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Tue, 1 Apr 2025 18:50:59 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id dX13L5M17GdBNwAAD6G6ig (envelope-from ); Tue, 01 Apr 2025 18:50:59 +0000 Date: Tue, 1 Apr 2025 20:50:50 +0200 From: Oscar Salvador To: Gregory Price Cc: linux-mm@kvack.org, linux-acpi@vger.kernel.org, kernel-team@meta.com, x86@kernel.org, linux-kernel@vger.kernel.org, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, rafael@kernel.org, lenb@kernel.org, david@redhat.com, gregkh@linuxfoundation.org, akpm@linux-foundation.org, dan.j.williams@intel.com, Jonathan.Cameron@huawei.com, alison.schofield@intel.com, rrichter@amd.com, rppt@kernel.org, bfaccini@nvidia.com, haibo1.xu@intel.com, dave.jiang@intel.com, Ira Weiny , Fan Ni Subject: Re: [PATCH v8 1/3] memory: implement memory_block_advise/probe_max_size Message-ID: References: <20250127153405.3379117-1-gourry@gourry.net> <20250127153405.3379117-2-gourry@gourry.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250127153405.3379117-2-gourry@gourry.net> X-Rspamd-Queue-Id: 4222F1C000E X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: wzdmxmoidgxiopxgfeku11otd3ebzptp X-HE-Tag: 1743533464-42605 X-HE-Meta: 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 ZTxU5A8K 9+Tm5/fGB48okXWJ2oWQjfhNXdm8VYkXsOzXEqn2iM1swGZeIS8nsI2wnaq+ZQwyQuEL/dWa3nZ53wVTFrNWm00eTjVLEMVFgb+hZe9VIaBoIpw6bGGN7Yvttld57Hlp/TWLW5qT2GWDkXJgeLLCW4uTntwBwYgcYYkGm4nm5zl0QcfVK2hCZ4AnwUdMMg2hZ0IeBbA+Byv+oBoUhzISuTOaYJHYK7q+Grnv54/qi1kzqpN073bW2GtMFng86U2+Ja6HtQJKguC6wQFd6l7wZJmSskXNAsA9jLYsbObcE2ci3KoIDJB3/AhkU1IrUjtV7Ubb9kQ7H8GB1ysyvwUh4qIIKBRjSmIBwiV1uElNFS4OkdqVjb4336I+tbmBpp3CMnTGjYp5UjFkAR5Sx6bDuvhCWHaGxlNNB24+mc/7UdroovRnB0NfayUEIU0RLonbYJDiIRaiC8KCQIrXLvuxyug65Uw== 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 Mon, Jan 27, 2025 at 10:34:03AM -0500, Gregory Price wrote: > Hotplug memory sources may have opinions on what the memblock size > should be - usually for alignment purposes. For example, CXL memory > extents can be 256MB with a matching alignment. If this size/alignment > is smaller than the block size, it can result in stranded capacity. > > Implement memory_block_advise_max_size for use prior to allocator init, > for software to advise the system on the max block size. > > Implement memory_block_probe_max_size for use by arch init code to > calculate the best block size. Use of advice is architecture defined. > > The probe value can never change after first probe. Calls to advise > after probe will return -EBUSY to aid debugging. > > On systems without hotplug, always return -ENODEV and 0 respectively. > > Suggested-by: Ira Weiny > Acked-by: David Hildenbrand > Acked-by: Mike Rapoport (Microsoft) > Acked-by: Dan Williams > Tested-by: Fan Ni > Reviewed-by: Ira Weiny > Signed-off-by: Gregory Price Acked-by: Oscar Salvador -- Oscar Salvador SUSE Labs