Messages in this thread |  | | | Date | Wed, 14 May 2008 11:41:01 -0700 (PDT) | | From | Linus Torvalds <> | | Subject | Re: [announce] "kill the Big Kernel Lock (BKL)" tree | |
On Wed, 14 May 2008, Ingo Molnar wrote:
>
> Linus, Alan: the increased visibility and debuggability of the BKL
> already uncovered a rather serious regression in upstream -git. You
> might want to cherry pick this single fix, it will apply just fine to
> current -git:
Ok, so I'm obviously happy. This is exactly the kind of thing I would want
to see.
That said, the way it is now set up, it's unreasonable to merge anything
directly, and while I can cherry-pick obvious fixes this way, I do think
we could do things better.
It should be possible to set things up so that it's a config option, and
we can mark it EXPERIMENTAL but still merge it into the standard kernel,
so that we'd have the debug stuff there. That would get a lot more
coverage, especially if it all still *works*, even if the debug stuff then
complains (ie it would be nicer if the lock itself didn't start breaking).
So for example, have CONFIG_DEBUG_BKL turn it into a mutex (and select
mutex debugging), and get all the debug coverage that way, but then when
somebody enters the scheduler with the lock held, first complain, but then
auto-release it anyway. That way, bugs get found and complained about, but
hopefully the machine still ends up working.
Linus
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