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=-8.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 14E5DC43464 for ; Fri, 18 Sep 2020 22:15:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C42E6208B8 for ; Fri, 18 Sep 2020 22:15:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600467331; bh=E5JKXqiDmun1+oTjYUTLAStPF2gHvSooZGuOGfFiGQA=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:List-ID: From; b=WcrV9LPSbUrSgGUdt/nzC+A8m0bXU8Nqhc1cBusKVWQsi5D2i69C/w4rztHw6dlcv huFEC3qSi3e5ymH3y0Pdo6G3TNe6FW2EN8VZArGSK0TNX+HpQb72pZu8XjYQqRya9s 8KKgEYhsafBiRIGb4nrqR0jDqjg1NPJJ98PMcBJg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726311AbgIRWPa (ORCPT ); Fri, 18 Sep 2020 18:15:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:54082 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726064AbgIRWP3 (ORCPT ); Fri, 18 Sep 2020 18:15:29 -0400 Received: from paulmck-ThinkPad-P72.home (unknown [50.45.173.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 27B8C21481; Fri, 18 Sep 2020 22:15:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600467329; bh=E5JKXqiDmun1+oTjYUTLAStPF2gHvSooZGuOGfFiGQA=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=JJFm0VxhNtdTjkxfX05cAR8JOyLbe7IG8ov6BPxX5eHXTXguwQusWMIWrT6RGGJAZ AxbPkLf8NaCXBE4dRzr2Dc1YFgZAx9RSw+TYk5vq6goBpFKQ/70WQj3cpeyxeWj6rk cdk1l8gr7MvT+v5Fd/PAmCX3mxLkF7q5Pu/K6X70= Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id F06373523242; Fri, 18 Sep 2020 15:15:28 -0700 (PDT) Date: Fri, 18 Sep 2020 15:15:28 -0700 From: "Paul E. McKenney" To: "Uladzislau Rezki (Sony)" Cc: LKML , RCU , linux-mm@kvack.org, Andrew Morton , Peter Zijlstra , Michal Hocko , Vlastimil Babka , Thomas Gleixner , "Theodore Y . Ts'o" , Joel Fernandes , Sebastian Andrzej Siewior , Oleksiy Avramchenko Subject: Re: [PATCH 0/4] kvfree_rcu() and _LOCK_NESTING/_PREEMPT_RT Message-ID: <20200918221528.GX29330@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org References: <20200918194817.48921-1-urezki@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200918194817.48921-1-urezki@gmail.com> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 18, 2020 at 09:48:13PM +0200, Uladzislau Rezki (Sony) wrote: > Hello, folk! > > This is another iteration of fixing kvfree_rcu() issues related > to CONFIG_PROVE_RAW_LOCK_NESTING and CONFIG_PREEMPT_RT configs. > > The first discussion is here https://lkml.org/lkml/2020/8/9/195. > > - As an outcome of it, there was a proposal from Peter, instead of > using a speciall "lock-less" flag it is better to move lock-less > access to the pcplist to the separate function. > > - To add a special worker thread that does prefetching of pages > if a per-cpu page cache is depleted(what is absolutely normal). > > As usual, thank you for paying attention to it and your help! > > Uladzislau Rezki (Sony) (4): > rcu/tree: Add a work to allocate pages from regular context > mm: Add __rcu_alloc_page_lockless() func. > rcu/tree: use __rcu_alloc_page_lockless() func. > rcu/tree: Use schedule_delayed_work() instead of WQ_HIGHPRI queue Thank you, Uladzislau! I have pulled this into -rcu for review and testing. I have not yet assigned it to an intended release. Thanx, Paul > include/linux/gfp.h | 1 + > kernel/rcu/tree.c | 90 ++++++++++++++++++++++++--------------------- > mm/page_alloc.c | 82 +++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 132 insertions(+), 41 deletions(-) > > -- > 2.20.1 >