Re: [patch] getting rid of the Big Kernel Spinlock, 2.4.0-test7

From: Alexander Viro (viro@math.psu.edu)
Date: Mon Aug 28 2000 - 11:32:05 EST


On Mon, 28 Aug 2000, Ingo Molnar wrote:

>
> during 2.3 we got rid of 99% of lock_kernel()s within the core kernel.
> IMHO the time has arrived to get rid of the big kernel spinlock forever -
> by changing it to a ordinary semaphore. Most lock_kernel() code paths are

Umm... I would not do that. Reason: right now BKL can be acquired while we
are holding a spinlock. It's a bad idea, but it's possible. With your
change it becomes deadly. Another reason: currently BKL can be taken in
the middle of operations on per-CPU data. It will not block, so nothing
will get that CPU while we are in lock_kernel(). Not true with your patch.

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