Date: Thu, 13 Dec 2012 00:33:37 +0200 From: Andriy Gapon <avg@FreeBSD.org> To: Alfred Perlstein <bright@mu.org> Cc: Adrian Chadd <adrian@FreeBSD.org>, src-committers@FreeBSD.org, John Baldwin <jhb@FreeBSD.org>, svn-src-all@FreeBSD.org, Alfred Perlstein <alfred@FreeBSD.org>, svn-src-head@FreeBSD.org Subject: Re: svn commit: r244112 - head/sys/kern Message-ID: <50C90641.4030000@FreeBSD.org> In-Reply-To: <50C904B8.6000502@mu.org> References: <201212110708.qBB78EWx025288@svn.freebsd.org> <201212121046.43706.jhb@freebsd.org> <CAJ-Vmo=U04GX%2BZyKuzXLwV%2BPpzU6_dm5BCmL=DWfsmhTVAR%2BsA@mail.gmail.com> <201212121658.49048.jhb@freebsd.org> <CAJ-Vmom8aivK7Z95%2BSwigReOTdn-OwXspK3pXO=0CVr1y1Unzg@mail.gmail.com> <50C904B8.6000502@mu.org>
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on 13/12/2012 00:27 Alfred Perlstein said the following: > On 12/12/12 2:15 PM, Adrian Chadd wrote: >> On 12 December 2012 13:58, John Baldwin <jhb@freebsd.org> wrote: >> >> >>> (Note that the primary reason I know for people not running with INVARIANTS >>> enabled is not that they don't want panics, but that they don't want the >>> performance hit.) >> Well, it would be nice to be able to enable invariants on some >> shipping "debug" versions of images in order to gather more data >> without crashing the kernel. > Yes, two of my employers were more of "we want to get more debug metrics, we > have the spare cycles, but we can't deal with superfluous panics". > > It also allows us "non-architects" to slip in a debug image when we have spare > cpu without getting yelled at for "crashing the $foo". There is clearly something wrong with this sort of mentality. If you find instances where a developer put panic(9) (or KASSERT or etc) to mean "maybe here is a bug, let's just panic", then let's get those things fixed. But most of assertions in our code that are know to me really mean that a real bug has already occurred, that portions of kernel state are corrupted and there is no going back to a sane state, only going forward to corrupting more and more. -- Andriy Gapon
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