Re: [PATCH] KUnit: memcpy: add benchmark

[Andrew Morton]

On Fri, 30 Jan 2026 00:36:30 +0100 Matteo Croce <technoboy85@xxxxxxxxx> wrote:

> > Is cond_resched() inside preempt_disable() actually legal?
> >
> > Might be, but it doesn't make a lot of sense, does it?
> >
> > > +     }
> > > +     preempt_enable();
> > > +
> >
> 
> Right. In a previous version I was doing
> preempt_disable()/preempt_enable() around the two ktime_get_ns(), but
> then I thought that enabling and disabling preemption 100 time was too
> much.
> I'll restore the preempt macros around the actual copy and remove
> cond_resched().

OK.

local_irq_save() would be more accurate.  

Does it really need to copy 4MB?  Smaller would make
local_irq_disable() more viable.

kmalloc(4MB) does seem to be pushing our luck.  I'm spotting

	./arch/arm/configs/pxa_defconfig:CONFIG_ARCH_FORCE_MAX_ORDER=8

which is 1MB?