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[96.255.20.138]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8c6e37c71f8sm54022985a.5.2026.01.22.16.34.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 22 Jan 2026 16:34:12 -0800 (PST) Date: Thu, 22 Jan 2026 19:34:10 -0500 From: Gregory Price To: "David Hildenbrand (Red Hat)" Cc: linux-mm@kvack.org, 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, mst@redhat.com, jasowang@redhat.com, xuanzhuo@linux.alibaba.com, eperezma@redhat.com, osalvador@suse.de, akpm@linux-foundation.org Subject: Re: [PATCH 3/8] mm/memory_hotplug: add APIs for explicit online type control Message-ID: References: <20260114085201.3222597-1-gourry@gourry.net> <20260114085201.3222597-4-gourry@gourry.net> <4520e7b0-8218-404d-8ede-e62d95c50825@kernel.org> Precedence: bulk X-Mailing-List: nvdimm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4520e7b0-8218-404d-8ede-e62d95c50825@kernel.org> On Thu, Jan 22, 2026 at 11:41:24PM +0100, David Hildenbrand (Red Hat) wrote: > > Right, but I don't want any other OOT kernel module to be able to make use > of add_memory_driver_managed() to do arbitrary things, because we don't know > if it's really user space setting the policy for that memory then. > Ah, this was lost on me. > So either restrict add_memory_driver_managed() to kmem+virtio_mem > completely, or add another variant that will be kmem-only (or however that > dax/cxl module is called). unclear to me how to restrict a function to specific drivers, but i can add add_and_online_memory_driver_managed() trivially so no big issue. You'd be ok with with this? add_and_online_memory_driver_managed(..., online_type) { ... existing add_memory_driver_managed() code ... } add_memory_driver_managed(...) { add_and_online_memory_driver_managed(..., mhp_get_default_policy()); } ~Gregory