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=-19.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 1E4F8C433E0 for ; Tue, 22 Dec 2020 08:31:49 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 95B1C224F9 for ; Tue, 22 Dec 2020 08:31:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 95B1C224F9 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 E0A966B009C; Tue, 22 Dec 2020 03:31:47 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id DBBAB6B009E; Tue, 22 Dec 2020 03:31:47 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CA9966B009F; Tue, 22 Dec 2020 03:31:47 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0091.hostedemail.com [216.40.44.91]) by kanga.kvack.org (Postfix) with ESMTP id B10306B009C for ; Tue, 22 Dec 2020 03:31:47 -0500 (EST) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 749E7180ACF8F for ; Tue, 22 Dec 2020 08:31:47 +0000 (UTC) X-FDA: 77620249854.27.order67_3b14e882745e Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin27.hostedemail.com (Postfix) with ESMTP id 4F0B33D668 for ; Tue, 22 Dec 2020 08:31:47 +0000 (UTC) X-HE-Tag: order67_3b14e882745e X-Filterd-Recvd-Size: 5988 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by imf34.hostedemail.com (Postfix) with ESMTP for ; Tue, 22 Dec 2020 08:31:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1608625906; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=/WoEGZEowYO96BAO0eOM0n/UUR242urezSyPqGgvq0g=; b=MZ31WnoN0OAAofuX3cgiRrQZvs5W+TUXomaT4eClRGC0vjeUjsIBwrlxcjhUxpQMpL7Ov0 N6OZ3BV2xAQI8pYZqdB/nPrWgOjDHX7sU3JJVK9HO02fH8a9ys6xZG5xiRqgnvgwSTHss0 L+5AAfqH+jjrDoQdAensdnzhOMzFzfc= 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-587-wqzghbuGNi6tQ04mWrWqPA-1; Tue, 22 Dec 2020 03:31:43 -0500 X-MC-Unique: wqzghbuGNi6tQ04mWrWqPA-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B5972800D53; Tue, 22 Dec 2020 08:31:41 +0000 (UTC) Received: from [10.36.113.220] (ovpn-113-220.ams2.redhat.com [10.36.113.220]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5DD431002382; Tue, 22 Dec 2020 08:31:35 +0000 (UTC) Subject: Re: [RFC PATCH 3/3] mm: support free hugepage pre zero out To: Alexander Duyck , Mel Gorman , Andrew Morton , Andrea Arcangeli , Dan Williams , "Michael S. Tsirkin" , Jason Wang , Dave Hansen , Michal Hocko , Liang Li , Mike Kravetz , Liang Li , linux-mm@kvack.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, qemu-devel@nongnu.org References: <20201222074910.GA30051@open-light-1.localdomain> From: David Hildenbrand Organization: Red Hat GmbH Message-ID: <585791f4-4b41-5e73-296e-691d5478a915@redhat.com> Date: Tue, 22 Dec 2020 09:31:34 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.5.0 MIME-Version: 1.0 In-Reply-To: <20201222074910.GA30051@open-light-1.localdomain> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 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: On 22.12.20 08:49, Liang Li wrote: > This patch add support of pre zero out free hugepage, we can use > this feature to speed up page population and page fault handing. > > Cc: Alexander Duyck > Cc: Mel Gorman > Cc: Andrea Arcangeli > Cc: Dan Williams > Cc: Dave Hansen > Cc: David Hildenbrand > Cc: Michal Hocko > Cc: Andrew Morton > Cc: Alex Williamson > Cc: Michael S. Tsirkin > Cc: Jason Wang > Cc: Mike Kravetz > Cc: Liang Li > Signed-off-by: Liang Li > --- > mm/page_prezero.c | 17 +++++++++++++++++ > 1 file changed, 17 insertions(+) > > diff --git a/mm/page_prezero.c b/mm/page_prezero.c > index c8ce720bfc54..dff4e0adf402 100644 > --- a/mm/page_prezero.c > +++ b/mm/page_prezero.c > @@ -26,6 +26,7 @@ static unsigned long delay_millisecs = 1000; > static unsigned long zeropage_enable __read_mostly; > static DEFINE_MUTEX(kzeropaged_mutex); > static struct page_reporting_dev_info zero_page_dev_info; > +static struct page_reporting_dev_info zero_hugepage_dev_info; > > inline void clear_zero_page_flag(struct page *page, int order) > { > @@ -69,9 +70,17 @@ static int start_kzeropaged(void) > zero_page_dev_info.delay_jiffies = msecs_to_jiffies(delay_millisecs); > > err = page_reporting_register(&zero_page_dev_info); > + > + zero_hugepage_dev_info.report = zero_free_pages; > + zero_hugepage_dev_info.mini_order = mini_page_order; > + zero_hugepage_dev_info.batch_size = batch_size; > + zero_hugepage_dev_info.delay_jiffies = msecs_to_jiffies(delay_millisecs); > + > + err |= hugepage_reporting_register(&zero_hugepage_dev_info); > pr_info("Zero page enabled\n"); > } else { > page_reporting_unregister(&zero_page_dev_info); > + hugepage_reporting_unregister(&zero_hugepage_dev_info); > pr_info("Zero page disabled\n"); > } > > @@ -90,7 +99,15 @@ static int restart_kzeropaged(void) > zero_page_dev_info.batch_size = batch_size; > zero_page_dev_info.delay_jiffies = msecs_to_jiffies(delay_millisecs); > > + hugepage_reporting_unregister(&zero_hugepage_dev_info); > + > + zero_hugepage_dev_info.report = zero_free_pages; > + zero_hugepage_dev_info.mini_order = mini_page_order; > + zero_hugepage_dev_info.batch_size = batch_size; > + zero_hugepage_dev_info.delay_jiffies = msecs_to_jiffies(delay_millisecs); > + > err = page_reporting_register(&zero_page_dev_info); > + err |= hugepage_reporting_register(&zero_hugepage_dev_info); > pr_info("Zero page enabled\n"); > } > > Free page reporting in virtio-balloon doesn't give you any guarantees regarding zeroing of pages. Take a look at the QEMU implementation - e.g., with vfio all reports are simply ignored. Also, I am not sure if mangling such details ("zeroing of pages") into the page reporting infrastructure is a good idea. -- Thanks, David / dhildenb