From 6065a244a039a23d933e4b803a4e052da2849208 Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Sun, 17 Aug 2014 12:30:47 -0500 Subject: ia64: Replace __get_cpu_var uses __get_cpu_var() is used for multiple purposes in the kernel source. One of them is address calculation via the form &__get_cpu_var(x). This calculates the address for the instance of the percpu variable of the current processor based on an offset. Other use cases are for storing and retrieving data from the current processors percpu area. __get_cpu_var() can be used as an lvalue when writing data or on the right side of an assignment. __get_cpu_var() is defined as : #define __get_cpu_var(var) (*this_cpu_ptr(&(var))) __get_cpu_var() always only does an address determination. However, store and retrieve operations could use a segment prefix (or global register on other platforms) to avoid the address calculation. this_cpu_write() and this_cpu_read() can directly take an offset into a percpu area and use optimized assembly code to read and write per cpu variables. This patch converts __get_cpu_var into either an explicit address calculation using this_cpu_ptr() or into a use of this_cpu operations that use the offset. Thereby address calculations are avoided and less registers are used when code is generated. At the end of the patch set all uses of __get_cpu_var have been removed so the macro is removed too. The patch set includes passes over all arches as well. Once these operations are used throughout then specialized macros can be defined in non -x86 arches as well in order to optimize per cpu access by f.e. using a global register that may be set to the per cpu base. Transformations done to __get_cpu_var() 1. Determine the address of the percpu instance of the current processor. DEFINE_PER_CPU(int, y); int *x = &__get_cpu_var(y); Converts to int *x = this_cpu_ptr(&y); 2. Same as #1 but this time an array structure is involved. DEFINE_PER_CPU(int, y[20]); int *x = __get_cpu_var(y); Converts to int *x = this_cpu_ptr(y); 3. Retrieve the content of the current processors instance of a per cpu variable. DEFINE_PER_CPU(int, y); int x = __get_cpu_var(y) Converts to int x = __this_cpu_read(y); 4. Retrieve the content of a percpu struct DEFINE_PER_CPU(struct mystruct, y); struct mystruct x = __get_cpu_var(y); Converts to memcpy(&x, this_cpu_ptr(&y), sizeof(x)); 5. Assignment to a per cpu variable DEFINE_PER_CPU(int, y) __get_cpu_var(y) = x; Converts to __this_cpu_write(y, x); 6. Increment/Decrement etc of a per cpu variable DEFINE_PER_CPU(int, y); __get_cpu_var(y)++ Converts to __this_cpu_inc(y) Cc: Tony Luck Cc: Fenghua Yu Cc: linux-ia64@vger.kernel.org Signed-off-by: Christoph Lameter Signed-off-by: Tejun Heo --- arch/ia64/include/asm/hw_irq.h | 2 +- arch/ia64/include/asm/sn/arch.h | 4 ++-- arch/ia64/include/asm/sn/nodepda.h | 2 +- arch/ia64/include/asm/switch_to.h | 2 +- arch/ia64/include/asm/uv/uv_hub.h | 2 +- 5 files changed, 6 insertions(+), 6 deletions(-) (limited to 'arch/ia64/include') diff --git a/arch/ia64/include/asm/hw_irq.h b/arch/ia64/include/asm/hw_irq.h index 029bab3..668786e 100644 --- a/arch/ia64/include/asm/hw_irq.h +++ b/arch/ia64/include/asm/hw_irq.h @@ -159,7 +159,7 @@ static inline ia64_vector __ia64_irq_to_vector(int irq) static inline unsigned int __ia64_local_vector_to_irq (ia64_vector vec) { - return __get_cpu_var(vector_irq)[vec]; + return __this_cpu_read(vector_irq[vec]); } #endif diff --git a/arch/ia64/include/asm/sn/arch.h b/arch/ia64/include/asm/sn/arch.h index 7caa1f4..31eb784 100644 --- a/arch/ia64/include/asm/sn/arch.h +++ b/arch/ia64/include/asm/sn/arch.h @@ -57,7 +57,7 @@ struct sn_hub_info_s { u16 nasid_bitmask; }; DECLARE_PER_CPU(struct sn_hub_info_s, __sn_hub_info); -#define sn_hub_info (&__get_cpu_var(__sn_hub_info)) +#define sn_hub_info this_cpu_ptr(&__sn_hub_info) #define is_shub2() (sn_hub_info->shub2) #define is_shub1() (sn_hub_info->shub2 == 0) @@ -72,7 +72,7 @@ DECLARE_PER_CPU(struct sn_hub_info_s, __sn_hub_info); * cpu. */ DECLARE_PER_CPU(short, __sn_cnodeid_to_nasid[MAX_COMPACT_NODES]); -#define sn_cnodeid_to_nasid (&__get_cpu_var(__sn_cnodeid_to_nasid[0])) +#define sn_cnodeid_to_nasid this_cpu_ptr(&__sn_cnodeid_to_nasid[0]) extern u8 sn_partition_id; diff --git a/arch/ia64/include/asm/sn/nodepda.h b/arch/ia64/include/asm/sn/nodepda.h index ee118b9..7c8b471 100644 --- a/arch/ia64/include/asm/sn/nodepda.h +++ b/arch/ia64/include/asm/sn/nodepda.h @@ -70,7 +70,7 @@ typedef struct nodepda_s nodepda_t; */ DECLARE_PER_CPU(struct nodepda_s *, __sn_nodepda); -#define sn_nodepda (__get_cpu_var(__sn_nodepda)) +#define sn_nodepda __this_cpu_read(__sn_nodepda) #define NODEPDA(cnodeid) (sn_nodepda->pernode_pdaindr[cnodeid]) /* diff --git a/arch/ia64/include/asm/switch_to.h b/arch/ia64/include/asm/switch_to.h index d38c7ea..e8f3585 100644 --- a/arch/ia64/include/asm/switch_to.h +++ b/arch/ia64/include/asm/switch_to.h @@ -32,7 +32,7 @@ extern void ia64_load_extra (struct task_struct *task); #ifdef CONFIG_PERFMON DECLARE_PER_CPU(unsigned long, pfm_syst_info); -# define PERFMON_IS_SYSWIDE() (__get_cpu_var(pfm_syst_info) & 0x1) +# define PERFMON_IS_SYSWIDE() (__this_cpu_read(pfm_syst_info) & 0x1) #else # define PERFMON_IS_SYSWIDE() (0) #endif diff --git a/arch/ia64/include/asm/uv/uv_hub.h b/arch/ia64/include/asm/uv/uv_hub.h index 53e9dfa..2a88c720 100644 --- a/arch/ia64/include/asm/uv/uv_hub.h +++ b/arch/ia64/include/asm/uv/uv_hub.h @@ -108,7 +108,7 @@ struct uv_hub_info_s { unsigned char n_val; }; DECLARE_PER_CPU(struct uv_hub_info_s, __uv_hub_info); -#define uv_hub_info (&__get_cpu_var(__uv_hub_info)) +#define uv_hub_info this_cpu_ptr(&__uv_hub_info) #define uv_cpu_hub_info(cpu) (&per_cpu(__uv_hub_info, cpu)) /* -- cgit v1.1