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=-9.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 D6950C43603 for ; Tue, 10 Dec 2019 15:46:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AA40520836 for ; Tue, 10 Dec 2019 15:46:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ogjctMbS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727211AbfLJPqb (ORCPT ); Tue, 10 Dec 2019 10:46:31 -0500 Received: from mail-pl1-f193.google.com ([209.85.214.193]:36822 "EHLO mail-pl1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727178AbfLJPqb (ORCPT ); Tue, 10 Dec 2019 10:46:31 -0500 Received: by mail-pl1-f193.google.com with SMTP id d15so40410pll.3; Tue, 10 Dec 2019 07:46:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=Rhfl0pj5au2KnJmwhjeT97g46p4i/DRaXShR2ok5irQ=; b=ogjctMbSOB5Sb9JjVoRGf7ox57Lu/1pkqV8At4y7SRHAPT0c9FrBGsWmqPgHvczTtL z6q9kVYaV6WKxVmFm56AOT4b55pUPorEO4eN71kVqYBobcpypfxq0n3MizCEwWW/6spW mj8YrFyUwY/Im+qLvrntjDVmZGsGU3STAMyZ4gDWXqf1m0hhgyq4iLEUo5dLldVx8VI+ 6a1MI+EN1sC2mO/nzdEyDvTqGNHilYcrrmwulYkV3sK3I1bfWtcWLUrzhR8ZrNmsaePP vYV10k/IUNQJBSb5rwFDavORfULYxmc5/wegGxpN1Te2E+JkdEvrw7tLNkIOKmK/nxmp OuJw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=Rhfl0pj5au2KnJmwhjeT97g46p4i/DRaXShR2ok5irQ=; b=NHwC25yNxOzz2rwEucvSVzj2S3kkYx74Pn2G+6nbCz4fcTlNxPIT6pqIeUMUNDzoOX kzthheJ/Eo+S0KzvKVbfrixGtElbz6AFlhgMRnC7ofB51ldME1F2bzvvKn3ZHDIwA+Uo zTfXROi4kWFe8+6159CfUJn4f3vKzf9JqQOuXRx3yBg0pwxS4supireCXnJDqG67Bjcs V0b0/KO+VkHrHRQCm75FTOo0f2SZsEF9XWWeJDaEJweffu2Y/ncwcCelCqST21USqP+X T8tnpEKZh/TvUxSoJ3/MSthvk9aUfEO/Bqhx1rSlOZYtA2gLqJ439leO5oyxU8grGWJj SMBw== X-Gm-Message-State: APjAAAUQZVKGrS+mmRzHmSV6NcjVn7VFs2EGy0xrelgkW1RURtYOhvJE IAuRF7B7GgM7zIOI3+GyBpc= X-Google-Smtp-Source: APXvYqwUisIpRC5v3E6jdY7aD+c/0u3eTGW1biMT4kYCSUD9kmjZnHYWUO97ANOmELGjB+FpxrDykA== X-Received: by 2002:a17:90a:fc94:: with SMTP id ci20mr5918591pjb.6.1575992790504; Tue, 10 Dec 2019 07:46:30 -0800 (PST) Received: from localhost.corp.microsoft.com ([167.220.255.5]) by smtp.googlemail.com with ESMTPSA id k13sm4113815pfp.48.2019.12.10.07.46.25 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 10 Dec 2019 07:46:30 -0800 (PST) From: lantianyu1986@gmail.com X-Google-Original-From: Tianyu.Lan@microsoft.com To: kys@microsoft.com, haiyangz@microsoft.com, sthemmin@microsoft.com, sashal@kernel.org, akpm@linux-foundation.org, dan.j.williams@intel.com, jgg@ziepe.ca, dave.hansen@linux.intel.com, david@redhat.com, namit@vmware.com, richardw.yang@linux.intel.com, christophe.leroy@c-s.fr, tglx@linutronix.de, Tianyu.Lan@microsoft.com, osalvador@suse.de, michael.h.kelley@microsoft.com Cc: linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, vkuznets@redhat.com, eric.devolder@oracle.com Subject: [RFC PATCH 1/4] mm/resource: Move child to new resource when release mem region. Date: Tue, 10 Dec 2019 23:46:08 +0800 Message-Id: <20191210154611.10958-2-Tianyu.Lan@microsoft.com> X-Mailer: git-send-email 2.14.5 In-Reply-To: <20191210154611.10958-1-Tianyu.Lan@microsoft.com> References: <20191210154611.10958-1-Tianyu.Lan@microsoft.com> Sender: linux-hyperv-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org From: Tianyu Lan When release mem region, old mem region may be splited to two regions. Current allocate new struct resource for high end mem region but not move child resources whose ranges are in the high end range to new resource. When adjust old mem region's range, adjust_resource() detects child region's range is out of new range and return error. Move child resources to high end resource before adjusting old mem range. Signed-off-by: Tianyu Lan --- This patch is to prepare for memory hot-remove function in Hyper-V balloon driver. --- kernel/resource.c | 38 ++++++++++++++++++++++++++++++++++---- 1 file changed, 34 insertions(+), 4 deletions(-) diff --git a/kernel/resource.c b/kernel/resource.c index 76036a41143b..1c7362825134 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -181,6 +181,38 @@ static struct resource *alloc_resource(gfp_t flags) return res; } +static void move_child_to_newresource(struct resource *old, + struct resource *new) +{ + struct resource *tmp, **p, **np; + + if (!old->child) + return; + + p = &old->child; + np = &new->child; + + for (;;) { + tmp = *p; + if (!tmp) + break; + + if (tmp->start >= new->start && tmp->end <= new->end) { + tmp->parent = new; + *np = tmp; + np = &tmp->sibling; + *p = tmp->sibling; + + if (!tmp->sibling) + *np = NULL; + continue; + } + + p = &tmp->sibling; + } +} + + /* Return the conflict entry if you can't request it */ static struct resource * __request_resource(struct resource *root, struct resource *new) { @@ -1246,9 +1278,6 @@ EXPORT_SYMBOL(__release_region); * Note: * - Additional release conditions, such as overlapping region, can be * supported after they are confirmed as valid cases. - * - When a busy memory resource gets split into two entries, the code - * assumes that all children remain in the lower address entry for - * simplicity. Enhance this logic when necessary. */ int release_mem_region_adjustable(struct resource *parent, resource_size_t start, resource_size_t size) @@ -1331,11 +1360,12 @@ int release_mem_region_adjustable(struct resource *parent, new_res->sibling = res->sibling; new_res->child = NULL; + move_child_to_newresource(res, new_res); + res->sibling = new_res; ret = __adjust_resource(res, res->start, start - res->start); if (ret) break; - res->sibling = new_res; new_res = NULL; } -- 2.14.5