[tip:x86/mm] mm/zsmalloc: Prepare to variable MAX_PHYSMEM_BITS

From: tip-bot for Kirill A. Shutemov
Date: Wed Feb 14 2018 - 08:16:24 EST


Commit-ID: 02390b87a9459937cdb299e6b34ff33992512ec7
Gitweb: https://git.kernel.org/tip/02390b87a9459937cdb299e6b34ff33992512ec7
Author: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
AuthorDate: Wed, 14 Feb 2018 14:16:49 +0300
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 14 Feb 2018 13:11:13 +0100

mm/zsmalloc: Prepare to variable MAX_PHYSMEM_BITS

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>
Reviewed-by: Nitin Gupta <ngupta@xxxxxxxxxx>
Acked-by: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: linux-mm@xxxxxxxxx
Link: http://lkml.kernel.org/r/20180214111656.88514-3-kirill.shutemov@xxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
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 876b4c7..6a59a6d 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 6b8f73d..7168de7 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 c301350..b7f61cd 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