Eric Lee / smarc-ti-linux-kernel

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Commit 5028eaa97dd1dab9cd7c30c4d38f71c708ca64bc

Authored by David Howells
Committed by Linus Torvalds
1 parent 9b8de7479d
Exists in master and in 20 other branches dlt-processor-sdk-linux-03.00.00.04, newt-ti-linux-3.12.y, processor-sdk-linux-01.00.00, processor-sdk-linux-02.00.01, smarc-ti-linux-3.12.10, smarc-ti-linux-3.12.y, smarc-ti-linux-3.14.y, smarc-ti-linux-3.15.y, smarc-ti-lsk-linux-4.1.y, smarct3x-processor-sdk-04.01.00.06, smarct3x-processor-sdk-linux-02.00.01, smarct3x-processor-sdk-linux-03.00.00.04, smarct4x-800-processor-sdk-linux-02.00.01, smarct4x-processor-sdk-04.01.00.06, smarct4x-processor-sdk-linux-02.00.01, smarct4x-processor-sdk-linux-03.00.00.04, ti-linux-3.12.y, ti-linux-3.14.y, ti-linux-3.15.y, ti-lsk-linux-4.1.y

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 <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Showing 3 changed files with 86 additions and 44 deletions Side-by-side Diff

include/asm-generic/percpu.h
Diff comments   View file @ 5028eaa
1 1 #ifndef _ASM_GENERIC_PERCPU_H_
2 2 #define _ASM_GENERIC_PERCPU_H_
  3 +
3 4 #include <linux/compiler.h>
4 5 #include <linux/threads.h>
  6 +#include <linux/percpu-defs.h>
5 7  
6   -/*
7   - * Determine the real variable name from the name visible in the
8   - * kernel sources.
9   - */
10   -#define per_cpu_var(var) per_cpu__##var
11   -
12 8 #ifdef CONFIG_SMP
13 9  
14 10 /*
... ... @@ -100,24 +96,6 @@
100 96 #ifndef PER_CPU_ATTRIBUTES
101 97 #define PER_CPU_ATTRIBUTES
102 98 #endif
103   -
104   -#define DECLARE_PER_CPU_SECTION(type, name, section) \
105   - extern \
106   - __attribute__((__section__(PER_CPU_BASE_SECTION section))) \
107   - PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name
108   -
109   -#define DECLARE_PER_CPU(type, name) \
110   - DECLARE_PER_CPU_SECTION(type, name, "")
111   -
112   -#define DECLARE_PER_CPU_SHARED_ALIGNED(type, name) \
113   - DECLARE_PER_CPU_SECTION(type, name, PER_CPU_SHARED_ALIGNED_SECTION) \
114   - ____cacheline_aligned_in_smp
115   -
116   -#define DECLARE_PER_CPU_PAGE_ALIGNED(type, name) \
117   - DECLARE_PER_CPU_SECTION(type, name, ".page_aligned")
118   -
119   -#define DECLARE_PER_CPU_FIRST(type, name) \
120   - DECLARE_PER_CPU_SECTION(type, name, PER_CPU_FIRST_SECTION)
121 99  
122 100 #endif /* _ASM_GENERIC_PERCPU_H_ */
include/linux/percpu-defs.h
Diff comments   View file @ 5028eaa
  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))) \
  27 + PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name
  28 +
  29 +/*
  30 + * Variant on the per-CPU variable declaration/definition theme used for
  31 + * ordinary per-CPU variables.
  32 + */
  33 +#define DECLARE_PER_CPU(type, name) \
  34 + DECLARE_PER_CPU_SECTION(type, name, "")
  35 +
  36 +#define DEFINE_PER_CPU(type, name) \
  37 + DEFINE_PER_CPU_SECTION(type, name, "")
  38 +
  39 +/*
  40 + * Declaration/definition used for per-CPU variables that must come first in
  41 + * the set of variables.
  42 + */
  43 +#define DECLARE_PER_CPU_FIRST(type, name) \
  44 + DECLARE_PER_CPU_SECTION(type, name, PER_CPU_FIRST_SECTION)
  45 +
  46 +#define DEFINE_PER_CPU_FIRST(type, name) \
  47 + DEFINE_PER_CPU_SECTION(type, name, PER_CPU_FIRST_SECTION)
  48 +
  49 +/*
  50 + * Declaration/definition used for per-CPU variables that must be cacheline
  51 + * aligned under SMP conditions so that, whilst a particular instance of the
  52 + * data corresponds to a particular CPU, inefficiencies due to direct access by
  53 + * other CPUs are reduced by preventing the data from unnecessarily spanning
  54 + * cachelines.
  55 + *
  56 + * An example of this would be statistical data, where each CPU's set of data
  57 + * is updated by that CPU alone, but the data from across all CPUs is collated
  58 + * by a CPU processing a read from a proc file.
  59 + */
  60 +#define DECLARE_PER_CPU_SHARED_ALIGNED(type, name) \
  61 + DECLARE_PER_CPU_SECTION(type, name, PER_CPU_SHARED_ALIGNED_SECTION) \
  62 + ____cacheline_aligned_in_smp
  63 +
  64 +#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name) \
  65 + DEFINE_PER_CPU_SECTION(type, name, PER_CPU_SHARED_ALIGNED_SECTION) \
  66 + ____cacheline_aligned_in_smp
  67 +
  68 +/*
  69 + * Declaration/definition used for per-CPU variables that must be page aligned.
  70 + */
  71 +#define DECLARE_PER_CPU_PAGE_ALIGNED(type, name) \
  72 + DECLARE_PER_CPU_SECTION(type, name, ".page_aligned")
  73 +
  74 +#define DEFINE_PER_CPU_PAGE_ALIGNED(type, name) \
  75 + DEFINE_PER_CPU_SECTION(type, name, ".page_aligned")
  76 +
  77 +/*
  78 + * Intermodule exports for per-CPU variables.
  79 + */
  80 +#define EXPORT_PER_CPU_SYMBOL(var) EXPORT_SYMBOL(per_cpu__##var)
  81 +#define EXPORT_PER_CPU_SYMBOL_GPL(var) EXPORT_SYMBOL_GPL(per_cpu__##var)
  82 +
  83 +
  84 +#endif /* _LINUX_PERCPU_DEFS_H */
include/linux/percpu.h
Diff comments   View file @ 5028eaa
... ... @@ -9,26 +9,6 @@
9 9  
10 10 #include <asm/percpu.h>
11 11  
12   -#define DEFINE_PER_CPU_SECTION(type, name, section) \
13   - __attribute__((__section__(PER_CPU_BASE_SECTION section))) \
14   - PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name
15   -
16   -#define DEFINE_PER_CPU(type, name) \
17   - DEFINE_PER_CPU_SECTION(type, name, "")
18   -
19   -#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name) \
20   - DEFINE_PER_CPU_SECTION(type, name, PER_CPU_SHARED_ALIGNED_SECTION) \
21   - ____cacheline_aligned_in_smp
22   -
23   -#define DEFINE_PER_CPU_PAGE_ALIGNED(type, name) \
24   - DEFINE_PER_CPU_SECTION(type, name, ".page_aligned")
25   -
26   -#define DEFINE_PER_CPU_FIRST(type, name) \
27   - DEFINE_PER_CPU_SECTION(type, name, PER_CPU_FIRST_SECTION)
28   -
29   -#define EXPORT_PER_CPU_SYMBOL(var) EXPORT_SYMBOL(per_cpu__##var)
30   -#define EXPORT_PER_CPU_SYMBOL_GPL(var) EXPORT_SYMBOL_GPL(per_cpu__##var)
31   -
32 12 /* enough to cover all DEFINE_PER_CPUs in modules */
33 13 #ifdef CONFIG_MODULES
34 14 #define PERCPU_MODULE_RESERVE (8 << 10)