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=-8.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, 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 B2F7CC433E1 for ; Tue, 25 Aug 2020 22:26:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 80C282075E for ; Tue, 25 Aug 2020 22:26:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="KrCG4gbw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726723AbgHYW0k (ORCPT ); Tue, 25 Aug 2020 18:26:40 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:24260 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726541AbgHYW0h (ORCPT ); Tue, 25 Aug 2020 18:26:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1598394395; 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=CVAr3vBma9VREIJq5jB5vDkVx59biKq2HSna+Tb5Zxw=; b=KrCG4gbw5dFgbwg84+Q9HM5ieakF5DpZBPNrJlrD2DIFob/3Qv4wJpRmmbEm/LMEU5dLm6 Ok3oUzuXLsJ2Ss2DtVt1bw0/GfLChc+BRnKx8iogJsaX22rHxj7d1oFr1SLyWMiHhMMLnN SGtghwMNOWrsEn8V4pldG/eYMdTdZic= 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-33-OoimmDYNPFaOcnn8Nw4DFg-1; Tue, 25 Aug 2020 18:26:31 -0400 X-MC-Unique: OoimmDYNPFaOcnn8Nw4DFg-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B7C048030B4; Tue, 25 Aug 2020 22:26:30 +0000 (UTC) Received: from llong.remote.csb (ovpn-112-124.rdu2.redhat.com [10.10.112.124]) by smtp.corp.redhat.com (Postfix) with ESMTP id 34CFE5D9D3; Tue, 25 Aug 2020 22:26:30 +0000 (UTC) Subject: =?UTF-8?B?UmU6IOWbnuWkjTogW1BBVENIXSBkZWJ1Z29iamVjdHM6IGluc3RhbGwg?= =?UTF-8?Q?cpu_hotplug_callback?= To: "Zhang, Qiang" , "tglx@linutronix.de" , "elver@google.com" Cc: "linux-kernel@vger.kernel.org" , "akpm@linux-foundation.org" References: <20200820032453.5222-1-qiang.zhang@windriver.com> From: Waiman Long Organization: Red Hat Message-ID: Date: Tue, 25 Aug 2020 18:26:29 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=gbk; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/25/20 12:53 AM, Zhang, Qiang wrote: > ________________________________________ > 发件人: linux-kernel-owner@vger.kernel.org 代表 qiang.zhang@windriver.com > 发送时间: 2020年8月20日 11:24 > 收件人: tglx@linutronix.de; elver@google.com; longman@redhat.com > 抄送: linux-kernel@vger.kernel.org > 主题: [PATCH] debugobjects: install cpu hotplug callback > > From: Zqiang > > When a cpu going offline, we should free objects in "percpu_obj_pool" > free_objs list which corresponding to this cpu. The percpu free object pool is supposed to be accessed only by that particular cpu without any lock. Trying to access it from another cpu can cause a race condition unless one can make sure that the offline cpu won't become online in the mean time. There shouldn't be too many free objects in the percpu pool. Is it worth the effort to free them? Cheers, Longman