Ask a question about size of ca->heap in bcache

[tang.junhui@xxxxxxxxxx]

Hi Mike, Coly, Kent,

As far as I known, ca->heap is used to sort buckets by bucket_prio,
and it would be pushed into ca->free_inc queue after sorting.
I find ca->heap is double the size of the ca->free_inc.
	    !init_fifo(&ca->free_inc,	free << 2, GFP_KERNEL) ||
	    !init_heap(&ca->heap,	free << 3, GFP_KERNEL) ||
I am puzzled about, we only need the size of ca->free_inc buckets, 
Why do we alloc ca->heap the double size of the ca->free_inc?


Thanks,
Tang Junhui