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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 B3301C433FF for ; Thu, 1 Aug 2019 15:07:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 76A502087E for ; Thu, 1 Aug 2019 15:07:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732345AbfHAPHb (ORCPT ); Thu, 1 Aug 2019 11:07:31 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58469 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731358AbfHAPHa (ORCPT ); Thu, 1 Aug 2019 11:07:30 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 0EFD7793E5; Thu, 1 Aug 2019 15:07:30 +0000 (UTC) Received: from [10.36.116.115] (ovpn-116-115.ams2.redhat.com [10.36.116.115]) by smtp.corp.redhat.com (Postfix) with ESMTP id EA43260852; Thu, 1 Aug 2019 15:07:27 +0000 (UTC) Subject: Re: [PATCH v3 5/5] mm,memory_hotplug: Allow userspace to enable/disable vmemmap To: Oscar Salvador , akpm@linux-foundation.org Cc: dan.j.williams@intel.com, pasha.tatashin@soleen.com, mhocko@suse.com, anshuman.khandual@arm.com, Jonathan.Cameron@huawei.com, vbabka@suse.cz, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20190725160207.19579-1-osalvador@suse.de> <20190725160207.19579-6-osalvador@suse.de> From: David Hildenbrand Openpgp: preference=signencrypt Autocrypt: addr=david@redhat.com; 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Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <20190725160207.19579-6-osalvador@suse.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Thu, 01 Aug 2019 15:07:30 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 25.07.19 18:02, Oscar Salvador wrote: > It seems that we have some users out there that want to expose all > hotpluggable memory to userspace, so this implements a toggling mechanism > for those users who want to disable it. > > By default, vmemmap pages mechanism is enabled. > > Signed-off-by: Oscar Salvador > --- > drivers/base/memory.c | 33 +++++++++++++++++++++++++++++++++ > include/linux/memory_hotplug.h | 3 +++ > mm/memory_hotplug.c | 7 +++++++ > 3 files changed, 43 insertions(+) > > diff --git a/drivers/base/memory.c b/drivers/base/memory.c > index d30d0f6c8ad0..5ec6b80de9dd 100644 > --- a/drivers/base/memory.c > +++ b/drivers/base/memory.c > @@ -578,6 +578,35 @@ static DEVICE_ATTR_WO(soft_offline_page); > static DEVICE_ATTR_WO(hard_offline_page); > #endif > -ENODOCUMENTATION :) > +#ifdef CONFIG_SPARSEMEM_VMEMMAP > +static ssize_t vmemmap_hotplug_show(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + if (vmemmap_enabled) > + return sprintf(buf, "enabled\n"); > + else > + return sprintf(buf, "disabled\n"); > +} > + > +static ssize_t vmemmap_hotplug_store(struct device *dev, > + struct device_attribute *attr, > + const char *buf, size_t count) > +{ > + if (!capable(CAP_SYS_ADMIN)) > + return -EPERM; > + > + if (sysfs_streq(buf, "enable")) > + vmemmap_enabled = true; > + else if (sysfs_streq(buf, "disable")) > + vmemmap_enabled = false; > + else > + return -EINVAL; > + > + return count; > +} > +static DEVICE_ATTR_RW(vmemmap_hotplug); > +#endif > + > /* > * Note that phys_device is optional. It is here to allow for > * differentiation between which *physical* devices each > @@ -794,6 +823,10 @@ static struct attribute *memory_root_attrs[] = { > &dev_attr_hard_offline_page.attr, > #endif > > +#ifdef CONFIG_SPARSEMEM_VMEMMAP > + &dev_attr_vmemmap_hotplug.attr, Don't like the name of that property, sorry. > +#endif > + > &dev_attr_block_size_bytes.attr, > &dev_attr_auto_online_blocks.attr, > NULL > diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h > index e1e8abf22a80..03d227d13301 100644 > --- a/include/linux/memory_hotplug.h > +++ b/include/linux/memory_hotplug.h > @@ -134,6 +134,9 @@ extern int arch_add_memory(int nid, u64 start, u64 size, > struct mhp_restrictions *restrictions); > extern u64 max_mem_size; > > +#ifdef CONFIG_SPARSEMEM_VMEMMAP > +extern bool vmemmap_enabled; > +#endif > extern bool memhp_auto_online; > /* If movable_node boot option specified */ > extern bool movable_node_enabled; > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > index 09d41339cd11..5ffe5375b87c 100644 > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c > @@ -68,6 +68,10 @@ void put_online_mems(void) > > bool movable_node_enabled = false; > > +#ifdef CONFIG_SPARSEMEM_VMEMMAP > +bool vmemmap_enabled __read_mostly = true; > +#endif > + > #ifndef CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE > bool memhp_auto_online; > #else > @@ -1108,6 +1112,9 @@ static unsigned long mhp_check_flags(unsigned long flags) > if (!flags) > return 0; > > + if (!vmemmap_enabled) > + return 0; > + > if (flags != MHP_MEMMAP_ON_MEMORY) { > WARN(1, "Wrong flags value (%lx). Ignoring flags.\n", flags); > return 0; > Hmmm, I wonder if that should that rather be a per-memory device driver thingy? E.g., a toggle for ACPI which will then not pass in MHP_MEMMAP_ON_MEMORY. -- Thanks, David / dhildenb