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[173.79.60.52]) by smtp.gmail.com with ESMTPSA id af79cd13be357-9158a237330sm2207058485a.16.2026.06.09.08.11.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 Jun 2026 08:11:53 -0700 (PDT) Date: Tue, 9 Jun 2026 11:11:51 -0400 From: Gregory Price To: "David Hildenbrand (Arm)" Cc: linux-mm@kvack.org, nvdimm@lists.linux.dev, linux-kernel@vger.kernel.org, kernel-team@meta.com, linux-cxl@vger.kernel.org, linux-kselftest@vger.kernel.org, djbw@kernel.org, vishal.l.verma@intel.com, dave.jiang@intel.com, akpm@linux-foundation.org, ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, osalvador@suse.de, shuah@kernel.org, alison.schofield@intel.com, Smita.KoralahalliChannabasappa@amd.com, ira.weiny@intel.com, apopple@nvidia.com Subject: Re: [PATCH v4 3/9] mm/memory_hotplug: export mhp_get_default_online_type Message-ID: References: <20260605211911.2160954-1-gourry@gourry.net> <20260605211911.2160954-4-gourry@gourry.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam10 X-Rspam-User: X-Stat-Signature: 7nnsqjfm7hqdijc8mm67pk5zmk4wokkr X-Rspamd-Queue-Id: 61DCA20013 X-HE-Tag: 1781017915-671889 X-HE-Meta: U2FsdGVkX1+9rX/jET0r/Yt/0bruN1y7FM7MhS6X/w7D1J8aZgEfxEcCwLxCao1FgmsmECdvRel0s0Dgb3cAuJnbY6EwFwJbSZRRE9QmoBXQamXKaffIXTGSRpQihMA3O9SfOxWtDmaoZyCr9mM4by4I5w76fkFB3EJ7HMd375ur1ye6sSJFDcp5Dd0F/4rEnxjhlWjYQfAFjkOyYcFBufKRZWEDh9lr2bKvu5jq5d/5DDJDYhY4Fa7BqJWp8pS1d94ITR4xbUNC2DutCQo+r5pPzA4eQPPew7XqAFjfRSu/S5qHxzqwIlFqouZhlBVFxYgGsji/u5U+jfb51LwCLM04PFfhLFr23jLFoslnG2lt79mYUlmXJf3QLYs32bM1gRA6RjZ52sIlfxtnyCMqo5AWkO67ukt/BSuSWHr20JcmJBlkzAgxEZVvlNnAltYIq6iIWPK55ukjIyFuEzn+rVsQ86fHSfpi47RX/R6QxZyWP/2UIINkF7lNGjQuLSHHKBf8BGjb2ls9f7A6kcpxXi52XA/yKTOzxpQRswyUhWsbEbALNGNpjTx0TvdFkEbN6vWFV1G0jYEK2ej/Aslq36vtZnnI11PVf7foynT6ipJIAjGriX/xPA1KZmHrcdO5G/8lnDpkzr/douUpl09s/rM/hOtCzkSMce549nTWYyZ+kD9tI2WDBCsTHZz/JEbC2vGr5GfYHr5OofaZvGJLvGmJH/5lOJVsDsoeSJeUWxcQPHXRitujfieLEE5UulVZz7HCv9XO3Q7hbUXuTLk24f7YcuV5Mtgqo7dGry5JLrdOpHvs67XfNyz25rmn+VH1QHC+G/3IrW6ZHpdB2emWgHlSr++0h/P90gdgu5MIjgEDwA3/RQvKTSvg1fQJ3ebTREncLUU1Az9lRU1+DdLLIZ/HKplxogv50lmJftXBCvgaF9+sSj/E/6QK9fU2jrXY8lBTU6L909qJV5I5PBa 7eyuzb01 iwl13yd3IuHxByaKMrgrE7XoJK5XRJ6pePioi8PHkV7+GLxyIHns9o0m0A7lBJjWIg+DZh2HrhZfx4+uc7z2V7N8TsGgubAc5L4eeuV+IUHSQ86/RGvfJWJ0wo4wNyb9Kb2GiM6Qr0ZCjm5BFVthjYxW2g1fnd9G+xb1Q2vy4gkIcReG14cVvuyKnWTlolNwxPespOfFJp1j5xU2o0snKay13Q303dwE0PjWtKOPWnXVvp4Nf/Q1Up896O0HrlZzziMdr37kjvOXzaCOPOpmAVrQ9NeQZ9sSDDeRo/55rp1nh+M2de72N2i3f/QQXTlfGV9/JT6aLHHwZHRCkOMJOKh7go8Wt1dSkmaNP8mPmgWEq7sXnUpbtVqTWLT440bQTBn5B0Wnnb9Rmia2J19hzcfx1hXtHlUsS++BCkfl2kCyfM6Xsndi79F2dYlaYdav3iHyUuDnLO5M1torJXAVS4gf/R1Ac9HVvpALbL5MjBgDX/Us= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Jun 09, 2026 at 11:52:21AM +0200, David Hildenbrand (Arm) wrote: > On 6/5/26 23:19, Gregory Price wrote: > > Drivers which may pass hotplug policy down to DAX need MMOP_ symbols > > and the mhp_get_default_online_type function for hotplug use cases. > > > > Some drivers (cxl) co-mingle their hotplug and devdax use-cases into > > the same driver code, and chose the dax_kmem path as the default driver > > path - making it difficult to require hotplug as a predicate to building > > the overall driver (it may break other non-hotplug use-cases). > > > > Export mhp_get_default_online_type function to allow these drivers to > > build when hotplug is disabled and still use the DAX use case. > > > > In the built-out case we simply return MMOP_OFFLINE as it's > > Ah, you mean without CONFIG_MEMORY_HOTPLUG > Yeah i'll update the commit message, thanks! > > non-destructive. The internal function can never return -1 either, > > so we choose this to allow for defining the function with 'enum mmop'. > > Acked-by: David Hildenbrand (Arm) > > -- > Cheers, > > David