[PATCH 2/9] mm/zsmalloc: Prepare to variable MAX_PHYSMEM_BITS

From: Kirill A. Shutemov
Date: Wed Feb 14 2018 - 06:17:20 EST


With boot-time switching between paging mode we will have variable
MAX_PHYSMEM_BITS.

Let's use the maximum variable possible for CONFIG_X86_5LEVEL=y
configuration to define zsmalloc data structures.

The patch introduces MAX_POSSIBLE_PHYSMEM_BITS to cover such case.
It also suits well to handle PAE special case.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Acked-by: Minchan Kim <minchan@xxxxxxxxxx>
Reviewed-by: Nitin Gupta <ngupta@xxxxxxxxxx>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@xxxxxxxxx>
---
arch/x86/include/asm/pgtable-3level_types.h | 1 +
arch/x86/include/asm/pgtable_64_types.h | 2 ++
mm/zsmalloc.c | 13 +++++++------
3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/pgtable-3level_types.h b/arch/x86/include/asm/pgtable-3level_types.h
index 876b4c77d983..6a59a6d0cc50 100644
--- a/arch/x86/include/asm/pgtable-3level_types.h
+++ b/arch/x86/include/asm/pgtable-3level_types.h
@@ -44,5 +44,6 @@ typedef union {
*/
#define PTRS_PER_PTE 512

+#define MAX_POSSIBLE_PHYSMEM_BITS 36

#endif /* _ASM_X86_PGTABLE_3LEVEL_DEFS_H */
diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
index 6b8f73dcbc2c..7168de7d34eb 100644
--- a/arch/x86/include/asm/pgtable_64_types.h
+++ b/arch/x86/include/asm/pgtable_64_types.h
@@ -40,6 +40,8 @@ typedef struct { pteval_t pte; } pte_t;
#define P4D_SIZE (_AC(1, UL) << P4D_SHIFT)
#define P4D_MASK (~(P4D_SIZE - 1))

+#define MAX_POSSIBLE_PHYSMEM_BITS 52
+
#else /* CONFIG_X86_5LEVEL */

/*
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index c3013505c305..b7f61cd1c709 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -84,18 +84,19 @@
* This is made more complicated by various memory models and PAE.
*/

-#ifndef MAX_PHYSMEM_BITS
-#ifdef CONFIG_HIGHMEM64G
-#define MAX_PHYSMEM_BITS 36
-#else /* !CONFIG_HIGHMEM64G */
+#ifndef MAX_POSSIBLE_PHYSMEM_BITS
+#ifdef MAX_PHYSMEM_BITS
+#define MAX_POSSIBLE_PHYSMEM_BITS MAX_PHYSMEM_BITS
+#else
/*
* If this definition of MAX_PHYSMEM_BITS is used, OBJ_INDEX_BITS will just
* be PAGE_SHIFT
*/
-#define MAX_PHYSMEM_BITS BITS_PER_LONG
+#define MAX_POSSIBLE_PHYSMEM_BITS BITS_PER_LONG
#endif
#endif
-#define _PFN_BITS (MAX_PHYSMEM_BITS - PAGE_SHIFT)
+
+#define _PFN_BITS (MAX_POSSIBLE_PHYSMEM_BITS - PAGE_SHIFT)

/*
* Memory for allocating for handle keeps object position by
--
2.15.1