) by mx.google.com with ESMTPS id v1si2506007plb.188.2017.06.16.10.53.08 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 16 Jun 2017 10:53:09 -0700 (PDT) Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v5GHnArg138148 for ; Fri, 16 Jun 2017 13:53:08 -0400 Received: from e06smtp14.uk.ibm.com (e06smtp14.uk.ibm.com [195.75.94.110]) by mx0a-001b2d01.pphosted.com with ESMTP id 2b4ktp8m84-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Fri, 16 Jun 2017 13:53:07 -0400 Received: from localhost by e06smtp14.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 16 Jun 2017 18:53:05 +0100 From: Laurent Dufour Subject: [RFC v5 10/11] x86/mm: Add speculative pagefault handling Date: Fri, 16 Jun 2017 19:52:34 +0200 In-Reply-To: <1497635555-25679-1-git-send-email-ldufour@linux.vnet.ibm.com> References: <1497635555-25679-1-git-send-email-ldufour@linux.vnet.ibm.com> Message-Id: <1497635555-25679-11-git-send-email-ldufour@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: 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 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 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] Signed-off-by: Laurent Dufour --- arch/x86/mm/fault.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 8ad91a01cbc8..c62a7ea5e27b 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -1365,6 +1365,19 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code, if (error_code & PF_INSTR) flags |= FAULT_FLAG_INSTRUCTION; + if (error_code & PF_USER) { + fault = handle_speculative_fault(mm, address, flags); + + /* + * We also check against VM_FAULT_ERROR because we have to + * raise a signal by calling later mm_fault_error() which + * requires the vma pointer to be set. So in that case, + * we fall through the normal path. + */ + if (!(fault & VM_FAULT_RETRY || fault & VM_FAULT_ERROR)) + goto done; + } + /* * When running in the kernel we expect faults to occur only to * addresses in user space. All other faults represent errors in @@ -1474,6 +1487,7 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code, return; } +done: /* * Major/minor page fault accounting. If any of the events * returned VM_FAULT_MAJOR, we account it as a major fault. -- 2.7.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org