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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 3CD80C433EF for ; Mon, 20 Sep 2021 14:30:45 +0000 (UTC) Received: from smtp4.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (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 CD7B0610A0 for ; Mon, 20 Sep 2021 14:30:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org CD7B0610A0 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id 9CC95403D8; Mon, 20 Sep 2021 14:30:44 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id vPEbUkkceuY4; Mon, 20 Sep 2021 14:30:43 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp4.osuosl.org (Postfix) with ESMTPS id 2F7F6403F8; Mon, 20 Sep 2021 14:30:42 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 57D82C0029; Mon, 20 Sep 2021 14:30:40 +0000 (UTC) Received: from smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by lists.linuxfoundation.org (Postfix) with ESMTP id 63563C0011 for ; Mon, 20 Sep 2021 14:30:39 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id 41BE540285 for ; Mon, 20 Sep 2021 14:30:39 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Authentication-Results: smtp2.osuosl.org (amavisd-new); dkim=pass (1024-bit key) header.d=redhat.com Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Npl-HdIgCNzh for ; Mon, 20 Sep 2021 14:30:38 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by smtp2.osuosl.org (Postfix) with ESMTPS id 5939F40101 for ; Mon, 20 Sep 2021 14:30:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1632148237; 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=OPXHqY9VOL97jpGsR9CxoGVxdCxjVyj0nMigqpjV/2w=; b=DNrru/9L25DJeZLEwmsspJ02sIBh7Dz2JKKY2UA17JZNCgbfxVU34ihJPVJBpJQVxONf5s G80T2xpzy1gzfy5GwpQIr3ulQuE0A2RjsuLcAQIa4J1NGVswBH1+iM0hVlKfMylyjjlujr WTdmad14yK1eAqfyzjlzAtz36V9/lyk= 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-408-erBAtSQmMLWTTu5FHcrD1Q-1; Mon, 20 Sep 2021 10:30:34 -0400 X-MC-Unique: erBAtSQmMLWTTu5FHcrD1Q-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7936A1030C24; Mon, 20 Sep 2021 14:30:32 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.194.236]) by smtp.corp.redhat.com (Postfix) with ESMTP id BD69360C17; Mon, 20 Sep 2021 14:29:21 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Subject: [PATCH v5 1/3] kernel/resource: clean up and optimize iomem_is_exclusive() Date: Mon, 20 Sep 2021 16:28:54 +0200 Message-Id: <20210920142856.17758-2-david@redhat.com> In-Reply-To: <20210920142856.17758-1-david@redhat.com> References: <20210920142856.17758-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Cc: Arnd Bergmann , "Michael S. Tsirkin" , Greg Kroah-Hartman , "Rafael J. Wysocki" , virtualization@lists.linux-foundation.org, linux-mm@kvack.org, Andy Shevchenko , Hanjun Guo , Andrew Morton , Dan Williams X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" We end up traversing subtrees of ranges we are not interested in; let's optimize this case, skipping such subtrees, cleaning up the function a bit. For example, in the following configuration (/proc/iomem): 00000000-00000fff : Reserved 00001000-00057fff : System RAM 00058000-00058fff : Reserved 00059000-0009cfff : System RAM 0009d000-000fffff : Reserved 000a0000-000bffff : PCI Bus 0000:00 000c0000-000c3fff : PCI Bus 0000:00 000c4000-000c7fff : PCI Bus 0000:00 000c8000-000cbfff : PCI Bus 0000:00 000cc000-000cffff : PCI Bus 0000:00 000d0000-000d3fff : PCI Bus 0000:00 000d4000-000d7fff : PCI Bus 0000:00 000d8000-000dbfff : PCI Bus 0000:00 000dc000-000dffff : PCI Bus 0000:00 000e0000-000e3fff : PCI Bus 0000:00 000e4000-000e7fff : PCI Bus 0000:00 000e8000-000ebfff : PCI Bus 0000:00 000ec000-000effff : PCI Bus 0000:00 000f0000-000fffff : PCI Bus 0000:00 000f0000-000fffff : System ROM 00100000-3fffffff : System RAM 40000000-403fffff : Reserved 40000000-403fffff : pnp 00:00 40400000-80a79fff : System RAM ... We don't have to look at any children of "0009d000-000fffff : Reserved" if we can just skip these 15 items directly because the parent range is not of interest. Reviewed-by: Dan Williams Signed-off-by: David Hildenbrand --- kernel/resource.c | 25 ++++++++++++++++++++----- 1 file changed, 20 insertions(+), 5 deletions(-) diff --git a/kernel/resource.c b/kernel/resource.c index ca9f5198a01f..2999f57da38c 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -73,6 +73,18 @@ static struct resource *next_resource(struct resource *p) return p->sibling; } +static struct resource *next_resource_skip_children(struct resource *p) +{ + while (!p->sibling && p->parent) + p = p->parent; + return p->sibling; +} + +#define for_each_resource(_root, _p, _skip_children) \ + for ((_p) = (_root)->child; (_p); \ + (_p) = (_skip_children) ? next_resource_skip_children(_p) : \ + next_resource(_p)) + static void *r_next(struct seq_file *m, void *v, loff_t *pos) { struct resource *p = v; @@ -1712,10 +1724,9 @@ static int strict_iomem_checks; */ bool iomem_is_exclusive(u64 addr) { - struct resource *p = &iomem_resource; - bool err = false; - loff_t l; + bool skip_children = false, err = false; int size = PAGE_SIZE; + struct resource *p; if (!strict_iomem_checks) return false; @@ -1723,15 +1734,19 @@ bool iomem_is_exclusive(u64 addr) addr = addr & PAGE_MASK; read_lock(&resource_lock); - for (p = p->child; p ; p = r_next(NULL, p, &l)) { + for_each_resource(&iomem_resource, p, skip_children) { /* * We can probably skip the resources without * IORESOURCE_IO attribute? */ if (p->start >= addr + size) break; - if (p->end < addr) + if (p->end < addr) { + skip_children = true; continue; + } + skip_children = false; + /* * A resource is exclusive if IORESOURCE_EXCLUSIVE is set * or CONFIG_IO_STRICT_DEVMEM is enabled and the -- 2.31.1 _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization