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Diffstat (limited to 'Documentation/admin-guide/mm')
| -rw-r--r-- | Documentation/admin-guide/mm/cma_debugfs.rst | 25 | ||||
| -rw-r--r-- | Documentation/admin-guide/mm/index.rst | 1 |
2 files changed, 26 insertions, 0 deletions
diff --git a/Documentation/admin-guide/mm/cma_debugfs.rst b/Documentation/admin-guide/mm/cma_debugfs.rst new file mode 100644 index 000000000000..4e06ffabd78a --- /dev/null +++ b/Documentation/admin-guide/mm/cma_debugfs.rst @@ -0,0 +1,25 @@ +===================== +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 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. diff --git a/Documentation/admin-guide/mm/index.rst b/Documentation/admin-guide/mm/index.rst index 5f61a6c429e0..11db46448354 100644 --- a/Documentation/admin-guide/mm/index.rst +++ b/Documentation/admin-guide/mm/index.rst @@ -26,6 +26,7 @@ the Linux memory management. :maxdepth: 1 concepts + cma_debugfs hugetlbpage idle_page_tracking ksm |