Re: [PATCH RFC] x86: avoid atomic operation in test_and_set_bit_lock if possible

Ingo Molnar
2011-03-25T19:26:34Z

* Andi Kleen <andi@firstfloor.org> wrote:

> > Could you please try the patch below?
>
> This is very likely not a good idea. I heard some systems can hang
> if you overwrite their PMUs this way and you're unlucky enough :-(

Wrong - in that case all kernels from 2.6.32 to 2.6.38 would already be locking
up. This patch simply restores behavior to essentially what it was before
v2.6.38 - but also adds the warning.

Thanks,

Ingo