Re: [patch] sched: fix scheduling latencies for !PREEMPT kernels

William Lee Irwin III
2004-09-15T01:47:23Z

On Tue, 2004-09-14 at 15:19, Alan Cox wrote:
>> Fix the data structure locking starting at the lowest level is how I've
>> always tackled these messes. When the low level locking is right the
>> rest just works (usually 8)).
>> "Lock data not code"

On Tue, Sep 14, 2004 at 08:22:29PM -0400, Lee Revell wrote:
> Although, there is at least one case (reiser3) where we know which data
> structures the BKL is supposed to be protecting, because the code does
> something like reiserfs_write_lock(foo_data_structure) which gets
> define'd away to lock_kernel(). And apparently some of the best and
> brightest on LKML have tried and failed to fix it, and even Hans says
> "it's HARD, the fix is reiser4".
> So, maybe some of the current uses should be tagged as WONTFIX.

I've not heard a peep about anyone trying to fix this. It should be
killed off along with the rest, of course, but like I said before, it's
the messiest, dirtiest, and ugliest code that's left to go through,
which is why it's been left for last. e.g. driver ->ioctl() methods.

-- wli