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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 841F1C43387 for ; Tue, 18 Dec 2018 21:06:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5C49A217D9 for ; Tue, 18 Dec 2018 21:06:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727749AbeLRVGM (ORCPT ); Tue, 18 Dec 2018 16:06:12 -0500 Received: from mail-wm1-f67.google.com ([209.85.128.67]:50934 "EHLO mail-wm1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726704AbeLRVGK (ORCPT ); Tue, 18 Dec 2018 16:06:10 -0500 Received: by mail-wm1-f67.google.com with SMTP id n190so4055784wmd.0 for ; Tue, 18 Dec 2018 13:06:09 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=jR71NccjeBqIVu10xTr8F8X64Hkkni4cPjl1I2vN5r8=; b=KRb5p7VEMlsH1p7vxQ4nSPC6obnIzd8xBLKj4BNeeOjT+HjuYFpN+KYrrWYQllUWYX DLoZo+sB7raejWT/wvP6rBLuPL+dF1Xrz1t4efFAXw9CnXS+6yJlP46MXCJdH0JbW0Ii iwQnD1Y3Se1cvwd+2kWji7/eXaOFHSdAqJS6O9Am+L1sh1P+tFTibU7U08uqLwJgEBZ3 Opl2jvXZkJvRu/rcN4M8iVbBwDTSri8zMJfgZ/nTYSD6EhK/oL2nYo92Eb2fGRsRSpMs QuV+Tde7DWA2+h4ntWgbpwtvIZ955e3svvvskoLj84f2KVapg1Jp1I1DcLL/kNTR81/x oDtw== X-Gm-Message-State: AA+aEWaGvoATufvAX9b+Yc+GyPs325XNZbLqGM7iPGIJ92EhDiATMTaO ROyj+2LkPgxP7jaILaHdedejMA== X-Google-Smtp-Source: AFSGD/W3aRzFRpSXJjnZk6on5WrzR1Lk4txz81iCAtU6PhAtf265yXsnhaUyeswAbqQGvUBoSDyRsQ== X-Received: by 2002:a1c:de57:: with SMTP id v84mr4537814wmg.55.1545167168748; Tue, 18 Dec 2018 13:06:08 -0800 (PST) Received: from t460s.bristot.redhat.com (host252-226-dynamic.249-95-r.retail.telecomitalia.it. [95.249.226.252]) by smtp.gmail.com with ESMTPSA id b13sm6779288wrn.28.2018.12.18.13.06.07 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 18 Dec 2018 13:06:08 -0800 (PST) Subject: Re: [PATCH V2 9/9] jump_label: Batch up if arch supports it To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Greg Kroah-Hartman , Pavel Tatashin , Masami Hiramatsu , Zhou Chengming , Jiri Kosina , Josh Poimboeuf , "Peter Zijlstra (Intel)" , Chris von Recklinghausen , Jason Baron , Scott Wood , Marcelo Tosatti , Clark Williams , x86@kernel.org References: <3c212982833e3b27f8610c8389413b81ed5fb0e1.1545149539.git.bristot@redhat.com> <20181218123556.5257b1a7@gandalf.local.home> <20181218153208.6f8bd858@gandalf.local.home> From: Daniel Bristot de Oliveira Message-ID: <9bc42806-e48f-a9a0-980a-3f0c83dd3d3a@redhat.com> Date: Tue, 18 Dec 2018 22:06:06 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.1 MIME-Version: 1.0 In-Reply-To: <20181218153208.6f8bd858@gandalf.local.home> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/18/18 9:32 PM, Steven Rostedt wrote: > Where? Mostly we have BUILD_BUG_ON() which isn't bad at all. > > The only other BUG I see in the jump label code is in the arch specific > code and that's from 2012. Lately, we are trying to get rid of BUG() > and panic() entirely, with a few exceptions (where there's really no > way to return. Like when the function graph stack is corrupted, and we > don't know where to go). > > If there's a way to continue in a critical state, it's best to WARN() > and continue on. That way, the user can have a chance to see what > happened. Got it! >> What I could do here is: >> >> Add a "fallback" boll that is disabled by default. >> If I hit this case: >> WARN() >> turn "fallback" on, returning to the old mode (without batch) >> >> Sound better? > Yes, please do. ack! Thanks, Steve! -- Daniel