From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (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 3xRcQt39cdzDqpD for ; Wed, 9 Aug 2017 00:36:22 +1000 (AEST) Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v78EXaVb075841 for ; Tue, 8 Aug 2017 10:36:19 -0400 Received: from e06smtp11.uk.ibm.com (e06smtp11.uk.ibm.com [195.75.94.107]) by mx0a-001b2d01.pphosted.com with ESMTP id 2c7evh1srb-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 08 Aug 2017 10:36:19 -0400 Received: from localhost by e06smtp11.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 8 Aug 2017 15:36:17 +0100 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 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 Subject: [PATCH 10/16] powerpc/mm: Add speculative page fault Date: Tue, 8 Aug 2017 16:35:43 +0200 In-Reply-To: <1502202949-8138-1-git-send-email-ldufour@linux.vnet.ibm.com> References: <1502202949-8138-1-git-send-email-ldufour@linux.vnet.ibm.com> Message-Id: <1502202949-8138-11-git-send-email-ldufour@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , This patch enable the speculative page fault on the PowerPC architecture. This will try a speculative page fault without holding the mmap_sem, if it returns with WM_FAULT_RETRY, the mmap_sem is acquired and the traditional page fault processing is done. Signed-off-by: Laurent Dufour --- arch/powerpc/mm/fault.c | 25 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c index 4c422632047b..c6cd40901dd0 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -291,9 +291,31 @@ int do_page_fault(struct pt_regs *regs, unsigned long address, if (is_write && is_user) store_update_sp = store_updates_sp(regs); - if (is_user) + if (is_user) { flags |= FAULT_FLAG_USER; + /* let's try a speculative page fault without grabbing the + * mmap_sem. + */ + + /* + * flags is set later based on the VMA's flags, for the common + * speculative service, we need some flags to be set. + */ + if (is_write) + flags |= FAULT_FLAG_WRITE; + + fault = handle_speculative_fault(mm, address, flags); + if (!(fault & VM_FAULT_RETRY || fault & VM_FAULT_ERROR)) + goto done; + + /* + * Resetting flags since the following code assumes + * FAULT_FLAG_WRITE is not set. + */ + flags &= ~FAULT_FLAG_WRITE; + } + /* When running in the kernel we expect faults to occur only to * addresses in user space. All other faults represent errors in the * kernel and should generate an OOPS. Unfortunately, in the case of an @@ -479,6 +501,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long address, rc = 0; } +done: /* * Major/minor page fault accounting. */ -- 2.7.4