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=-16.1 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,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 25217C49EAF for ; Fri, 25 Jun 2021 02:21:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0DB9D613C1 for ; Fri, 25 Jun 2021 02:21:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233077AbhFYCXh (ORCPT ); Thu, 24 Jun 2021 22:23:37 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:31977 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233067AbhFYCXg (ORCPT ); Thu, 24 Jun 2021 22:23:36 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1624587676; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=TVF+yBkqDYOUwCcDvKcI0pdyyfRgoEI6L6WiisW4bFA=; b=WeqzRoifDMFkAHsWaHj51GjWSeUXZORlXzlm1i1K+6tIJbzZAAMLM9x3Bh/f8H4nprIxCi ymORVFL+7UJ2NCXqwE0eFtL+l25REo9Tsr5UMm3s7C2tCKXTsPilkRJ7JJWbld7tvq4Xm1 W9dQSBpKv0h+a+l3CAT12DEYcHWSYsA= 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-135-XPV7t3a-MFiJzce4OlbM1A-1; Thu, 24 Jun 2021 22:21:14 -0400 X-MC-Unique: XPV7t3a-MFiJzce4OlbM1A-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 5ED251084F57; Fri, 25 Jun 2021 02:21:13 +0000 (UTC) Received: from gshan.redhat.com (vpn2-54-70.bne.redhat.com [10.64.54.70]) by smtp.corp.redhat.com (Postfix) with ESMTP id 406785C1A3; Fri, 25 Jun 2021 02:21:00 +0000 (UTC) From: Gavin Shan To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, alexander.duyck@gmail.com, david@redhat.com, mst@redhat.com, akpm@linux-foundation.org, anshuman.khandual@arm.com, catalin.marinas@arm.com, will@kernel.org, shan.gavin@gmail.com Subject: [PATCH v5 3/4] mm/page_reporting: Allow driver to specify reporting Date: Fri, 25 Jun 2021 12:21:49 +0800 Message-Id: <20210625042150.46964-4-gshan@redhat.com> In-Reply-To: <20210625042150.46964-1-gshan@redhat.com> References: <20210625042150.46964-1-gshan@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 becomes heavily fragmented. PAGE_SIZE: 64KB HPAGE_SIZE: 512MB pageblock_order: 13 (512MB) MAX_ORDER: 14 This allows the drivers to specify the page reporting order when the page reporting device is registered. It falls back to @pageblock_order 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 --- v5: Restore @page_reporting_order to @pageblock_order when device is registered and minimal page reporting order isn't provided --- include/linux/page_reporting.h | 3 +++ mm/page_reporting.c | 11 ++++++++--- 2 files changed, 11 insertions(+), 3 deletions(-) diff --git a/include/linux/page_reporting.h b/include/linux/page_reporting.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 { /* Current state of page reporting */ atomic_t state; + + /* Minimal order of page reporting */ + unsigned int order; }; /* Tear-down and bring-up for page reporting devices */ diff --git a/mm/page_reporting.c b/mm/page_reporting.c index 133222234f25..077925cfcc06 100644 --- a/mm/page_reporting.c +++ b/mm/page_reporting.c @@ -319,6 +319,7 @@ DEFINE_STATIC_KEY_FALSE(page_reporting_enabled); int page_reporting_register(struct page_reporting_dev_info *prdev) { + unsigned int order; int err = 0; mutex_lock(&page_reporting_mutex); @@ -329,9 +330,13 @@ int page_reporting_register(struct page_reporting_dev_info *prdev) goto err_out; } - /* Update the page reporting order with @pageblock_order */ - if (page_reporting_order > pageblock_order) - page_reporting_order = pageblock_order; + /* + * Update the page reporting order if it's specified by driver. + * Otherwise, it falls back to @pageblock_order. + */ + order = prdev->order ? : pageblock_order; + if (page_reporting_order > order) + page_reporting_order = order; /* initialize state and work structures */ atomic_set(&prdev->state, PAGE_REPORTING_IDLE); -- 2.23.0