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=-15.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,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 F3F89C49EA6 for ; Fri, 25 Jun 2021 02:22:51 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 988F460FF1 for ; Fri, 25 Jun 2021 02:22:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 988F460FF1 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 9CFDB6B0036; Thu, 24 Jun 2021 22:22:50 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9A69E6B005D; Thu, 24 Jun 2021 22:22:50 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 86F136B006C; Thu, 24 Jun 2021 22:22:50 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0045.hostedemail.com [216.40.44.45]) by kanga.kvack.org (Postfix) with ESMTP id 5699D6B0036 for ; Thu, 24 Jun 2021 22:22:50 -0400 (EDT) Received: from smtpin01.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 8196880E0FF9 for ; Fri, 25 Jun 2021 02:22:50 +0000 (UTC) X-FDA: 78290648100.01.D96C0A0 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf12.hostedemail.com (Postfix) with ESMTP id 317B637A for ; Fri, 25 Jun 2021 02:22:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1624587769; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=4lkWZczGLo6bj9yod8penMbf2i8IGatT7z7u0uZSSvw=; b=D/ufYx1vEO0euzPxrGAnrtiCp6S3fZq+SzBazaQdZLB47rsCcJvoKL0wG57GPANzrqNVY7 1EYjp9Y60uK3ugFFYMBwfQ9zJiYXxPBKd7YTNfqDJwlt5vdjI8oQPKGkn7eVaL3rAsuU6t Lkh4lWI1GjPdJ1tT9jHD404qVUsUsDQ= 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-596-jT0qJBjwPVeebUO6BXIsHA-1; Thu, 24 Jun 2021 22:22:48 -0400 X-MC-Unique: jT0qJBjwPVeebUO6BXIsHA-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 2ECB6362F9; Fri, 25 Jun 2021 02:22:47 +0000 (UTC) Received: from [10.64.54.70] (vpn2-54-70.bne.redhat.com [10.64.54.70]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 360C119C45; Fri, 25 Jun 2021 02:22:36 +0000 (UTC) Reply-To: Gavin Shan Subject: Re: [PATCH v4 3/4] mm/page_reporting: Allow driver to specify reporting order From: Gavin Shan To: Alexander Duyck Cc: linux-mm , LKML , David Hildenbrand , "Michael S. Tsirkin" , Andrew Morton , Anshuman Khandual , Catalin Marinas , Will Deacon , shan.gavin@gmail.com References: <20210625014710.42954-1-gshan@redhat.com> <20210625014710.42954-4-gshan@redhat.com> Message-ID: Date: Fri, 25 Jun 2021 14:24:06 +1000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b="D/ufYx1v"; spf=none (imf12.hostedemail.com: domain of gshan@redhat.com has no SPF policy when checking 170.10.133.124) smtp.mailfrom=gshan@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 317B637A X-Stat-Signature: fb99qu1zgmfjdkeugxscyiaxuwq6rg79 X-HE-Tag: 1624587770-112539 Content-Transfer-Encoding: quoted-printable 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 6/25/21 2:00 PM, Gavin Shan wrote: > On 6/25/21 11:19 AM, Alexander Duyck wrote: >> On Thu, Jun 24, 2021 at 4:46 PM Gavin Shan wrote: >>> >>> The page reporting order (threshold) is sticky to @pageblock_order >>> by default. The page reporting can never be triggered because the >>> freeing page can't come up with a free area like that huge. The >>> situation becomes worse when the system memory becomes heavily >>> fragmented. >>> >>> For example, the following configurations are used on ARM64 when 64KB >>> base page size is enabled. In this specific case, the page reporting >>> won't be triggered until the freeing page comes up with a 512MB free >>> area. That's hard to be met, especially when the system memory become= s >>> heavily fragmented. >>> >>> =C2=A0=C2=A0=C2=A0 PAGE_SIZE:=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0 64KB >>> =C2=A0=C2=A0=C2=A0 HPAGE_SIZE:=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0 512MB >>> =C2=A0=C2=A0=C2=A0 pageblock_order:=C2=A0=C2=A0=C2=A0 13=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0 (512MB) >>> =C2=A0=C2=A0=C2=A0 MAX_ORDER:=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0 14 >>> >>> This allows the drivers to specify the page reporting order when the >>> page reporting device is registered. It falls back to @pageblock_orde= r >>> if it's not specified by the driver. The existing users (hv_balloon >>> and virtio_balloon) don't specify it and @pageblock_order is still >>> taken as their page reporting order. So this shouldn't introduce any >>> functional changes. >>> >>> Signed-off-by: Gavin Shan >>> Reviewed-by: Alexander Duyck >>> --- >>> =C2=A0 include/linux/page_reporting.h | 3 +++ >>> =C2=A0 mm/page_reporting.c=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0 | 6 ++++++ >>> =C2=A0 2 files changed, 9 insertions(+) >>> >>> diff --git a/include/linux/page_reporting.h b/include/linux/page_repo= rting.h >>> index 3b99e0ec24f2..fe648dfa3a7c 100644 >>> --- a/include/linux/page_reporting.h >>> +++ b/include/linux/page_reporting.h >>> @@ -18,6 +18,9 @@ struct page_reporting_dev_info { >>> >>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 /* Current state of = page reporting */ >>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 atomic_t state; >>> + >>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 /* Minimal order of page report= ing */ >>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 unsigned int order; >>> =C2=A0 }; >>> >>> =C2=A0 /* Tear-down and bring-up for page reporting devices */ >>> diff --git a/mm/page_reporting.c b/mm/page_reporting.c >>> index 34bf4d26c2c4..382958eef8a9 100644 >>> --- a/mm/page_reporting.c >>> +++ b/mm/page_reporting.c >>> @@ -329,6 +329,12 @@ int page_reporting_register(struct page_reportin= g_dev_info *prdev) >>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0 goto err_out; >>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 } >>> >>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 /* >>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 * Update the page reporti= ng order if it's specified by driver. >>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 * Otherwise, it falls bac= k to @pageblock_order. >>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 */ >>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 page_reporting_order =3D prdev-= >order ? : pageblock_order; >>> + >> >> An alternative to this would be to look at setting up some >> comparisons. I might add another variable and do something like: >> order =3D prdev->order ? : pageblock_order; >> if (order < page_reporting_order) >> =C2=A0=C2=A0=C2=A0=C2=A0 page_reporting_order =3D order; >> >> You could essentially do something similar in the previous patch but >> just use pageblock_order directly rather than having to add a local >> variable. >> >> That way if you need to still pull down the page reporting order you >> can do so without prdev->order or pageblock_order overwriting the >> value and pushing it back up. >> >=20 > Thanks, Alex. Lets do both in v5, which will be posted shortly. >=20 Alex, I just posted v5 to have the checks you suggested. Could you help to have a quick scan. It's pointless to let Andrew drop the patches and apply the last one again :) Thanks, Gavin