malloc() size in CMA region seems to be aligned to CMA_ALIGNMENT

[lunar12 lunartwix]

A 4MB dma_alloc_coherent  in kernel after malloc(2*1024) 40 times in
CMA region by user space will cause an error on our ARM 3.18 kernel
platform with a 32MB CMA.

It seems that the malloc in CMA region will be aligned to
CMA_ALIGNMENT everytime even if the requested malloc size is very
small so the CMA region is not available after the malloc operations.

Is there any configuraiton that can change this behavior??

Thanks

Cheers
Ken