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b=qhO/nZtXmIhT2VGrdqHAddbRpiL01JMmkUumvb5LI5Y2P8CPcD5N9xL77Q11Huw5Eh51+VzZoZWK0DdKPkPMPBKeJotHoixQ5h/vZMJqxOhiwN4OrXHenIWfC8zQaVS5G9meW/WPRHy2ovfh3jfWUGQcUwSgBrCIRjQyws+Or0eUCUgShHpidCUhgWWOU8zsTUBpvX9pzsyOPjKE5eShqoTMu/uDPosZRIAyL1zZOIHUIEFAWBG9C4OR9H2783XTcLEyqdqP9khjAjIAvizjJbkQ3elJgDzxvHVqALVj71BBQMwWciaMcp/T6IcY3P3W/46FJ78596me9PlDrMJ5tQ== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from DS7PR12MB9473.namprd12.prod.outlook.com (2603:10b6:8:252::5) by CH1PPF2C6B99E0C.namprd12.prod.outlook.com (2603:10b6:61f:fc00::609) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8655.33; Wed, 30 Apr 2025 20:34:22 +0000 Received: from DS7PR12MB9473.namprd12.prod.outlook.com ([fe80::5189:ecec:d84a:133a]) by DS7PR12MB9473.namprd12.prod.outlook.com ([fe80::5189:ecec:d84a:133a%5]) with mapi id 15.20.8678.028; Wed, 30 Apr 2025 20:34:21 +0000 From: Zi Yan To: Nico Pache Cc: linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, akpm@linux-foundation.org, corbet@lwn.net, rostedt@goodmis.org, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, david@redhat.com, baohua@kernel.org, baolin.wang@linux.alibaba.com, ryan.roberts@arm.com, willy@infradead.org, peterx@redhat.com, shuah@kernel.org, wangkefeng.wang@huawei.com, usamaarif642@gmail.com, sunnanyong@huawei.com, vishal.moola@gmail.com, thomas.hellstrom@linux.intel.com, yang@os.amperecomputing.com, kirill.shutemov@linux.intel.com, aarcange@redhat.com, raquini@redhat.com, dev.jain@arm.com, anshuman.khandual@arm.com, catalin.marinas@arm.com, tiwai@suse.de, will@kernel.org, dave.hansen@linux.intel.com, jack@suse.cz, cl@gentwo.org, jglisse@google.com, surenb@google.com, zokeefe@google.com, Liam.Howlett@oracle.com, lorenzo.stoakes@oracle.com, hannes@cmpxchg.org, rientjes@google.com, mhocko@suse.com, rdunlap@infradead.org Subject: Re: [PATCH v5 3/4] khugepaged: add defer option to mTHP options Date: Wed, 30 Apr 2025 16:34:18 -0400 X-Mailer: MailMate (2.0r6249) Message-ID: In-Reply-To: <20250428182904.93989-4-npache@redhat.com> References: <20250428182904.93989-1-npache@redhat.com> <20250428182904.93989-4-npache@redhat.com> Content-Type: text/plain Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: BL1PR13CA0276.namprd13.prod.outlook.com (2603:10b6:208:2bc::11) To DS7PR12MB9473.namprd12.prod.outlook.com (2603:10b6:8:252::5) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS7PR12MB9473:EE_|CH1PPF2C6B99E0C:EE_ X-MS-Office365-Filtering-Correlation-Id: 2e6744a7-b748-4dd6-028d-08dd88266382 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|7416014|376014|1800799024|7053199007; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?WO+G6PKnaPN/wgspLN1P4f3eo86Tasnj0mbPocb3YJ03d0zk/AZmri3/NgUh?= =?us-ascii?Q?L++zHcAy6epRfF+2E5PtZozoXTedouxx3wK3DLTtXvtZRaOGzmKMZntUVoKV?= =?us-ascii?Q?L84WSKvgoUAGZZtElFIa6H3hMcq0f6BmqTTbkHHfBCXdKbEj5hIl6pQ7w+Qm?= =?us-ascii?Q?++xnG1kT4zp3hjaPde+A0MsOyxzODQMKdyB8KWOtS8lD1IeOJ+W0iLZyWWf5?= =?us-ascii?Q?NB2HQK8Hgi6IadKTQSMTM3SHoFgDhgkDsS9sNr2Yfv3HQSBdnIYHtAaojm7t?= =?us-ascii?Q?m67+STNOcsbUrWqoSSaG0B8a2y5HICHiQC6g+z/vS0VA0l9qwTxDiyP476J+?= =?us-ascii?Q?pBrEV+2wahl5dUG25xw3TuQ5JmkmqxBsarAl1yHYvDFz5sXrLKRaNtvUFKPz?= =?us-ascii?Q?FXkHLIUrT9TzkkAU0+JQaiv1PYAjT1LrN1yKMG3Lgmw+ny+CQx3YGEtRiLUa?= =?us-ascii?Q?xrY/q6w5hQ3xow1MAnBqIC96kyxAvxgsgY2Q/FNuLt6mesZ15Hdeu2AZvcGW?= =?us-ascii?Q?P67RYwcTZ0ar2ChwawGjibD5vJJCzsHCW0ow/GR296BsyG5DWSwfu6elyAJ6?= =?us-ascii?Q?o2Fg+hnO58XxRkX3tIhdw7qB/vlRt+tKewug3iujtCiP5auYRfhdMst6RRJY?= =?us-ascii?Q?5KiMP5t1WY1/y3bzhd54VGCGSCh5QipeamXl7EUIdavLvlxZ2hOmlc5eYCV7?= =?us-ascii?Q?eiIJ1Q4/WhnvskEqGNY5FbywsWtnVnEpyk6aRVdK4Ojdb8fomOjefaq+jdnx?= =?us-ascii?Q?N+yEWXocNt8AXZjjh3F4470+Tjcw5/E5F6ssG0KD1WZ2ZHQqN88SdJT5UG8M?= =?us-ascii?Q?dHb9zSbkVqNZIrH4J/iFwBjQOpnmsz0Wwgn+UYqTbbxhfr6k3IauKoSfX406?= =?us-ascii?Q?3dUEbK127zD0XVEYS9SqwpRW6tn9A8/t3s+wMWCKBEOWR1Rm5X+2f3ZTUzUA?= =?us-ascii?Q?zTF+PXx79irb/OOwcD0Q6ZeTLYYKh+BKi+WhezZod1CnnWR8qidzej2UsGNU?= =?us-ascii?Q?2CLxziw/J0R5uRlpCIkUy7fAZvVO0T5DCe75h7p9AmaS6k1hMosEdvJMhhsL?= =?us-ascii?Q?5nCVhVo8zmDLs9ClriPr7LAmggAfNqCC88dB6W4kuGpzejHj45vwS2JyCRmw?= =?us-ascii?Q?n7SqkhseCFOC/BJPpPhL9zHbG4irRg70TnB5KNF8TWsxclFD+0eyxK+9zZrf?= =?us-ascii?Q?34q2Yg0EkS95K+JiPrIrvYKOTIezPwKOdXmoyQuS1CF6UUXz8FuV5y7W9G1C?= =?us-ascii?Q?qvIGeGa1/lYosbg/4/vIp0CRaxDOFlZyzdlEEEyLo7qk78Ei0HW2SzusBsO9?= =?us-ascii?Q?TtfpTMM9JWZ7gtlqooUH43xyMqU6boD8VXL5jFjnPQ24GYJbTEQQIeZW/O3D?= =?us-ascii?Q?fzkspkkDhq9AY9qnVcq4WvQGKFzoRsBC6XLJSGvbrkRher0PyRm8+iqapyaN?= =?us-ascii?Q?e5oTXKPisey9ueygDXuBxNZDyNM4sh4BXlslo+Q7/lTJqkdtyfbqmAV6jvQN?= =?us-ascii?Q?SMIT/tw1C5nXQl1CcFMtOA8BQ7HAC+N6PLxMWjQwXB29Q8jJmJ0sOC7vAgso?= =?us-ascii?Q?HNS4Ys1j70d2WaL3XzJ5ir2P1nf7cj30r7xXNmDY?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 2e6744a7-b748-4dd6-028d-08dd88266382 X-MS-Exchange-CrossTenant-AuthSource: DS7PR12MB9473.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 30 Apr 2025 20:34:21.8535 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: SRaD+unTTg9mXkPBSfY3rAP9raxwA1Y3qCqG4ZIMYI2LY407ONqXgFIB9C0S8pga X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH1PPF2C6B99E0C On 28 Apr 2025, at 14:29, Nico Pache wrote: > Now that we have defer to globally disable THPs at fault time, lets add= > a defer setting to the mTHP options. This will allow khugepaged to > operate at that order, while avoiding it at PF time. > > Signed-off-by: Nico Pache > --- > include/linux/huge_mm.h | 5 +++++ > mm/huge_memory.c | 38 +++++++++++++++++++++++++++++++++----- > mm/khugepaged.c | 8 ++++---- > 3 files changed, 42 insertions(+), 9 deletions(-) > > diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h > index 57e6c962afb1..a877c59bea67 100644 > --- a/include/linux/huge_mm.h > +++ b/include/linux/huge_mm.h > @@ -96,6 +96,7 @@ extern struct kobj_attribute thpsize_shmem_enabled_at= tr; > #define TVA_SMAPS (1 << 0) /* Will be used for procfs */ > #define TVA_IN_PF (1 << 1) /* Page fault handler */ > #define TVA_ENFORCE_SYSFS (1 << 2) /* Obey sysfs configuration */ > +#define TVA_IN_KHUGEPAGE ((1 << 2) | (1 << 3)) /* Khugepaged defer sup= port */ Why is TVA_IN_KHUGEPAGE a superset of TVA_ENFORCE_SYSFS? Because khugepag= ed also obeys sysfs configuration? I wonder if explicitly coding the behavior is better. For example, in __thp_vma_allowable_orders(), enforce_sysfs =3D tva_flags & (TVA_ENFOR= CE_SYSFS | TVA_IN_KHUGEPAGE). > > #define thp_vma_allowable_order(vma, vm_flags, tva_flags, order) \ > (!!thp_vma_allowable_orders(vma, vm_flags, tva_flags, BIT(order))) > @@ -182,6 +183,7 @@ extern unsigned long transparent_hugepage_flags; > extern unsigned long huge_anon_orders_always; > extern unsigned long huge_anon_orders_madvise; > extern unsigned long huge_anon_orders_inherit; > +extern unsigned long huge_anon_orders_defer; > > static inline bool hugepage_global_enabled(void) > { > @@ -306,6 +308,9 @@ unsigned long thp_vma_allowable_orders(struct vm_ar= ea_struct *vma, > /* Optimization to check if required orders are enabled early. */ > if ((tva_flags & TVA_ENFORCE_SYSFS) && vma_is_anonymous(vma)) { And code here becomes tva_flags & (TVA_ENFORCE_SYSFS | TVA_IN_KHUGEPAGE).= Otherwise, LGTM. Reviewed-by: Zi Yan -- Best Regards, Yan, Zi