Add an optimized mm_zero_struct_page(), so struct page's are zeroed without calling memset(). We do eight regular stores, thus avoid cost of membar.
Signed-off-by: Pavel Tatashin <[email protected]> Reviewed-by: Steven Sistare <[email protected]> Reviewed-by: Daniel Jordan <[email protected]> Reviewed-by: Bob Picco <[email protected]> --- arch/sparc/include/asm/pgtable_64.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h index 6fbd931f0570..23ad51ea5340 100644 --- a/arch/sparc/include/asm/pgtable_64.h +++ b/arch/sparc/include/asm/pgtable_64.h @@ -230,6 +230,24 @@ extern unsigned long _PAGE_ALL_SZ_BITS; extern struct page *mem_map_zero; #define ZERO_PAGE(vaddr) (mem_map_zero) +/* This macro must be updated when the size of struct page changes, + * so use static assert to enforce the assumed size. + */ +#define mm_zero_struct_page(pp) \ + do { \ + unsigned long *_pp = (void *)(pp); \ + \ + BUILD_BUG_ON(sizeof(struct page) != 64); \ + _pp[0] = 0; \ + _pp[1] = 0; \ + _pp[2] = 0; \ + _pp[3] = 0; \ + _pp[4] = 0; \ + _pp[5] = 0; \ + _pp[6] = 0; \ + _pp[7] = 0; \ + } while (0) + /* PFNs are real physical page numbers. However, mem_map only begins to record * per-page information starting at pfn_base. This is to handle systems where * the first physical page in the machine is at some huge physical address, -- 2.13.3
