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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT 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 A1D6AC43387 for ; Tue, 18 Dec 2018 11:31:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6AB7A21850 for ; Tue, 18 Dec 2018 11:31:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="WNIaTBw7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726556AbeLRLb0 (ORCPT ); Tue, 18 Dec 2018 06:31:26 -0500 Received: from merlin.infradead.org ([205.233.59.134]:36784 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726341AbeLRLbZ (ORCPT ); Tue, 18 Dec 2018 06:31:25 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=dAov5ZcSFlQtD214rmeCOiBw6GEx1p+y+/aWc9vcmlU=; b=WNIaTBw7iKsJ649GXfERq+vDF yv/vz0c8dI79ALAf4Srj7kbdCTealfT2sbLT2tXgyBMiKO2cZf30TeymiZVVHe3W6Hv0zCDVOY0VJ K7ktubIl7wKcUhmk7V9qeyOkmvt73tTp+N85I1CYBxBGHmp6X4JxNVMui1sxyifizcqdSZPIGiVfX MdDbcf8gQyC6z20E4lBG2ansDIYDcWjqSjp+/Txml/CBrl5BkfJQnc/VUGJdOZ7TsecE1zCzoqI8M g9Y5zIA3QrssOY8l9bzt6iYveoiEd2LBaeBDuFFYppoZAXeTYMynKLVseHoSIZm4wIv3nBz9I3RaF 4joFqZG7Q==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gZDar-0007gK-16; Tue, 18 Dec 2018 11:31:21 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id D07FF2027DA8E; Tue, 18 Dec 2018 12:31:19 +0100 (CET) Date: Tue, 18 Dec 2018 12:31:19 +0100 From: Peter Zijlstra To: Sebastian Andrzej Siewior Cc: zhe.he@windriver.com, acme@kernel.org, ak@linux.intel.com, alexander.shishkin@linux.intel.com, bp@alien8.de, hpa@zytor.com, jolsa@kernel.org, jolsa@redhat.com, kan.liang@linux.intel.com, mingo@redhat.com, namhyung@kernel.org, tglx@linutronix.de, x86@kernel.org, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org Subject: Re: [PATCH] perf/x86/intel: Avoid unnecessary reallocations of memory allocated in cpu hotplug prepare state Message-ID: <20181218113119.GG15430@hirez.programming.kicks-ass.net> References: <1545129033-21757-1-git-send-email-zhe.he@windriver.com> <20181218110209.GD15430@hirez.programming.kicks-ass.net> <20181218111637.b53u5pi3nxnyldaq@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181218111637.b53u5pi3nxnyldaq@linutronix.de> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 18, 2018 at 12:16:37PM +0100, Sebastian Andrzej Siewior wrote: > On 2018-12-18 12:02:09 [+0100], Peter Zijlstra wrote: > > On Tue, Dec 18, 2018 at 06:30:33PM +0800, zhe.he@windriver.com wrote: > > > Besides, in preempt-rt full mode, the freeing can happen in atomic context and > > > thus cause the following BUG. > > > > Hurm, I though we fixed all those long ago.. > > > > And no, the patch is horrible; that's what we have things like > > x86_pmu::cpu_dead() for. > > ehm, you say we keep memory allocation +free on CPU up/down? Sure, why not?