We know that if a system supports multiple hugetlb page sizes,
the desired hugetlb page size can be specified in bits [26:31]
of the mmap() flag arguments. The value in these 6 bits will be
the shift of each hugetlb page size.
So add a macro to get the page size shift and then calculate the
corresponding hugetlb page size, using flag x.
Cc: Ben Gardon <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Michael Kerrisk <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Suggested-by: Ben Gardon <[email protected]>
Signed-off-by: Yanan Wang <[email protected]>
Reviewed-by: Ben Gardon <[email protected]>
---
include/uapi/linux/mman.h | 2 ++
tools/include/uapi/linux/mman.h | 2 ++
2 files changed, 4 insertions(+)
diff --git a/include/uapi/linux/mman.h b/include/uapi/linux/mman.h
index f55bc680b5b0..d72df73b182d 100644
--- a/include/uapi/linux/mman.h
+++ b/include/uapi/linux/mman.h
@@ -41,4 +41,6 @@
#define MAP_HUGE_2GB HUGETLB_FLAG_ENCODE_2GB
#define MAP_HUGE_16GB HUGETLB_FLAG_ENCODE_16GB
+#define MAP_HUGE_PAGE_SIZE(x) (1ULL << ((x >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK))
+
#endif /* _UAPI_LINUX_MMAN_H */
diff --git a/tools/include/uapi/linux/mman.h b/tools/include/uapi/linux/mman.h
index f55bc680b5b0..d72df73b182d 100644
--- a/tools/include/uapi/linux/mman.h
+++ b/tools/include/uapi/linux/mman.h
@@ -41,4 +41,6 @@
#define MAP_HUGE_2GB HUGETLB_FLAG_ENCODE_2GB
#define MAP_HUGE_16GB HUGETLB_FLAG_ENCODE_16GB
+#define MAP_HUGE_PAGE_SIZE(x) (1ULL << ((x >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK))
+
#endif /* _UAPI_LINUX_MMAN_H */
--
2.19.1