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_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 300AEC19759 for ; Thu, 1 Aug 2019 21:59:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ECE602080C for ; Thu, 1 Aug 2019 21:59:26 +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="NFJ5mx3p" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732862AbfHAV70 (ORCPT ); Thu, 1 Aug 2019 17:59:26 -0400 Received: from merlin.infradead.org ([205.233.59.134]:55528 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726403AbfHAV7Z (ORCPT ); Thu, 1 Aug 2019 17:59:25 -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=FlbNAsgaWkp1ShDCheHxAkj85en9Tu2y9Hru44fhYz0=; b=NFJ5mx3pun9BIYphO0C68UAUu bNIl5t6nnsxHXQq8rOyvK1+2xENKG1banbuqonFceMoKyQfDoNijJJq1cmdDthZGkLdEJaHaa+JRR sy9AZHK01JafhzTXpLIhZcM24Nt52lWl/kRGtNf5E6LX5xx1DNeoa8ZNntincpMLRDHuDoi7WC/+y HA3O23EObKhT4TPP+bFOaHWWnfil3CE5Ggc/aCnZxceKFfwCToLfXOTGqgxuInpjTOEyU5G52eQ61 7gsEOZqcrfczHuU7P7Dx4ONddvwcraEmcYcTxxpMkFOgVNQGyPcL7cM+eMlCVnQ+Z2HDd9+SLiVEF If+0fSSdQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1htJ6I-0002fJ-Mv; Thu, 01 Aug 2019 21:59:07 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 51E57202953B0; Thu, 1 Aug 2019 23:59:04 +0200 (CEST) Date: Thu, 1 Aug 2019 23:59:04 +0200 From: Peter Zijlstra To: Suren Baghdasaryan Cc: Ingo Molnar , lizefan@huawei.com, Johannes Weiner , axboe@kernel.dk, Dennis Zhou , Dennis Zhou , Andrew Morton , linux-mm , linux-doc@vger.kernel.org, LKML , kernel-team , Nick Kralevich , Thomas Gleixner Subject: Re: [PATCH 1/1] psi: do not require setsched permission from the trigger creator Message-ID: <20190801215904.GC2332@hirez.programming.kicks-ass.net> References: <20190730013310.162367-1-surenb@google.com> <20190730081122.GH31381@hirez.programming.kicks-ass.net> <20190801095112.GA31381@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 Thu, Aug 01, 2019 at 11:28:30AM -0700, Suren Baghdasaryan wrote: > > By marking it FIFO-99 you're in effect saying that your stupid > > statistics gathering is more important than your life. It will preempt > > the task that's in control of the band-saw emergency break, it will > > preempt the task that's adjusting the electromagnetic field containing > > this plasma flow. > > > > That's insane. > > IMHO an opt-in feature stops being "stupid" as soon as the user opted > in to use it, therefore explicitly indicating interest in it. However > I assume you are using "stupid" here to indicate that it's "less > important" rather than it's "useless". Quite; PSI does have its uses. RT just isn't one of them.