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- =====================
- CMA Debugfs Interface
- =====================
- The CMA debugfs interface is useful to retrieve basic information out of the
- different CMA areas and to test allocation/release in each of the areas.
- Each CMA area represents a directory under <debugfs>/cma/, represented by
- its CMA name like below:
- <debugfs>/cma/<cma_name>
- The structure of the files created under that directory is as follows:
- - [RO] base_pfn: The base PFN (Page Frame Number) of the zone.
- - [RO] count: Amount of memory in the CMA area.
- - [RO] order_per_bit: Order of pages represented by one bit.
- - [RO] bitmap: The bitmap of page states in the zone.
- - [WO] alloc: Allocate N pages from that CMA area. For example::
- echo 5 > <debugfs>/cma/<cma_name>/alloc
- would try to allocate 5 pages from the 'cma_name' area.
- - [WO] free: Free N pages from that CMA area, similar to the above.
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