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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B93BDC433FE for ; Mon, 11 Oct 2021 09:07:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 98AEB60F5B for ; Mon, 11 Oct 2021 09:07:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235387AbhJKJJQ convert rfc822-to-8bit (ORCPT ); Mon, 11 Oct 2021 05:09:16 -0400 Received: from eu-smtp-delivery-151.mimecast.com ([185.58.86.151]:53218 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235182AbhJKJJP (ORCPT ); Mon, 11 Oct 2021 05:09:15 -0400 Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-231-ej5tqsneN3Wj5_e8EA6vRA-1; Mon, 11 Oct 2021 10:07:13 +0100 X-MC-Unique: ej5tqsneN3Wj5_e8EA6vRA-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) by AcuMS.aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) with Microsoft SMTP Server (TLS) id 15.0.1497.23; Mon, 11 Oct 2021 10:07:10 +0100 Received: from AcuMS.Aculab.com ([fe80::994c:f5c2:35d6:9b65]) by AcuMS.aculab.com ([fe80::994c:f5c2:35d6:9b65%12]) with mapi id 15.00.1497.023; Mon, 11 Oct 2021 10:07:10 +0100 From: David Laight To: 'Joe Perches' , Andy Shevchenko , Brendan Higgins , Peter Zijlstra , "Thomas Gleixner" , "linux-kernel@vger.kernel.org" , "linux-kselftest@vger.kernel.org" , "kunit-dev@googlegroups.com" , "linux-media@vger.kernel.org" CC: Ingo Molnar , Will Deacon , Waiman Long , Boqun Feng , Sakari Ailus , Laurent Pinchart , Mauro Carvalho Chehab , Andrew Morton , Miguel Ojeda , "jic23@kernel.org" , "linux@rasmusvillemoes.dk" , Thorsten Leemhuis Subject: RE: [PATCH v4 2/7] kernel.h: Split out container_of() and typeof_member() macros Thread-Topic: [PATCH v4 2/7] kernel.h: Split out container_of() and typeof_member() macros Thread-Index: AQHXu5hFfxTcZGJlCEqsZaCSpNxtnavNhYtQ Date: Mon, 11 Oct 2021 09:07:10 +0000 Message-ID: <33e1be3f6e3b40eeb6f3cd5524e649fe@AcuMS.aculab.com> References: <20211007154407.29746-1-andriy.shevchenko@linux.intel.com> <20211007154407.29746-3-andriy.shevchenko@linux.intel.com> <86b05929e5aa8fa6e975c59cf523ad84498351b6.camel@perches.com> In-Reply-To: <86b05929e5aa8fa6e975c59cf523ad84498351b6.camel@perches.com> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=C51A453 smtp.mailfrom=david.laight@aculab.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Joe Perches > Sent: 07 October 2021 17:28 ... > IMO: this new file is missing 2 #include directives. ... > This is not a self-contained header as it requires > #include > which should be at the top of this file. ... > And this requires > > #include And I bet the biggest problem is the time spent by the compiler searching down the -I path for headers. If you count system calls during a build I suspect that failed opens of .h files dominate. To see how much this really costs try running a build with a (traditional) NFS mounted source tree - where every directory name in a filename requires an NFS file handle lookup. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)