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=-11.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 BB9E1C4338F for ; Fri, 20 Aug 2021 17:57:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9ECD461053 for ; Fri, 20 Aug 2021 17:57:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234428AbhHTR6Q (ORCPT ); Fri, 20 Aug 2021 13:58:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:40298 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234160AbhHTR6Q (ORCPT ); Fri, 20 Aug 2021 13:58:16 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5C4DD61056; Fri, 20 Aug 2021 17:57:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1629482258; bh=PMMuLswqXvvS4sA3R+OiUDxdV3fVCb2CblbI0j0/hws=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=mHErCOB9OHPl/euw92KIJaoIA2n/q0VOPX3EEoZIvJ29wxkyl40g1bCa1S7Zga0cQ jCczkL0N5l36yI9X9cKDIYBfHBVe68HhE9tI31xpbuaWvwcna+KJlaWlWl8VLxuNRs 1GQbMatwRfFdKv6dCXaVX+0MTECd19mtQW8+6HCd5JMAOirnyHA/XiiBsKgf4oXUCQ pCdEyBwL8VHLJUn8pc2qslcqFdxWzfmeQzDJZAUApzPGDt+KKPU6DzzoReOF0Ce/nQ CNGiaCjIRva7AxihbqNI+frOOstddbPQ8Vx55MkhllgXo+9XvnBsKLYi1moYAc8FuN 99itUPrja+bWg== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id 2D21B5C0399; Fri, 20 Aug 2021 10:57:38 -0700 (PDT) Date: Fri, 20 Aug 2021 10:57:38 -0700 From: "Paul E. McKenney" To: Steven Rostedt Cc: gregkh@linuxfoundation.org, mathieu.desnoyers@efficios.com, akpm@linux-foundation.org, metze@samba.org, mingo@redhat.com, peterz@infradead.org, stable@vger.kernel.org Subject: Re: FAILED: patch "[PATCH] tracepoint: Use rcu get state and cond sync for static call" failed to apply to 5.10-stable tree Message-ID: <20210820175738.GH4126399@paulmck-ThinkPad-P17-Gen-1> Reply-To: paulmck@kernel.org References: <1628500832155134@kroah.com> <20210819170933.5c4c6a38@oasis.local.home> <20210819204204.00f9ad28@rorschach.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210819204204.00f9ad28@rorschach.local.home> Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Thu, Aug 19, 2021 at 08:42:04PM -0400, Steven Rostedt wrote: > On Thu, 19 Aug 2021 17:09:33 -0400 > Steven Rostedt wrote: > > > Mathieu, seems that the "slow down 10x" patch was able to be backported > > to 5.10, where as this patch was not. Reason being is that > > start_poll_synchronize_rcu() was added in 5.13. > > I can get this to work if I backport the following RCU patches: > > 29d2bb94a8a126ce80ffbb433b648b32fdea524e > srcu: Provide internal interface to start a Tree SRCU grace period > > 5358c9fa54b09b5d3d7811b033aa0838c1bbaaf2 > srcu: Provide polling interfaces for Tree SRCU grace periods > > 1a893c711a600ab57526619b56e6f6b7be00956e > srcu: Provide internal interface to start a Tiny SRCU grace period > > 8b5bd67cf6422b63ee100d76d8de8960ca2df7f0 > srcu: Provide polling interfaces for Tiny SRCU grace periods > > The first three can be cherry-picked without issue. The last one has a > small conflict, of: > > include/linux/srcutiny.h.rej: > --- include/linux/srcutiny.h > +++ include/linux/srcutiny.h > @@ -16,6 +16,7 @@ > struct srcu_struct { > short srcu_lock_nesting[2]; /* srcu_read_lock() nesting depth. */ > unsigned short srcu_idx; /* Current reader array element in bit 0x2. */ > + unsigned short srcu_idx_max; /* Furthest future srcu_idx request. */ > u8 srcu_gp_running; /* GP workqueue running? */ > u8 srcu_gp_waiting; /* GP waiting for readers? */ > struct swait_queue_head srcu_wq; > > > Which I just added that line, and everything worked. > > Paul, do you have any issues with these four patches getting backported? I believe that you also need to backport 74612a07b83f ("srcu: Make Tiny SRCU use multi-bit grace-period counter"). Otherwise, Tiny SRCU polling grace periods will be at best working by accident. This will also make your small conflict go away. Thanx, Paul > Greg, Are you OK with them too? > > Once those are backported, this patch can be backported as well, and > everything should work. This patch really needs to stay with: > > 231264d6927f6740af36855a622d0e240be9d94c > tracepoint: Fix static call function vs data state mismatch > > Otherwise I would say to revert it if this one can't be backported with > it. > > -- Steve