Date: Thu, 15 Nov 2012 16:39:55 +0000 From: Attilio Rao <attilio@freebsd.org> To: Adrian Chadd <adrian@freebsd.org> Cc: "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org>, Giovanni Trematerra <giovanni.trematerra@gmail.com>, freebsd-arch@freebsd.org Subject: Re: [RFQ] make witness panic an option Message-ID: <CAJ-FndCZPand_rx_uXUeetGMUZu1syGwjdFS7jv9BwdzuXvXOA@mail.gmail.com> In-Reply-To: <CAJ-VmonE3myRyeZ%2BAe0ZOXf7wKvC44rRVkFfDaEwnk8C-=5uoA@mail.gmail.com> References: <CAJ-Vmo=i=Amo_QqHi4GnGie0Gc0YnK3XaRKjvBO-=SFboFYPmA@mail.gmail.com> <CACfq090EiEiG7Ou2ZMUafWN6GLT9RNK1Q4tiOHnOBWe8GYJDjA@mail.gmail.com> <CAJ-VmonE3myRyeZ%2BAe0ZOXf7wKvC44rRVkFfDaEwnk8C-=5uoA@mail.gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On 11/15/12, Adrian Chadd <adrian@freebsd.org> wrote: > On 15 November 2012 05:27, Giovanni Trematerra > <giovanni.trematerra@gmail.com> wrote: > >> I really do think that is a very bad idea. >> When a locking assertion fails you have just to stop your mind and >> think what's wrong, >> no way to postpone on this. > > Not all witness panics are actually fatal. For a developer who is > sufficiently cluey in their area, they are quite likely able to just > stare at the code paths for a while to figure out why the > incorrectness occured. The problem is that such mechanism can be abused, just like the BLESSING one and that's why this is disabled by default. I believe having a mechanism to use printf for witness is not a good idea. > As I said, I do this primarily so I can sprinkle lots of lock > owned/unowned assertions around my driver(s) and then use that to > catch when things aren't being correct. Having to reboot upon _every_ > lock assertion quickly got old. You can use it as a local patch then. This is not really the usual way to develop locking policies. 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-FndCZPand_rx_uXUeetGMUZu1syGwjdFS7jv9BwdzuXvXOA>