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 CF9DEC4332F for ; Fri, 10 Nov 2023 00:56:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345494AbjKJA4x (ORCPT ); Thu, 9 Nov 2023 19:56:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35928 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229491AbjKJA4v (ORCPT ); Thu, 9 Nov 2023 19:56:51 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AF6293A8D for ; Thu, 9 Nov 2023 16:56:49 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1F4F5C433C8; Fri, 10 Nov 2023 00:56:45 +0000 (UTC) Date: Thu, 9 Nov 2023 19:56:49 -0500 From: Steven Rostedt To: Josh Poimboeuf Cc: Ankur Arora , linux-kernel@vger.kernel.org, tglx@linutronix.de, peterz@infradead.org, torvalds@linux-foundation.org, paulmck@kernel.org, linux-mm@kvack.org, x86@kernel.org, akpm@linux-foundation.org, luto@kernel.org, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, willy@infradead.org, mgorman@suse.de, jon.grimm@amd.com, bharata@amd.com, raghavendra.kt@amd.com, boris.ostrovsky@oracle.com, konrad.wilk@oracle.com, jgross@suse.com, andrew.cooper3@citrix.com, mingo@kernel.org, bristot@kernel.org, mathieu.desnoyers@efficios.com, geert@linux-m68k.org, glaubitz@physik.fu-berlin.de, anton.ivanov@cambridgegreys.com, mattst88@gmail.com, krypton@ulrich-teichert.org, David.Laight@ACULAB.COM, richard@nod.at, mjguzik@gmail.com, Jiri Kosina , Miroslav Benes , Petr Mladek , Joe Lawrence , live-patching@vger.kernel.org Subject: Re: [RFC PATCH 07/86] Revert "livepatch,sched: Add livepatch task switching to cond_resched()" Message-ID: <20231109195649.2b2869fc@gandalf.local.home> In-Reply-To: <20231109175118.olggitpaltz47n3b@treble> References: <20231107215742.363031-1-ankur.a.arora@oracle.com> <20231107215742.363031-8-ankur.a.arora@oracle.com> <20231107181609.7e9e9dcc@gandalf.local.home> <20231109172637.ayue3jexgdxd53tu@treble> <20231109123147.2bb11809@gandalf.local.home> <20231109175118.olggitpaltz47n3b@treble> X-Mailer: Claws Mail 3.19.1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 9 Nov 2023 09:51:18 -0800 Josh Poimboeuf wrote: > > I guess I'm not fully understanding what the cond rescheds are for. But > > would an IPI to all CPUs setting NEED_RESCHED, fix it? > > If all livepatch arches had the ORC unwinder, yes. > > The problem is that frame pointer (and similar) unwinders can't reliably > unwind past an interrupt frame. Perhaps we can use this to push those archs with bad unwinders to port over ORC unwinding ;-) -- Steve