Re: [PATCH v2] mm/cma: always check which page cause allocation failure

[Vlastimil Babka]

On 11/25/2015 06:32 AM, Joonsoo Kim wrote:
> Now, we have tracepoint in test_pages_isolated() to notify
> pfn which cannot be isolated. But, in alloc_contig_range(),
> some error path doesn't call test_pages_isolated() so it's still
> hard to know exact pfn that causes allocation failure.
> 
> This patch change this situation by calling test_pages_isolated()
> in almost error path. In allocation failure case, some overhead
> is added by this change, but, allocation failure is really rare
> event so it would not matter.
> 
> In fatal signal pending case, we don't call test_pages_isolated()
> because this failure is intentional one.
> 
> There was a bogus outer_start problem due to unchecked buddy order
> and this patch also fix it. Before this patch, it didn't matter,
> because end result is same thing. But, after this patch,
> tracepoint will report failed pfn so it should be accurate.
> 
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>

Acked-by: Vlastimil Babka <vbabka@xxxxxxx>

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