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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 3B40DC2D0CA for ; Thu, 12 Dec 2019 17:13:07 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E5FEE22527 for ; Thu, 12 Dec 2019 17:13:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="N7xxQiFm" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E5FEE22527 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 8E6418E000D; Thu, 12 Dec 2019 12:13:06 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 896308E000C; Thu, 12 Dec 2019 12:13:06 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 75E688E000D; Thu, 12 Dec 2019 12:13:06 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0020.hostedemail.com [216.40.44.20]) by kanga.kvack.org (Postfix) with ESMTP id 607598E000C for ; Thu, 12 Dec 2019 12:13:06 -0500 (EST) Received: from smtpin18.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id 0B35D4FFA for ; Thu, 12 Dec 2019 17:13:06 +0000 (UTC) X-FDA: 76257134772.18.work30_72541a35fa249 X-HE-Tag: work30_72541a35fa249 X-Filterd-Recvd-Size: 5737 Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [207.211.31.120]) by imf07.hostedemail.com (Postfix) with ESMTP for ; Thu, 12 Dec 2019 17:13:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1576170785; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=FRA+T3LczXKLz/t1x5ONbwAW2HplNDXABfw4iwLSung=; b=N7xxQiFmRiCWDLKfj5+IFuxgT4h/JlaJqlqVmTC0h+Mos6+EvgmG6fyO0GSfEAOF+8Mrvc pmmZ1WhnmcYv2ad/ZSPMSVvAIVk1ibJjvSVTq1cdB9sVP2Q/6jpl1YiS40GmCZIvIwvVyT 6HqCb/66B7k93frMabnlUgs94z4QsmY= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-257-v1whvpOoM_OtlY-bBijBcA-1; Thu, 12 Dec 2019 12:13:01 -0500 X-MC-Unique: v1whvpOoM_OtlY-bBijBcA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 52813800D5A; Thu, 12 Dec 2019 17:12:59 +0000 (UTC) Received: from t480s.redhat.com (ovpn-117-65.ams2.redhat.com [10.36.117.65]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7388F5C21B; Thu, 12 Dec 2019 17:12:56 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, virtio-dev@lists.oasis-open.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, Michal Hocko , Andrew Morton , "Michael S . Tsirkin" , David Hildenbrand , Oscar Salvador , Michal Hocko , Pavel Tatashin , Wei Yang , Dan Williams , Qian Cai Subject: [PATCH RFC v4 08/13] mm/memory_hotplug: Introduce offline_and_remove_memory() Date: Thu, 12 Dec 2019 18:11:32 +0100 Message-Id: <20191212171137.13872-9-david@redhat.com> In-Reply-To: <20191212171137.13872-1-david@redhat.com> References: <20191212171137.13872-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Content-Transfer-Encoding: quoted-printable 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: virtio-mem wants to offline and remove a memory block once it unplugged all subblocks (e.g., using alloc_contig_range()). Let's provide an interface to do that from a driver. virtio-mem already supports to offline partially unplugged memory blocks. Offlining a fully unplugged memory block will not require to migrate any pages. All unplugged subblocks are PageOffline() and have a reference count of 0 - so offlining code will simply skip them. All we need an interface to trigger the "offlining" and the removing in a single operation - to make sure the memory block cannot get onlined by user space again before it gets removed. To keep things simple, allow to only work on a single memory block. Cc: Andrew Morton Cc: David Hildenbrand Cc: Oscar Salvador Cc: Michal Hocko Cc: Pavel Tatashin Cc: Wei Yang Cc: Dan Williams Cc: Qian Cai Signed-off-by: David Hildenbrand --- include/linux/memory_hotplug.h | 1 + mm/memory_hotplug.c | 35 ++++++++++++++++++++++++++++++++++ 2 files changed, 36 insertions(+) diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplu= g.h index ba0dca6aac6e..586f5c59c291 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h @@ -310,6 +310,7 @@ extern void try_offline_node(int nid); extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages= ); extern int remove_memory(int nid, u64 start, u64 size); extern void __remove_memory(int nid, u64 start, u64 size); +extern int offline_and_remove_memory(int nid, u64 start, u64 size); =20 #else static inline bool is_mem_section_removable(unsigned long pfn, diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index da01453a04e6..d04369e6d3cc 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1825,4 +1825,39 @@ int remove_memory(int nid, u64 start, u64 size) return rc; } EXPORT_SYMBOL_GPL(remove_memory); + +/* + * Try to offline and remove a memory block. Might take a long time to + * finish in case memory is still in use. Primarily useful for memory de= vices + * that logically unplugged all memory (so it's no longer in use) and wa= nt to + * offline + remove the memory block. + */ +int offline_and_remove_memory(int nid, u64 start, u64 size) +{ + struct memory_block *mem; + int rc =3D -EINVAL; + + if (!IS_ALIGNED(start, memory_block_size_bytes()) || + size !=3D memory_block_size_bytes()) + return rc; + + lock_device_hotplug(); + mem =3D find_memory_block(__pfn_to_section(PFN_DOWN(start))); + if (mem) + rc =3D device_offline(&mem->dev); + /* Ignore if the device is already offline. */ + if (rc > 0) + rc =3D 0; + + /* + * In case we succeeded to offline the memory block, remove it. + * This cannot fail as it cannot get onlined in the meantime. + */ + if (!rc && try_remove_memory(nid, start, size)) + BUG(); + unlock_device_hotplug(); + + return rc; +} +EXPORT_SYMBOL_GPL(offline_and_remove_memory); #endif /* CONFIG_MEMORY_HOTREMOVE */ --=20 2.23.0