Re: [PATCH 4/5] mm/hotplug: Avoid RCU stalls when removing large amounts of memory

["Alastair D'Silva" <alastair@d-silva.org>]

On Mon, 2019-06-17 at 09:53 +0300, Mike Rapoport wrote:
> On Mon, Jun 17, 2019 at 02:36:30PM +1000, Alastair D'Silva wrote:
> > From: Alastair D'Silva <alastair@d-silva.org>
> > 
> > When removing sufficiently large amounts of memory, we trigger RCU
> > stall
> > detection. By periodically calling cond_resched(), we avoid bogus
> > stall
> > warnings.
> > 
> > Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
> > ---
> >  mm/memory_hotplug.c | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> > index e096c987d261..382b3a0c9333 100644
> > --- a/mm/memory_hotplug.c
> > +++ b/mm/memory_hotplug.c
> > @@ -578,6 +578,9 @@ void __remove_pages(struct zone *zone, unsigned
> > long phys_start_pfn,
> >  		__remove_section(zone, __pfn_to_section(pfn),
> > map_offset,
> >  				 altmap);
> >  		map_offset = 0;
> > +
> > +		if (!(i & 0x0FFF))
> 
> No magic numbers please. And a comment would be appreciated.
> 

Agreed, thanks for the review.

-- 
Alastair D'Silva           mob: 0423 762 819
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