projects / deliverable / linux.git / blame
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1 | #ifndef _LINUX_PERCPU_DEFS_H |
| 2 | #define _LINUX_PERCPU_DEFS_H | |
| 3 | ||
| 4 | /* | |
| 5 | * Determine the real variable name from the name visible in the | |
| 6 | * kernel sources. | |
| 7 | */ | |
| 8 | #define per_cpu_var(var) per_cpu__##var | |
| 9 | ||
| 10 | /* | |
| 11 | * Base implementations of per-CPU variable declarations and definitions, where | |
| 12 | * the section in which the variable is to be placed is provided by the | |
| 13 | * 'section' argument. This may be used to affect the parameters governing the | |
| 14 | * variable's storage. | |
| 15 | * | |
| 16 | * NOTE! The sections for the DECLARE and for the DEFINE must match, lest | |
| 17 | * linkage errors occur due the compiler generating the wrong code to access | |
| 18 | * that section. | |
| 19 | */ | |
| 20 | #define DECLARE_PER_CPU_SECTION(type, name, section) \ | |
| 21 | extern \ | |
| 22 | __attribute__((__section__(PER_CPU_BASE_SECTION section))) \ | |
| 23 | PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name | |
| 24 | ||
| 25 | #define DEFINE_PER_CPU_SECTION(type, name, section) \ | |
| 26 | __attribute__((__section__(PER_CPU_BASE_SECTION section))) \ | |
| b01e8dc3 TH |
27 | PER_CPU_ATTRIBUTES PER_CPU_DEF_ATTRIBUTES \ |
| 28 | __typeof__(type) per_cpu__##name | |
| 5028eaa9 DH |
29 | |
| 30 | /* | |
| 31 | * Variant on the per-CPU variable declaration/definition theme used for | |
| 32 | * ordinary per-CPU variables. | |
| 33 | */ | |
| 34 | #define DECLARE_PER_CPU(type, name) \ | |
| 35 | DECLARE_PER_CPU_SECTION(type, name, "") | |
| 36 | ||
| 37 | #define DEFINE_PER_CPU(type, name) \ | |
| 38 | DEFINE_PER_CPU_SECTION(type, name, "") | |
| 39 | ||
| 40 | /* | |
| 41 | * Declaration/definition used for per-CPU variables that must come first in | |
| 42 | * the set of variables. | |
| 43 | */ | |
| 44 | #define DECLARE_PER_CPU_FIRST(type, name) \ | |
| 45 | DECLARE_PER_CPU_SECTION(type, name, PER_CPU_FIRST_SECTION) | |
| 46 | ||
| 47 | #define DEFINE_PER_CPU_FIRST(type, name) \ | |
| 48 | DEFINE_PER_CPU_SECTION(type, name, PER_CPU_FIRST_SECTION) | |
| 49 | ||
| 50 | /* | |
| 51 | * Declaration/definition used for per-CPU variables that must be cacheline | |
| 52 | * aligned under SMP conditions so that, whilst a particular instance of the | |
| 53 | * data corresponds to a particular CPU, inefficiencies due to direct access by | |
| 54 | * other CPUs are reduced by preventing the data from unnecessarily spanning | |
| 55 | * cachelines. | |
| 56 | * | |
| 57 | * An example of this would be statistical data, where each CPU's set of data | |
| 58 | * is updated by that CPU alone, but the data from across all CPUs is collated | |
| 59 | * by a CPU processing a read from a proc file. | |
| 60 | */ | |
| 61 | #define DECLARE_PER_CPU_SHARED_ALIGNED(type, name) \ | |
| 62 | DECLARE_PER_CPU_SECTION(type, name, PER_CPU_SHARED_ALIGNED_SECTION) \ | |
| 63 | ____cacheline_aligned_in_smp | |
| 64 | ||
| 65 | #define DEFINE_PER_CPU_SHARED_ALIGNED(type, name) \ | |
| 66 | DEFINE_PER_CPU_SECTION(type, name, PER_CPU_SHARED_ALIGNED_SECTION) \ | |
| 67 | ____cacheline_aligned_in_smp | |
| 68 | ||
| 69 | /* | |
| 70 | * Declaration/definition used for per-CPU variables that must be page aligned. | |
| 71 | */ | |
| 72 | #define DECLARE_PER_CPU_PAGE_ALIGNED(type, name) \ | |
| 73 | DECLARE_PER_CPU_SECTION(type, name, ".page_aligned") | |
| 74 | ||
| 75 | #define DEFINE_PER_CPU_PAGE_ALIGNED(type, name) \ | |
| 76 | DEFINE_PER_CPU_SECTION(type, name, ".page_aligned") | |
| 77 | ||
| 78 | /* | |
| 79 | * Intermodule exports for per-CPU variables. | |
| 80 | */ | |
| 81 | #define EXPORT_PER_CPU_SYMBOL(var) EXPORT_SYMBOL(per_cpu__##var) | |
| 82 | #define EXPORT_PER_CPU_SYMBOL_GPL(var) EXPORT_SYMBOL_GPL(per_cpu__##var) | |
| 83 | ||
| 84 | ||
| 85 | #endif /* _LINUX_PERCPU_DEFS_H */ |