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Wed, 22 Apr 2026 04:04:29 +0000 (GMT) Received: from [9.124.218.94] (unknown [9.124.218.94]) by smtpav01.dal12v.mail.ibm.com (Postfix) with ESMTP; Wed, 22 Apr 2026 04:04:29 +0000 (GMT) Message-ID: <45b93560-acdb-4552-bac5-bd085d778085@linux.ibm.com> Date: Wed, 22 Apr 2026 09:34:27 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH v6 2/5] mm: migrate: Add migrate_misplaced_folios_batch() To: Gregory Price , Bharata B Rao Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Jonathan.Cameron@huawei.com, dave.hansen@intel.com, mgorman@techsingularity.net, mingo@redhat.com, peterz@infradead.org, raghavendra.kt@amd.com, riel@surriel.com, rientjes@google.com, sj@kernel.org, weixugc@google.com, willy@infradead.org, ying.huang@linux.alibaba.com, ziy@nvidia.com, dave@stgolabs.net, nifan.cxl@gmail.com, xuezhengchu@huawei.com, yiannis@zptcorp.com, akpm@linux-foundation.org, david@redhat.com, byungchul@sk.com, kinseyho@google.com, joshua.hahnjy@gmail.com, yuanchu@google.com, balbirs@nvidia.com, alok.rathore@samsung.com, shivankg@amd.com References: <20260323095104.238982-1-bharata@amd.com> <20260323095104.238982-3-bharata@amd.com> <24cd6a95-1304-4732-9273-43c73ea858b2@linux.ibm.com> Content-Language: en-US From: Donet Tom In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-GUID: Rl6q9ucgDa0d5Gak78s0l1-YoJd854dU X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNDIyMDAzNiBTYWx0ZWRfX6qFXJ9T0cms8 Z6pv6Zw6F7gsqkwXIEFx18ZjtihXvxvKqjwGd4tO67jqg7KyIV45dKhYDk35dYEdp3m4QHCwVk/ QcBi2Qw7TPvzV1UFH22DIF8ddZJGZ8FI77LUGwFSMfSSGoAxnxj2S8OsJ9nF1hr+dPeTevc4ryQ 9zzd5VaTSqq/Q60alOF2SRp9Yc/ltRDk2yLGW0t75COJ3YsfX0/5OVGoaw2rjv0xgqbdjO9da4Q rw58ieb9BHo6X6WBj2wv8n7OovJ9JxzyfNmp0XSJMSu9e4nctpPaOWZSDb+k4Hcl2HQP+GZzLR9 EegF/FPbV8ob3l4M7i4hTsjkPWXBEErv0wqirrIwdaC85FPBFBkYUvKn8QIDRtaZoja6HuTCKo4 n9f/33+wCuGerLQj6ND1AmPOSlXu/Ca02ytbDsndzmOULmoFePVZf8EcY+ZxH8opO0deQHWdDEh W9/3eY9trIkxRv8yVfw== X-Authority-Analysis: v=2.4 cv=a6kAM0SF c=1 sm=1 tr=0 ts=69e848d9 cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=IkcTkHD0fZMA:10 a=A5OVakUREuEA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=V8glGbnc2Ofi9Qvn3v5h:22 a=v6K55fGTm8UQkk20tRYA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 X-Proofpoint-ORIG-GUID: TU3Ad5bqm1kLedrdzCL7UQFw3rpQfocV X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-04-21_03,2026-04-21_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 suspectscore=0 spamscore=0 adultscore=0 bulkscore=0 lowpriorityscore=0 impostorscore=0 clxscore=1015 phishscore=0 priorityscore=1501 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2604200000 definitions=main-2604220036 Hi Gregory On 4/22/26 9:07 AM, Gregory Price wrote: > On Wed, Apr 22, 2026 at 08:56:59AM +0530, Bharata B Rao wrote: >> On 21-Apr-26 9:35 PM, Gregory Price wrote: >>> On Tue, Apr 21, 2026 at 08:55:02PM +0530, Donet Tom wrote: >>>>> +/** >>>>> + * migrate_misplaced_folios_batch() - Batch variant of migrate_misplaced_folio >>>>> + * Attempts to migrate a folio list to the specified destination. >>>>> + * @folio_list: Isolated list of folios to be batch-migrated. >>>>> + * @node: The NUMA node ID to where the folios should be migrated. >>>>> + * >>>>> + * Caller is expected to have isolated the folios by calling >>>>> + * migrate_misplaced_folio_prepare(), which will result in an >>>>> + * elevated reference count on the folio. All the isolated folios >>>>> + * in the list must belong to the same memcg so that NUMA_PAGE_MIGRATE >>>>> + * stat can be attributed correctly to the memcg. >> ^ This is the expectation from the caller. pghot caller ensures this. >> I could add a debug check in this routine to verify if that is indeed so. >> > Wondering if the interface name should somehow reflect this as well, to > make it a bit clearer. I agree—this would make the interface clearer. -Donet > > ~Gregory