From nobody Tue Feb 10 03:44:22 2026 Received: from mail-qv1-f44.google.com (mail-qv1-f44.google.com [209.85.219.44]) (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 3B8F933EB0C for ; Wed, 14 Jan 2026 23:51:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.44 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768434666; cv=none; b=EOtXM+6EhU20fq/koNtgOw1OYTz/aArS43bHu6UoRa0G4YpyEh56dCy98GZ61zrT/sxfCWYcWW5M5EGRgQHat0Y3Pa5XgUzG8ZC/NuUGL5QAB1qqP80EestC6GHDIW+LeHxeZisAUC8ho30sH98mpdn0Z7o36yuzveaGe5sOBuc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768434666; c=relaxed/simple; bh=Ts4OR3TE6GFvXvPkLNSwvDxigmljGOw1xgooqw3bmMo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=J4zDG0PcMaSxbTyqei//mXu1lZn3cEErqL1eB+MwlZIw02g97IZxoH1OzD9iZKhD1K59UDqCFO/Dp1+wNKkS9/rSeFIVWXnpYP8z7JR0WUh3Z5DsF48U1WfXr3QGlt56Sk0vD7nUifP6dUV8730uOLOQuTRC/EpoHcMRS5gHge4= 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=ihE+/VXX; arc=none smtp.client-ip=209.85.219.44 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="ihE+/VXX" Received: by mail-qv1-f44.google.com with SMTP id 6a1803df08f44-88888c41a13so3862086d6.3 for ; Wed, 14 Jan 2026 15:51:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gourry.net; s=google; t=1768434662; x=1769039462; 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=cXtSnfgPBjwiSCGU9CrPH4hnxnqEFEy6STkxK/VjbLc=; b=ihE+/VXXhtldTRYErCRvdjpADw9wHTRvRCANVMEwJLJU23Ij5Z9lPJzw0O8RFJiLvq 4Kf16raRuBv2HCgnDWrWD4k25rVmfx6KCqX7E5U7TLoqExEl+r7sa8wW1iry4SHxyHL7 r/TLHsjXmrEWBLGEna/gVarCXSCE37Pz8d1BDSvRg09FpKXoBc3v19rGvK1u2/WBeuY8 BDoVzYSZVIf7gFS6ZcktXhHXz6X4bgsevWdAJTcaVNOphlKRnELrOoR+dlXAdQ2gKfGF w3RdFFp8STz/h9LFfZfSQf8+PurKhUD7fkjW5MAZKKFjXJRfl0iIdtNI/fiduAM6Wxt5 j9uQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1768434662; x=1769039462; 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=cXtSnfgPBjwiSCGU9CrPH4hnxnqEFEy6STkxK/VjbLc=; b=spH66mqlgJUwYXtcc/I+FfkP/GP/0tFiKOT2rysvQEtNLhE6Lv6p5MGGmQfn5yc0A2 AvAKgvq7PxQQl5eQgs/waqebV8a9YV7VDSuchSBnxIOgCpQJZuX3f/9mvBy9TC32Dtzh a7SeZFxd+XCwG9xTTl57XTCVOtH80/g5On5PmyDaUk7wYlsAmJdJFdcM9H2rySSW61xQ nQAALhT6iqoCHwtWLuNZKnX8lecgSUN4Ig0jnf/M7KVkttD0s2t2Ce5bz+LJw7CweC1x 04KPKFqQEbCsOJm45NhC+nKazFaKjPdPFNrIs+M/x9ssGPMRSHZcSNzdgWmr0kAnhvR0 Ytfg== X-Forwarded-Encrypted: i=1; AJvYcCVs6iJMrrr0d0CXG1M2AlOC1OtNSG9adSNYal7wzSUrqgWacHFF6pfp4YLLiPpEubaNGa9F99fi86xo6aE=@vger.kernel.org X-Gm-Message-State: AOJu0YxaXS40IVEZHpd3dUNqu4EZ9ykeCi8mHYYSn9k49i5j07ZR12DF 3IMtIScEpwTKVqMZQmc3toAHFBsQcMY/LEmFCGCqfrZ+WKZ3O+/i/RShWMdqeU2ECUQ= X-Gm-Gg: AY/fxX5uVTfIpi02sd/LStZgj5paUsWzzq8+gbKWoUd5He7FEKWdP/q3sOgXdNdZ/C3 gNAaXD08rctm7AaV4dqBig56FZxzVOm2fDxFLrVGtwnxTspqzirvmjNNs/kiTmi/szqtEvY9otr CviHEZCjktxRqCXzU5JGorT3VUR+OuR+QgtpbwW0AUXqCGJt6QWnkzLEDFvSqIPOZlFnJ3QI66O 6VcdmzXbVMUlfgehJuszmBJRJobTdwhmXH7hZUpzYnCehuW6L+c+eoVXsaFbl+XOSKh+wvUgPjL zyHSgFgNsjGnV4wKHmTThPi6k+V/G5sm2qbO6oRsWmPrd/JhZrW9MKyhGty3WgdYbE0ELmmSVBj S3jjCVIQPFF8tZCLKhTWrvm9jVYP5idoCm85q56i2GrlfM92SZCz0kCVBHN2KXcrVcsreXkzshU yrDQnqyq9MmnEwBB3tCUnDYIg7djfURFN0eEq+OFGKPCJGwz6Qefv2ECJZiWVH+AtsUE5gpbi1w q4= X-Received: by 2002:a05:6214:246c:b0:88a:2f46:8224 with SMTP id 6a1803df08f44-89275c89a31mr55155636d6.68.1768434662147; Wed, 14 Jan 2026 15:51:02 -0800 (PST) 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 6a1803df08f44-890772346f8sm188449106d6.35.2026.01.14.15.51.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 14 Jan 2026 15:51:01 -0800 (PST) From: Gregory Price To: linux-mm@kvack.org Cc: linux-cxl@vger.kernel.org, nvdimm@lists.linux.dev, linux-kernel@vger.kernel.org, virtualization@lists.linux.dev, kernel-team@meta.com, dan.j.williams@intel.com, vishal.l.verma@intel.com, dave.jiang@intel.com, david@kernel.org, mst@redhat.com, jasowang@redhat.com, xuanzhuo@linux.alibaba.com, eperezma@redhat.com, osalvador@suse.de, akpm@linux-foundation.org Subject: [PATCH v2 2/5] mm/memory_hotplug: add 'online_type' argument to add_memory_driver_managed Date: Wed, 14 Jan 2026 18:50:18 -0500 Message-ID: <20260114235022.3437787-3-gourry@gourry.net> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260114235022.3437787-1-gourry@gourry.net> References: <20260114235022.3437787-1-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" Enable external callers to select how to online the memory rather than implicitly depending on the system defauilt. Refactor: Extract __add_memory_resource to take an explicit online type, and update add_memory_resource to pass the system default. Export mhp_get_default_online_type() and update existing callers of add_memory_driver_managed to use it explicitly to make it clear what the behavior of the function is. dax_kmem and virtio_mem drivers were updated. Signed-off-by: Gregory Price --- drivers/dax/kmem.c | 3 ++- drivers/virtio/virtio_mem.c | 3 ++- include/linux/memory_hotplug.h | 2 +- mm/memory_hotplug.c | 31 +++++++++++++++++++++++-------- 4 files changed, 28 insertions(+), 11 deletions(-) diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c index c036e4d0b610..bb13d9ced2e9 100644 --- a/drivers/dax/kmem.c +++ b/drivers/dax/kmem.c @@ -175,7 +175,8 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax) * this as RAM automatically. */ rc =3D add_memory_driver_managed(data->mgid, range.start, - range_len(&range), kmem_name, mhp_flags); + range_len(&range), kmem_name, mhp_flags, + mhp_get_default_online_type()); =20 if (rc) { dev_warn(dev, "mapping%d: %#llx-%#llx memory add failed\n", diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c index 1688ecd69a04..63c0b2b235ab 100644 --- a/drivers/virtio/virtio_mem.c +++ b/drivers/virtio/virtio_mem.c @@ -654,7 +654,8 @@ static int virtio_mem_add_memory(struct virtio_mem *vm,= uint64_t addr, /* Memory might get onlined immediately. */ atomic64_add(size, &vm->offline_size); rc =3D add_memory_driver_managed(vm->mgid, addr, size, vm->resource_name, - MHP_MERGE_RESOURCE | MHP_NID_IS_MGID); + MHP_MERGE_RESOURCE | MHP_NID_IS_MGID, + mhp_get_default_online_type()); if (rc) { atomic64_sub(size, &vm->offline_size); dev_warn(&vm->vdev->dev, "adding memory failed: %d\n", rc); diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h index f2f16cdd73ee..b68bc410db67 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h @@ -295,7 +295,7 @@ extern int add_memory_resource(int nid, struct resource= *resource, mhp_t mhp_flags); extern int add_memory_driver_managed(int nid, u64 start, u64 size, const char *resource_name, - mhp_t mhp_flags); + mhp_t mhp_flags, int online_type); extern void move_pfn_range_to_zone(struct zone *zone, unsigned long start_= pfn, unsigned long nr_pages, struct vmem_altmap *altmap, int migratetype, diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 5718556121f0..2b4e31161fc1 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -239,6 +239,7 @@ int mhp_get_default_online_type(void) =20 return mhp_default_online_type; } +EXPORT_SYMBOL_GPL(mhp_get_default_online_type); =20 void mhp_set_default_online_type(int online_type) { @@ -1490,7 +1491,8 @@ static int create_altmaps_and_memory_blocks(int nid, = struct memory_group *group, * * we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */ -int add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags) +static int __add_memory_resource(int nid, struct resource *res, mhp_t mhp_= flags, + int online_type) { struct mhp_params params =3D { .pgprot =3D pgprot_mhp(PAGE_KERNEL) }; enum memblock_flags memblock_flags =3D MEMBLOCK_NONE; @@ -1580,12 +1582,9 @@ int add_memory_resource(int nid, struct resource *re= s, mhp_t mhp_flags) merge_system_ram_resource(res); =20 /* online pages if requested */ - if (mhp_get_default_online_type() !=3D MMOP_OFFLINE) { - int online_type =3D mhp_get_default_online_type(); - + if (online_type !=3D MMOP_OFFLINE) walk_memory_blocks(start, size, &online_type, online_memory_block); - } =20 return ret; error: @@ -1601,7 +1600,13 @@ int add_memory_resource(int nid, struct resource *re= s, mhp_t mhp_flags) return ret; } =20 -/* requires device_hotplug_lock, see add_memory_resource() */ +int add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags) +{ + return __add_memory_resource(nid, res, mhp_flags, + mhp_get_default_online_type()); +} + +/* requires device_hotplug_lock, see __add_memory_resource() */ int __add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags) { struct resource *res; @@ -1649,9 +1654,16 @@ EXPORT_SYMBOL_GPL(add_memory); * * The resource_name (visible via /proc/iomem) has to have the format * "System RAM ($DRIVER)". + * + * @online_type specifies the online behavior: MMOP_ONLINE, MMOP_ONLINE_KE= RNEL, + * MMOP_ONLINE_MOVABLE to online with that type, MMOP_OFFLINE to leave off= line. + * Users that want the system default should call mhp_get_default_online_t= ype(). + * + * Returns 0 on success, negative error code on failure. */ int add_memory_driver_managed(int nid, u64 start, u64 size, - const char *resource_name, mhp_t mhp_flags) + const char *resource_name, mhp_t mhp_flags, + int online_type) { struct resource *res; int rc; @@ -1661,6 +1673,9 @@ int add_memory_driver_managed(int nid, u64 start, u64= size, resource_name[strlen(resource_name) - 1] !=3D ')') return -EINVAL; =20 + if (online_type < 0 || online_type > MMOP_ONLINE_MOVABLE) + return -EINVAL; + lock_device_hotplug(); =20 res =3D register_memory_resource(start, size, resource_name); @@ -1669,7 +1684,7 @@ int add_memory_driver_managed(int nid, u64 start, u64= size, goto out_unlock; } =20 - rc =3D add_memory_resource(nid, res, mhp_flags); + rc =3D __add_memory_resource(nid, res, mhp_flags, online_type); if (rc < 0) release_memory_resource(res); =20 --=20 2.52.0