From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752140AbdEVGND (ORCPT ); Mon, 22 May 2017 02:13:03 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:48347 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751425AbdEVGNC (ORCPT ); Mon, 22 May 2017 02:13:02 -0400 From: "Mike Rapoport" To: Andrew Morton Cc: Arnd Bergmann , "Kirill A. Shutemov" , Andrea Arcangeli , linux-mm , lkml , Mike Rapoport Subject: [PATCH] mm: introduce MADV_CLR_HUGEPAGE Date: Mon, 22 May 2017 09:12:42 +0300 X-Mailer: git-send-email 2.7.4 X-TM-AS-GCONF: 00 x-cbid: 17052206-0020-0000-0000-0000036F90B3 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17052206-0021-0000-0000-000041D45DB6 Message-Id: <1495433562-26625-1-git-send-email-rppt@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-05-22_05:,, 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-1705220032 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently applications can explicitly enable or disable THP for a memory region using MADV_HUGEPAGE or MADV_NOHUGEPAGE. However, once either of these advises is used, the region will always have VM_HUGEPAGE/VM_NOHUGEPAGE flag set in vma->vm_flags. The MADV_CLR_HUGEPAGE resets both these flags and allows managing THP in the region according to system-wide settings. Signed-off-by: Mike Rapoport --- include/uapi/asm-generic/mman-common.h | 3 +++ mm/khugepaged.c | 7 +++++++ mm/madvise.c | 5 +++++ 3 files changed, 15 insertions(+) diff --git a/include/uapi/asm-generic/mman-common.h b/include/uapi/asm-generic/mman-common.h index 8c27db0..3201712 100644 --- a/include/uapi/asm-generic/mman-common.h +++ b/include/uapi/asm-generic/mman-common.h @@ -58,6 +58,9 @@ overrides the coredump filter bits */ #define MADV_DODUMP 17 /* Clear the MADV_DONTDUMP flag */ +#define MADV_CLR_HUGEPAGE 18 /* Clear flags controlling backing with + hugepages */ + /* compatibility flags */ #define MAP_FILE 0 diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 945fd1c..b9ee9bb 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -336,6 +336,13 @@ int hugepage_madvise(struct vm_area_struct *vma, * it got registered before VM_NOHUGEPAGE was set. */ break; + case MADV_CLR_HUGEPAGE: + *vm_flags &= ~(VM_HUGEPAGE | VM_NOHUGEPAGE); + /* + * The vma will be treated according to the + * system-wide settings in transparent_hugepage_flags + */ + break; } return 0; diff --git a/mm/madvise.c b/mm/madvise.c index 25b78ee..ae650a3 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -105,6 +105,7 @@ static long madvise_behavior(struct vm_area_struct *vma, break; case MADV_HUGEPAGE: case MADV_NOHUGEPAGE: + case MADV_CLR_HUGEPAGE: error = hugepage_madvise(vma, &new_flags, behavior); if (error) { /* @@ -684,6 +685,7 @@ madvise_behavior_valid(int behavior) #ifdef CONFIG_TRANSPARENT_HUGEPAGE case MADV_HUGEPAGE: case MADV_NOHUGEPAGE: + case MADV_CLR_HUGEPAGE: #endif case MADV_DONTDUMP: case MADV_DODUMP: @@ -739,6 +741,9 @@ madvise_behavior_valid(int behavior) * MADV_NOHUGEPAGE - mark the given range as not worth being backed by * transparent huge pages so the existing pages will not be * coalesced into THP and new pages will not be allocated as THP. + * MADV_CLR_HUGEPAGE - clear MADV_HUGEPAGE/MADV_NOHUGEPAGE marking; + * the range will be treated by khugepaged according to the + * system wide settings * MADV_DONTDUMP - the application wants to prevent pages in the given range * from being included in its core dump. * MADV_DODUMP - cancel MADV_DONTDUMP: no longer exclude from core dump. -- 2.7.4