From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io1-f72.google.com (mail-io1-f72.google.com [209.85.166.72]) by kanga.kvack.org (Postfix) with ESMTP id B3B5B8E0002 for ; Tue, 15 Jan 2019 12:17:42 -0500 (EST) Received: by mail-io1-f72.google.com with SMTP id f24so2490027ioh.21 for ; Tue, 15 Jan 2019 09:17:42 -0800 (PST) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id x16sor2000402iol.120.2019.01.15.09.17.41 for (Google Transport Security); Tue, 15 Jan 2019 09:17:41 -0800 (PST) MIME-Version: 1.0 References: <20190115164435.8423-1-olof@lixom.net> <20190115170510.GA4274@infradead.org> In-Reply-To: <20190115170510.GA4274@infradead.org> From: Olof Johansson Date: Tue, 15 Jan 2019 09:17:30 -0800 Message-ID: Subject: Re: [PATCH] mm: Make CONFIG_FRAME_VECTOR a visible option Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Hellwig Cc: Andrew Morton , linux-mm , Linux Kernel Mailing List , Jan Kara On Tue, Jan 15, 2019 at 9:05 AM Christoph Hellwig wrote: > > On Tue, Jan 15, 2019 at 08:44:35AM -0800, Olof Johansson wrote: > > CONFIG_FRAME_VECTOR was made an option to avoid including the bloat on > > platforms that try to keep footprint down, which makes sense. > > > > The problem with this is external modules that aren't built in-tree. > > Since they don't have in-tree Kconfig, whether they can be loaded now > > depends on whether your kernel config enabled some completely unrelated > > driver that happened to select it. That's a weird and unpredictable > > situation, and makes for some awkward requirements for the standalone > > modules. > > > > For these reasons, give someone the option to manually enable this when > > configuring the kernel. > > NAK, we should not confuse kernel users for stuff that is out of tree. I'd argue it's *more* confusing to expect users to know about and enable some random V4L driver to get this exported kernel API included or not. Happy to add "If in doubt, say 'n' here" help text, like we do for many many other kernel config options. In this particular case, a module (under early development and not yet ready to upstream, but will be) worked with a random distro kernel that enables the kitchen sink of drivers, but not with a more slimmed down kernel config. Having to enable a driver you'll never use, just to enable some generic exported helpers, is just backwards. -Olof 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=-1.0 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS 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 B2831C43387 for ; Tue, 15 Jan 2019 17:17:43 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6DDE120657 for ; Tue, 15 Jan 2019 17:17:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lixom-net.20150623.gappssmtp.com header.i=@lixom-net.20150623.gappssmtp.com header.b="Lz8/VpBQ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6DDE120657 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lixom.net Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id F3CA68E0005; Tue, 15 Jan 2019 12:17:42 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id EEC518E0002; Tue, 15 Jan 2019 12:17:42 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DDC378E0005; Tue, 15 Jan 2019 12:17:42 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from mail-io1-f72.google.com (mail-io1-f72.google.com [209.85.166.72]) by kanga.kvack.org (Postfix) with ESMTP id B3B5B8E0002 for ; Tue, 15 Jan 2019 12:17:42 -0500 (EST) Received: by mail-io1-f72.google.com with SMTP id f24so2490027ioh.21 for ; Tue, 15 Jan 2019 09:17:42 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:dkim-signature:mime-version:references :in-reply-to:from:date:message-id:subject:to:cc; bh=OyTWDGjB04njMwsJJg++MJFclcQB0WwiuSGTWP72bao=; b=rT24fcqKXIwbMdCKLPlQQk/yYw0KY0tzKj3D8DA5AHuUoOfFE3B4ZDI4O6nkiHs++t d4dYoS6BVgefvdVxmPgGmZxskVa/yHPwdf6+hdCwGR+1t6oROuQkwmSdefiPWCKQ+Qfs D5uJxytKowFiDnzquoFzkYM4qswUAHvLOYnNuf7AcuOcTd4RYsogdbmroYzG89e0/4aA M/W+UQpSgjC0AVjMPCnNM1g7bEbNAaT1ixvVBbFoN/YseEG/8mLMMgrte9wrokr5KnpK f7QeF9x/R2aYwuoPSR9/61WPPnmDIFz7LRufZogx/2Q0a/0GDQZHRZj9DQy5bv6TBJOk RRxA== X-Gm-Message-State: AJcUukdclCcewBVyvjflKsjgo7oZBiFOntmKCpmCzbrpiaFuMHLexZbC CnLjAFzxXser4ik8kKPetAeN00gj/F7RFeE/zHL5cifrRJZGLfs5YH0Iq+qaU7FJiSPOcNo5D5t VfYuy1gJbaSLnVVZPzG2O/yZKQICdJ7Asvybn1sLmblrGwbXMOGNSAMcHmGzRrBGyGq43M1dnTS 8g4V9grkxJWiGdtDZWkN19624NtAV1MyMq/xoQ8EcRfkW5s6g6tVn8gUSoLUpaEyEKQECE6L49w lVsR7ByUwdbfLernpQ3FsH8ydf0fuWf0H7ag5olZIwZlN8lN7yw8SXcaWX1pjRJhdB908Tpqhiw Ai+A18rTOnn73ls7HzbTHh5mrZ2xOXk1SYrV5zrsQIdJl/YcpqZHPoK6IRB37N3NAAFckyd5PiG x X-Received: by 2002:a5e:a708:: with SMTP id b8mr2577752iod.126.1547572662519; Tue, 15 Jan 2019 09:17:42 -0800 (PST) X-Received: by 2002:a5e:a708:: with SMTP id b8mr2577726iod.126.1547572661876; Tue, 15 Jan 2019 09:17:41 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1547572661; cv=none; d=google.com; s=arc-20160816; b=YkZ4GZaG933bUVuZMccX8pc563ZJkQFZLT84GG85Fxn/bbIHkZ27A55Pmilz/qo45O ZS253i9fLh4jv3OYm+kB/JKtEo6K79fpcrauGrxlT7CWJrAzk/msaepyREBKO344S6m2 deJAg3WcCLJnJWhPJYMsZS0L7BZ2coqzhdXtms/HdpDl0kAvLW6LGHhn2By9JINqd/2Q B/Lq2mPTyequl0XexAtriOVE2UpJ2ZYu8ofu5A05WP5Qrmosa0KAEj3IxVGtKXkroJ9d KO52GtSrAlPp1eKlG2Er3FsaKTqh+0+kbgJAemCgRySCcmorfskALJLWwLsBsUzm7jOX 9Ceg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:dkim-signature; bh=OyTWDGjB04njMwsJJg++MJFclcQB0WwiuSGTWP72bao=; b=rWU6wG5zuqeUQUiWdu7VV9/cYW+HxRKECrs/3MCB++F1fLDmPLloCy0tz/QpczREQ6 nxKCMeaZ3me4TS/Lp1+Utq1fBlrco/h093qe0Jli9oPjvczWm/UzDs2d65vlVc+DH14X ag1u20+4OEkvxdydKWlZxNKlYd2yKyd1wenmomcQWzMAadc6sHQzxTHP6UTatnaO02LV y6ZjPMbS1LcoqqkYvymZxk132vR1ayIyuBapvMQKV7irQpWWHXCW3DM908oieC2sfJtY 7qzaSSmTUyxKWKewDUbTLfB2GNE2F4nD5QG/fiTwBq8rKzsMMfLH9IoPxMug7CMmrxOD Jc9g== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@lixom-net.20150623.gappssmtp.com header.s=20150623 header.b="Lz8/VpBQ"; spf=neutral (google.com: 209.85.220.65 is neither permitted nor denied by best guess record for domain of olof@lixom.net) smtp.mailfrom=olof@lixom.net Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id x16sor2000402iol.120.2019.01.15.09.17.41 for (Google Transport Security); Tue, 15 Jan 2019 09:17:41 -0800 (PST) Received-SPF: neutral (google.com: 209.85.220.65 is neither permitted nor denied by best guess record for domain of olof@lixom.net) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@lixom-net.20150623.gappssmtp.com header.s=20150623 header.b="Lz8/VpBQ"; spf=neutral (google.com: 209.85.220.65 is neither permitted nor denied by best guess record for domain of olof@lixom.net) smtp.mailfrom=olof@lixom.net DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=lixom-net.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=OyTWDGjB04njMwsJJg++MJFclcQB0WwiuSGTWP72bao=; b=Lz8/VpBQBg9euPlPuE3cH1KxMTOGd5Rv1KU30bRzWfQOgpwAWL4UmW9ioOyUm22N6P ZLjksmvypvb0QuQe5TlvppW0ws6ereoHPJm3+CtmmFBo2hygTe3M+fOS7fYixDal8+wB g8HPWZtWJwsTKKPb+eO5tKXi+1AtJD1Tq+7tIoJrNNEZH6auJ4QmIhrcxHJBPIFg8Qk2 n942cAdmSPaZZTIU0PJMVLWTNDVjAjrVWXKbqU1LowvHfhzmeOCa8W9YIDUqHlEgG0k9 mM4BCog/mblnuF2+BFAnWtIrHaptDAi123wS2RG+phIi+h7/TQNiOqFTbsESuR+rUNVh 3G5Q== X-Google-Smtp-Source: ALg8bN6+NkI4MSEtHcJA5JExc6UAEsP+8T2ckmtM7ADijpiq1c3056xWHNsqJfLW60/Xd6baPbF/C8nYFc88HBLV04I= X-Received: by 2002:a5e:c107:: with SMTP id v7mr2805592iol.155.1547572661412; Tue, 15 Jan 2019 09:17:41 -0800 (PST) MIME-Version: 1.0 References: <20190115164435.8423-1-olof@lixom.net> <20190115170510.GA4274@infradead.org> In-Reply-To: <20190115170510.GA4274@infradead.org> From: Olof Johansson Date: Tue, 15 Jan 2019 09:17:30 -0800 Message-ID: Subject: Re: [PATCH] mm: Make CONFIG_FRAME_VECTOR a visible option To: Christoph Hellwig Cc: Andrew Morton , linux-mm , Linux Kernel Mailing List , Jan Kara Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Message-ID: <20190115171730.bem8DZ6oRqZLGZFdqsN8sqR7WUZ7F5apN0CiuROg5zo@z> On Tue, Jan 15, 2019 at 9:05 AM Christoph Hellwig wrote: > > On Tue, Jan 15, 2019 at 08:44:35AM -0800, Olof Johansson wrote: > > CONFIG_FRAME_VECTOR was made an option to avoid including the bloat on > > platforms that try to keep footprint down, which makes sense. > > > > The problem with this is external modules that aren't built in-tree. > > Since they don't have in-tree Kconfig, whether they can be loaded now > > depends on whether your kernel config enabled some completely unrelated > > driver that happened to select it. That's a weird and unpredictable > > situation, and makes for some awkward requirements for the standalone > > modules. > > > > For these reasons, give someone the option to manually enable this when > > configuring the kernel. > > NAK, we should not confuse kernel users for stuff that is out of tree. I'd argue it's *more* confusing to expect users to know about and enable some random V4L driver to get this exported kernel API included or not. Happy to add "If in doubt, say 'n' here" help text, like we do for many many other kernel config options. In this particular case, a module (under early development and not yet ready to upstream, but will be) worked with a random distro kernel that enables the kitchen sink of drivers, but not with a more slimmed down kernel config. Having to enable a driver you'll never use, just to enable some generic exported helpers, is just backwards. -Olof