Re: [PATCH] mm,page_alloc,cma: conditionally prefer cma pageblocks for movable allocations

[Roman Gushchin]

On Thu, Mar 12, 2020 at 12:03:58AM +0100, Vlastimil Babka wrote:
> On 3/11/20 11:58 PM, Roman Gushchin wrote:
> >> 
> >> I agree it should be in the noise. But please do put it behind CONFIG_CMA
> >> #ifdef. My x86_64 desktop distro kernel doesn't have CONFIG_CMA. Even if this is
> >> effectively no-op with __rmqueue_cma_fallback() returning NULL immediately, I
> >> think the compiler cannot eliminate the two zone_page_state()'s which are
> >> atomic_long_read(), even if it's just ultimately READ_ONCE() here, that's a
> >> volatile cast which means elimination not possible AFAIK? Other architectures
> >> might be even more involved.
> > 
> > I agree.
> > 
> > Andrew,
> > can you, please, squash the following diff into the patch?
> 
> Thanks,
> 
> then please add to the result
> 
> Acked-by: Vlastimil Babka <vbabka@xxxxxxx>

Thank you!