85 lines
2.9 KiB
C
85 lines
2.9 KiB
C
|
#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 */
|