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=-5.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 E2D59C35254 for ; Mon, 10 Feb 2020 03:36:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B48AE206ED for ; Mon, 10 Feb 2020 03:36:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="blLQahos" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727434AbgBJDgh (ORCPT ); Sun, 9 Feb 2020 22:36:37 -0500 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:59911 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727254AbgBJDgh (ORCPT ); Sun, 9 Feb 2020 22:36:37 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1581305796; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=lTuxfPbb6227xDCDjuRdfuxy4DLz08JTlzUDeWBWd+U=; b=blLQahosxJu9XgsLSNlj7pheMMD5+n5HATG1ryTCm8NswSmey6Z2oLCulGlBkdubaQ3of2 9glfaD0E7BFgDjVvIgAQ6PCdq9/9r3FgXKoRB2dwk9XtfNqDWZ0kgTnh+ijmBVTgUc9A0g Ck34a4Q4R6WEWO2qVzbMDKclMLVod+8= 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-323-spqzCyNfNzOURPVaw2RKOw-1; Sun, 09 Feb 2020 22:36:34 -0500 X-MC-Unique: spqzCyNfNzOURPVaw2RKOw-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 71600100726D; Mon, 10 Feb 2020 03:36:33 +0000 (UTC) Received: from localhost (ovpn-12-27.pek2.redhat.com [10.72.12.27]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 6FE755C1D4; Mon, 10 Feb 2020 03:36:30 +0000 (UTC) Date: Mon, 10 Feb 2020 11:36:27 +0800 From: Baoquan He To: Wei Yang Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, dan.j.williams@intel.com, david@redhat.com Subject: Re: [PATCH 2/7] mm/sparse.c: Introduce a new function clear_subsection_map() Message-ID: <20200210033627.GZ8965@MiWiFi-R3L-srv> References: <20200209104826.3385-1-bhe@redhat.com> <20200209104826.3385-3-bhe@redhat.com> <20200209230713.GB7326@richard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200209230713.GB7326@richard> User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/10/20 at 07:07am, Wei Yang wrote: > On Sun, Feb 09, 2020 at 06:48:21PM +0800, Baoquan He wrote: > >Wrap the codes clearing subsection map of one memory region in > >section_deactivate() into clear_subsection_map(). > > > > Patch 1 and 2 server the same purpose -- to #ifdef the VMEMMAP. Hmm, I didn't say patch 1 and 2 are preparation works because they had better be done even if we don't take off subsection map from SPARSEMEM|!VMEMMAP case. Wrapping the subsection map filling and clearing codes into separate new functions, can make section_activate() and section_deactivate() much clearer on code logic. If you don't mind, I will keep them for now, and see what other people will say. Thanks Baoquan > > >--- > > mm/sparse.c | 44 +++++++++++++++++++++++++++++++++++++------- > > 1 file changed, 37 insertions(+), 7 deletions(-) > > > >diff --git a/mm/sparse.c b/mm/sparse.c > >index 9ad741ccbeb6..696f6b9f706e 100644 > >--- a/mm/sparse.c > >+++ b/mm/sparse.c > >@@ -726,14 +726,25 @@ static void free_map_bootmem(struct page *memmap) > > } > > #endif /* CONFIG_SPARSEMEM_VMEMMAP */ > > > >-static void section_deactivate(unsigned long pfn, unsigned long nr_pages, > >- struct vmem_altmap *altmap) > >+/** > >+ * clear_subsection_map - Clear subsection map of one memory region > >+ * > >+ * @pfn - start pfn of the memory range > >+ * @nr_pages - number of pfns to add in the region > >+ * > >+ * This is only intended for hotplug, and clear the related subsection > >+ * map inside one section. > >+ * > >+ * Return: > >+ * * -EINVAL - Section already deactived. > >+ * * 0 - Subsection map is emptied. > >+ * * 1 - Subsection map is not empty. > >+ */ > >+static int clear_subsection_map(unsigned long pfn, unsigned long nr_pages) > > { > > DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 }; > > DECLARE_BITMAP(tmp, SUBSECTIONS_PER_SECTION) = { 0 }; > > struct mem_section *ms = __pfn_to_section(pfn); > >- bool section_is_early = early_section(ms); > >- struct page *memmap = NULL; > > unsigned long *subsection_map = ms->usage > > ? &ms->usage->subsection_map[0] : NULL; > > > >@@ -744,8 +755,28 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages, > > if (WARN(!subsection_map || !bitmap_equal(tmp, map, SUBSECTIONS_PER_SECTION), > > "section already deactivated (%#lx + %ld)\n", > > pfn, nr_pages)) > >- return; > >+ return -EINVAL; > >+ > >+ bitmap_xor(subsection_map, map, subsection_map, SUBSECTIONS_PER_SECTION); > > > >+ if (bitmap_empty(subsection_map, SUBSECTIONS_PER_SECTION)) > >+ return 0; > >+ > >+ return 1; > >+} > >+ > >+static void section_deactivate(unsigned long pfn, unsigned long nr_pages, > >+ struct vmem_altmap *altmap) > >+{ > >+ struct mem_section *ms = __pfn_to_section(pfn); > >+ bool section_is_early = early_section(ms); > >+ struct page *memmap = NULL; > >+ int rc; > >+ > >+ > >+ rc = clear_subsection_map(pfn, nr_pages); > >+ if(IS_ERR_VALUE((unsigned long)rc)) > >+ return; > > /* > > * There are 3 cases to handle across two configurations > > * (SPARSEMEM_VMEMMAP={y,n}): > >@@ -763,8 +794,7 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages, > > * > > * For 2/ and 3/ the SPARSEMEM_VMEMMAP={y,n} cases are unified > > */ > >- bitmap_xor(subsection_map, map, subsection_map, SUBSECTIONS_PER_SECTION); > >- if (bitmap_empty(subsection_map, SUBSECTIONS_PER_SECTION)) { > >+ if (!rc) { > > unsigned long section_nr = pfn_to_section_nr(pfn); > > > > /* > >-- > >2.17.2 > > -- > Wei Yang > Help you, Help me >