Document the structure and files under the new debugfs interface. Signed-off-by: Sasha Levin <[email protected]> --- Documentation/cma/debugfs.txt | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) create mode 100644 Documentation/cma/debugfs.txt
diff --git a/Documentation/cma/debugfs.txt b/Documentation/cma/debugfs.txt new file mode 100644 index 0000000..6cef20a --- /dev/null +++ b/Documentation/cma/debugfs.txt @@ -0,0 +1,21 @@ +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 zone represents a directory under <debugfs>/cma/, indexed by the +kernel's CMA index. So the first CMA zone would be: + + <debugfs>/cma/cma-0 + +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-2/alloc + +would try to allocate 5 pages from the cma-2 area. + + - [WO] free: Free N pages from that CMA area, similar to the above. -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
