Re: [PATCH 1/4] mm: introduce zone lock wrappers

[Dmitry Ilvokhin <d@ilvokhin.com>]

On Wed, Feb 25, 2026 at 05:51:05PM -0500, Steven Rostedt wrote:
> On Wed, 11 Feb 2026 15:22:13 +0000
> Dmitry Ilvokhin <d@ilvokhin.com> wrote:
> 
> 
> > diff --git a/include/linux/zone_lock.h b/include/linux/zone_lock.h
> > new file mode 100644
> > index 000000000000..c531e26280e6
> > --- /dev/null
> > +++ b/include/linux/zone_lock.h
> > @@ -0,0 +1,38 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +#ifndef _LINUX_ZONE_LOCK_H
> > +#define _LINUX_ZONE_LOCK_H
> > +
> > +#include <linux/mmzone.h>
> > +#include <linux/spinlock.h>
> > +
> > +static inline void zone_lock_init(struct zone *zone)
> > +{
> > +	spin_lock_init(&zone->lock);
> > +}
> > +
> > +#define zone_lock_irqsave(zone, flags)				\
> > +do {								\
> > +	spin_lock_irqsave(&(zone)->lock, flags);		\
> > +} while (0)
> > +
> > +#define zone_trylock_irqsave(zone, flags)			\
> > +({								\
> > +	spin_trylock_irqsave(&(zone)->lock, flags);		\
> > +})
> > +
> > +static inline void zone_unlock_irqrestore(struct zone *zone, unsigned long flags)
> > +{
> > +	spin_unlock_irqrestore(&zone->lock, flags);
> > +}
> > +
> > +static inline void zone_lock_irq(struct zone *zone)
> > +{
> > +	spin_lock_irq(&zone->lock);
> > +}
> > +
> > +static inline void zone_unlock_irq(struct zone *zone)
> > +{
> > +	spin_unlock_irq(&zone->lock);
> > +}
> > +
> > +#endif /* _LINUX_ZONE_LOCK_H */
> 
> Have you thought about adding guards as well. It could make the code simpler:
> 
>   (Not tested)
> 
> #include <linux/cleanup.h>
> [..]
> 
> DEFINE_LOCK_GUARD_1(zonelock_irqsave, struct zone *,
> 		    zone_lock_irqsave(_T->lock, _T->flags),
> 		    zone_unlock_irqrestore(_T->lock, _T->flags),
> 		    unsigned long flags)
> DECLARE_LOCK_GUARD_1_ATTRS(zonelock_irqsave, __acquires(_T), __releases(*(struct zone ***)_T))
> #define class_zonelock_irqsave_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(zonelock_irqsave, _T)
> 
> DEFINE_LOCK_GUARD_1(zonelock_irq, struct zone *,
> 		    zone_lock_irq(_T->lock),
> 		    zone_unlock_irq(_T->lock))
> DECLARE_LOCK_GUARD_1_ATTRS(zonelock_irq, __acquires(_T), __releases(*(struct zone ***)_T))
> #define class_zonelock_irq_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(zonelock_irq, _T)
> 
> Then you could even remove the "flags" variables from the C code, and some goto unlocks.
> 

Thanks, Steve.

I like the idea: guards could indeed simplify parts of the
locking and reduce some of the explicit flags handling.

For this series, though, I'd prefer to keep the changes mostly
mechanical and focused on introducing the wrappers and tracepoints.
Converting to guards would make the transformation less mechanical
and potentially harder to review.

I'd be happy to follow up with a separate patch to explore adding
guards for zone locks and see whether we can simplify the existing
logic further.

> -- Steve