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[96.255.20.138]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8c71b859eaesm282041685a.46.2026.01.29.13.04.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 29 Jan 2026 13:04:54 -0800 (PST) From: Gregory Price To: linux-mm@kvack.org Cc: linux-cxl@vger.kernel.org, nvdimm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, kernel-team@meta.com, dave@stgolabs.net, jonathan.cameron@huawei.com, dave.jiang@intel.com, alison.schofield@intel.com, vishal.l.verma@intel.com, ira.weiny@intel.com, dan.j.williams@intel.com, willy@infradead.org, jack@suse.cz, terry.bowman@amd.com, john@jagalactic.com Subject: [PATCH 3/9] dax: plumb online_type from dax_kmem creators to hotplug Date: Thu, 29 Jan 2026 16:04:36 -0500 Message-ID: <20260129210442.3951412-4-gourry@gourry.net> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260129210442.3951412-1-gourry@gourry.net> References: <20260129210442.3951412-1-gourry@gourry.net> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" There is no way for drivers leveraging dax_kmem to plumb through a preferred auto-online policy - the system default policy is forced. Add online_type field to DAX device creation path to allow drivers to specify an auto-online policy when using the kmem driver. Current callers initialize online_type to mhp_get_default_online_type() which resolves to the system default (memhp_default_online_type). No functional change to existing drivers. Cc:David Hildenbrand Signed-off-by: Gregory Price --- drivers/cxl/core/region.c | 2 ++ drivers/cxl/cxl.h | 1 + drivers/dax/bus.c | 3 +++ drivers/dax/bus.h | 1 + drivers/dax/cxl.c | 1 + drivers/dax/dax-private.h | 2 ++ drivers/dax/hmem/hmem.c | 2 ++ drivers/dax/kmem.c | 13 +++++++++++-- drivers/dax/pmem.c | 2 ++ 9 files changed, 25 insertions(+), 2 deletions(-) diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c index 5bd1213737fa..eef5d5fe3f95 100644 --- a/drivers/cxl/core/region.c +++ b/drivers/cxl/core/region.c @@ -1,6 +1,7 @@ // SPDX-License-Identifier: GPL-2.0-only /* Copyright(c) 2022 Intel Corporation. All rights reserved. */ #include +#include #include #include #include @@ -3459,6 +3460,7 @@ static int devm_cxl_add_dax_region(struct cxl_region = *cxlr) if (IS_ERR(cxlr_dax)) return PTR_ERR(cxlr_dax); =20 + cxlr_dax->online_type =3D mhp_get_default_online_type(); dev =3D &cxlr_dax->dev; rc =3D dev_set_name(dev, "dax_region%d", cxlr->id); if (rc) diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h index ba17fa86d249..07d57d13f4c7 100644 --- a/drivers/cxl/cxl.h +++ b/drivers/cxl/cxl.h @@ -591,6 +591,7 @@ struct cxl_dax_region { struct device dev; struct cxl_region *cxlr; struct range hpa_range; + int online_type; /* MMOP_ value for kmem driver */ }; =20 /** diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c index fde29e0ad68b..121a6dd0afe7 100644 --- a/drivers/dax/bus.c +++ b/drivers/dax/bus.c @@ -1,6 +1,7 @@ // SPDX-License-Identifier: GPL-2.0 /* Copyright(c) 2017-2018 Intel Corporation. All rights reserved. */ #include +#include #include #include #include @@ -395,6 +396,7 @@ static ssize_t create_store(struct device *dev, struct = device_attribute *attr, .size =3D 0, .id =3D -1, .memmap_on_memory =3D false, + .online_type =3D mhp_get_default_online_type(), }; struct dev_dax *dev_dax =3D __devm_create_dev_dax(&data); =20 @@ -1494,6 +1496,7 @@ static struct dev_dax *__devm_create_dev_dax(struct d= ev_dax_data *data) ida_init(&dev_dax->ida); =20 dev_dax->memmap_on_memory =3D data->memmap_on_memory; + dev_dax->online_type =3D data->online_type; =20 inode =3D dax_inode(dax_dev); dev->devt =3D inode->i_rdev; diff --git a/drivers/dax/bus.h b/drivers/dax/bus.h index cbbf64443098..4ac92a4edfe7 100644 --- a/drivers/dax/bus.h +++ b/drivers/dax/bus.h @@ -24,6 +24,7 @@ struct dev_dax_data { resource_size_t size; int id; bool memmap_on_memory; + int online_type; /* MMOP_ value for kmem driver */ }; =20 struct dev_dax *devm_create_dev_dax(struct dev_dax_data *data); diff --git a/drivers/dax/cxl.c b/drivers/dax/cxl.c index 13cd94d32ff7..856a0cd24f3b 100644 --- a/drivers/dax/cxl.c +++ b/drivers/dax/cxl.c @@ -27,6 +27,7 @@ static int cxl_dax_region_probe(struct device *dev) .id =3D -1, .size =3D range_len(&cxlr_dax->hpa_range), .memmap_on_memory =3D true, + .online_type =3D cxlr_dax->online_type, }; =20 return PTR_ERR_OR_ZERO(devm_create_dev_dax(&data)); diff --git a/drivers/dax/dax-private.h b/drivers/dax/dax-private.h index c6ae27c982f4..9559718cc988 100644 --- a/drivers/dax/dax-private.h +++ b/drivers/dax/dax-private.h @@ -77,6 +77,7 @@ struct dev_dax_range { * @dev: device core * @pgmap: pgmap for memmap setup / lifetime (driver owned) * @memmap_on_memory: allow kmem to put the memmap in the memory + * @online_type: MMOP_* online type for memory hotplug * @nr_range: size of @ranges * @ranges: range tuples of memory used */ @@ -91,6 +92,7 @@ struct dev_dax { struct device dev; struct dev_pagemap *pgmap; bool memmap_on_memory; + int online_type; int nr_range; struct dev_dax_range *ranges; }; diff --git a/drivers/dax/hmem/hmem.c b/drivers/dax/hmem/hmem.c index c18451a37e4f..119914b08fd9 100644 --- a/drivers/dax/hmem/hmem.c +++ b/drivers/dax/hmem/hmem.c @@ -1,5 +1,6 @@ // SPDX-License-Identifier: GPL-2.0 #include +#include #include #include #include @@ -36,6 +37,7 @@ static int dax_hmem_probe(struct platform_device *pdev) .id =3D -1, .size =3D region_idle ? 0 : range_len(&mri->range), .memmap_on_memory =3D false, + .online_type =3D mhp_get_default_online_type(), }; =20 return PTR_ERR_OR_ZERO(devm_create_dev_dax(&data)); diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c index c036e4d0b610..550dc605229e 100644 --- a/drivers/dax/kmem.c +++ b/drivers/dax/kmem.c @@ -16,6 +16,11 @@ #include "dax-private.h" #include "bus.h" =20 +/* Internal function exported only to kmem module */ +extern int __add_memory_driver_managed(int nid, u64 start, u64 size, + const char *resource_name, + mhp_t mhp_flags, int online_type); + /* * Default abstract distance assigned to the NUMA node onlined * by DAX/kmem if the low level platform driver didn't initialize @@ -72,6 +77,7 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax) struct dax_kmem_data *data; struct memory_dev_type *mtype; int i, rc, mapped =3D 0; + int online_type; mhp_t mhp_flags; int numa_node; int adist =3D MEMTIER_DEFAULT_DAX_ADISTANCE; @@ -134,6 +140,8 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax) goto err_reg_mgid; data->mgid =3D rc; =20 + online_type =3D dev_dax->online_type; + for (i =3D 0; i < dev_dax->nr_range; i++) { struct resource *res; struct range range; @@ -174,8 +182,9 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax) * Ensure that future kexec'd kernels will not treat * this as RAM automatically. */ - rc =3D add_memory_driver_managed(data->mgid, range.start, - range_len(&range), kmem_name, mhp_flags); + rc =3D __add_memory_driver_managed(data->mgid, range.start, + range_len(&range), kmem_name, mhp_flags, + online_type); =20 if (rc) { dev_warn(dev, "mapping%d: %#llx-%#llx memory add failed\n", diff --git a/drivers/dax/pmem.c b/drivers/dax/pmem.c index bee93066a849..a5925146b09f 100644 --- a/drivers/dax/pmem.c +++ b/drivers/dax/pmem.c @@ -1,5 +1,6 @@ // SPDX-License-Identifier: GPL-2.0 /* Copyright(c) 2016 - 2018 Intel Corporation. All rights reserved. */ +#include #include #include #include "../nvdimm/pfn.h" @@ -63,6 +64,7 @@ static struct dev_dax *__dax_pmem_probe(struct device *de= v) .pgmap =3D &pgmap, .size =3D range_len(&range), .memmap_on_memory =3D false, + .online_type =3D mhp_get_default_online_type(), }; =20 return devm_create_dev_dax(&data); --=20 2.52.0