Re: [PATCH 2/2] percpu: km: no need to consider pcpu_group_offsets[0]

[Dennis Zhou]

On Tue, Feb 26, 2019 at 03:15:50PM +0000, Christopher Lameter wrote:
> On Mon, 25 Feb 2019, dennis@xxxxxxxxxx wrote:
> 
> > > @@ -67,7 +67,7 @@ static struct pcpu_chunk *pcpu_create_chunk(gfp_t gfp)
> > >  		pcpu_set_page_chunk(nth_page(pages, i), chunk);
> > >
> > >  	chunk->data = pages;
> > > -	chunk->base_addr = page_address(pages) - pcpu_group_offsets[0];
> > > +	chunk->base_addr = page_address(pages);
> > >
> > >  	spin_lock_irqsave(&pcpu_lock, flags);
> > >  	pcpu_chunk_populated(chunk, 0, nr_pages, false);
> > > --
> > > 2.16.4
> > >
> >
> > While I do think you're right, creating a chunk is not a part of the
> > critical path and subtracting 0 is incredibly minor overhead. So I'd
> > rather keep the code as is to maintain consistency between percpu-vm.c
> > and percpu-km.c.
> 
> Well it is confusing if there the expression is there but never used. It
> is clearer with the patch.
> 

Okay. I'll apply it with your ack if that's fine.

Thanks,
Dennis