From owner-svn-src-head@freebsd.org Tue Nov 17 22:37:54 2020 Return-Path: Delivered-To: svn-src-head@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id BF3C6471433 for ; Tue, 17 Nov 2020 22:37:54 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: from mail-qv1-xf2e.google.com (mail-qv1-xf2e.google.com [IPv6:2607:f8b0:4864:20::f2e]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "smtp.gmail.com", Issuer "GTS CA 1O1" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4CbLS24psqz3pT0 for ; Tue, 17 Nov 2020 22:37:54 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: by mail-qv1-xf2e.google.com with SMTP id q7so11680379qvt.12 for ; Tue, 17 Nov 2020 14:37:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bsdimp-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=m2wn517wNjHq1/zPdKuyflo4WGHn7NMQqgyEGtj/9Vg=; b=yoXfCrvw5cEbK1EQVqULMkSKc9mybrAONc2006f3+B/LVgGyWTSS57ymPaemezyRia 6vw0C7LGByhesyz4aI+GjmUVNY422z2DZvbHqoLzBs1fE+yUXk8RhIh309ZB7iutGAb1 lfbxQvbUncrf20YQlyq/hayODQ4ks3i43iby5EQ491vrwbV781dimIUG0qqkdRG7rJX/ CMu58qXDKbLUc7yCnhlU3rDgMPAuWWk1ASpnAHx0ZKOIjS1EBah10IzGo1yo9GK+jdrD tdyeiyfLb3T4YJKUL+cDrrBX7o9mmZH9odbPeY2U5hGNHgHQeeLhlrVCDpr/u3IdgNVn T8zg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=m2wn517wNjHq1/zPdKuyflo4WGHn7NMQqgyEGtj/9Vg=; b=NXARYTmqai5HwKa92V7CeCfm5TNFvjw715tEjIkw0/MAs/xPVbRRRA+tETRFFD+7kl xUEehjRwtojXKEeuIj4SszkGyjpDfdzADnzig84HzYotAoq8XmbaxUqlW5lA1kg1k9FI UyYG8HaPlz/6LleJHfA9TCcHQy9wUVzRzl5Dyfah8yFbWzpAg8uwrk7xjj2hUa1qBsoR 6KEqctoq+vbyqyycdbYEiTEpQKyrUmqFJW49yweetcbcSaES3kLqiqgZmSx5nlUPahxt vPnp/vMY/L45a9BJDzgUVxmst3nCeCsMem//m77vxPGc/iyblh20ZFTNfo5hUcpibqHQ X5Nw== X-Gm-Message-State: AOAM532g7DOxa6Blhrahxc8o1Db9V1ttQ2EmIrr+Iqwcqhv5UK/KVzP5 IKedJLq9SNo21XXL07SN4trSLLvTcQqD83XQ3G616w== X-Google-Smtp-Source: ABdhPJw4MaVOJnhqRaNSktRoPUZvgWfmZxgweH/qBXD/xaBtyJrJhTFpQ94uxpdlUUi5xKit10DhAko0elcbHnzKUnk= X-Received: by 2002:ad4:4e13:: with SMTP id dl19mr2011060qvb.24.1605652673723; Tue, 17 Nov 2020 14:37:53 -0800 (PST) MIME-Version: 1.0 References: <202011141920.0AEJKbpO050396@repo.freebsd.org> <20201114205036.tnxvwarsddmu4shz@mutt-hbsd> <20201114205355.j2ejnhouipjr6yhk@mutt-hbsd> <0015bc22-4568-93cc-5c77-e97c4f5e215c@FreeBSD.org> In-Reply-To: <0015bc22-4568-93cc-5c77-e97c4f5e215c@FreeBSD.org> From: Warner Losh Date: Tue, 17 Nov 2020 15:37:42 -0700 Message-ID: Subject: Re: svn commit: r367692 - head/sys/sys To: John Baldwin Cc: Mateusz Guzik , Shawn Webb , src-committers , svn-src-all , svn-src-head X-Rspamd-Queue-Id: 4CbLS24psqz3pT0 X-Spamd-Bar: ---- Authentication-Results: mx1.freebsd.org; none X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[] Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.34 X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 17 Nov 2020 22:37:54 -0000 On Tue, Nov 17, 2020 at 3:18 PM John Baldwin wrote: > On 11/14/20 2:34 PM, Warner Losh wrote: > > true, but a version bump forces that and versions are cheap enough... > > Strictly speaking, version bumps don't force anything to recompile, they > just ensure that newer modules won't load on older kernels. In this case, > the change to sys/ucred.h will result in sys/ucred.h's mtime changing so > that any kernel modules being built via NO_CLEAN=yes will rebuild ok. > > I'm not quite sure where this mantra that version bumps force rebuilds > came from, but they don't. It's true that since it lives in > and most things include that, it mostly forces a rebuild, but that's > mostly a side effect, not due to explicit magic around __FreeBSD_version. > It's more that modules stop loading when there's a version bump. This is both good and bad. It's good when there's a legit, KBI change that's likely to affect modules. This one seems on the edge. ZFS is affected, but most drivers are not. It's bad when there's not really a problem since the last bump and you have to rebuild your kernel + modules to be a matched set. For production, you always want this, but sometimes you want to be able to run slightly newer modules than the kernel and that's oftentimes OK because some bumps don't affect KBI. Warner