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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 BE81BC433DB for ; Wed, 10 Feb 2021 21:28:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 87EB964ED3 for ; Wed, 10 Feb 2021 21:28:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233591AbhBJV2U (ORCPT ); Wed, 10 Feb 2021 16:28:20 -0500 Received: from mga11.intel.com ([192.55.52.93]:46735 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233516AbhBJVXJ (ORCPT ); Wed, 10 Feb 2021 16:23:09 -0500 IronPort-SDR: BwQ+LmibILsn51LIKJDlluimr1FklBOJ/+9dEgXKB9yd5TM+YnerTPiW2GPTSoHfwEyQoe6ujs 5KBupbDitFzw== X-IronPort-AV: E=McAfee;i="6000,8403,9891"; a="178645165" X-IronPort-AV: E=Sophos;i="5.81,169,1610438400"; d="scan'208";a="178645165" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Feb 2021 13:22:29 -0800 IronPort-SDR: vLcPPosfFeI720bC7q2jpXy18vziRwYYrMpoxtOPHTVzo3YSWOA/doG5f00f+pgd30auxq7BNd XYo+94dUTmvA== X-IronPort-AV: E=Sophos;i="5.81,169,1610438400"; d="scan'208";a="436823973" Received: from iweiny-desk2.sc.intel.com (HELO localhost) ([10.3.52.147]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Feb 2021 13:22:28 -0800 Date: Wed, 10 Feb 2021 13:22:28 -0800 From: Ira Weiny To: Matthew Wilcox Cc: Christoph Hellwig , Andrew Morton , David Sterba , clm@fb.com, josef@toxicpanda.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH V2 4/8] mm/highmem: Add VM_BUG_ON() to mem*_page() calls Message-ID: <20210210212228.GF3014244@iweiny-DESK2.sc.intel.com> References: <20210210062221.3023586-1-ira.weiny@intel.com> <20210210062221.3023586-5-ira.weiny@intel.com> <20210210125502.GD2111784@infradead.org> <20210210162901.GB3014244@iweiny-DESK2.sc.intel.com> <20210210185606.GF308988@casper.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210210185606.GF308988@casper.infradead.org> User-Agent: Mutt/1.11.1 (2018-12-01) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 10, 2021 at 06:56:06PM +0000, Matthew Wilcox wrote: > On Wed, Feb 10, 2021 at 08:29:01AM -0800, Ira Weiny wrote: > > And I thought it was a good idea. Any file system development should have > > tests with DEBUG_VM which should cover Matthew's concern while not having the > > overhead in production. Seemed like a decent compromise? > > Why do you think these paths are only used during file system development? I can't guarantee it but right now most of the conversions I have worked on are in FS's. > They're definitely used by networking, by device drivers of all kinds > and they're probably even used by the graphics system. > > While developers *should* turn on DEBUG_VM during development, a > shockingly high percentage don't even turn on lockdep. Honestly, I don't feel strongly enough to argue it. Andrew? David? David this is going through your tree so would you feel more comfortable with 1 or the other? Ira