Re: [v5 1/2] mm: disable interrupts while initializing deferred pages

[Pavel Tatashin <pasha.tatashin@oracle.com>]

> > 
> > We must remove cond_resched() because we can't sleep anymore. They were
> > added to fight NMI timeouts, so I will replace them with
> > touch_nmi_watchdog() in a follow-up fix.
> 
> This makes no sense.  Any code section where we can add cond_resched()
> was never subject to NMI timeouts because that code cannot be running with
> disabled interrupts.
> 

Hi Andrew,

I was talking about this patch:

9b6e63cbf85b89b2dbffa4955dbf2df8250e5375
mm, page_alloc: add scheduling point to memmap_init_zone

Which adds cond_resched() to memmap_init_zone() to avoid NMI timeouts.

memmap_init_zone() is used both, early in boot, when non-deferred struct
pages are initialized, but also may be used later, during memory hotplug.

As I understand, the later case could cause the timeout on non-preemptible
kernels.

My understanding, is that the same logic was used here when cond_resched()s
were added.

Please correct me if I am wrong.

Thank you,
Pavel