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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5F403C433F5 for ; Thu, 29 Sep 2022 17:15:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235809AbiI2RPg (ORCPT ); Thu, 29 Sep 2022 13:15:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49324 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235523AbiI2RPd (ORCPT ); Thu, 29 Sep 2022 13:15:33 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C4307147F27 for ; Thu, 29 Sep 2022 10:15:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:From: References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender:Reply-To: 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=IXV18MOebWFMGlFHhzMjusA+9x187BRqzF/HBTVlDh0=; b=QEqAFeVc/75n0stI3gtZLrHkiF nDTOa2TXGQ3NWgwMxafegi410YdOwV2YsfhJxaTRR/pWJEI4SkHST0t6qehgfjEExV2mYOq7pfjZZ FQhqkzpzZpv4oXLQ3VUKg9Ecsea2Jt0OsvoT0pY54KPWgbMBKocdB9h2hSz4P2zdFhQH+90bkRKzU uUJDd/BXlbRLipjY+amr8M8Qet6J8miV0SP+3jCKQKQ1bLypYJOzESpiUP72yLg+broJkP7eqUkpn zGf/NjSo7i8IygzT/3B7jA+k5Y5NaOXeutKk5bl2ed/XlufAmeTXakm9V90WsUnQzc++/Ik2XASw7 5R/kZX1w==; Received: from [179.232.144.59] (helo=[192.168.0.5]) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_128_GCM:128) (Exim) id 1odx87-00Gpee-5A; Thu, 29 Sep 2022 19:15:23 +0200 Message-ID: <4baa3654-9a1b-b60c-4a3c-55debe9e8044@igalia.com> Date: Thu, 29 Sep 2022 14:15:05 -0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.2.2 Subject: Re: [PATCH] x86/split_lock: Restore warn mode (and add a new one) to avoid userspace regression Content-Language: en-US To: Dave Hansen , tony.luck@intel.com, tglx@linutronix.de, linux-kernel@vger.kernel.org, x86@kernel.org Cc: mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, luto@kernel.org, kernel-dev@igalia.com, kernel@gpiccoli.net, Fenghua Yu , Joshua Ashton , Paul Gofman , Pavel Machek , Pierre-Loup Griffais , Melissa Wen References: <20220928142109.150263-1-gpiccoli@igalia.com> <24f31510-5b33-ada5-9f0e-117420403e8c@intel.com> <1c742ae1-98cb-a5c1-ba3f-5e79b8861f0b@igalia.com> <7917fde2-a381-5404-c5ae-6ffd433f85ec@igalia.com> From: "Guilherme G. Piccoli" In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Two responses in one: First, I like Tony's idea - heuristic based on CPU number seems to make sense. This number could be purely based on CPU number with a hardcoded value, or based in a Kconfig (after N CPUs, add misery). Now, second part below, inline: On 29/09/2022 13:26, Dave Hansen wrote: > [...] > Let's be precise here, though. It isn't that folks can't play. It's > that we *intentionally* put something in place that kept them from > playing. They can play just fine after disabling split lock detection. > Agreed with your wording, would just maybe "s/put something/added a policy" heheh >> [...] > They don't have to live with it. They can turn it off. That's why the > command-line disable is there. > If they know how to do it, right? I'd rather have it as a new non-default mechanism or at least, a Kconfig option in which gamer distros could tune for their users, so we're not requiring them to tune x86-specific parameters to play some game.