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| author | Ben Pfaff <blp@nicira.com> | 2013-08-06 14:40:25 -0700 |
|---|---|---|
| committer | Ben Pfaff <blp@nicira.com> | 2013-08-08 13:18:10 -0700 |
| commit | 2ba4f163d9ea84aa8b8e9d8678371a70af766b5e (patch) | |
| tree | 5a68d5749381779a32216618b2c8974b603c13f4 /lib/ovs-thread.h | |
| parent | 9c4c45edc36b88bcb2956140965dbde9224ff967 (diff) | |
| download | openvswitch-2ba4f163d9ea84aa8b8e9d8678371a70af766b5e.tar.gz | |
ovs-thread: Add support for globally visible per-thread data.
DEFINE_PER_THREAD_DATA always declared its data item as "static", meaning
that it was only directly visible within a single translation unit.
This commit adds additional forms of per-thread data that allow the data
to be accessible from multiple translation units.
Signed-off-by: Ben Pfaff <blp@nicira.com>
Diffstat (limited to 'lib/ovs-thread.h')
| -rw-r--r-- | lib/ovs-thread.h | 94 |
1 files changed, 78 insertions, 16 deletions
diff --git a/lib/ovs-thread.h b/lib/ovs-thread.h index 0d54a43fb..abe479ae6 100644 --- a/lib/ovs-thread.h +++ b/lib/ovs-thread.h @@ -193,7 +193,15 @@ void xpthread_create(pthread_t *, pthread_attr_t *, void *(*)(void *), void *); * cross-thread access? yes no yes */ -/* DEFINE_PER_THREAD_DATA(TYPE, NAME, INITIALIZER). +/* For static data, use this macro in a source file: + * + * DEFINE_STATIC_PER_THREAD_DATA(TYPE, NAME, INITIALIZER). + * + * For global data, "declare" the data in the header and "define" it in + * the source file, with: + * + * DECLARE_EXTERN_PER_THREAD_DATA(TYPE, NAME). + * DEFINE_EXTERN_PER_THREAD_DATA(NAME, INITIALIZER). * * One should prefer to use POSIX per-thread data, via pthread_key_t, when its * performance is acceptable, because of its portability (see the table above). @@ -231,23 +239,40 @@ void xpthread_create(pthread_t *, pthread_attr_t *, void *(*)(void *), void *); #error #endif -#define DEFINE_PER_THREAD_DATA(TYPE, NAME, ...) \ - typedef TYPE NAME##_type; \ - static thread_local NAME##_type NAME##_var = __VA_ARGS__; \ - \ - static NAME##_type * \ - NAME##_get_unsafe(void) \ - { \ - return &NAME##_var; \ - } \ - \ - static NAME##_type * \ - NAME##_get(void) \ - { \ - return NAME##_get_unsafe(); \ +#define DEFINE_STATIC_PER_THREAD_DATA(TYPE, NAME, ...) \ + typedef TYPE NAME##_type; \ + \ + static NAME##_type * \ + NAME##_get_unsafe(void) \ + { \ + static thread_local NAME##_type var = __VA_ARGS__; \ + return &var; \ + } \ + \ + static NAME##_type * \ + NAME##_get(void) \ + { \ + return NAME##_get_unsafe(); \ } +#define DECLARE_EXTERN_PER_THREAD_DATA(TYPE, NAME) \ + typedef TYPE NAME##_type; \ + extern thread_local NAME##_type NAME##_var; \ + \ + static inline NAME##_type * \ + NAME##_get_unsafe(void) \ + { \ + return &NAME##_var; \ + } \ + \ + static inline NAME##_type * \ + NAME##_get(void) \ + { \ + return NAME##_get_unsafe(); \ + } +#define DEFINE_EXTERN_PER_THREAD_DATA(NAME, ...) \ + thread_local NAME##_type NAME##_var = __VA_ARGS__; #else /* no C implementation support for thread-local storage */ -#define DEFINE_PER_THREAD_DATA(TYPE, NAME, ...) \ +#define DEFINE_STATIC_PER_THREAD_DATA(TYPE, NAME, ...) \ typedef TYPE NAME##_type; \ static pthread_key_t NAME##_key; \ \ @@ -282,6 +307,43 @@ void xpthread_create(pthread_t *, pthread_attr_t *, void *(*)(void *), void *); } \ return value; \ } +#define DECLARE_EXTERN_PER_THREAD_DATA(TYPE, NAME) \ + typedef TYPE NAME##_type; \ + static pthread_key_t NAME##_key; \ + \ + static inline NAME##_type * \ + NAME##_get_unsafe(void) \ + { \ + return pthread_getspecific(NAME##_key); \ + } \ + \ + NAME##_type *NAME##_get(void); +#define DEFINE_EXTERN_PER_THREAD_DATA(NAME, ...) \ + static void \ + NAME##_once_init(void) \ + { \ + if (pthread_key_create(&NAME##_key, free)) { \ + abort(); \ + } \ + } \ + \ + NAME##_type * \ + NAME##_get(void) \ + { \ + static pthread_once_t once = PTHREAD_ONCE_INIT; \ + NAME##_type *value; \ + \ + pthread_once(&once, NAME##_once_init); \ + value = NAME##_get_unsafe(); \ + if (!value) { \ + static const NAME##_type initial_value = __VA_ARGS__; \ + \ + value = xmalloc(sizeof *value); \ + *value = initial_value; \ + xpthread_setspecific(NAME##_key, value); \ + } \ + return value; \ + } #endif /* DEFINE_PER_THREAD_MALLOCED_DATA(TYPE, NAME). |