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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 D508CC43600 for ; Wed, 5 May 2021 01:39:51 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8727E61029 for ; Wed, 5 May 2021 01:39:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8727E61029 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 255A36B00F1; Tue, 4 May 2021 21:39:51 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 22C386B00F3; Tue, 4 May 2021 21:39:51 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0A6B26B00F4; Tue, 4 May 2021 21:39:51 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0215.hostedemail.com [216.40.44.215]) by kanga.kvack.org (Postfix) with ESMTP id E34636B00F1 for ; Tue, 4 May 2021 21:39:50 -0400 (EDT) Received: from smtpin05.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id AA2FD688E for ; Wed, 5 May 2021 01:39:50 +0000 (UTC) X-FDA: 78105470940.05.4F42941 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf15.hostedemail.com (Postfix) with ESMTP id A08DBA0002C8 for ; Wed, 5 May 2021 01:39:44 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 4AD16610A1; Wed, 5 May 2021 01:39:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1620178789; bh=Rafeu5LnTZS3KhNBFFXQaMSWAjdm7+qZ97t+zWEKyD0=; h=Date:From:To:Subject:In-Reply-To:From; b=GlR1JofhSxfaH+Mim+HdJIiWEeE92NjNanmEyBxx3ZaYvYCyL9QBcW+VozI6xORGF ElYKdYtkLpNVJukFbFhrl8LPdwcz84IVis/hHMEnJQb5NswgOq+ncVDD8D4AYHGpM/ +iciJnrXWQXzxhta6M8QGuFrWMq10mtu2M60SdKQ= Date: Tue, 04 May 2021 18:39:48 -0700 From: Andrew Morton To: akpm@linux-foundation.org, anshuman.khandual@arm.com, david@redhat.com, linux-mm@kvack.org, mhocko@suse.com, mm-commits@vger.kernel.org, osalvador@suse.de, pasha.tatashin@soleen.com, torvalds@linux-foundation.org, vbabka@suse.cz Subject: [patch 130/143] mm,memory_hotplug: add kernel boot option to enable memmap_on_memory Message-ID: <20210505013948.ScZdDBHBc%akpm@linux-foundation.org> In-Reply-To: <20210504183219.a3cc46aee4013d77402276c5@linux-foundation.org> User-Agent: s-nail v14.8.16 Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=GlR1Jofh; dmarc=none; spf=pass (imf15.hostedemail.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org X-Rspamd-Server: rspam03 X-Stat-Signature: ytu8zm7bj33i9ob86s6r1k89z9f4x6w3 X-Rspamd-Queue-Id: A08DBA0002C8 Received-SPF: none (linux-foundation.org>: No applicable sender policy available) receiver=imf15; identity=mailfrom; envelope-from=""; helo=mail.kernel.org; client-ip=198.145.29.99 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1620178784-855327 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: From: Oscar Salvador Subject: mm,memory_hotplug: add kernel boot option to enable memmap_on_memory 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. Link: https://lkml.kernel.org/r/20210421102701.25051-7-osalvador@suse.de Signed-off-by: Oscar Salvador Reviewed-by: David Hildenbrand Acked-by: Michal Hocko Cc: Anshuman Khandual Cc: Pavel Tatashin Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- Documentation/admin-guide/kernel-parameters.txt | 17 ++++++++++++++ mm/Makefile | 5 +++- mm/memory_hotplug.c | 10 +++++++- 3 files changed, 30 insertions(+), 2 deletions(-) --- a/Documentation/admin-guide/kernel-parameters.txt~mmmemory_hotplug-add-kernel-boot-option-to-enable-memmap_on_memory +++ a/Documentation/admin-guide/kernel-parameters.txt @@ -2801,6 +2801,23 @@ 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, runtime hotplugged memory will + allocate its internal metadata (struct pages) + from the hotadded memory which will allow to + hotadd a lot of memory without requiring + additional memory to do so. + This feature is disabled by default because it + has some implication on large (e.g. GB) + allocations in some configurations (e.g. small + memory blocks). + The state of the flag can be read in + /sys/module/memory_hotplug/parameters/memmap_on_memory. + Note that even when enabled, there are a few cases where + the feature is not effective. + memtest= [KNL,X86,ARM,PPC] Enable memtest Format: default : 0 --- a/mm/Makefile~mmmemory_hotplug-add-kernel-boot-option-to-enable-memmap_on_memory +++ a/mm/Makefile @@ -58,9 +58,13 @@ obj-y := filemap.o mempool.o oom_kill. 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 --- a/mm/memory_hotplug.c~mmmemory_hotplug-add-kernel-boot-option-to-enable-memmap_on_memory +++ a/mm/memory_hotplug.c @@ -42,7 +42,15 @@ #include "internal.h" #include "shuffle.h" -static bool memmap_on_memory; + +/* + * memory_hotplug.memmap_on_memory parameter + */ +static bool memmap_on_memory __ro_after_init; +#ifdef CONFIG_MHP_MEMMAP_ON_MEMORY +module_param(memmap_on_memory, bool, 0444); +MODULE_PARM_DESC(memmap_on_memory, "Enable memmap on memory for memory hotplug"); +#endif /* * online_page_callback contains pointer to current page onlining function. _