[PATCH v4 06/36] mm: Introduce offset_in_thp

Matthew Wilcox
2020-05-15T13:17:04Z

Mirroring offset_in_page(), this gives you the offset within this
particular page, no matter what size page it is. It optimises down
to offset_in_page() if CONFIG_TRANSPARENT_HUGEPAGE is not set.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
include/linux/mm.h | 1 +
1 file changed, 1 insertion(+)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 088acbda722d..9a55dce6a535 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1577,6 +1577,7 @@ static inline void clear_page_pfmemalloc(struct page *page)
extern void pagefault_out_of_memory(void);

#define offset_in_page(p) ((unsigned long)(p) & ~PAGE_MASK)
+#define offset_in_thp(page, p) ((unsigned long)(p) & (thp_size(page) - 1))

/*
* Flags passed to show_mem() and show_free_areas() to suppress output in
--
2.26.2