From patchwork Thu Sep 28 20:30:09 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: 13403518 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 99E31E743C0 for ; Thu, 28 Sep 2023 20:30:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231921AbjI1Uaw (ORCPT ); Thu, 28 Sep 2023 16:30:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48338 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230251AbjI1Uav (ORCPT ); Thu, 28 Sep 2023 16:30:51 -0400 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.126]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B77DC193; Thu, 28 Sep 2023 13:30:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1695933049; x=1727469049; h=from:subject:date:message-id:mime-version: content-transfer-encoding:to:cc; bh=cAy0mCyyU34BrYjzihAk6QBEdSFRsmrEsY5ivGjaggs=; b=QMUsHl739ekDWK7c9cHUlvPYZ75/TBKEaB6hmJnsyObFqlf2PEqT41hb gWTTEblkJsDrncd0jvNLu+7GT54Y4RglIt9VL3Me892dN/8nDtYpc8Lq2 OPnHAGRnF2o3fDmDecJuM3QFWXx+yOvdBj6BuBGm3Ps3co4iE/y4KWhse ppXp0eCSZ3qHi+2CPFeJm1uSJeUST5lqwmpD3ZQBKHv7PCcB6mtdPLU4L 2kmMLp6/a/zpGjbQEib8ArmspDctljrbvr46JbjikB1tspdUmbb4deFyt uRAlL5svvTivMIzX/YN1vX7ZTUJ8JtFRYkN2q5UgeFRI/ytM5rFEtwEuf g==; X-IronPort-AV: E=McAfee;i="6600,9927,10847"; a="367229664" X-IronPort-AV: E=Sophos;i="6.03,185,1694761200"; d="scan'208";a="367229664" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Sep 2023 13:30:31 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10847"; a="815374351" X-IronPort-AV: E=Sophos;i="6.03,185,1694761200"; d="scan'208";a="815374351" Received: from bdsebast-mobl1.amr.corp.intel.com (HELO [192.168.1.200]) ([10.212.125.211]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Sep 2023 13:30:30 -0700 From: Vishal Verma Subject: [PATCH v4 0/2] mm: use memmap_on_memory semantics for dax/kmem Date: Thu, 28 Sep 2023 14:30:09 -0600 Message-Id: <20230928-vv-kmem_memmap-v4-0-6ff73fec519a@intel.com> MIME-Version: 1.0 X-B4-Tracking: v=1; b=H4sIAFHiFWUC/3XNQQ7CIBAF0KsY1mIoIIIr72GMmdKpJbbUgBKN6 d0d3Wg0Lmbxf/L+3FnGFDCz9ezOEpaQwxgp6PmM+Q7iAXloKDMppBKmUrwUfhxw2NMNcOJLbZW 3jdBy5RihGjLyOkH0HbF46XsqTwnbcH192e4odyGfx3R7PS3Vs/27XyoueGsadN5AK73ZhHjGf uHHgT2ninzzlRQ/XBK3tm4AaqWdU99cvbkV1Q9XxLUw6ADapbHuk0/T9ACKqImFPwEAAA== 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 0.12.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=3152; i=vishal.l.verma@intel.com; h=from:subject:message-id; bh=cAy0mCyyU34BrYjzihAk6QBEdSFRsmrEsY5ivGjaggs=; b=owGbwMvMwCXGf25diOft7jLG02pJDKmij4Itwm6bPF8XxpAX828Kx6+++ga1a8WXpk/iy1n0q 9o+Vd+po5SFQYyLQVZMkeXvno+Mx+S25/MEJjjCzGFlAhnCwMUpABOpamFk2HH85zqnqsfuZSuE s9LX79q9c3Vz0pKJW9756Ng/MWt568LI8C+Uf5KPdvLpIs+jV226St8k1mfPY7Ker2L8XCI48fN xDgA= X-Developer-Key: i=vishal.l.verma@intel.com; a=openpgp; fpr=F8682BE134C67A12332A2ED07AFA61BEA3B84DFF Precedence: bulk List-ID: X-Mailing-List: linux-cxl@vger.kernel.org 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 teaches the memory_hotplug code to allow for splitting add_memory() and remove_memory() requests over memblock sized chunks. Patch 2 adds a sysfs control for the kmem driver that would allow an opt-out of using memmap_on_memory for the memory being added. Signed-off-by: Vishal Verma --- 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 (2): 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 | 38 +++++++++++ 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 | 165 ++++++++++++++++++++++++++++------------------ 8 files changed, 150 insertions(+), 66 deletions(-) --- base-commit: 25b5b1a0646c3d39e1d885e27c10be1c9e202bf2 change-id: 20230613-vv-kmem_memmap-5483c8d04279 Best regards,