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 99702C10F00 for ; Sat, 7 Mar 2020 08:43:05 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5EDFD20675 for ; Sat, 7 Mar 2020 08:43:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="TzRp27hy" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5EDFD20675 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 0FA296B000C; Sat, 7 Mar 2020 03:43:05 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 0AC426B000D; Sat, 7 Mar 2020 03:43:05 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EB54F6B000E; Sat, 7 Mar 2020 03:43:04 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0166.hostedemail.com [216.40.44.166]) by kanga.kvack.org (Postfix) with ESMTP id D16FE6B000C for ; Sat, 7 Mar 2020 03:43:04 -0500 (EST) Received: from smtpin09.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 6E81B180AD801 for ; Sat, 7 Mar 2020 08:43:04 +0000 (UTC) X-FDA: 76567926288.09.glue73_55010319ca123 X-HE-Tag: glue73_55010319ca123 X-Filterd-Recvd-Size: 4732 Received: from us-smtp-delivery-1.mimecast.com (us-smtp-1.mimecast.com [205.139.110.61]) by imf22.hostedemail.com (Postfix) with ESMTP for ; Sat, 7 Mar 2020 08:43:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1583570583; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:in-reply-to:in-reply-to:references:references; bh=R8AU1A5SL98Kjgv1MM+nmqEgpfgnpubxGqxGINQWrSE=; b=TzRp27hyFSpdNAnti96V1UKdoIV86/6yMsCy0bk1JmfmwZvlyiVFD2x+OgZ+KXh8VTk4xX 47tZVFswaFA6kvXmYKAD2HzzdyU3Eu/7of4EIQEeKp30Do0wPL3gogeftjEc1vpgTSEXwQ ND5UZ97HAjnW1lambYsZGUCfJ0ISfUQ= 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-288-NjesuyceNHCruIQHMSAv3A-1; Sat, 07 Mar 2020 03:43:00 -0500 X-MC-Unique: NjesuyceNHCruIQHMSAv3A-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7B571107ACC7; Sat, 7 Mar 2020 08:42:58 +0000 (UTC) Received: from MiWiFi-R3L-srv.redhat.com (ovpn-12-29.pek2.redhat.com [10.72.12.29]) by smtp.corp.redhat.com (Postfix) with ESMTP id 51AD75D9CA; Sat, 7 Mar 2020 08:42:55 +0000 (UTC) From: Baoquan He To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, akpm@linux-foundation.org, mhocko@suse.com, david@redhat.com, richardw.yang@linux.intel.com, dan.j.williams@intel.com, osalvador@suse.de, rppt@linux.ibm.com, bhe@redhat.com Subject: [PATCH v3 5/7] mm/sparse.c: add note about only VMEMMAP supporting sub-section support Date: Sat, 7 Mar 2020 16:42:27 +0800 Message-Id: <20200307084229.28251-6-bhe@redhat.com> In-Reply-To: <20200307084229.28251-1-bhe@redhat.com> References: <20200307084229.28251-1-bhe@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 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: And tell check_pfn_span() gating the porper alignment and size of hot added memory region. And also move the code comments from inside section_deactivate() to being above it. The code comments are reasonable for the whole function, and the moving makes code cleaner. Signed-off-by: Baoquan He --- mm/sparse.c | 37 ++++++++++++++++++++----------------- 1 file changed, 20 insertions(+), 17 deletions(-) diff --git a/mm/sparse.c b/mm/sparse.c index 2142045ab5c5..0fbd79c4ad81 100644 --- a/mm/sparse.c +++ b/mm/sparse.c @@ -772,6 +772,22 @@ static bool is_subsection_map_empty(struct mem_section *ms) } #endif +/* + * To deactivate a memory region, there are 3 cases to handle across + * two configurations (SPARSEMEM_VMEMMAP={y,n}): + * + * 1. deactivation of a partial hot-added section (only possible in + * the SPARSEMEM_VMEMMAP=y case). + * a) section was present at memory init. + * b) section was hot-added post memory init. + * 2. deactivation of a complete hot-added section. + * 3. deactivation of a complete section from memory init. + * + * For 1, when subsection_map does not empty we will not be freeing the + * usage map, but still need to free the vmemmap range. + * + * For 2 and 3, the SPARSEMEM_VMEMMAP={y,n} cases are unified + */ static void section_deactivate(unsigned long pfn, unsigned long nr_pages, struct vmem_altmap *altmap) { @@ -784,23 +800,6 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages, return; empty = is_subsection_map_empty(ms); - /* - * There are 3 cases to handle across two configurations - * (SPARSEMEM_VMEMMAP={y,n}): - * - * 1/ deactivation of a partial hot-added section (only possible - * in the SPARSEMEM_VMEMMAP=y case). - * a/ section was present at memory init - * b/ section was hot-added post memory init - * 2/ deactivation of a complete hot-added section - * 3/ deactivation of a complete section from memory init - * - * For 1/, when subsection_map does not empty we will not be - * freeing the usage map, but still need to free the vmemmap - * range. - * - * For 2/ and 3/ the SPARSEMEM_VMEMMAP={y,n} cases are unified - */ if (empty) { unsigned long section_nr = pfn_to_section_nr(pfn); @@ -907,6 +906,10 @@ static struct page * __meminit section_activate(int nid, unsigned long pfn, * * This is only intended for hotplug. * + * Note that only VMEMMAP supports sub-section aligned hotplug, + * the proper alignment and size are gated by check_pfn_span(). + * + * * Return: * * 0 - On success. * * -EEXIST - Section has been present. -- 2.17.2