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 64FB1CDB47E for ; Wed, 18 Oct 2023 23:26:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231922AbjJRX0J (ORCPT ); Wed, 18 Oct 2023 19:26:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38046 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229632AbjJRX0B (ORCPT ); Wed, 18 Oct 2023 19:26:01 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0123BB6 for ; Wed, 18 Oct 2023 16:25:59 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 087FDC433C7; Wed, 18 Oct 2023 23:25:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1697671557; bh=af17yLZpE3wW13wgbbG7qsclNS+Q+/70kryD8tR9vus=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=dcC+16VZjCAqBhgmAGKfV0sppXpPVjtU9Hz+1b+ySEvlu/YldQfbU1aodtjPY+FnR VMLblIq3AZjPdjrts4AaUBoCIbWuZwtbANJUyG7v3kq+KgvHB7gAOpWerlzcmNeNtu 15y4uPHEJCO8WXbGjotfhg5fsuINk8P56ChrxUdmSBmIpCr04BIzcce8J41D6fA4HQ EH3f+CxzFjPmeBNEi7mcka0fO5tbPawT3ZI5WwQSlWkhkh/O76exOO04Zg64EHhB0R V8PNt34ZvQRgFHgE3HqHXgpD9iXRkCliQ0mMVR26jeml47O95tKAryiL9ceZmk/036 I9i8UAQDGOk3Q== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id 810FBCE0BB0; Wed, 18 Oct 2023 16:25:56 -0700 (PDT) Date: Wed, 18 Oct 2023 16:25:56 -0700 From: "Paul E. McKenney" To: Thomas Gleixner Cc: Ankur Arora , Linus Torvalds , Peter Zijlstra , linux-kernel@vger.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, rostedt@goodmis.org, 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, Frederic Weisbecker , urezki@gmail.com Subject: Re: [PATCH v2 7/9] sched: define TIF_ALLOW_RESCHED Message-ID: <63d6ddfa-16ca-4c19-b542-a95f27d72f96@paulmck-laptop> Reply-To: paulmck@kernel.org References: <87ttrngmq0.ffs@tglx> <87jzshhexi.ffs@tglx> <87il74qghh.fsf@oracle.com> <7520a5b9-b604-4da2-b874-32505f175f39@paulmck-laptop> <875y334k6m.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <875y334k6m.ffs@tglx> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 19, 2023 at 12:53:05AM +0200, Thomas Gleixner wrote: > On Wed, Oct 18 2023 at 10:51, Paul E. McKenney wrote: > > On Wed, Oct 18, 2023 at 05:09:46AM -0700, Ankur Arora wrote: > > Can you folks please trim your replies. It's annoying to scroll > through hundreds of quoted lines to figure out that nothing is there. > > >> This probably allows for more configuration flexibility across archs? > >> Would allow for TREE_RCU=y, for instance. That said, so far I've only > >> been working with PREEMPT_RCU=y.) > > > > Then this is a bug that needs to be fixed. We need a way to make > > RCU readers non-preemptible. > > Why? So that we don't get tail latencies from preempted RCU readers that result in memory-usage spikes on systems that have good and sufficient quantities of memory, but which do not have enough memory to tolerate readers being preempted. Thanx, Paul