From nobody Mon Apr 6 10:43:31 2026 Received: from mail-qk1-f171.google.com (mail-qk1-f171.google.com [209.85.222.171]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 427F5392824 for ; Sat, 21 Mar 2026 15:04:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.222.171 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774105464; cv=none; b=CmaiY4rFW4BIUrw44rqmo8h5DOiODCB3KAUhYpR26yIkwsUByHc0EbBNK9YU9AHtNTDe8fWdvJF0pOrrmTZ0WUgm3DyDQgwkzbRoJuwCC4BAF8AsOqkgMqpmTqgpcYretwVpVaVGHHUUmExHh/A5Xb0g74NnNhJDAQid9mbmMJc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774105464; c=relaxed/simple; bh=Wowz7DV1aUnJYA8F9t35yrzNxk7X9sC3o+wv4gNWZWA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=G3HXWQH9eobNbEIR/iJNGpqZBgLxCo9cS1wLhXnfF7OpAq+Fc0yEyfw3gomxo1LDyUYc7sEeg8JV+ZP76rRFu28+/BC5cjEamDpmqzAlLp7Nd2pPNvM+tjXFAQfqWP9GMKTGLex8tqvvL4j06QXn8cR01HKErb4Dfg7zhCGF6hs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=gourry.net; spf=pass smtp.mailfrom=gourry.net; dkim=pass (2048-bit key) header.d=gourry.net header.i=@gourry.net header.b=irS2qXWx; arc=none smtp.client-ip=209.85.222.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=gourry.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gourry.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gourry.net header.i=@gourry.net header.b="irS2qXWx" Received: by mail-qk1-f171.google.com with SMTP id af79cd13be357-8cd71fb9f06so186830585a.2 for ; Sat, 21 Mar 2026 08:04:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gourry.net; s=google; t=1774105460; x=1774710260; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=DpXtFQ1E8PxzzJ3jH0sASsMe/zJtVJUABHrep2C4jPI=; b=irS2qXWxWFeexAZMY+IiOHXE4lVvRhIKgIfbqdPOgR3M+D5Pr7sfFiF7DA6Y3jxSFj dLYH4jt0Or2o8Ci+d7sCnulb6ziFtZfsXjpCiYysZ4IUEr1nFoFY2ltSMhyL/HpkqlPm 4KzB67t+QzA8kJJZsm54xUetG5BIVv9SNjJ8TaB4x42xiSDf3pWT1I/BtdfxXck+lRJy CO+O0jUqrH+rEfrPiqzYAjgbmwdx7KAs84xJxpcNm+4jGWS/B9vFKibU99hXqDkrf0vW gjmkRUGF0eYJPql4RwmTmUDEy5cEFgHh6Yq4at3JxketATqN6r3GOPXmdKHyXX0jtsHy n0cg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1774105460; x=1774710260; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=DpXtFQ1E8PxzzJ3jH0sASsMe/zJtVJUABHrep2C4jPI=; b=aW+94o7LQ2wkccDv5TZ7tXOBVZqjbVv1aDwHm72RqfaDdiN2014MrwjFob+I+dcUF2 X+WsFV8We2mO//pmvDbYApw5PtheHzzbopvE1G7CiZXPTNHkoeFM/yPoUO+1NNRufhqK UyI0VgDhnBzUrgQmzTUO0Uw2ki7U8A1EDKX0cZLHoOuCfe560y2VqSGmmN4ftPOF+Epb dEbSVz/uZ3WP4RT3MHm5zG3BYV17+u0O2DeL+Q6wtINa1JOkBBmajQAdHgptnpiIwYN7 vldYUaRsSbXhPXhXuFGuPLO5PCqd7LnVlGpivH1g2h6slnWQOh6I1Ot1mK7gv4KbiPk2 AXbg== X-Forwarded-Encrypted: i=1; AJvYcCUy0bPedWFQLl3MIKiFo+vhzYmpEBxr2/WGTT43qEhYSu5MDHP0kVdfkp98lIBqQQ6zkKF93sFZFip4AlY=@vger.kernel.org X-Gm-Message-State: AOJu0YyJQwaTp28iRD3EYiCnJtsjGGWJ0yI/N9sPTYV/Ey5kYVwtvZNG 8eg3V6NZLXoqZffAKgSYdVU1jJs7A0+6xFGhX2OOJWB9eZGP82Fn4nqjIclMHikY5bQ= X-Gm-Gg: ATEYQzzDstjZ2zpvY+7qdVHal4ScCzTd9J0jg3tCQLsHJXobF6d/CNgiO3yB8OtO+Y0 HZF9TXMJr6j2gQMCp0iR718g/kvQEbMsRJCqOkwCl/VGxZvC2tJGA4QWtiCHo8vPf8mOuVQdO1h lE17F47BMOtiXPvxAsvf+WSYSSci/9QzfgNiMbFibEVWezRlO7x6dpdT1V9lBXKspZfqDYwY7SD 4ur6wXwqZCY8chIzwpI31HLNjj95JRYhlOx7m/wZkAM1Zfj9Beny2lb+mTp+rAo2sx/LzdYz477 IX2k1MQyFDz6jVkFzkx8N6nlViGOYovfnMNX1elU81Enso38X615E7k8Bz/RJS0Zxyk1iNehP/Q eTFzpg7Cb2733DMmle4ZEN9C68iooRk2s1aboYu/aKyrTB5CMjdKNBC8Y5JGjo/2izcxEYUZnIH LJ3d/baCHTgK6/YOiI5OdvPzQbVi5BuWypUGwS9L9i7gK/kzeWRvAYNaoJ+Oms7xYN+NzKgSe+6 lc0uudf7JpmUS4= X-Received: by 2002:a05:620a:4055:b0:8cf:dd4b:8a53 with SMTP id af79cd13be357-8cfdd4b9250mr167236585a.30.1774105459722; Sat, 21 Mar 2026 08:04:19 -0700 (PDT) Received: from gourry-fedora-PF4VCD3F.lan (pool-96-255-20-138.washdc.ftas.verizon.net. [96.255.20.138]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8cfc90ba89fsm391979885a.40.2026.03.21.08.04.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 21 Mar 2026 08:04:18 -0700 (PDT) From: Gregory Price To: linux-mm@kvack.org, vishal.l.verma@intel.com, dave.jiang@intel.com, akpm@linux-foundation.org, david@kernel.org, osalvador@suse.de Cc: dan.j.williams@intel.com, ljs@kernel.org, Liam.Howlett@oracle.com, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, linux-kernel@vger.kernel.org, nvdimm@lists.linux.dev, linux-cxl@vger.kernel.org, kernel-team@meta.com Subject: [PATCH 6/8] dax: plumb hotplug online_type through dax Date: Sat, 21 Mar 2026 11:04:02 -0400 Message-ID: <20260321150404.3288786-7-gourry@gourry.net> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260321150404.3288786-1-gourry@gourry.net> References: <20260321150404.3288786-1-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 'enum mmop' 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() to retain backward compatibility and to make explicit to the drivers what is actually happening underneath. No functional changes to existing callers. Cc:David Hildenbrand Signed-off-by: Gregory Price --- drivers/dax/bus.c | 3 +++ drivers/dax/bus.h | 2 ++ drivers/dax/cxl.c | 1 + drivers/dax/dax-private.h | 3 +++ drivers/dax/hmem/hmem.c | 1 + drivers/dax/kmem.c | 13 +++++++++++-- 6 files changed, 21 insertions(+), 2 deletions(-) diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c index c94c09622516..2c6140dc9382 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..f037cd8a2d51 100644 --- a/drivers/dax/bus.h +++ b/drivers/dax/bus.h @@ -3,6 +3,7 @@ #ifndef __DAX_BUS_H__ #define __DAX_BUS_H__ #include +#include #include =20 struct dev_dax; @@ -24,6 +25,7 @@ struct dev_dax_data { resource_size_t size; int id; bool memmap_on_memory; + enum mmop online_type; }; =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..d6fbec863361 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 mhp_get_default_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..734fb83f5eb4 100644 --- a/drivers/dax/dax-private.h +++ b/drivers/dax/dax-private.h @@ -8,6 +8,7 @@ #include #include #include +#include =20 /* private routines between core files */ struct dax_device; @@ -77,6 +78,7 @@ 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 +93,7 @@ struct dev_dax { struct device dev; struct dev_pagemap *pgmap; bool memmap_on_memory; + enum mmop 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 1cf7c2a0ee1c..acbc574ced93 100644 --- a/drivers/dax/hmem/hmem.c +++ b/drivers/dax/hmem/hmem.c @@ -36,6 +36,7 @@ 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 798f389df992..d4c34b2e3766 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, enum mmop online_type); + /* Memory resource name used for add_memory_driver_managed(). */ static const char *kmem_name; /* Set if any memory will remain added when the driver will be unloaded. */ @@ -49,6 +54,7 @@ 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; + enum mmop online_type; mhp_t mhp_flags; int numa_node; int adist =3D MEMTIER_DEFAULT_LOWTIER_ADISTANCE; @@ -111,6 +117,8 @@ 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; @@ -151,8 +159,9 @@ 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", --=20 2.53.0