From patchwork Tue Feb 9 13:38:50 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oscar Salvador X-Patchwork-Id: 12078179 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0D55BC433DB for ; Tue, 9 Feb 2021 13:39:08 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8A0AB64ED5 for ; Tue, 9 Feb 2021 13:39:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8A0AB64ED5 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id B35B56B0070; Tue, 9 Feb 2021 08:39:03 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id AEC6B6B0071; Tue, 9 Feb 2021 08:39:03 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 966E76B0072; Tue, 9 Feb 2021 08:39:03 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0038.hostedemail.com [216.40.44.38]) by kanga.kvack.org (Postfix) with ESMTP id 7A89B6B0070 for ; Tue, 9 Feb 2021 08:39:03 -0500 (EST) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 4381AA8C8 for ; Tue, 9 Feb 2021 13:39:03 +0000 (UTC) X-FDA: 77798835366.28.pigs85_170ae4b27607 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin28.hostedemail.com (Postfix) with ESMTP id 2271DAF85 for ; Tue, 9 Feb 2021 13:39:03 +0000 (UTC) X-HE-Tag: pigs85_170ae4b27607 X-Filterd-Recvd-Size: 4976 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf34.hostedemail.com (Postfix) with ESMTP for ; Tue, 9 Feb 2021 13:39:02 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 99922AFF5; Tue, 9 Feb 2021 13:39:01 +0000 (UTC) From: Oscar Salvador To: Andrew Morton Cc: David Hildenbrand , Michal Hocko , VlastimilBabkavbabka@suse.cz, pasha.tatashin@soleen.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Anshuman Khandual , Oscar Salvador Subject: [PATCH v2 3/7] mm,memory_hotplug: Add kernel boot option to enable memmap_on_memory Date: Tue, 9 Feb 2021 14:38:50 +0100 Message-Id: <20210209133854.17399-4-osalvador@suse.de> X-Mailer: git-send-email 2.13.7 In-Reply-To: <20210209133854.17399-1-osalvador@suse.de> References: <20210209133854.17399-1-osalvador@suse.de> 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: Self stored memmap leads to a sparse memory situation which is unsuitable for workloads that requires large contiguous memory chunks, so make this an opt-in which needs to be explicitly enabled. To control this, let memory_hotplug have its own memory space, as suggested by David, so we can add memory_hotplug.memmap_on_memory parameter. Signed-off-by: Oscar Salvador --- Documentation/admin-guide/kernel-parameters.txt | 14 +++++++++++++ mm/Makefile | 5 ++++- mm/memory_hotplug.c | 26 ++++++++++++++++++++++++- 3 files changed, 43 insertions(+), 2 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 5adf1e57e932..696beb5f6c92 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2811,6 +2811,20 @@ seconds. Use this parameter to check at some other rate. 0 disables periodic checking. + memory_hotplug.memmap_on_memory + [KNL,X86,ARM] Boolean flag to enable this feature. + Format: {on | off (default)} + When enabled, memory to build the pages tables for the + memmap array describing the hot-added range will be taken + from the range itself, so the memmap page tables will be + self-hosted. + Since only single memory device ranges are supported at + the moment, this option is disabled by default because + it might have an impact on workloads that needs large + contiguous memory chunks. + The state of the flag can be read in + /sys/module/memory_hotplug/parameters/memmap_on_memory. + memtest= [KNL,X86,ARM,PPC] Enable memtest Format: default : 0 diff --git a/mm/Makefile b/mm/Makefile index b2a564eec27f..9e284dba50ef 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -58,9 +58,13 @@ obj-y := filemap.o mempool.o oom_kill.o fadvise.o \ page-alloc-y := page_alloc.o page-alloc-$(CONFIG_SHUFFLE_PAGE_ALLOCATOR) += shuffle.o +# Give 'memory_hotplug' its own module-parameter namespace +memory-hotplug-$(CONFIG_MEMORY_HOTPLUG) += memory_hotplug.o + obj-y += page-alloc.o obj-y += init-mm.o obj-y += memblock.o +obj-y += $(memory-hotplug-y) ifdef CONFIG_MMU obj-$(CONFIG_ADVISE_SYSCALLS) += madvise.o @@ -83,7 +87,6 @@ obj-$(CONFIG_SLUB) += slub.o obj-$(CONFIG_KASAN) += kasan/ obj-$(CONFIG_KFENCE) += kfence/ obj-$(CONFIG_FAILSLAB) += failslab.o -obj-$(CONFIG_MEMORY_HOTPLUG) += memory_hotplug.o obj-$(CONFIG_MEMTEST) += memtest.o obj-$(CONFIG_MIGRATION) += migrate.o obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += huge_memory.o khugepaged.o diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 9bcc460e8bfe..95695483a622 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -42,7 +42,31 @@ #include "internal.h" #include "shuffle.h" -static bool memmap_on_memory_enabled; +/* + * memory_hotplug.memmap_on_memory parameter + */ +static bool memmap_on_memory_enabled __ro_after_init; + +static int memmap_on_memory_show(char *buffer, const struct kernel_param *kp) +{ + return sprintf(buffer, "%s\n", + memmap_on_memory_enabled ? "on" : "off"); +} + +static __meminit int memmap_on_memory_store(const char *val, + const struct kernel_param *kp) +{ + /* + * Fail silently in case we cannot enable it due to platform constraints. + * User can always check whether it is enabled or not via /sys/module. + */ + if (!IS_ENABLED(CONFIG_ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE)) + return 0; + + return param_set_bool(val, kp); +} +module_param_call(memmap_on_memory, memmap_on_memory_store, + memmap_on_memory_show, &memmap_on_memory_enabled, 0400); /* * online_page_callback contains pointer to current page onlining function.