From owner-svn-src-head@freebsd.org Tue Apr 11 06:21:06 2017 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id A5705D39A68; Tue, 11 Apr 2017 06:21:06 +0000 (UTC) (envelope-from pkelsey@gmail.com) Received: from mail-pf0-x244.google.com (mail-pf0-x244.google.com [IPv6:2607:f8b0:400e:c00::244]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 6D18CFFD; Tue, 11 Apr 2017 06:21:06 +0000 (UTC) (envelope-from pkelsey@gmail.com) Received: by mail-pf0-x244.google.com with SMTP id o126so11802874pfb.1; Mon, 10 Apr 2017 23:21:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:sender:in-reply-to:references:from:date:message-id :subject:to:cc; bh=cFbAu4IRz2bq1VNmWydhWGGEuKEiVTawLVOdBnumFTY=; b=aQ7kvlQaKUAfBlmTiW2ciE3sDiOA56TpIu3z5eZkSWORZ2dni9qw5nDa+x5DbK/2kD 23yCIS5HNhUDiKHWFkvw7FATNwQwEecCbZjzwryAq5ghtmR1d5pHyij9iP5yaBbqJz61 y9ZklQ6NBgx1HhWr5dGXl7YahSMN6nm9x9ct6bTIoVAdL3hjq8Q0TRj811L8ZiFJAV7Y SjiNn0GkL0p491BDiYs8x6jLoE2dICus8AsivKYxzdspZxJxIaJjE3ckH1x8Kq+XGIya wWiWBEOz96UDVrXxytMbNKE5Yq2UaB2AtUTx7hq+QaQaAqJqYvurF89uaYNWThOyFGpE EmfA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:sender:in-reply-to:references:from :date:message-id:subject:to:cc; bh=cFbAu4IRz2bq1VNmWydhWGGEuKEiVTawLVOdBnumFTY=; b=SCFX62OXsylqMDYE1+B1LWb16kcddNKm3TELkARhhAmzQh45vJsGGvJ+33ascAsQFo 6iryCj+4omG/kEQkiAbpDf7Wt2/LCc1Hw9ZVouAm4sCuUJlBYbexpdbqACScAx5YVDG3 LK61g4uaeyDfADIPaiQ9vIy1VT10gzvsPQXTnI7IETi0hGyS0ODKmC82f3dIsBIsgVW5 6Le1HfPK3NzUE2LWBxpsFgXLQqFeqV6C3hnWN5eiqvRxfe2047iiRcjLqaLrKnjEMcYV xjgZEiBwfWpag2K0THUJLPr2PLP0SYQCGFKV8yBPVMuBUk9yTvvD7f46lI3+YvhucWNy 3hgA== X-Gm-Message-State: AFeK/H3euhwFYaHUxT9HQ7F5GnAzuRKkdzZzyZV+rUeOqIOVv83LgCEcN3V02dyZFcwG7Guxs/yWl7agL3qinw== X-Received: by 10.99.117.8 with SMTP id q8mr53551030pgc.106.1491891665796; Mon, 10 Apr 2017 23:21:05 -0700 (PDT) MIME-Version: 1.0 Sender: pkelsey@gmail.com Received: by 10.100.162.34 with HTTP; Mon, 10 Apr 2017 23:21:05 -0700 (PDT) In-Reply-To: <2086739.zQDsh9Zz6K@ralph.baldwin.cx> References: <201704090200.v39203Vf072867@repo.freebsd.org> <3233183.B722KJrnTC@ralph.baldwin.cx> <2086739.zQDsh9Zz6K@ralph.baldwin.cx> From: Patrick Kelsey Date: Tue, 11 Apr 2017 02:21:05 -0400 X-Google-Sender-Auth: hda3QoAVw-NhHhcV7RYBOt5ygHA Message-ID: Subject: Re: svn commit: r316648 - in head/sys: amd64/amd64 amd64/include arm/arm arm/include arm64/include cddl/dev/dtrace/aarch64 cddl/dev/dtrace/amd64 cddl/dev/dtrace/arm cddl/dev/dtrace/i386 cddl/dev/dtrace... To: John Baldwin Cc: Jung-uk Kim , svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.23 X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.23 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, 11 Apr 2017 06:21:06 -0000 On Tue, Apr 11, 2017 at 1:24 AM, John Baldwin wrote: > On Monday, April 10, 2017 04:26:03 PM Patrick Kelsey wrote: > > On Mon, Apr 10, 2017 at 1:43 PM, John Baldwin wrote: > > > > > On Monday, April 10, 2017 01:23:04 PM Jung-uk Kim wrote: > > > > On 04/08/2017 22:00, Patrick Kelsey wrote: > > > > > Author: pkelsey > > > > > Date: Sun Apr 9 02:00:03 2017 > > > > > New Revision: 316648 > > > > > URL: https://svnweb.freebsd.org/changeset/base/316648 > > > > > > > > > > Log: > > > > > Corrected misspelled versions of rendezvous. > > > > > > > > > > The MFC will include a compat definition of > > > smp_no_rendevous_barrier() > > > > > that calls smp_no_rendezvous_barrier(). > > > > > > > > > > Reviewed by: gnn, kib > > > > > MFC after: 1 week > > > > > Differential Revision: https://reviews.freebsd.org/D10313 > > > > ... > > > > > > > > We knew about the problem but we didn't fix it because it breaks KPI. > > > > For example, sysutils/virtualbox-ose-kmod. If you really want to MFC > > > > this change, you have to implement shims. > > > > > > Also, the function isn't actually called, but is only used in > comparisons > > > in smp_rendezvous_action(). To do a compat shim you will need to > either > > > change these comparisons to compare against both function pointers or > > > define the alternate symbol as an alias of the existing function. That > > > only helps the KBI though. For the KPI would just use a #define to > point > > > to the new name. > > > > > > > That's a good point about the comparisons in smp_rendezvous_action() - > if I > > had managed to miss that detail all the way through the compat shim > > implementation, it would have littered pointless empty function > invocations > > and atomic increments into all the uses of smp_rendezvous() that used > > smp_no_rendezvous_barrier for at least one of the stages. > > > > I don't think we have an established place to define machine-independent > > symbol aliases. Approaching that through linker scripts would require > > spamming a PROVIDE() statement into each of the arch-specific scripts. > > Since this is a function, I think a better way than the symbol alias + > > #define approach would be to just define a function pointer called > > smp_no_rendevous_barrier that gets statically initialized to > > smp_no_rendezvous_barrier. In that case, the extern decl takes care of > the > > KPI, the corresponding symbol definition takes care of the KBI, and it > has > > a minimal, MI, code footprint. > > I was thinking something along the lines of __weak_reference() from > sys/cdefs.h. Actually, maybe > __strong_reference(smp_no_rendezvous, smp_no_rendevous_barrier) > would be sufficient? > > __strong_reference() is it. > > Either that, or I relax the goal of purging it entirely and put the > compat > > shim in current also to sidestep the port-patching issue. > > Well, I'd like to not have it live around forever, but we could add the > compat shim to HEAD in the short term (also makes MFC slightly simpler as > you just group the two commits together when you MFC). Once the port is > patched with the updated FreeBSD_version we can remove the shim from HEAD. > > So far it doesn't look like patching ports will be much of an issue. I extracted sources for all ports that contained INSTALL_KLD in their Makefile and grepped them for smp_no_rendevous - the only ports turned up that way are emulators/virtualbox-ose-additions and emulators/virtualbox-ose-kmod. One set of patches will serve both, and I've sent them off to the maintainers. -Patrick