From mboxrd@z Thu Jan 1 00:00:00 1970 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=-16.7 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=unavailable 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 C8CE8C2BB40 for ; Thu, 17 Dec 2020 13:09:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8D17D2396F for ; Thu, 17 Dec 2020 13:09:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728620AbgLQNJb (ORCPT ); Thu, 17 Dec 2020 08:09:31 -0500 Received: from mx2.suse.de ([195.135.220.15]:47602 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727786AbgLQNJb (ORCPT ); Thu, 17 Dec 2020 08:09:31 -0500 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 74ABEAE65; Thu, 17 Dec 2020 13:08:10 +0000 (UTC) From: Oscar Salvador To: akpm@linux-foundation.org Cc: david@redhat.com, mhocko@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, vbabka@suse.cz, pasha.tatashin@soleen.com, Oscar Salvador Subject: [PATCH 5/5] mm,memory_hotplug: Add kernel boot option to enable memmap_on_memory Date: Thu, 17 Dec 2020 14:07:58 +0100 Message-Id: <20201217130758.11565-6-osalvador@suse.de> X-Mailer: git-send-email 2.13.7 In-Reply-To: <20201217130758.11565-1-osalvador@suse.de> References: <20201217130758.11565-1-osalvador@suse.de> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- .../admin-guide/kernel-parameters.txt | 14 ++++++++++++ mm/Makefile | 5 ++++- mm/memory_hotplug.c | 22 ++++++++++++++++++- 3 files changed, 39 insertions(+), 2 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index c722ec19cd00..8ff3d7c87165 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2776,6 +2776,20 @@ seconds. Use this parameter to check at some other rate. 0 disables periodic checking. + memory_hotplug.memmap_on_memory + [KNL,X86,ARM,PPC] 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 6b581f8337e8..0425cec6cb17 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 9371e7d3f583..f5f95f49b98a 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -42,7 +42,27 @@ #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) +{ + if (!IS_ENABLED(CONFIG_ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE)) + return -EINVAL; + + 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. -- 2.26.2