Re: [PATCH v10 6/6] x86/split_lock: Enable split lock detection by kernel parameter

[Peter Zijlstra]

On Thu, Nov 21, 2019 at 10:53:03AM -0800, Fenghua Yu wrote:

> We are working on a separate patch set to fix all split lock issues
> in atomic bitops. Per Peter Anvin and Tony Luck suggestions:
> 1. Still keep the byte optimization if nr is constant. No split lock.
> 2. If type of *addr is unsigned long, do quadword atomic instruction
>    on addr. No split lock.
> 3. If type of *addr is unsigned int, do word atomic instruction
>    on addr. No split lock.
> 4. Otherwise, re-calculate addr to point the 32-bit address which contains
>    the bit and operate on the bit. No split lock.

Yeah, let's not do that. That sounds overly complicated for no real
purpose.