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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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4520e7b0-8218-404d-8ede-e62d95c50825@kernel.org> X-Stat-Signature: urg6icrhd8b67h1ja4gques38kjjq599 X-Rspamd-Queue-Id: 78632160004 X-Rspam-User: X-Rspamd-Server: rspam04 X-HE-Tag: 1769128455-811513 X-HE-Meta: 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 yUO0zXbr BWnog3ka8N9Jb3TdsBk8mYWtDolSkenNsHOJrZEY5EYhaHPigZSS7mW7vTREWJdR8E+6xsnricjWJAPmLHXTbw7ZlEhkxkbaph8a8WOuCP8Dd9kZSCZJUygsjZJIFk1oUMO9Sbaxweh4jQl3WZoa7LSaR93DLDfe90wztUCMnbnabCMkvJpcQ/+RQ1xqFfkiF8CdQ4a7VtINxiM5hH545O67YzmXgGHSYMwc/j1ujPpHu72g+7T6IBcz31xjctYkbV3JJgr1gSlvkRhxRCv+kClYSW4AfzaXCI4PtpmgOK/J6OWa4DNeiMeW9CTDx7O0AAASsR1dy3x4AQ1Twd1c+IZ5pr4AQew7ZrGgVCiw/MAHcYOlK6d8giXpENw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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