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

From: Ingo Molnar (
Date: Mon Aug 28 2000 - 11:47:02 EST

On Mon, 28 Aug 2000, Alexander Viro wrote:

> 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.

hm, shouldnt we fix those places? It sounds extremely dangerous to get the
BKL with a spinlock held.

> With your change it becomes deadly. [...]

agreed, i missed that. Is there any core kernel code that does this? [the
VFS? :-)]

> 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.

oops, another thinko indeed. Sigh. Are there any prominent examples of
this? I think we want to fix these.


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