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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 3B9A5C41514 for ; Mon, 26 Aug 2019 07:31:47 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 0C78B206BA for ; Mon, 26 Aug 2019 07:31:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0C78B206BA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 9D86E6B0537; Mon, 26 Aug 2019 03:31:46 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9AFD56B0539; Mon, 26 Aug 2019 03:31:46 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8C52A6B053A; Mon, 26 Aug 2019 03:31:46 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0065.hostedemail.com [216.40.44.65]) by kanga.kvack.org (Postfix) with ESMTP id 680536B0537 for ; Mon, 26 Aug 2019 03:31:46 -0400 (EDT) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id 1217D181AC9AE for ; Mon, 26 Aug 2019 07:31:46 +0000 (UTC) X-FDA: 75863759412.22.iron02_66a9b6817143f X-HE-Tag: iron02_66a9b6817143f X-Filterd-Recvd-Size: 3512 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by imf40.hostedemail.com (Postfix) with ESMTP for ; Mon, 26 Aug 2019 07:31:45 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 26 Aug 2019 00:31:44 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,431,1559545200"; d="scan'208";a="196992425" Received: from richard.sh.intel.com (HELO localhost) ([10.239.159.54]) by fmsmga001.fm.intel.com with ESMTP; 26 Aug 2019 00:31:43 -0700 From: Wei Yang To: akpm@linux-foundation.org, vbabka@suse.cz, kirill.shutemov@linux.intel.com, yang.shi@linux.alibaba.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Wei Yang Subject: [PATCH 1/2] mm/mmap.c: update *next* gap after itself Date: Mon, 26 Aug 2019 15:31:05 +0800 Message-Id: <20190826073106.29971-2-richardw.yang@linux.intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190826073106.29971-1-richardw.yang@linux.intel.com> References: <20190826073106.29971-1-richardw.yang@linux.intel.com> 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: Since we link a vma to the leaf of a rb_tree, *next* must be a parent of vma if *next* is not NULL. This means if we update *next* gap first, it will be re-update again if vma's gap is bigger. For example, we have a vma tree like this: a [0x9000, 0x10000] / \ b c [0x8000, 0x9000] [0x10000, 0x11000] The gap for each node is: a's gap = 0x8000 b's gap = 0x8000 c's gap = 0x0 Now we want to insert d [0x6000, 0x7000], then the tree look like this: a [0x9000, 0x10000] / \ b c [0x8000, 0x9000] [0x10000, 0x11000] / d [0x6000, 0x7000] b is the *next* of d. If we update b's gap first, it would be 0x1000 and propagate to a. And then when update d's gap, which is 0x6000 and propagate through b to a again. If we update d's gap first, the un-consistent gap 0x1000 will not be propagated. Signed-off-by: Wei Yang --- mm/mmap.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index aa66753b175e..672ad7dc6b3c 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -587,12 +587,6 @@ static unsigned long count_vma_pages_range(struct mm_struct *mm, void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma, struct rb_node **rb_link, struct rb_node *rb_parent) { - /* Update tracking information for the gap following the new vma. */ - if (vma->vm_next) - vma_gap_update(vma->vm_next); - else - mm->highest_vm_end = vm_end_gap(vma); - /* * vma->vm_prev wasn't known when we followed the rbtree to find the * correct insertion point for that vma. As a result, we could not @@ -605,6 +599,13 @@ void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma, rb_link_node(&vma->vm_rb, rb_parent, rb_link); vma->rb_subtree_gap = 0; vma_gap_update(vma); + + /* Update tracking information for the gap following the new vma. */ + if (vma->vm_next) + vma_gap_update(vma->vm_next); + else + mm->highest_vm_end = vm_end_gap(vma); + vma_rb_insert(vma, &mm->mm_rb); } -- 2.17.1