From owner-svn-src-all@freebsd.org Sat Apr 9 20:57:01 2016 Return-Path: Delivered-To: svn-src-all@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 E0FFDB09B87; Sat, 9 Apr 2016 20:57:01 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from bigwig.baldwin.cx (bigwig.baldwin.cx [IPv6:2001:470:1f11:75::1]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id C1E521BEC; Sat, 9 Apr 2016 20:57:01 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from ralph.baldwin.cx (c-73-231-226-104.hsd1.ca.comcast.net [73.231.226.104]) by bigwig.baldwin.cx (Postfix) with ESMTPSA id 7D9C0B918; Sat, 9 Apr 2016 16:57:00 -0400 (EDT) From: John Baldwin To: "Bjoern A. Zeeb" Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r297742 - head/sys/netinet Date: Sat, 09 Apr 2016 13:22:19 -0700 Message-ID: <3095089.J0o1iEDduN@ralph.baldwin.cx> User-Agent: KMail/4.14.3 (FreeBSD/10.2-STABLE; KDE/4.14.3; amd64; ; ) In-Reply-To: References: <201604091205.u39C5Oks041429@repo.freebsd.org> <5630207.6cr5Ycyqbh@ralph.baldwin.cx> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.2.7 (bigwig.baldwin.cx); Sat, 09 Apr 2016 16:57:00 -0400 (EDT) X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 09 Apr 2016 20:57:02 -0000 On Saturday, April 09, 2016 06:31:24 PM Bjoern A. Zeeb wrote: > On Sat, 9 Apr 2016, John Baldwin wrote: > > trash user data. In the rest of the tree, we tend to prefer marking items > > as NOFREE instead of this approach putting a priority on stability and > > reliability over memory efficiency. > > > > For all of the zones that you removed NOFREE from, do you know why that was > > added in the first place (e.g. which stale pointers to pcbs could be > > referenced after free)? Did you verify that those conditions have been > > fixed? > > I did check. I did check a few years ago (and I think you had > reviewed that; maybe it was trouble). And the TCP bits here were > the last ones that were problematic back then. With the changes from > r281599 this should no longer be a problem. > > As for the others, a few years ago Andre already removed the NOFREE > and we unconditionally made him back the change out, which was a > mistake as otherwise some of these zones would have been "clean" for > years. Others have had KASSERTs ensuring that on VNET stack they were > actually empty. Ok. I believe one of the old ones fixed long ago were the pcb sysctls. I couldn't recall any other cases that required NOFREE. The network stack is often fairly loose with references especially those that add per-packet overhead (at least historically, the ifnet reference in m_pkthdr is one of the "big" remaining issues IIRC), so I sort of assume it still needs NOFREE as a general rule. -- John Baldwin