Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S939174AbdD0P5j (ORCPT ); Thu, 27 Apr 2017 11:57:39 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:33716 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1032941AbdD0PxL (ORCPT ); Thu, 27 Apr 2017 11:53:11 -0400 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 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 Subject: [RFC v3 03/17] mm: Introduce pte_spinlock Date: Thu, 27 Apr 2017 17:52:42 +0200 X-Mailer: git-send-email 2.7.4 In-Reply-To: <1493308376-23851-1-git-send-email-ldufour@linux.vnet.ibm.com> References: <1493308376-23851-1-git-send-email-ldufour@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 17042715-0020-0000-0000-00000354C8D2 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17042715-0021-0000-0000-0000417A6E73 Message-Id: <1493308376-23851-4-git-send-email-ldufour@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-04-27_14:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1703280000 definitions=main-1704270259 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1655 Lines: 52 This is needed because in handle_pte_fault() pte_offset_map() is called and then fe->ptl is fetched and spin_locked. This was previously embedded in the call to pte_offset_map_lock(). Signed-off-by: Laurent Dufour --- mm/memory.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index bce32c9d73c2..441c0e3f3a0f 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2100,6 +2100,13 @@ static inline void wp_page_reuse(struct vm_fault *vmf) pte_unmap_unlock(vmf->pte, vmf->ptl); } +static bool pte_spinlock(struct vm_fault *vmf) +{ + vmf->ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd); + spin_lock(vmf->ptl); + return true; +} + static bool pte_map_lock(struct vm_fault *vmf) { vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, vmf->address, &vmf->ptl); @@ -3398,8 +3405,8 @@ static int do_numa_page(struct vm_fault *vmf) * page table entry is not accessible, so there would be no * concurrent hardware modifications to the PTE. */ - vmf->ptl = pte_lockptr(vma->vm_mm, vmf->pmd); - spin_lock(vmf->ptl); + if (!pte_spinlock(vmf)) + return VM_FAULT_RETRY; if (unlikely(!pte_same(*vmf->pte, pte))) { pte_unmap_unlock(vmf->pte, vmf->ptl); goto out; @@ -3566,8 +3573,8 @@ static int handle_pte_fault(struct vm_fault *vmf) if (pte_protnone(vmf->orig_pte) && vma_is_accessible(vmf->vma)) return do_numa_page(vmf); - vmf->ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd); - spin_lock(vmf->ptl); + if (!pte_spinlock(vmf)) + return VM_FAULT_RETRY; entry = vmf->orig_pte; if (unlikely(!pte_same(*vmf->pte, entry))) goto unlock; -- 2.7.4