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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 65CC2C2D0E7 for ; Wed, 1 Apr 2020 07:10:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3C5932073B for ; Wed, 1 Apr 2020 07:10:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585725005; bh=kzem1Bc2AHbTTQjVnBgBGysf8SzYnGXPZklGbiFzjso=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=aQcZGxdRtPmeikyKSis5iE1MEbZFUVQx50pRKsp5uIBLH2WH+4yN8ivUP5n91bN3H 2cVo7sBi1AGc+6y8jdCz+sVydRUznS2NYKjh1DxH2/6Xu506JIyKEX6O3c2p1jy1hy OBPu124rtvQnbATvZHfJ6N4DL7jp7uzGiSl50UwA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731975AbgDAHKE (ORCPT ); Wed, 1 Apr 2020 03:10:04 -0400 Received: from mail-wm1-f66.google.com ([209.85.128.66]:51162 "EHLO mail-wm1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731823AbgDAHKD (ORCPT ); Wed, 1 Apr 2020 03:10:03 -0400 Received: by mail-wm1-f66.google.com with SMTP id t128so5381408wma.0; Wed, 01 Apr 2020 00:10:02 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=tKcCvBkl/5wFmhqyWXdNyuguB+1XgXDUmUQ8zhlCfl0=; b=GimWW9vahLRTeKGDBwlaxrahNw06822ARp9fna0DxzM+KxmbLJ/v2mT1rj5pvcL5w+ CyVkT6whSkyl3bLHD74RRKwVnPQEMLY8+9Um0/+A/5KP7p7Z4LhrOEfFS1IrMFE3cRv/ OWvTPVIh/5RfN2HFykkj51lqDaL+eeO+ZukJeBf6QFFm8TIAAvAo5a13QJughJrqmxqn o86FhKk4Pv0I+olbesVuwzNe+4lEJlJjFV3M2CZTtjVqVL51NMWv58rRdOAjTPrD6s81 fjaA+Zrs1NzykRLoR5SwEcSf5TdpqDWgUcUl+KtTcqHwDC6XD73eORDGsN5vzDmUDF4Z sdWA== X-Gm-Message-State: AGi0PuZaSk2bpgbFWYwjRF36q2Sz+AQS9UdNFhHXKwELUEFNjB852Rvz w99NF3o70Y/1Zh6YJNAdIes= X-Google-Smtp-Source: APiQypJKzF9JIQqbmrZ1L+OJq9oATJtUV+U+TwMIOVFC0ButeSV7aj/VbyF6MRit5GbMNX5BdI0M+Q== X-Received: by 2002:a7b:cb59:: with SMTP id v25mr2931801wmj.13.1585725001425; Wed, 01 Apr 2020 00:10:01 -0700 (PDT) Received: from localhost (ip-37-188-180-223.eurotel.cz. [37.188.180.223]) by smtp.gmail.com with ESMTPSA id f141sm1517974wmf.3.2020.04.01.00.09.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 01 Apr 2020 00:10:00 -0700 (PDT) Date: Wed, 1 Apr 2020 09:09:58 +0200 From: Michal Hocko To: Uladzislau Rezki Cc: Joel Fernandes , linux-kernel@vger.kernel.org, linux-mm@kvack.org, rcu@vger.kernel.org, willy@infradead.org, peterz@infradead.org, neilb@suse.com, vbabka@suse.cz, mgorman@suse.de, Andrew Morton , Josh Triplett , Lai Jiangshan , Mathieu Desnoyers , "Paul E. McKenney" , Steven Rostedt Subject: Re: [PATCH RFC] rcu/tree: Use GFP_MEMALLOC for alloc memory to free memory pattern Message-ID: <20200401070958.GB22681@dhcp22.suse.cz> References: <20200331131628.153118-1-joel@joelfernandes.org> <20200331145806.GB236678@google.com> <20200331153450.GM30449@dhcp22.suse.cz> <20200331161215.GA27676@pc636> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200331161215.GA27676@pc636> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 31-03-20 18:12:15, Uladzislau Rezki wrote: > > > > __GFP_ATOMIC | __GFP_HIGH is the way to get an additional access to > > memory reserves regarless of the sleeping status. > > > Michal, just one question here regarding proposed flags. Can we also > tight it with __GFP_RETRY_MAYFAIL flag? Means it also can repeat a few > times in order to increase the chance of being success. yes, __GFP_RETRY_MAYFAIL is perfectly valid with __GFP_ATOMIC. Please note that __GFP_ATOMIC, despite its name, doesn't imply an atomic allocation which cannot sleep. Quite confusing, I know. A much better name would be __GFP_RESERVES or something like that. -- Michal Hocko SUSE Labs