Re: [patch V2 0/7] fs: Substitute bit-spinlocks for PREEMPT_RT and debugging

[Christoph Hellwig]

On Thu, Aug 08, 2019 at 09:54:03AM +0200, Thomas Gleixner wrote:
> > I know.  But the problem here is that normally PG_locked is used together 
> > with wait_on_page_bit_*, but this one instances uses the bit spinlock
> > helpers.  This is the equivalent of calling spin_lock on a struct mutex
> > rather than having a mutex_lock_spin helper for this case.
> 
> Yes, I know :(

But this means we should exclude slub from the bit_spin_lock removal.
It really should use it's own version of it anyhow insted of pretending
that the page lock is a bit spinlock.

> 
> > Does SLUB work on -rt at all?
> 
> It's the only allocator we support with a few tweaks :)

What do you do about this particular piece of code there?