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 DCC88C4332F for ; Mon, 12 Dec 2022 10:15:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231565AbiLLKPA (ORCPT ); Mon, 12 Dec 2022 05:15:00 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46094 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229730AbiLLKO4 (ORCPT ); Mon, 12 Dec 2022 05:14:56 -0500 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 949C41FE; Mon, 12 Dec 2022 02:14:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; 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; bh=2hHKL+D8xenvvKDhRsDXsAlyRtvLxbR4M+slc846P9k=; b=fxrjLtvF1k3a6iHnHITMHwxWsR x1jooI+/+iWKirFdNHvEeitxokOhOtqUZQY3uYXkFg2x4yWDvC5LQeci8fLyZb8cKvjgTIxNk1ap9 7orogizmyjHnYPCL71cR3LNAmx9ysrYJ+dTKAaLfArxEvYaZ7vl+L/gvH82VnsEJjcRJd40ll8TYx qValtaNRNzp5tLiWArhcHABbeBbH00WqjVAUMAs7/BFSY5dHGCr9W9JAHJaErDLzOTkGOc/JaZXJE 2lCkLgdfHVwm+8WIDY8LFS9FQyzIUXFFOYzepc/P5LyOEw38f4zN3f8ZxZBkVWlvx+6J2+2N7HOM8 rkL+PerA==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1p4fpB-009kA5-3D; Mon, 12 Dec 2022 10:14:18 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 4BE39300293; Mon, 12 Dec 2022 11:14:16 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 2FF2A2024870B; Mon, 12 Dec 2022 11:14:16 +0100 (CET) Date: Mon, 12 Dec 2022 11:14:16 +0100 From: Peter Zijlstra To: Tejun Heo Cc: torvalds@linux-foundation.org, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@kernel.org, joshdon@google.com, brho@google.com, pjt@google.com, derkling@google.com, haoluo@google.com, dvernet@meta.com, dschatzberg@meta.com, dskarlat@cs.cmu.edu, riel@surriel.com, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, kernel-team@meta.com Subject: Re: [PATCHSET RFC] sched: Implement BPF extensible scheduler class Message-ID: References: <20221130082313.3241517-1-tj@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221130082313.3241517-1-tj@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 29, 2022 at 10:22:42PM -1000, Tejun Heo wrote: > Rolling out kernel upgrades is a slow and iterative process. At a large scale > it can take months to roll a new kernel out to a fleet of servers. While this > latency is expected and inevitable for normal kernel upgrades, it can become > highly problematic when kernel changes are required to fix bugs. Livepatch [9] > is available to quickly roll out critical security fixes to large fleets, but > the scope of changes that can be applied with livepatching is fairly limited, > and would likely not be usable for patching scheduling policies. With > sched_ext, new scheduling policies can be rapidly rolled out to production > environments. I don't think we can or should use this argument to push BPF into ever more places.