Date: Fri, 10 May 2013 00:13:59 +0200 From: Attilio Rao <attilio@freebsd.org> To: Marcel Moolenaar <marcel@xcllnt.net> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, Marcel Moolenaar <marcel@freebsd.org>, src-committers@freebsd.org Subject: Re: svn commit: r250411 - in head/sys: conf kern sys Message-ID: <CAJ-FndAnfXXbgYxJk=v1wtLHPqmbAHnLsxtdFY8Ae3_P3dd4zA@mail.gmail.com> In-Reply-To: <CC06FD75-868C-40B3-9C10-D66B56327803@xcllnt.net> References: <201305091628.r49GSI33039873@svn.freebsd.org> <CAJ-FndBY%2ByuUdvO4zP3kf2W4gDvB-uih19bqdmkFW3E4NcrHtw@mail.gmail.com> <CC06FD75-868C-40B3-9C10-D66B56327803@xcllnt.net>
next in thread | previous in thread | raw e-mail | index | archive | help
On Thu, May 9, 2013 at 10:56 PM, Marcel Moolenaar <marcel@xcllnt.net> wrote: > > On May 9, 2013, at 9:46 AM, Attilio Rao <attilio@freebsd.org> wrote: > >> On Thu, May 9, 2013 at 6:28 PM, Marcel Moolenaar <marcel@freebsd.org> wrote: >>> Author: marcel >>> Date: Thu May 9 16:28:18 2013 >>> New Revision: 250411 >>> URL: http://svnweb.freebsd.org/changeset/base/250411 >>> >>> Log: >>> Add option WITNESS_NO_VNODE to suppress printing LORs between VNODE >>> locks. To support this, VNODE locks are created with the LK_IS_VNODE >>> flag. This flag is propagated down using the LO_IS_VNODE flag. >>> >>> Note that WITNESS still records the LOR. Only the printing and the >>> optional entering into the kernel debugger is bypassed with the >>> WITNESS_NO_VNODE option. >> >> This is the wrong way to deal with such problem and I avoided to do >> something like that on purpose. > > I disagree. We have known LOR messages between VNODE locks that > pollute the console and so far we haven't fixed the root cause > in some form or shape. Silencing this known case is good to > maximize the attention LORs need to be given while still have > witness involved to catch locking problems with vnodes that are > of a different nature. > >> >> The way to fix this is to implement LK_NOWITNESS on a per-lock basis >> into lockmgr, propagate the same concept to the vn_lock() (which >> should be basically done automatically) and finally identify the >> false-positive case and commit for them explicitely LK_NOWITNESS on a >> per-call basis, explaining in detail why the single case reported is a >> false-positive. > > This is worse. You want witness involved. > >> Please revert this patch asap. > > This change does not inhibit people from fixing the problem at the > root cause, and in the mean time maximize witness' effectiveness. > Calling for a backout is unwarranted and unnecessarily aggressive. I completely disagree with the whole content of your e-mail. Thanks for disrupting a useful tool along with other commits which happened in the past by other people about invariants effectiveness. Attilio -- Peace can only be achieved by understanding - A. Einstein
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAJ-FndAnfXXbgYxJk=v1wtLHPqmbAHnLsxtdFY8Ae3_P3dd4zA>