Date: Mon, 17 Dec 2012 14:23:51 -0800 From: Navdeep Parhar <np@FreeBSD.org> To: Adrian Chadd <adrian@freebsd.org> Cc: Alfred Perlstein <alfred@freebsd.org>, src-committers@freebsd.org, John Baldwin <jhb@freebsd.org>, svn-src-all@freebsd.org, Alfred Perlstein <bright@mu.org>, Andriy Gapon <avg@freebsd.org>, Gleb Smirnoff <glebius@freebsd.org>, Robert Watson <rwatson@freebsd.org>, Bruce Evans <brde@optusnet.com.au>, svn-src-head@freebsd.org Subject: Re: svn commit: r244112 - head/sys/kern Message-ID: <50CF9B77.6090006@FreeBSD.org> In-Reply-To: <CAJ-VmonBP5chxPROAQya8ckmLzJrMRK%2B2qD_SKpROJO=T71_Kw@mail.gmail.com> References: <201212110708.qBB78EWx025288@svn.freebsd.org> <50CBC285.7060307@mu.org> <20121215161414.V1029@besplex.bde.org> <201212171439.27297.jhb@freebsd.org> <50CF8CE7.4020906@mu.org> <50CF92F0.5020904@FreeBSD.org> <CAJ-VmonBP5chxPROAQya8ckmLzJrMRK%2B2qD_SKpROJO=T71_Kw@mail.gmail.com>
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On 12/17/12 14:02, Adrian Chadd wrote: > On 17 December 2012 13:47, Andriy Gapon <avg@freebsd.org> wrote: > >> But you see, the following is still illogical _to me_. > > And this is the core of the problem. > > A lot of developers are interpreting the KASSERT() conditions as an > invariant condition that, if in any way enabled, should be completely > trusted, believed and cause an immediate panic(). > > However, we leave them out on shipping, production kernels. Why's > that? Because the contract here is "the code should never hit these > situations, so we don't bother checking." > > It's totally understandable at this point why there's such a huge > amount of confusion here. On one hand we have a construct that allows > the developer to enforce correct behaviour and panic early if it gets > caught out; on the other hand we totally ignore all of that in > shipping, production kernels. > > Why are they there, if we just ship production releases with > INVARIANTS disabled? Read the section titled "NOTE TO PEOPLE WHO THINK THAT FreeBSD 10.x IS SLOW:" in /usr/src/UPDATING if you're wondering why. Regards, Navdeep
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