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| author | Keir Fraser <keir.fraser@citrix.com> | 2010-07-13 18:17:28 +0100 |
|---|---|---|
| committer | Keir Fraser <keir.fraser@citrix.com> | 2010-07-13 18:17:28 +0100 |
| commit | ddf3a0035f8bf9018cf1577826e0d35a6829e3a1 (patch) | |
| tree | fda21bee0ae920e2d6ad1a8db42029620da5584d | |
| parent | d0a3c6c7a14fc7f8ed4007656dcc4f0ad0a6f030 (diff) | |
| download | xen-ddf3a0035f8bf9018cf1577826e0d35a6829e3a1.tar.gz xen-ddf3a0035f8bf9018cf1577826e0d35a6829e3a1.tar.bz2 xen-ddf3a0035f8bf9018cf1577826e0d35a6829e3a1.zip | |
x86: optimize this_cpu()
Besides the .text space savings of over 2.5k on x86-64 (1.5k for
x86-32) this removes a load (plus a lea on x86-64) from various
frequently executed code paths, and finally provides a reason (other
than legibility) to prefer this_cpu() over per_cpu() in all places
where smp_processor_id() isn't being called anyway.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
| -rw-r--r-- | xen/include/asm-x86/current.h | 13 | ||||
| -rw-r--r-- | xen/include/asm-x86/percpu.h | 2 |
2 files changed, 11 insertions, 4 deletions
diff --git a/xen/include/asm-x86/current.h b/xen/include/asm-x86/current.h index 0a423fba67..bed04f1c24 100644 --- a/xen/include/asm-x86/current.h +++ b/xen/include/asm-x86/current.h @@ -16,8 +16,12 @@ struct vcpu; struct cpu_info { struct cpu_user_regs guest_cpu_user_regs; - unsigned int processor_id; - struct vcpu *current_vcpu; + unsigned int processor_id; + struct vcpu *current_vcpu; + unsigned long per_cpu_offset; +#ifdef __x86_64__ /* get_stack_bottom() must be 16-byte aligned */ + unsigned long __pad_for_stack_bottom; +#endif }; static inline struct cpu_info *get_cpu_info(void) @@ -35,7 +39,10 @@ static inline struct cpu_info *get_cpu_info(void) #define current (get_current()) #define get_processor_id() (get_cpu_info()->processor_id) -#define set_processor_id(id) (get_cpu_info()->processor_id = (id)) +#define set_processor_id(id) do { \ + struct cpu_info *ci__ = get_cpu_info(); \ + ci__->per_cpu_offset = __per_cpu_offset[ci__->processor_id = (id)]; \ +} while (0) #define guest_cpu_user_regs() (&get_cpu_info()->guest_cpu_user_regs) diff --git a/xen/include/asm-x86/percpu.h b/xen/include/asm-x86/percpu.h index fb1d4140ec..e6faa8ce07 100644 --- a/xen/include/asm-x86/percpu.h +++ b/xen/include/asm-x86/percpu.h @@ -16,7 +16,7 @@ void percpu_init_areas(void); #define per_cpu(var, cpu) \ (*RELOC_HIDE(&per_cpu__##var, __per_cpu_offset[cpu])) #define __get_cpu_var(var) \ - (per_cpu(var, smp_processor_id())) + (*RELOC_HIDE(&per_cpu__##var, get_cpu_info()->per_cpu_offset)) #define DECLARE_PER_CPU(type, name) extern __typeof__(type) per_cpu__##name |