From patchwork Mon Sep 28 18:21:10 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 11804539 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 D125B6CB for ; Mon, 28 Sep 2020 18:22:43 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A1F1620757 for ; Mon, 28 Sep 2020 18:22:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="WYqzVoKX" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A1F1620757 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kMxmf-000870-8B; Mon, 28 Sep 2020 18:21:57 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kMxme-00086V-2H for xen-devel@lists.xenproject.org; Mon, 28 Sep 2020 18:21:56 +0000 X-Inumbo-ID: 5486eb5b-76b8-4789-a710-fa9000a6fd87 Received: from us-smtp-delivery-124.mimecast.com (unknown [216.205.24.124]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTP id 5486eb5b-76b8-4789-a710-fa9000a6fd87; Mon, 28 Sep 2020 18:21:55 +0000 (UTC) Dkim-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1601317315; 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=85B0mZRKs5mkl5E8BDbfnUinjf/rtUnPl3Qk/CJCPXg=; b=WYqzVoKXMO6IkcRYCJzkXQK+t3xvqBx/aWKw7ixKoDOMWsiOLa9ZhRII5CLYaBV0HcebzI hsvs9eO5vIL3mKMCn8aKcpJ+ukLx6j/4H5qAO9eryadQjgJ7BJUom/C5NfZz9ESox6V1Uj Bb/hpl7okH5/DlT34ql84kO/JNftqYI= 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-137-NY6l3ukFNlmJxz48QH7ihg-1; Mon, 28 Sep 2020 14:21:51 -0400 X-MC-Unique: NY6l3ukFNlmJxz48QH7ihg-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 F39EC8015AA; Mon, 28 Sep 2020 18:21:48 +0000 (UTC) Received: from t480s.redhat.com (ovpn-112-106.ams2.redhat.com [10.36.112.106]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6B58827CD4; Mon, 28 Sep 2020 18:21:39 +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 , David Hildenbrand , Alexander Duyck , Mel Gorman , Michal Hocko , Dave Hansen , Vlastimil Babka , Wei Yang , Oscar Salvador , Mike Rapoport Subject: [PATCH v1 5/5] mm/memory_hotplug: update comment regarding zone shuffling Date: Mon, 28 Sep 2020 20:21:10 +0200 Message-Id: <20200928182110.7050-6-david@redhat.com> In-Reply-To: <20200928182110.7050-1-david@redhat.com> References: <20200928182110.7050-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" 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. 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 Signed-off-by: David Hildenbrand Reviewed-by: Wei Yang Acked-by: Michal Hocko --- 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 9db80ee29caa..c589bd8801bb 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -859,13 +859,10 @@ 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);