proposed changes look good.
comment needed regarding the reason for internally managed per-thread data
(limitation of Posix' PTHREAD_KEYS_MAX)
Kais
On Tue, Aug 6, 2013 at 4:56 PM, Ben Pfaff <b...@nicira.com> wrote:
> 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 <b...@nicira.com>
> ---
> lib/ovs-thread.h | 94
> ++++++++++++++++++++++++++++++++++++++++++++----------
> lib/random.c | 2 +-
> lib/timeval.c | 2 +-
> lib/util.c | 4 ++-
> lib/vlog.c | 2 +-
> 5 files changed, 84 insertions(+), 20 deletions(-)
>
> diff --git a/lib/ovs-thread.h b/lib/ovs-thread.h
> index 0d54a43..abe479a 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).
> diff --git a/lib/random.c b/lib/random.c
> index da29fd0..d6f7d9d 100644
> --- a/lib/random.c
> +++ b/lib/random.c
> @@ -39,7 +39,7 @@
> * cryptographic-quality randomness. */
>
> /* Current random state. */
> -DEFINE_PER_THREAD_DATA(uint32_t, seed, 0);
> +DEFINE_STATIC_PER_THREAD_DATA(uint32_t, seed, 0);
>
> static uint32_t random_next(void);
>
> diff --git a/lib/timeval.c b/lib/timeval.c
> index 05da99e..faf8e7b 100644
> --- a/lib/timeval.c
> +++ b/lib/timeval.c
> @@ -65,7 +65,7 @@ static long long int deadline = LLONG_MAX;
>
> /* Monotonic time, in milliseconds, at which the last call to time_poll()
> woke
> * up. */
> -DEFINE_PER_THREAD_DATA(long long int, last_wakeup, 0);
> +DEFINE_STATIC_PER_THREAD_DATA(long long int, last_wakeup, 0);
>
> static void set_up_timer(void);
> static void set_up_signal(int flags);
> diff --git a/lib/util.c b/lib/util.c
> index 1751c6f..76c33cd 100644
> --- a/lib/util.c
> +++ b/lib/util.c
> @@ -46,7 +46,9 @@ DEFINE_PER_THREAD_MALLOCED_DATA(char *, subprogram_name);
> static char *program_version;
>
> /* Buffer used by ovs_strerror(). */
> -DEFINE_PER_THREAD_DATA(struct { char s[128]; }, strerror_buffer, { "" });
> +DEFINE_STATIC_PER_THREAD_DATA(struct { char s[128]; },
> + strerror_buffer,
> + { "" });
>
> void
> ovs_assert_failure(const char *where, const char *function,
> diff --git a/lib/vlog.c b/lib/vlog.c
> index 26d0e6c..ac229b4 100644
> --- a/lib/vlog.c
> +++ b/lib/vlog.c
> @@ -100,7 +100,7 @@ static struct facility facilities[VLF_N_FACILITIES] = {
> };
>
> /* Sequence number for the message currently being composed. */
> -DEFINE_PER_THREAD_DATA(unsigned int, msg_num, 0);
> +DEFINE_STATIC_PER_THREAD_DATA(unsigned int, msg_num, 0);
>
> /* VLF_FILE configuration.
> *
> --
> 1.7.10.4
>
> _______________________________________________
> dev mailing list
> dev@openvswitch.org
> http://openvswitch.org/mailman/listinfo/dev
>
_______________________________________________
dev mailing list
dev@openvswitch.org
http://openvswitch.org/mailman/listinfo/dev
