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=-2.1 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, 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 7BBE4C43143 for ; Thu, 21 Jun 2018 22:13:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1D97A22496 for ; Thu, 21 Jun 2018 22:13:47 +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="iT9F2Afx" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1D97A22496 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933782AbeFUWNp (ORCPT ); Thu, 21 Jun 2018 18:13:45 -0400 Received: from merlin.infradead.org ([205.233.59.134]:35588 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933559AbeFUWNo (ORCPT ); Thu, 21 Jun 2018 18:13:44 -0400 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=4/xV+ZRTQVeIss7uup/iktGy+zad9J77s5Uc5iOIQBM=; b=iT9F2Afx2XvS2zcFtgCaQz6KD Xpu2QuhFxYIkTKw6q5StaQaHFSw6KsAUZCTI/3DzrKKPqJTXPlBGzGEObqGtysoWjo+j/FNf5wwue dTuBN4+qx9QB5HBoO7GX7R6O3GjmO1u8StZxhedbzJBvKiqpxOLA3mbL9wAh5PbLaoBdigJ6RDqLp uvUDddKXMM+pAYR736VnYugeHDFIqNiW2T9yU2g194F2j4Kq2/YmMdCypseQRnh2ONE2/G6WWqSaC aUPlm5ee+E/G7FJKNCzcgEST2UeOFH06WcXxoz4HVhY6p+2MGo3XLzrvumdDGPYSBYy1tEQNnZWzr vvGGijc2g==; 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 1fW7pi-00031b-So; Thu, 21 Jun 2018 22:13:39 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 9E5A02029F1D7; Fri, 22 Jun 2018 00:13:37 +0200 (CEST) Date: Fri, 22 Jun 2018 00:13:37 +0200 From: Peter Zijlstra To: Fenghua Yu Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Ashok Raj , Dave Hansen , Rafael Wysocki , Tony Luck , Alan Cox , Ravi V Shankar , Arjan van de Ven , linux-kernel , x86 Subject: Re: [RFC PATCH 00/16] x86/split_lock: Enable #AC exception for split locked accesses Message-ID: <20180621221337.GE2494@hirez.programming.kicks-ass.net> References: <1527435965-202085-1-git-send-email-fenghua.yu@intel.com> <20180621193738.GA13636@worktop.programming.kicks-ass.net> <20180621201851.GC114883@romley-ivt3.sc.intel.com> <20180621220003.GD114883@romley-ivt3.sc.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180621220003.GD114883@romley-ivt3.sc.intel.com> User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 21, 2018 at 03:00:03PM -0700, Fenghua Yu wrote: > For example, on a consolidated real-time machine, some cores are running > Another example, in a public cloud deployed in the field, a user process In either case a single split-lock shouldn't be a real problem, if you program the event with a count of 1 and have the NMI handler kill the offending task, you should be good. Not saying the #AC isn't nicer, just saying the PMU based thing can still work.