Show the CMA pages used by cma_alloc in meminfo node.
Tested on RV1126 EVB DDR3:
CmaTotal: 270336 kB
CmaAllocated: 44408 kB
CmaReleased: 225928 kB
CmaFree: 0 kB
The CmaTotal = CmaAllocated + CmaReleased, and the CmaFree is pages
under cma area unused by system.
The CmaAllocated can be calculated by CMA_DEBUGFS.
Tested on RV1126 EVB DDR3:
cat /sys/kernel/debug/cma/*/used
10756
346
The results from cma used is in page count, 1 page = 4kByte
CmaAllocated = 44408kB = 10756 + 346 pages
Change-Id: Ib79001367562c968e6432816b158cba551978173
Signed-off-by: Jianqun Xu <jay.xu@rock-chips.com>
7a669a6418