From patchwork Mon Oct 5 12:15:34 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 11816559 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9A3BC112E for ; Mon, 5 Oct 2020 12:17:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 781B72078D for ; Mon, 5 Oct 2020 12:17:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="YZdfR0lj" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726147AbgJEMQ6 (ORCPT ); Mon, 5 Oct 2020 08:16:58 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:40781 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726695AbgJEMQt (ORCPT ); Mon, 5 Oct 2020 08:16:49 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1601900207; 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=0AsZOi2g9AlkyekUiDSDSjeyhdmKjvuUsI97IJKTuTs=; b=YZdfR0ljpM7fzBrBABmRoUzWrkLAfLXoXdiax/g0ahk33jfi1DMlQhgA9eA9e2o5Ie526H U9Fwljtlf16ESs6e8BiWCKAXeZjpju+2/YwoESI/w75nP1ksgqfKIY5gbDSI2/uLk/39Ff sLOBsn1uH0WkdEGG0UTxhp77lUq4lFI= 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-70-7gZGHkSGNu2LzffQTpddTg-1; Mon, 05 Oct 2020 08:16:45 -0400 X-MC-Unique: 7gZGHkSGNu2LzffQTpddTg-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 887B4801AB1; Mon, 5 Oct 2020 12:16:43 +0000 (UTC) Received: from t480s.redhat.com (ovpn-114-222.ams2.redhat.com [10.36.114.222]) by smtp.corp.redhat.com (Postfix) with ESMTP id A40231A8EC; Mon, 5 Oct 2020 12:16:36 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, linux-hyperv@vger.kernel.org, xen-devel@lists.xenproject.org, linux-acpi@vger.kernel.org, Andrew Morton , Matthew Wilcox , David Hildenbrand , Wei Yang , Michal Hocko , Alexander Duyck , Mel Gorman , Michal Hocko , Dave Hansen , Vlastimil Babka , Oscar Salvador , Mike Rapoport , Pankaj Gupta Subject: [PATCH v2 5/5] mm/memory_hotplug: update comment regarding zone shuffling Date: Mon, 5 Oct 2020 14:15:34 +0200 Message-Id: <20201005121534.15649-6-david@redhat.com> In-Reply-To: <20201005121534.15649-1-david@redhat.com> References: <20201005121534.15649-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org As we no longer shuffle via generic_online_page() and when undoing isolation, we can simplify the comment. We now effectively shuffle only once (properly) when onlining new memory. Reviewed-by: Wei Yang Acked-by: Michal Hocko Cc: Andrew Morton Cc: Alexander Duyck Cc: Mel Gorman Cc: Michal Hocko Cc: Dave Hansen Cc: Vlastimil Babka Cc: Wei Yang Cc: Oscar Salvador Cc: Mike Rapoport Cc: Pankaj Gupta Signed-off-by: David Hildenbrand Acked-by: Vlastimil Babka Acked-by: Pankaj Gupta --- mm/memory_hotplug.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 03a00cb68bf7..b44d4c7ba73b 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -858,13 +858,10 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, undo_isolate_page_range(pfn, pfn + nr_pages, MIGRATE_MOVABLE); /* - * When exposing larger, physically contiguous memory areas to the - * buddy, shuffling in the buddy (when freeing onlined pages, putting - * them either to the head or the tail of the freelist) is only helpful - * for maintaining the shuffle, but not for creating the initial - * shuffle. Shuffle the whole zone to make sure the just onlined pages - * are properly distributed across the whole freelist. Make sure to - * shuffle once pageblocks are no longer isolated. + * Freshly onlined pages aren't shuffled (e.g., all pages are placed to + * the tail of the freelist when undoing isolation). Shuffle the whole + * zone to make sure the just onlined pages are properly distributed + * across the whole freelist - to create an initial shuffle. */ shuffle_zone(zone);