Commit-ID: af6a25f0e1ec0265c267e6ee4513925eaba6d0ed
Gitweb: http://git.kernel.org/tip/af6a25f0e1ec0265c267e6ee4513925eaba6d0ed
Author: Richard Kennedy <richard@xxxxxxxxxxxxxxx>
AuthorDate: Tue, 24 May 2011 14:49:59 +0100
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Wed, 25 May 2011 16:16:41 +0200
x86: Reorder mm_context_t to remove x86_64 alignment padding and thus shrink mm_struct
Reorder mm_context_t to remove alignment padding on 64 bit
builds shrinking its size from 64 to 56 bytes.
This allows mm_struct to shrink from 840 to 832 bytes, so using
one fewer cache lines, and getting more objects per slab when
using slub.
slabinfo mm_struct reports
before :-
Sizes (bytes) Slabs
-----------------------------------
Object : 840 Total : 7
SlabObj: 896 Full : 1
SlabSiz: 16384 Partial: 4
Loss : 56 CpuSlab: 2
Align : 64 Objects: 18
after :-
Sizes (bytes) Slabs
----------------------------------
Object : 832 Total : 7
SlabObj: 832 Full : 1
SlabSiz: 16384 Partial: 4
Loss : 0 CpuSlab: 2
Align : 64 Objects: 19
Signed-off-by: Richard Kennedy <richard@xxxxxxxxxxxxxxx>
Cc: wilsons@xxxxxxxx
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/1306244999.1999.5.camel@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
arch/x86/include/asm/mmu.h | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/mmu.h b/arch/x86/include/asm/mmu.h
index aeff3e8..5f55e69 100644
--- a/arch/x86/include/asm/mmu.h
+++ b/arch/x86/include/asm/mmu.h
@@ -11,14 +11,14 @@
typedef struct {
void *ldt;
int size;
- struct mutex lock;
- void *vdso;
#ifdef CONFIG_X86_64
/* True if mm supports a task running in 32 bit compatibility mode. */
unsigned short ia32_compat;
#endif
+ struct mutex lock;
+ void *vdso;
} mm_context_t;
#ifdef CONFIG_SMP
--
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