From patchwork Thu Jun 15 22:00:23 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: 13281787 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 D2A9AEB64DC for ; Thu, 15 Jun 2023 22:01:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233922AbjFOWBK (ORCPT ); Thu, 15 Jun 2023 18:01:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45394 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232139AbjFOWBG (ORCPT ); Thu, 15 Jun 2023 18:01:06 -0400 Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DB5F9296C; Thu, 15 Jun 2023 15:01:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1686866464; x=1718402464; h=from:date:subject:mime-version:content-transfer-encoding: message-id:references:in-reply-to:to:cc; bh=y9Fdd4CaXjYhM8c/kYRc/ffM8uFuEd3rHTJq5W9ozIE=; b=jJRSesBqLUd0urCv9o194jwNNzu4qMqaGTDmQ4n4qnPNrnMSmuTAR86q BP2sh/aOYCumaxuy+oVXIvRhS0YcejEucDVx7xePs5XnvWQtof6HULkgG jfjVfhj2LzMqtcwWNkdQBD0tEgEdXTLbvZlFuFBmnQ4pEW8CvkDeRnAaq zkxQKhTPjVHlsvDkYeqCynTH3a7/T1ZB3Lv6DOlbs1ZeDlUUlFx/glKyK 6JIM9b26z5NEfqYAfXvxTq2QLvjiI+5GuPS4spQrr0moNG6I/i+IRd+87 vlm6BPXIqfQnGuIZuyYl4EDc/OIixOwP7F4lcTf9xz1p3xbvNLzpwzrnh Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10742"; a="343791130" X-IronPort-AV: E=Sophos;i="6.00,245,1681196400"; d="scan'208";a="343791130" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jun 2023 15:01:03 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10742"; a="715770091" X-IronPort-AV: E=Sophos;i="6.00,245,1681196400"; d="scan'208";a="715770091" Received: from smaurice-mobl.amr.corp.intel.com (HELO [192.168.1.200]) ([10.212.120.175]) by fmsmga007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jun 2023 15:01:00 -0700 From: Vishal Verma Date: Thu, 15 Jun 2023 16:00:23 -0600 Subject: [PATCH 1/3] mm/memory_hotplug: Allow an override for the memmap_on_memory param MIME-Version: 1.0 Message-Id: <20230613-vv-kmem_memmap-v1-1-f6de9c6af2c6@intel.com> References: <20230613-vv-kmem_memmap-v1-0-f6de9c6af2c6@intel.com> In-Reply-To: <20230613-vv-kmem_memmap-v1-0-f6de9c6af2c6@intel.com> To: "Rafael J. Wysocki" , Len Brown , Andrew Morton , David Hildenbrand , Oscar Salvador , Dan Williams , Dave Jiang Cc: linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, nvdimm@lists.linux.dev, linux-cxl@vger.kernel.org, Huang Ying , Dave Hansen , Vishal Verma X-Mailer: b4 0.13-dev-02a79 X-Developer-Signature: v=1; a=openpgp-sha256; l=5348; i=vishal.l.verma@intel.com; h=from:subject:message-id; bh=y9Fdd4CaXjYhM8c/kYRc/ffM8uFuEd3rHTJq5W9ozIE=; b=owGbwMvMwCXGf25diOft7jLG02pJDCndXdJbnAJ++yhZVS3cvOTdxff5fUeOOrvs/W7jtJclP WTj/uU/OkpZGMS4GGTFFFn+7vnIeExuez5PYIIjzBxWJpAhDFycAjARjZWMDOcv2YmZnLWzVvS7 ZmDA/pxvkXo8w7k/p3WUixhuPrsgsYuR4cuznZa5advZfkrwz5A/cUmgei/3H+NlJ99c6hPf5ON 4lxcA 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 For memory hotplug to consider MHP_MEMMAP_ON_MEMORY behavior, the 'memmap_on_memory' module parameter was a hard requirement. In preparation for the dax/kmem driver to use memmap_on_memory semantics, arrange for the module parameter check to be bypassed via the appropriate mhp_flag. Recall that the kmem driver could contribute huge amounts of hotplugged memory originating from special purposes devices such as CXL memory expanders. In some cases memmap_on_memory may be the /only/ way this new memory can be hotplugged. Hence it makes sense for kmem to have a way to force memmap_on_memory without depending on a module param, if all the other conditions for it are met. The only other user of this interface is acpi/acpi_memoryhotplug.c, which only enables the mhp_flag if an initial mhp_supports_memmap_on_memory() test passes. Maintain the existing behavior and semantics for this by performing the initial check from acpi without the MHP_MEMMAP_ON_MEMORY flag, so its decision falls back to the module parameter. Cc: "Rafael J. Wysocki" Cc: Len Brown Cc: Andrew Morton Cc: David Hildenbrand Cc: Oscar Salvador Cc: Dan Williams Cc: Dave Jiang Cc: Dave Hansen Cc: Huang Ying Signed-off-by: Vishal Verma --- include/linux/memory_hotplug.h | 2 +- drivers/acpi/acpi_memhotplug.c | 2 +- mm/memory_hotplug.c | 24 ++++++++++++++++-------- 3 files changed, 18 insertions(+), 10 deletions(-) diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h index 9fcbf5706595..c9ddcd3cad70 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h @@ -358,7 +358,7 @@ extern struct zone *zone_for_pfn_range(int online_type, int nid, extern int arch_create_linear_mapping(int nid, u64 start, u64 size, struct mhp_params *params); void arch_remove_linear_mapping(u64 start, u64 size); -extern bool mhp_supports_memmap_on_memory(unsigned long size); +extern bool mhp_supports_memmap_on_memory(unsigned long size, mhp_t mhp_flags); #endif /* CONFIG_MEMORY_HOTPLUG */ #endif /* __LINUX_MEMORY_HOTPLUG_H */ diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c index 24f662d8bd39..119d3bb49753 100644 --- a/drivers/acpi/acpi_memhotplug.c +++ b/drivers/acpi/acpi_memhotplug.c @@ -211,7 +211,7 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device) if (!info->length) continue; - if (mhp_supports_memmap_on_memory(info->length)) + if (mhp_supports_memmap_on_memory(info->length, 0)) mhp_flags |= MHP_MEMMAP_ON_MEMORY; result = __add_memory(mgid, info->start_addr, info->length, mhp_flags); diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 8e0fa209d533..bb3845830922 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1283,15 +1283,21 @@ static int online_memory_block(struct memory_block *mem, void *arg) return device_online(&mem->dev); } -bool mhp_supports_memmap_on_memory(unsigned long size) +bool mhp_supports_memmap_on_memory(unsigned long size, mhp_t mhp_flags) { unsigned long nr_vmemmap_pages = size / PAGE_SIZE; unsigned long vmemmap_size = nr_vmemmap_pages * sizeof(struct page); unsigned long remaining_size = size - vmemmap_size; /* - * Besides having arch support and the feature enabled at runtime, we - * need a few more assumptions to hold true: + * The MHP_MEMMAP_ON_MEMORY flag indicates a caller that wants to force + * memmap_on_memory (if other conditions are met), regardless of the + * module parameter. drivers/dax/kmem.c is an example, where large + * amounts of hotplug memory may come from, and the only option to + * successfully online all of it is to place the memmap on this memory. + * + * Besides having arch support and the feature enabled at runtime or + * via the mhp_flag, we need a few more assumptions to hold true: * * a) We span a single memory block: memory onlining/offlinin;g happens * in memory block granularity. We don't want the vmemmap of online @@ -1315,10 +1321,12 @@ bool mhp_supports_memmap_on_memory(unsigned long size) * altmap as an alternative source of memory, and we do not exactly * populate a single PMD. */ - return mhp_memmap_on_memory() && - size == memory_block_size_bytes() && - IS_ALIGNED(vmemmap_size, PMD_SIZE) && - IS_ALIGNED(remaining_size, (pageblock_nr_pages << PAGE_SHIFT)); + + if ((mhp_flags & MHP_MEMMAP_ON_MEMORY) || mhp_memmap_on_memory()) + return size == memory_block_size_bytes() && + IS_ALIGNED(vmemmap_size, PMD_SIZE) && + IS_ALIGNED(remaining_size, (pageblock_nr_pages << PAGE_SHIFT)); + return false; } /* @@ -1375,7 +1383,7 @@ int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags) * Self hosted memmap array */ if (mhp_flags & MHP_MEMMAP_ON_MEMORY) { - if (!mhp_supports_memmap_on_memory(size)) { + if (!mhp_supports_memmap_on_memory(size, mhp_flags)) { ret = -EINVAL; goto error; }