From patchwork Tue Jan 7 12:03:20 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: George Dunlap X-Patchwork-Id: 11320809 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8A666930 for ; Tue, 7 Jan 2020 12:04:50 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5B958207E0 for ; Tue, 7 Jan 2020 12:04:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=citrix.com header.i=@citrix.com header.b="bk0dcMw1" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5B958207E0 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=citrix.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1ionaC-0004Tg-Q6; Tue, 07 Jan 2020 12:03:36 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1ionaA-0004TV-Pt for xen-devel@lists.xenproject.org; Tue, 07 Jan 2020 12:03:34 +0000 X-Inumbo-ID: b545f8c2-3145-11ea-bf56-bc764e2007e4 Received: from esa1.hc3370-68.iphmx.com (unknown [216.71.145.142]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id b545f8c2-3145-11ea-bf56-bc764e2007e4; Tue, 07 Jan 2020 12:03:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=citrix.com; s=securemail; t=1578398606; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=puuRhkcyonFCapVybkAEaRG0oYkhfg3Y/NVLt/pkJSU=; b=bk0dcMw13QkK4dVLz6v+9TgNyUijRYScr438YjWfJPGlZYgx6zt5+pBI J2LBWrE/qrWAXbGJzQMpohb4lofHch92NHxBYHCXrz9aF1CsU5Y8/0sAt R9JA+fl+HOk37J5zJnHSzYsGLISzeuHiDOMX81N2XfhiZcoq+4mzzpCbZ I=; Authentication-Results: esa1.hc3370-68.iphmx.com; dkim=none (message not signed) header.i=none; spf=None smtp.pra=george.dunlap@citrix.com; spf=Pass smtp.mailfrom=George.Dunlap@citrix.com; spf=None smtp.helo=postmaster@mail.citrix.com Received-SPF: None (esa1.hc3370-68.iphmx.com: no sender authenticity information available from domain of george.dunlap@citrix.com) identity=pra; client-ip=162.221.158.21; receiver=esa1.hc3370-68.iphmx.com; envelope-from="George.Dunlap@citrix.com"; x-sender="george.dunlap@citrix.com"; x-conformance=sidf_compatible Received-SPF: Pass (esa1.hc3370-68.iphmx.com: domain of George.Dunlap@citrix.com designates 162.221.158.21 as permitted sender) identity=mailfrom; client-ip=162.221.158.21; receiver=esa1.hc3370-68.iphmx.com; envelope-from="George.Dunlap@citrix.com"; x-sender="George.Dunlap@citrix.com"; x-conformance=sidf_compatible; x-record-type="v=spf1"; x-record-text="v=spf1 ip4:209.167.231.154 ip4:178.63.86.133 ip4:195.66.111.40/30 ip4:85.115.9.32/28 ip4:199.102.83.4 ip4:192.28.146.160 ip4:192.28.146.107 ip4:216.52.6.88 ip4:216.52.6.188 ip4:162.221.158.21 ip4:162.221.156.83 ip4:168.245.78.127 ~all" Received-SPF: None (esa1.hc3370-68.iphmx.com: no sender authenticity information available from domain of postmaster@mail.citrix.com) identity=helo; client-ip=162.221.158.21; receiver=esa1.hc3370-68.iphmx.com; envelope-from="George.Dunlap@citrix.com"; x-sender="postmaster@mail.citrix.com"; x-conformance=sidf_compatible IronPort-SDR: ZTtoPcgauaF8uaPhVdzwQ0w5BeDQ+sTmMsbDZYSOQl1cJAfA0BJVvpjvcfAWUg3xqnq5nKdeoU BZ3DyqBObAxa7PqRhhDLZpgctDljG1wuIkmVnmuUFzaW40L1OxHINCzSW73BRQgf06QY53OcQv SRzWJlVEeaIdxu4u1pEHBhu7nEhLLr4dpyE174n98qrooG7ErG6C1Dw0i29+LkfgpEZf9hD3Rq 5luAgu9hopkHJ/asfHNJGoq2xyepL0046wPgbgwX9yKbr/hp+7zLnskAXGR7rVYeGh8zwhKNRi gik= X-SBRS: 2.7 X-MesageID: 10698775 X-Ironport-Server: esa1.hc3370-68.iphmx.com X-Remote-IP: 162.221.158.21 X-Policy: $RELAYED X-IronPort-AV: E=Sophos;i="5.69,406,1571716800"; d="scan'208";a="10698775" From: George Dunlap To: Date: Tue, 7 Jan 2020 12:03:20 +0000 Message-ID: <20200107120320.222364-1-george.dunlap@citrix.com> X-Mailer: git-send-email 2.24.1 MIME-Version: 1.0 Subject: [Xen-devel] [PATCH] MAINTAINERS: Add explicit check-in policy section X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Lars Kurth , Stefano Stabellini , Julien Grall , Wei Liu , Konrad Wilk , Andrew Cooper , Tim Deegan , George Dunlap , Jan Beulich , Ian Jackson Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" The "nesting" section in the MAINTAINERS file was not initially intended to describe the check-in policy for patches, but only how nesting worked; but since there was no check-in policy, it has been acting as a de-facto policy. One problem with this is that the policy is not complete: It doesn't cover open objections, time to check-in, or so on. The other problem with the policy is that, as written, it doesn't account for maintainers submitting patches to files which they themselves maintain. This is fine for situations where there are are multiple maintainers, but not for situations where there is only one maintainer. Add an explicit "Check-in policy" section to the MAINTAINERS document to serve as the canonical reference for the check-in policy. Move paragraphs not explicitly related to nesting into it. While here, "promote" the "The meaning of nesting" section title. DISCUSSION This seems to be a change from people's understanding of the current policy. Most people's understanding of the current policy seems to be: 1. In order to get a change to a given file committed, it must have an Ack or Review from at least one *maintainer* of that file other than the submitter. 2. In the case where a file has only one maintainer, it must have an Ack or Review from a "nested" maintainer. I.e., if I submitted something to x86/mm, it would require an Ack from Jan or Andy, or (in exceptional circumstances) The Rest; but an Ack from (say) Roger or Juergen wouldn't suffice. Let's call this the "maintainer-ack" approach (because it must have an ack or r-b from a maintainer to be checked in), and the proposal in this patch the "maintainer-approval" (since SoB from a maintainer indicates approval). The core issue I have with "maintainer-ack" is that it makes the maintainer less privileged with regard to writing code than non-maintainers. If component X has maintainers A and B, then a non-maintainer can have code checked in if reviewed either by A or B. If A or B wants code checked in, they have to wait for exactly one person to review it. In fact, if B is quite busy, the easiest way for A really to get their code checked in might be to hand it to a non-maintainer N, and ask N to submit it as their own. Then A can Ack the patches and check them in. The current system, therefore, either sets up a perverse incentive (if you think the behavior described above is unacceptable) or unnecessary bureaucracy (if you think it's acceptable). Either way I think we should set up our system to avoid it. Other variations on "maintainer-ack" have been proposed: - Allow maintainer's patches to go in with an R-b from "designated reviewers" - Allow maintainer's patches to go in with an Ack from more general maintainer Both fundamentally make it harder for maintainers to get their code in and/or reviewed effectively than non-maintainers, setting up the perverse incentive / unnecessary bureaucracy. Signed-off-by: George Dunlap --- v2: - Modify "sufficient time" to "sufficient time and/or warning". - Add a comment explicitly stating that there are exceptions. - Move some of the alternate proposals into the changelog itself CC: Ian Jackson CC: Wei Liu CC: Andrew Cooper CC: Jan Beulich CC: Tim Deegan CC: Konrad Wilk CC: Stefano Stabellini CC: Julien Grall CC: Lars Kurth This is a follow-up to the discussion in `[PATCH for-4.12] passthrough/vtd: Drop the "workaround_bios_bug" logic entirely`, specifically Message-ID: <5C9CF25A020000780022291B@prv1-mh.provo.novell.com> Another approach would be to say that in the case of multiple maintainers, the maintainers themselves can decide to mandate each other's Ack. For instance, Dario and I could agree that we don't need each others' ack for changes to the scheduler, but Andy and Jan could agree that they do need each other's Ack for changes to the x86 code. Checks that maintainers themselves have agreed on will produce neither perverse incentives, nor be considered "unnecessary". --- MAINTAINERS | 53 +++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 47 insertions(+), 6 deletions(-) diff --git a/MAINTAINERS b/MAINTAINERS index eaea4620e2..9d15afa595 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -104,7 +104,53 @@ Descriptions of section entries: xen-maintainers- -The meaning of nesting: + Check-in policy + =============== + +In order for a patch to be checked in, in general, several conditions +must be met: + +1. In order to get a change to a given file committed, it must have + the approval of at least one maintainer of that file. + + A patch of course needs Acks from the maintainers of each file that + it changes; so a patch which changes xen/arch/x86/traps.c, + xen/arch/x86/mm/p2m.c, and xen/arch/x86/mm/shadow/multi.c would + require an Ack from each of the three sets of maintainers. + + See below for rules on nested maintainership. + +2. It must have an Acked-by or a Reviewed-by from someone other than + the submitter. + +3. Sufficient time and/or warning must have been given for anyone to + respond. This depends in large part upon the urgency and nature of + the patch. For a straightforward uncontroversial patch, a day or + two is sufficient; for a controversial patch, perhaps waiting a + week and then saying "I intend to check this in tomorrow unless I + hear otherwise". + +4. There must be no "open" objections. + +In a case where one person submits a patch and a maintainer gives an +Ack, the Ack stands in for both the approval requirement (#1) and the +Acked-by-non-submitter requirement (#2). + +In a case where a maintainer themselves submits a patch, the +Signed-off-by meets the approval requirement (#1); so an Ack or Review +from anyone in the community suffices for requirement #2. + +Maintainers may choose to override non-maintainer objections in the +case that consensus can't be reached. + +As always, no policy can cover all possible situations. In +exceptional circumstances, committers may commit a patch in absence of +one or more of the above requirements, if they are reasonably +confident that the other maintainers will approve of their decision in +retrospect. + + The meaning of nesting + ====================== Many maintainership areas are "nested": for example, there are entries for xen/arch/x86 as well as xen/arch/x86/mm, and even @@ -118,11 +164,6 @@ the Ack of the xen/arch/x86/mm/shadow maintainer for that part of the patch, but would not require the Ack of the xen/arch/x86 maintainer or the xen/arch/x86/mm maintainer. -(A patch of course needs acks from the maintainers of each file that -it changes; so a patch which changes xen/arch/x86/traps.c, -xen/arch/x86/mm/p2m.c, and xen/arch/x86/mm/shadow/multi.c would -require an Ack from each of the three sets of maintainers.) - 2. In unusual circumstances, a more general maintainer's Ack can stand in for or even overrule a specific maintainer's Ack. Unusual circumstances might include: