From 066123a535927b3f17cac2305258cc71abdb0d92 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 10 Apr 2009 12:02:40 -0700 Subject: percpu: unbreak alpha percpu For the time being, move the generic percpu_*() accessors to linux/percpu.h. asm-generic/percpu.h is meant to carry generic stuff for low level stuff - declarations, definitions and pointer offset calculation and so on but not for generic interface. Signed-off-by: Ingo Molnar --- include/linux/percpu.h | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) (limited to 'include/linux/percpu.h') diff --git a/include/linux/percpu.h b/include/linux/percpu.h index ee5615d6521..cfda2d5ad31 100644 --- a/include/linux/percpu.h +++ b/include/linux/percpu.h @@ -168,4 +168,56 @@ static inline void free_percpu(void *p) #define alloc_percpu(type) (type *)__alloc_percpu(sizeof(type), \ __alignof__(type)) +/* + * Optional methods for optimized non-lvalue per-cpu variable access. + * + * @var can be a percpu variable or a field of it and its size should + * equal char, int or long. percpu_read() evaluates to a lvalue and + * all others to void. + * + * These operations are guaranteed to be atomic w.r.t. preemption. + * The generic versions use plain get/put_cpu_var(). Archs are + * encouraged to implement single-instruction alternatives which don't + * require preemption protection. + */ +#ifndef percpu_read +# define percpu_read(var) \ + ({ \ + typeof(per_cpu_var(var)) __tmp_var__; \ + __tmp_var__ = get_cpu_var(var); \ + put_cpu_var(var); \ + __tmp_var__; \ + }) +#endif + +#define __percpu_generic_to_op(var, val, op) \ +do { \ + get_cpu_var(var) op val; \ + put_cpu_var(var); \ +} while (0) + +#ifndef percpu_write +# define percpu_write(var, val) __percpu_generic_to_op(var, (val), =) +#endif + +#ifndef percpu_add +# define percpu_add(var, val) __percpu_generic_to_op(var, (val), +=) +#endif + +#ifndef percpu_sub +# define percpu_sub(var, val) __percpu_generic_to_op(var, (val), -=) +#endif + +#ifndef percpu_and +# define percpu_and(var, val) __percpu_generic_to_op(var, (val), &=) +#endif + +#ifndef percpu_or +# define percpu_or(var, val) __percpu_generic_to_op(var, (val), |=) +#endif + +#ifndef percpu_xor +# define percpu_xor(var, val) __percpu_generic_to_op(var, (val), ^=) +#endif + #endif /* __LINUX_PERCPU_H */ -- cgit v1.2.3-70-g09d2 From 9b8de7479d0dbab1ed98b5b015d44232c9d3d08e Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 21 Apr 2009 23:00:24 +0100 Subject: FRV: Fix the section attribute on UP DECLARE_PER_CPU() In non-SMP mode, the variable section attribute specified by DECLARE_PER_CPU() does not agree with that specified by DEFINE_PER_CPU(). This means that architectures that have a small data section references relative to a base register may throw up linkage errors due to too great a displacement between where the base register points and the per-CPU variable. On FRV, the .h declaration says that the variable is in the .sdata section, but the .c definition says it's actually in the .data section. The linker throws up the following errors: kernel/built-in.o: In function `release_task': kernel/exit.c:78: relocation truncated to fit: R_FRV_GPREL12 against symbol `per_cpu__process_counts' defined in .data section in kernel/built-in.o kernel/exit.c:78: relocation truncated to fit: R_FRV_GPREL12 against symbol `per_cpu__process_counts' defined in .data section in kernel/built-in.o To fix this, DECLARE_PER_CPU() should simply apply the same section attribute as does DEFINE_PER_CPU(). However, this is made slightly more complex by virtue of the fact that there are several variants on DEFINE, so these need to be matched by variants on DECLARE. Signed-off-by: David Howells Signed-off-by: Linus Torvalds --- arch/alpha/include/asm/percpu.h | 2 +- arch/ia64/include/asm/smp.h | 2 +- arch/x86/include/asm/desc.h | 2 +- arch/x86/include/asm/hardirq.h | 2 +- arch/x86/include/asm/processor.h | 6 +++--- arch/x86/include/asm/tlbflush.h | 2 +- include/asm-generic/percpu.h | 43 ++++++++++++++++++++++++++++++++++++++-- include/linux/percpu.h | 24 ---------------------- net/rds/rds.h | 2 +- 9 files changed, 50 insertions(+), 35 deletions(-) (limited to 'include/linux/percpu.h') diff --git a/arch/alpha/include/asm/percpu.h b/arch/alpha/include/asm/percpu.h index 3495e8e00d7..e9e0bb5a23b 100644 --- a/arch/alpha/include/asm/percpu.h +++ b/arch/alpha/include/asm/percpu.h @@ -73,6 +73,6 @@ extern unsigned long __per_cpu_offset[NR_CPUS]; #endif /* SMP */ -#define DECLARE_PER_CPU(type, name) extern __typeof__(type) per_cpu_var(name) +#include #endif /* __ALPHA_PERCPU_H */ diff --git a/arch/ia64/include/asm/smp.h b/arch/ia64/include/asm/smp.h index 59840833625..d217d1d4e05 100644 --- a/arch/ia64/include/asm/smp.h +++ b/arch/ia64/include/asm/smp.h @@ -58,7 +58,7 @@ extern struct smp_boot_data { extern char no_int_routing __devinitdata; extern cpumask_t cpu_core_map[NR_CPUS]; -DECLARE_PER_CPU(cpumask_t, cpu_sibling_map); +DECLARE_PER_CPU_SHARED_ALIGNED(cpumask_t, cpu_sibling_map); extern int smp_num_siblings; extern void __iomem *ipi_base_addr; extern unsigned char smp_int_redirect; diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h index 5623c50d67b..c45f415ce31 100644 --- a/arch/x86/include/asm/desc.h +++ b/arch/x86/include/asm/desc.h @@ -37,7 +37,7 @@ extern gate_desc idt_table[]; struct gdt_page { struct desc_struct gdt[GDT_ENTRIES]; } __attribute__((aligned(PAGE_SIZE))); -DECLARE_PER_CPU(struct gdt_page, gdt_page); +DECLARE_PER_CPU_PAGE_ALIGNED(struct gdt_page, gdt_page); static inline struct desc_struct *get_cpu_gdt_table(unsigned int cpu) { diff --git a/arch/x86/include/asm/hardirq.h b/arch/x86/include/asm/hardirq.h index 039db6aa8e0..37555e52f98 100644 --- a/arch/x86/include/asm/hardirq.h +++ b/arch/x86/include/asm/hardirq.h @@ -26,7 +26,7 @@ typedef struct { #endif } ____cacheline_aligned irq_cpustat_t; -DECLARE_PER_CPU(irq_cpustat_t, irq_stat); +DECLARE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat); /* We can have at most NR_VECTORS irqs routed to a cpu at a time */ #define MAX_HARDIRQS_PER_CPU NR_VECTORS diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index fcf4d92e7e0..c2cceae709c 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -138,7 +138,7 @@ extern struct tss_struct doublefault_tss; extern __u32 cleared_cpu_caps[NCAPINTS]; #ifdef CONFIG_SMP -DECLARE_PER_CPU(struct cpuinfo_x86, cpu_info); +DECLARE_PER_CPU_SHARED_ALIGNED(struct cpuinfo_x86, cpu_info); #define cpu_data(cpu) per_cpu(cpu_info, cpu) #define current_cpu_data __get_cpu_var(cpu_info) #else @@ -270,7 +270,7 @@ struct tss_struct { } ____cacheline_aligned; -DECLARE_PER_CPU(struct tss_struct, init_tss); +DECLARE_PER_CPU_SHARED_ALIGNED(struct tss_struct, init_tss); /* * Save the original ist values for checking stack pointers during debugging @@ -393,7 +393,7 @@ union irq_stack_union { }; }; -DECLARE_PER_CPU(union irq_stack_union, irq_stack_union); +DECLARE_PER_CPU_FIRST(union irq_stack_union, irq_stack_union); DECLARE_INIT_PER_CPU(irq_stack_union); DECLARE_PER_CPU(char *, irq_stack_ptr); diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h index d3539f998f8..16a5c84b032 100644 --- a/arch/x86/include/asm/tlbflush.h +++ b/arch/x86/include/asm/tlbflush.h @@ -152,7 +152,7 @@ struct tlb_state { struct mm_struct *active_mm; int state; }; -DECLARE_PER_CPU(struct tlb_state, cpu_tlbstate); +DECLARE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate); static inline void reset_lazy_tlbstate(void) { diff --git a/include/asm-generic/percpu.h b/include/asm-generic/percpu.h index b0e63c672eb..af47b9e1006 100644 --- a/include/asm-generic/percpu.h +++ b/include/asm-generic/percpu.h @@ -73,11 +73,50 @@ extern void setup_per_cpu_areas(void); #endif /* SMP */ +#ifndef PER_CPU_BASE_SECTION +#ifdef CONFIG_SMP +#define PER_CPU_BASE_SECTION ".data.percpu" +#else +#define PER_CPU_BASE_SECTION ".data" +#endif +#endif + +#ifdef CONFIG_SMP + +#ifdef MODULE +#define PER_CPU_SHARED_ALIGNED_SECTION "" +#else +#define PER_CPU_SHARED_ALIGNED_SECTION ".shared_aligned" +#endif +#define PER_CPU_FIRST_SECTION ".first" + +#else + +#define PER_CPU_SHARED_ALIGNED_SECTION "" +#define PER_CPU_FIRST_SECTION "" + +#endif + #ifndef PER_CPU_ATTRIBUTES #define PER_CPU_ATTRIBUTES #endif -#define DECLARE_PER_CPU(type, name) extern PER_CPU_ATTRIBUTES \ - __typeof__(type) per_cpu_var(name) +#define DECLARE_PER_CPU_SECTION(type, name, section) \ + extern \ + __attribute__((__section__(PER_CPU_BASE_SECTION section))) \ + PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name + +#define DECLARE_PER_CPU(type, name) \ + DECLARE_PER_CPU_SECTION(type, name, "") + +#define DECLARE_PER_CPU_SHARED_ALIGNED(type, name) \ + DECLARE_PER_CPU_SECTION(type, name, PER_CPU_SHARED_ALIGNED_SECTION) \ + ____cacheline_aligned_in_smp + +#define DECLARE_PER_CPU_PAGE_ALIGNED(type, name) \ + DECLARE_PER_CPU_SECTION(type, name, ".page_aligned") + +#define DECLARE_PER_CPU_FIRST(type, name) \ + DECLARE_PER_CPU_SECTION(type, name, PER_CPU_FIRST_SECTION) #endif /* _ASM_GENERIC_PERCPU_H_ */ diff --git a/include/linux/percpu.h b/include/linux/percpu.h index cfda2d5ad31..f052d818499 100644 --- a/include/linux/percpu.h +++ b/include/linux/percpu.h @@ -9,30 +9,6 @@ #include -#ifndef PER_CPU_BASE_SECTION -#ifdef CONFIG_SMP -#define PER_CPU_BASE_SECTION ".data.percpu" -#else -#define PER_CPU_BASE_SECTION ".data" -#endif -#endif - -#ifdef CONFIG_SMP - -#ifdef MODULE -#define PER_CPU_SHARED_ALIGNED_SECTION "" -#else -#define PER_CPU_SHARED_ALIGNED_SECTION ".shared_aligned" -#endif -#define PER_CPU_FIRST_SECTION ".first" - -#else - -#define PER_CPU_SHARED_ALIGNED_SECTION "" -#define PER_CPU_FIRST_SECTION "" - -#endif - #define DEFINE_PER_CPU_SECTION(type, name, section) \ __attribute__((__section__(PER_CPU_BASE_SECTION section))) \ PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name diff --git a/net/rds/rds.h b/net/rds/rds.h index 619f0a30a4e..71794449ca4 100644 --- a/net/rds/rds.h +++ b/net/rds/rds.h @@ -638,7 +638,7 @@ struct rds_message *rds_send_get_message(struct rds_connection *, void rds_rdma_unuse(struct rds_sock *rs, u32 r_key, int force); /* stats.c */ -DECLARE_PER_CPU(struct rds_statistics, rds_stats); +DECLARE_PER_CPU_SHARED_ALIGNED(struct rds_statistics, rds_stats); #define rds_stats_inc_which(which, member) do { \ per_cpu(which, get_cpu()).member++; \ put_cpu(); \ -- cgit v1.2.3-70-g09d2 From 5028eaa97dd1dab9cd7c30c4d38f71c708ca64bc Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 21 Apr 2009 23:00:29 +0100 Subject: PERCPU: Collect the DECLARE/DEFINE declarations together Collect the DECLARE/DEFINE declarations together in linux/percpu-defs.h so that they're in one place, and give them descriptive comments, particularly the SHARED_ALIGNED variant. It would be nice to collect these in linux/percpu.h, but that's not possible without sorting out the severe #include recursion between the x86 arch headers and the general headers (and possibly other arches too). Signed-off-by: David Howells Signed-off-by: Linus Torvalds --- include/asm-generic/percpu.h | 26 ++------------ include/linux/percpu-defs.h | 84 ++++++++++++++++++++++++++++++++++++++++++++ include/linux/percpu.h | 20 ----------- 3 files changed, 86 insertions(+), 44 deletions(-) create mode 100644 include/linux/percpu-defs.h (limited to 'include/linux/percpu.h') diff --git a/include/asm-generic/percpu.h b/include/asm-generic/percpu.h index af47b9e1006..d7d50d7ee51 100644 --- a/include/asm-generic/percpu.h +++ b/include/asm-generic/percpu.h @@ -1,13 +1,9 @@ #ifndef _ASM_GENERIC_PERCPU_H_ #define _ASM_GENERIC_PERCPU_H_ + #include #include - -/* - * Determine the real variable name from the name visible in the - * kernel sources. - */ -#define per_cpu_var(var) per_cpu__##var +#include #ifdef CONFIG_SMP @@ -101,22 +97,4 @@ extern void setup_per_cpu_areas(void); #define PER_CPU_ATTRIBUTES #endif -#define DECLARE_PER_CPU_SECTION(type, name, section) \ - extern \ - __attribute__((__section__(PER_CPU_BASE_SECTION section))) \ - PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name - -#define DECLARE_PER_CPU(type, name) \ - DECLARE_PER_CPU_SECTION(type, name, "") - -#define DECLARE_PER_CPU_SHARED_ALIGNED(type, name) \ - DECLARE_PER_CPU_SECTION(type, name, PER_CPU_SHARED_ALIGNED_SECTION) \ - ____cacheline_aligned_in_smp - -#define DECLARE_PER_CPU_PAGE_ALIGNED(type, name) \ - DECLARE_PER_CPU_SECTION(type, name, ".page_aligned") - -#define DECLARE_PER_CPU_FIRST(type, name) \ - DECLARE_PER_CPU_SECTION(type, name, PER_CPU_FIRST_SECTION) - #endif /* _ASM_GENERIC_PERCPU_H_ */ diff --git a/include/linux/percpu-defs.h b/include/linux/percpu-defs.h new file mode 100644 index 00000000000..8f921d74f49 --- /dev/null +++ b/include/linux/percpu-defs.h @@ -0,0 +1,84 @@ +#ifndef _LINUX_PERCPU_DEFS_H +#define _LINUX_PERCPU_DEFS_H + +/* + * Determine the real variable name from the name visible in the + * kernel sources. + */ +#define per_cpu_var(var) per_cpu__##var + +/* + * Base implementations of per-CPU variable declarations and definitions, where + * the section in which the variable is to be placed is provided by the + * 'section' argument. This may be used to affect the parameters governing the + * variable's storage. + * + * NOTE! The sections for the DECLARE and for the DEFINE must match, lest + * linkage errors occur due the compiler generating the wrong code to access + * that section. + */ +#define DECLARE_PER_CPU_SECTION(type, name, section) \ + extern \ + __attribute__((__section__(PER_CPU_BASE_SECTION section))) \ + PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name + +#define DEFINE_PER_CPU_SECTION(type, name, section) \ + __attribute__((__section__(PER_CPU_BASE_SECTION section))) \ + PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name + +/* + * Variant on the per-CPU variable declaration/definition theme used for + * ordinary per-CPU variables. + */ +#define DECLARE_PER_CPU(type, name) \ + DECLARE_PER_CPU_SECTION(type, name, "") + +#define DEFINE_PER_CPU(type, name) \ + DEFINE_PER_CPU_SECTION(type, name, "") + +/* + * Declaration/definition used for per-CPU variables that must come first in + * the set of variables. + */ +#define DECLARE_PER_CPU_FIRST(type, name) \ + DECLARE_PER_CPU_SECTION(type, name, PER_CPU_FIRST_SECTION) + +#define DEFINE_PER_CPU_FIRST(type, name) \ + DEFINE_PER_CPU_SECTION(type, name, PER_CPU_FIRST_SECTION) + +/* + * Declaration/definition used for per-CPU variables that must be cacheline + * aligned under SMP conditions so that, whilst a particular instance of the + * data corresponds to a particular CPU, inefficiencies due to direct access by + * other CPUs are reduced by preventing the data from unnecessarily spanning + * cachelines. + * + * An example of this would be statistical data, where each CPU's set of data + * is updated by that CPU alone, but the data from across all CPUs is collated + * by a CPU processing a read from a proc file. + */ +#define DECLARE_PER_CPU_SHARED_ALIGNED(type, name) \ + DECLARE_PER_CPU_SECTION(type, name, PER_CPU_SHARED_ALIGNED_SECTION) \ + ____cacheline_aligned_in_smp + +#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name) \ + DEFINE_PER_CPU_SECTION(type, name, PER_CPU_SHARED_ALIGNED_SECTION) \ + ____cacheline_aligned_in_smp + +/* + * Declaration/definition used for per-CPU variables that must be page aligned. + */ +#define DECLARE_PER_CPU_PAGE_ALIGNED(type, name) \ + DECLARE_PER_CPU_SECTION(type, name, ".page_aligned") + +#define DEFINE_PER_CPU_PAGE_ALIGNED(type, name) \ + DEFINE_PER_CPU_SECTION(type, name, ".page_aligned") + +/* + * Intermodule exports for per-CPU variables. + */ +#define EXPORT_PER_CPU_SYMBOL(var) EXPORT_SYMBOL(per_cpu__##var) +#define EXPORT_PER_CPU_SYMBOL_GPL(var) EXPORT_SYMBOL_GPL(per_cpu__##var) + + +#endif /* _LINUX_PERCPU_DEFS_H */ diff --git a/include/linux/percpu.h b/include/linux/percpu.h index f052d818499..1581ff235c7 100644 --- a/include/linux/percpu.h +++ b/include/linux/percpu.h @@ -9,26 +9,6 @@ #include -#define DEFINE_PER_CPU_SECTION(type, name, section) \ - __attribute__((__section__(PER_CPU_BASE_SECTION section))) \ - PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name - -#define DEFINE_PER_CPU(type, name) \ - DEFINE_PER_CPU_SECTION(type, name, "") - -#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name) \ - DEFINE_PER_CPU_SECTION(type, name, PER_CPU_SHARED_ALIGNED_SECTION) \ - ____cacheline_aligned_in_smp - -#define DEFINE_PER_CPU_PAGE_ALIGNED(type, name) \ - DEFINE_PER_CPU_SECTION(type, name, ".page_aligned") - -#define DEFINE_PER_CPU_FIRST(type, name) \ - DEFINE_PER_CPU_SECTION(type, name, PER_CPU_FIRST_SECTION) - -#define EXPORT_PER_CPU_SYMBOL(var) EXPORT_SYMBOL(per_cpu__##var) -#define EXPORT_PER_CPU_SYMBOL_GPL(var) EXPORT_SYMBOL_GPL(per_cpu__##var) - /* enough to cover all DEFINE_PER_CPUs in modules */ #ifdef CONFIG_MODULES #define PERCPU_MODULE_RESERVE (8 << 10) -- cgit v1.2.3-70-g09d2