From patchwork Thu Nov 2 18:27:12 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Verma, Vishal L" X-Patchwork-Id: 13444125 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E90A22134A for ; Thu, 2 Nov 2023 18:28:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="WWh/wJnA" Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.9]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5C8E6DB; Thu, 2 Nov 2023 11:28:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1698949680; x=1730485680; h=from:subject:date:message-id:mime-version: content-transfer-encoding:to:cc; bh=4qUOmcq7thBdlj5wGqR9iQ3jAeBk8UU8mGmQFkFS1rc=; b=WWh/wJnAHBW64upifbZWDO/M8ydNKfO72jddd/zEVKubgRX+gBHqp/Up +vMk5s/+UaAxawuEzOFwSFcbxPn0vDHahp0L9pQO/uZp3xmBLv4NeKvyJ DNcYM3UtMCGPn6Xj/8c58kAlr5su0f8SKg3ez1HeHKyg2c/IqNVp+xQd9 w9ohi/O9rvEGmsvdIepG9eUt3TgsLGy06nS33glGsAKDrTELEh0MCRiml xVVXrt0awApgWgi1iwNQNx32c4ftTZekxKtvd2HEaM8n5gbK042LQbE32 eo1Th7MHbNMBWLeto6Y5eWq98YW0MT2OD4R5zPQ/uUV5kF6GY4c5bU1kK w==; X-IronPort-AV: E=McAfee;i="6600,9927,10882"; a="7421155" X-IronPort-AV: E=Sophos;i="6.03,272,1694761200"; d="scan'208";a="7421155" Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orvoesa101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Nov 2023 11:28:00 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10882"; a="761359758" X-IronPort-AV: E=Sophos;i="6.03,272,1694761200"; d="scan'208";a="761359758" Received: from fmahinh-mobl.amr.corp.intel.com (HELO [192.168.1.200]) ([10.212.91.244]) by orsmga002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Nov 2023 11:27:58 -0700 From: Vishal Verma Subject: [PATCH v9 0/3] mm: use memmap_on_memory semantics for dax/kmem Date: Thu, 02 Nov 2023 12:27:12 -0600 Message-Id: <20231102-vv-kmem_memmap-v9-0-973d6b3a8f1a@intel.com> Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-B4-Tracking: v=1; b=H4sIAADqQ2UC/3XQy07DMBAF0F+pvMbI9vgxZsV/IIQmflCLJqmSE oGq/jtuF6SKYeHFHenMtX1mc5pKmtnT7symtJS5jEMN/mHHwp6G98RLrJkpoUBYCXxZ+Eef+rd 6ejpyoxECRqGV86yijubEu4mGsK9s+Dwc6vA4pVy+bi0vrzXvy3wap+9b6SKv03/3L5ILnm1MP ljKKtjnMpzS4TGMPbuuWtTKnRINV5UjdpGoA+09bDmsHIVsOFSuhU2eKBuLfsv1yr3ChuvKbc4 OcgpGetpy88ulEKbhpnIyOkqPMgtqLm/vuLQNt5ULh1lECAKc3HJ3x1Xb7q5vJ2ejs0bFbLYcV y7/+Dqs3CRNCAASEO/55XL5AT91It96AgAA To: Andrew Morton , David Hildenbrand , Oscar Salvador , Dan Williams , Dave Jiang Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, nvdimm@lists.linux.dev, linux-cxl@vger.kernel.org, Huang Ying , Dave Hansen , "Aneesh Kumar K.V" , Michal Hocko , Jonathan Cameron , Jeff Moyer , Vishal Verma , Jonathan Cameron X-Mailer: b4 0.13-dev-26615 X-Developer-Signature: v=1; a=openpgp-sha256; l=6045; i=vishal.l.verma@intel.com; h=from:subject:message-id; bh=4qUOmcq7thBdlj5wGqR9iQ3jAeBk8UU8mGmQFkFS1rc=; b=owGbwMvMwCXGf25diOft7jLG02pJDKnOr7Ruu+5unaW+c9n1k2yHeddveWFjXSUV32mxKEb0G EObn7tXRykLgxgXg6yYIsvfPR8Zj8ltz+cJTHCEmcPKBDKEgYtTACZSK8fIcDFw7cWiD6+8b/VM Fbz/632OUdFMVqX0i09EZ+1mmZn7ZgIjw7l87feuPO6+x/j6TWcznwqcwublGHg5cPbXn8q9pXG 8bAA= X-Developer-Key: i=vishal.l.verma@intel.com; a=openpgp; fpr=F8682BE134C67A12332A2ED07AFA61BEA3B84DFF The dax/kmem driver can potentially hot-add large amounts of memory originating from CXL memory expanders, or NVDIMMs, or other 'device memories'. There is a chance there isn't enough regular system memory available to fit the memmap for this new memory. It's therefore desirable, if all other conditions are met, for the kmem managed memory to place its memmap on the newly added memory itself. The main hurdle for accomplishing this for kmem is that memmap_on_memory can only be done if the memory being added is equal to the size of one memblock. To overcome this, allow the hotplug code to split an add_memory() request into memblock-sized chunks, and try_remove_memory() to also expect and handle such a scenario. Patch 1 replaces an open-coded kmemdup() Patch 2 teaches the memory_hotplug code to allow for splitting add_memory() and remove_memory() requests over memblock sized chunks. Patch 3 allows the dax region drivers to request memmap_on_memory semantics. CXL dax regions default this to 'on', all others default to off to keep existing behavior unchanged. Signed-off-by: Vishal Verma --- Changes in v9: - Fix error unwinding for the ENOMEM case in remove_memory_blocks_and_altmaps() (Ying, David) - Misc readability and style cleanups (David) - Link to v8: https://lore.kernel.org/r/20231101-vv-kmem_memmap-v8-0-5e4a83331388@intel.com Changes in v8: - Fix unwinding in create_altmaps_and_memory_blocks() to remove partially added blocks and altmaps. (David, Ying) - Simplify remove_memory_blocks_and_altmaps() since an altmap is assured. (David) - Since we remove per memory-block altmaps, the walk through memory blocks for a larger range isn't needed. Instead we can lookup the memory block directly from the pfn, allowing the test_has_altmap_cb() callback to be dropped and removed. (David) - Link to v7: https://lore.kernel.org/r/20231025-vv-kmem_memmap-v7-0-4a76d7652df5@intel.com Changes in v7: - Make the add_memory_resource() flow symmetrical w.r.t. try_remove_memory() in terms of how the altmap path is taken (David Hildenbrand) - Move a comment, clean up usage of 'memblock' vs. 'memory_block' (David Hildenbrand) - Don't use the altmap path for the mhp_supports_memmap_on_memory(memblock_size) == false case (Huang Ying) - Link to v6: https://lore.kernel.org/r/20231016-vv-kmem_memmap-v6-0-078f0d3c0371@intel.com Changes in v6: - Add a prep patch to replace an open coded kmemdup in add_memory_resource() (Dan Williams) - Fix ordering of firmware_map_remove w.r.t taking the hotplug lock (David Hildenbrand) - Remove unused 'nid' variable, and a stray whitespace (David Hildenbrand) - Clean up and simplify the altmap vs non-altmap paths for try_remove_memory (David Hildenbrand) - Add a note to the changelog in patch 1 linking to the PUD mappings proposal (David Hildenbrand) - Remove the new sysfs ABI from the kmem/dax drivers until ABI documentation for /sys/bus/dax can be established (will split this out into a separate patchset) (Dan Williams) - Link to v5: https://lore.kernel.org/r/20231005-vv-kmem_memmap-v5-0-a54d1981f0a3@intel.com Changes in v5: - Separate out per-memblock operations from per memory block operations in try_remove_memory(), and rename the inner function appropriately. This does expand the scope of the memory hotplug lock to include remove_memory_block_devices(), but the alternative was to drop the lock in the inner function separately for each iteration, and then re-acquire it in try_remove_memory() creating a small window where the lock isn't held. (David Hildenbrand) - Remove unnecessary rc check from the memmap_on_memory_store sysfs helper in patch 2 (Dan Carpenter) - Link to v4: https://lore.kernel.org/r/20230928-vv-kmem_memmap-v4-0-6ff73fec519a@intel.com Changes in v4: - Rebase to Aneesh's PPC64 memmap_on_memory series v8 [2]. - Tweak a goto / error path in add_memory_create_devices() (Jonathan) - Retain the old behavior for dax devices, only default to memmap_on_memory for CXL (Jonathan) - Link to v3: https://lore.kernel.org/r/20230801-vv-kmem_memmap-v3-0-406e9aaf5689@intel.com [2]: https://lore.kernel.org/linux-mm/20230808091501.287660-1-aneesh.kumar@linux.ibm.com Changes in v3: - Rebase on Aneesh's patches [1] - Drop Patch 1 - it is not needed since [1] allows for dynamic setting of the memmap_on_memory param (David) - Link to v2: https://lore.kernel.org/r/20230720-vv-kmem_memmap-v2-0-88bdaab34993@intel.com [1]: https://lore.kernel.org/r/20230801044116.10674-1-aneesh.kumar@linux.ibm.com Changes in v2: - Drop the patch to create an override path for the memmap_on_memory module param (David) - Move the chunking into memory_hotplug.c so that any caller of add_memory() can request this behavior. (David) - Handle remove_memory() too. (David, Ying) - Add a sysfs control in the kmem driver for memmap_on_memory semantics (David, Jonathan) - Add a #else case to define mhp_supports_memmap_on_memory() if CONFIG_MEMORY_HOTPLUG is unset. (0day report) - Link to v1: https://lore.kernel.org/r/20230613-vv-kmem_memmap-v1-0-f6de9c6af2c6@intel.com --- Vishal Verma (3): mm/memory_hotplug: replace an open-coded kmemdup() in add_memory_resource() mm/memory_hotplug: split memmap_on_memory requests across memblocks dax/kmem: allow kmem to add memory with memmap_on_memory drivers/dax/bus.h | 1 + drivers/dax/dax-private.h | 1 + drivers/dax/bus.c | 3 + drivers/dax/cxl.c | 1 + drivers/dax/hmem/hmem.c | 1 + drivers/dax/kmem.c | 8 +- drivers/dax/pmem.c | 1 + mm/memory_hotplug.c | 208 ++++++++++++++++++++++++++++++---------------- 8 files changed, 150 insertions(+), 74 deletions(-) --- base-commit: 25b5b1a0646c3d39e1d885e27c10be1c9e202bf2 change-id: 20230613-vv-kmem_memmap-5483c8d04279 Best regards,