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=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 EDDE7C43387 for ; Tue, 8 Jan 2019 08:20:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AA72820665 for ; Tue, 8 Jan 2019 08:20:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1546935637; bh=3JGwhMx6n9nR5JpfUor00G2ZX8GTgHYScx/dPcHXk3E=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=owERHPERw5zIphVSq1hNYjVQhuEV/jKXlvm8kBa/h5BI7oeKMBgmY3DCHe+sc5nb+ jJH8Qo6bhUjQKBG7FJcVwIFIbP2ylVasfjKiI8ARBITk7oWbVfwrals+CBcjxyHUHw 9sjN3AiDYcW+NBYB1u83+cuq9qmCla5L98DkSlAA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728041AbfAHIUh (ORCPT ); Tue, 8 Jan 2019 03:20:37 -0500 Received: from mx2.suse.de ([195.135.220.15]:42540 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727368AbfAHIUg (ORCPT ); Tue, 8 Jan 2019 03:20:36 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 578A4AB4D; Tue, 8 Jan 2019 08:20:35 +0000 (UTC) Date: Tue, 8 Jan 2019 09:20:32 +0100 From: Michal Hocko To: Qian Cai Cc: akpm@linux-foundation.org, Pavel.Tatashin@microsoft.com, mingo@kernel.org, mgorman@techsingularity.net, iamjoonsoo.kim@lge.com, tglx@linutronix.de, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] mm/page_owner: fix for deferred struct page init Message-ID: <20190108082032.GP31793@dhcp22.suse.cz> References: <20190103202235.GE31793@dhcp22.suse.cz> <20190104130906.GO31793@dhcp22.suse.cz> <20190104151737.GT31793@dhcp22.suse.cz> <20190104153245.GV31793@dhcp22.suse.cz> <20190107184309.GM31793@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 07-01-19 20:53:08, Qian Cai wrote: > > > On 1/7/19 1:43 PM, Michal Hocko wrote: > > On Fri 04-01-19 15:18:08, Qian Cai wrote: > > [...] > >> Though, I can't see any really benefit of this approach apart from "beautify" > > > > This is not about beautifying! This is about making the code long term > > maintainable. As you can see it is just too easy to break it with the > > current scheme. And that is bad especially when the code is broken > > because of an optimization. > > > > Understood, but the code is now fixed. If there is something fundamentally > broken in the future, it may be a good time then to create a looks like > hundred-line cleanup patch for long-term maintenance at the same time to fix > real bugs. Yeah, so revert = fix and redisign the thing to make the code more robust longterm + allow to catch more allocation. I really fail to see why this has to be repeated several times in this thread. Really. -- Michal Hocko SUSE Labs