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=-5.6 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=no 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 EB080C433DF for ; Fri, 14 Aug 2020 15:26:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B37D920866 for ; Fri, 14 Aug 2020 15:26:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597418786; bh=BuFd0GUohYMykV0bEdLt1waKCKM21ZGzCtbhCO68IFc=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:List-ID: From; b=hOpQMYRzwE5IugVR5iJD/Jvd5VGz9nMBfFVuF50MfUCijV3d9g38zsGEcEbATL60n 747jJfffMvGBojuM7IyPcdK3sMY9Wh4JTyGSS7biYFzdCuQ6XWcCwHfA4CBja+i+8O pHLh4X/I7LEyVZvrOokbDWt5aXzE2J8rbHxe/iig= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726897AbgHNP0Z (ORCPT ); Fri, 14 Aug 2020 11:26:25 -0400 Received: from mail.kernel.org ([198.145.29.99]:57040 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726297AbgHNP0Y (ORCPT ); Fri, 14 Aug 2020 11:26:24 -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 02285207DA; Fri, 14 Aug 2020 15:26:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597418784; bh=BuFd0GUohYMykV0bEdLt1waKCKM21ZGzCtbhCO68IFc=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=IIINUl+lN73fm93kQbcZAXjSlQanUn+3mjuNuD3Nidj6TRiHH1x8JytdH4XNdcU58 9vtGYsGEm0hgOvf4QSYePNsgOTrf5uahsMt09h8BEg99lleRxbDlvyFEdc/ZArMpHw ShSpemX1MWdH1Tp9ugrVarn7gsSnCw5beyosMS8U= Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id CDEEE3522A0E; Fri, 14 Aug 2020 08:26:23 -0700 (PDT) Date: Fri, 14 Aug 2020 08:26:23 -0700 From: "Paul E. McKenney" To: peterz@infradead.org Cc: Thomas Gleixner , Michal Hocko , Uladzislau Rezki , LKML , RCU , linux-mm@kvack.org, Andrew Morton , Vlastimil Babka , Matthew Wilcox , "Theodore Y . Ts'o" , Joel Fernandes , Sebastian Andrzej Siewior , Oleksiy Avramchenko Subject: Re: [RFC-PATCH 1/2] mm: Add __GFP_NO_LOCKS flag Message-ID: <20200814152623.GN4295@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org References: <20200813095840.GA25268@pc636> <874kp6llzb.fsf@nanos.tec.linutronix.de> <20200813133308.GK9477@dhcp22.suse.cz> <87sgcqty0e.fsf@nanos.tec.linutronix.de> <20200813182618.GX2674@hirez.programming.kicks-ass.net> <20200813185257.GF4295@paulmck-ThinkPad-P72> <20200813220619.GA2674@hirez.programming.kicks-ass.net> <875z9m3xo7.fsf@nanos.tec.linutronix.de> <20200814083037.GD3982@worktop.programming.kicks-ass.net> <20200814102306.GK35926@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200814102306.GK35926@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 14, 2020 at 12:23:06PM +0200, peterz@infradead.org wrote: > On Fri, Aug 14, 2020 at 10:30:37AM +0200, Peter Zijlstra wrote: > > > > 1. Prohibit invoking allocators from raw atomic context, such > > > > as when holding a raw spinlock. > > > > > > Clearly the simplest solution but not Pauls favourite and > > > unfortunately he has a good reason. > > > > Which isn't actually stated anywhere I suppose ? > > Introduce raw_kfree_rcu() that doesn't do the allocation, and fix the > few wonky callsites. The problem with that is common code along with the tendency of people to just use the one that "works everywhere". Thanx, Paul