diff mbox series

[RFC,09/24] x86/mm: Introduce VMEMMAP_SIZE/VMEMMAP_END macro

Message ID 20200915125947.26204-10-songmuchun@bytedance.com (mailing list archive)
State New, archived
Headers show
Series mm/hugetlb: Free some vmemmap pages of hugetlb page | expand

Commit Message

Muchun Song Sept. 15, 2020, 12:59 p.m. UTC 
In the later patch, we will walk the page table for vmemmap area.
So we want to know the range of vmemmap area addresses in order to
distinguish whether it comes from vememmap areas. If not, just we
can do not walk the page table.

Signed-off-by: Muchun Song <songmuchun@bytedance.com>
---
 arch/x86/include/asm/pgtable_64_types.h | 8 ++++++++
 1 file changed, 8 insertions(+)
diff mbox series

Patch

diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
index 52e5f5f2240d..bedbd2e7d06c 100644
--- a/arch/x86/include/asm/pgtable_64_types.h
+++ b/arch/x86/include/asm/pgtable_64_types.h
@@ -139,6 +139,14 @@  extern unsigned int ptrs_per_p4d;
 # define VMEMMAP_START		__VMEMMAP_BASE_L4
 #endif /* CONFIG_DYNAMIC_MEMORY_LAYOUT */
 
+/*
+ * VMEMMAP_SIZE - allows the whole linear region to be covered by
+ *                a struct page array.
+ */
+#define VMEMMAP_SIZE		(1UL << (__VIRTUAL_MASK_SHIFT - PAGE_SHIFT - \
+					 1 + ilog2(sizeof(struct page))))
+#define VMEMMAP_END		(VMEMMAP_START + VMEMMAP_SIZE)
+
 #define VMALLOC_END		(VMALLOC_START + (VMALLOC_SIZE_TB << 40) - 1)
 
 #define MODULES_VADDR		(__START_KERNEL_map + KERNEL_IMAGE_SIZE)