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 B2150C43334 for ; Wed, 20 Jul 2022 07:19:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236084AbiGTHTi (ORCPT ); Wed, 20 Jul 2022 03:19:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39070 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229636AbiGTHTg (ORCPT ); Wed, 20 Jul 2022 03:19:36 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 047F667149; Wed, 20 Jul 2022 00:19:35 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 8EEF7618F3; Wed, 20 Jul 2022 07:19:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DE7A0C3411E; Wed, 20 Jul 2022 07:19:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1658301575; bh=V1NbvFzLlzExU4YZRl5lHdz61pGcNaE0GTIqY4M7dL8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=hZeD8MveCXG20IL/+EPCfavIscQcIcY0trj9N5KQmpAtwpju3vbbHduHllXYwwV/y nXFHsMJZoyppGB7no6jH9THruV4hWMJjUkP+fPPsoiOvp5BOlMyUhfk+mtqnwE/SjI GATMKchnvV2MgJ+ln4etS/REB3QKoBz/builobbDmeomul1bp9Jle7yV0//M98DCko 93OoczrfVYfoZUzXNjVPRIZYs89JdK319O+RJCj9gw1u/VF1+jPfGBrJA+C8Ozk0RZ RJXAHgxHt4apWNZi6JLQDovpf3oL6BsDMWr9CkFrgeFC1lKPYZpr4Mo/Gkh+5TE4DC YX6ToNjbhM4cg== Received: from ip-185-104-136-31.ptr.icomera.net ([185.104.136.31] helo=wait-a-minute.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1oE3zY-008iPV-CI; Wed, 20 Jul 2022 08:19:32 +0100 Date: Wed, 20 Jul 2022 08:19:11 +0100 Message-ID: <875yjs45g0.wl-maz@kernel.org> From: Marc Zyngier To: paulmck@kernel.org Cc: Neeraj Upadhyay , frederic@kernel.org, josh@joshtriplett.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, joel@joelfernandes.org, linux-kernel@vger.kernel.org, zhangfei.gao@foxmail.com, boqun.feng@gmail.com, urezki@gmail.com, shameerali.kolothum.thodi@huawei.com, pbonzini@redhat.com, mtosatti@redhat.com, eric.auger@redhat.com, chenxiang66@hisilicon.com, zhangfei.gao@linaro.org, rcu@vger.kernel.org Subject: Re: [PATCH v3] srcu: Reduce blocking agressiveness of expedited grace periods further In-Reply-To: <20220719171547.GQ1790663@paulmck-ThinkPad-P17-Gen-1> References: <20220701031545.9868-1-quic_neeraju@quicinc.com> <87o7xlzey3.wl-maz@kernel.org> <20220719171547.GQ1790663@paulmck-ThinkPad-P17-Gen-1> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/27.1 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.104.136.31 X-SA-Exim-Rcpt-To: paulmck@kernel.org, quic_neeraju@quicinc.com, frederic@kernel.org, josh@joshtriplett.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, joel@joelfernandes.org, linux-kernel@vger.kernel.org, zhangfei.gao@foxmail.com, boqun.feng@gmail.com, urezki@gmail.com, shameerali.kolothum.thodi@huawei.com, pbonzini@redhat.com, mtosatti@redhat.com, eric.auger@redhat.com, chenxiang66@hisilicon.com, zhangfei.gao@linaro.org, rcu@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Paul, On Tue, 19 Jul 2022 18:15:47 +0100, "Paul E. McKenney" wrote: > > On Tue, Jul 19, 2022 at 09:25:56AM +0100, Marc Zyngier wrote: > > > > Is there any chance for this fix to make it into 5.19? The regression > > is significant enough on low-end systems, and I'd rather see it > > addressed. > > I wasn't planning on it, based on my (possibly quite flawed) assumption > that it affected only embedded systems running in a virtual environment. Not quite. This affects any system running virtual machines based on KVM and using QEMU as the VMM (the machines I run this on don't quite qualify as "embedded"). > My plan was to send it in my pull request for the next merge window > next week. My pull request is next week, yes, the merge window opens > the following Sunday. ;-) > > It has a Fixes tag, so it will be backported. > > But if it is important to get it into v5.19 rather than v5.19.x for small > "x", please let me know and I will see what Linus does with the resulting > v5.19-rc7 pull request. I think that the sooner we address this in an upstream kernel, the better, and I'd definitely support you sending this to Linus for -rc7! Thanks, M. -- Without deviation from the norm, progress is not possible.