X-Git-Url: https://git.whamcloud.com/?a=blobdiff_plain;ds=sidebyside;f=lnet%2Flnet%2Flib-eq.c;h=d0991d9593e0d828b0cb9515153d7fde312b117f;hb=8d8d0f2cacd5769a2e324fbd37f5a0674748621f;hp=b4e4ccc97a99c8075f54407796e0835d3aa3d5f4;hpb=e8ad5c163bfe4085a3132872374bc50b38cb9564;p=fs%2Flustre-release.git diff --git a/lnet/lnet/lib-eq.c b/lnet/lnet/lib-eq.c index b4e4ccc..d0991d9 100644 --- a/lnet/lnet/lib-eq.c +++ b/lnet/lnet/lib-eq.c @@ -41,6 +41,31 @@ #define DEBUG_SUBSYSTEM S_LNET #include +/** + * Create an event queue that has room for \a count number of events. + * + * The event queue is circular and older events will be overwritten by new + * ones if they are not removed in time by the user using the functions + * LNetEQGet(), LNetEQWait(), or LNetEQPoll(). It is up to the user to + * determine the appropriate size of the event queue to prevent this loss + * of events. Note that when EQ handler is specified in \a callback, no + * event loss can happen, since the handler is run for each event deposited + * into the EQ. + * + * \param count The number of events to be stored in the event queue. It + * will be rounded up to the next power of two. + * \param callback A handler function that runs when an event is deposited + * into the EQ. The constant value LNET_EQ_HANDLER_NONE can be used to + * indicate that no event handler is desired. + * \param handle On successful return, this location will hold a handle for + * the newly created EQ. + * + * \retval 0 On success. + * \retval -EINVAL If an parameter is not valid. + * \retval -ENOMEM If memory for the EQ can't be allocated. + * + * \see lnet_eq_handler_t for the discussion on EQ handler semantics. + */ int LNetEQAlloc(unsigned int count, lnet_eq_handler_t callback, lnet_handle_eq_t *handle) @@ -52,7 +77,7 @@ LNetEQAlloc(unsigned int count, lnet_eq_handler_t callback, /* We need count to be a power of 2 so that when eq_{enq,deq}_seq * overflow, they don't skip entries, so the queue has the same - * apparant capacity at all times */ + * apparent capacity at all times */ if (count != LOWEST_BIT_SET(count)) { /* not a power of 2 already */ do { /* knock off all but the top bit... */ @@ -99,6 +124,16 @@ LNetEQAlloc(unsigned int count, lnet_eq_handler_t callback, return (0); } +/** + * Release the resources associated with an event queue if it's idle; + * otherwise do nothing and it's up to the user to try again. + * + * \param eqh A handle for the event queue to be released. + * + * \retval 0 If the EQ is not in use and freed. + * \retval -ENOENT If \a eqh does not point to a valid EQ. + * \retval -EBUSY If the EQ is still in use by some MDs. + */ int LNetEQFree(lnet_handle_eq_t eqh) { @@ -172,7 +207,22 @@ lib_get_event (lnet_eq_t *eq, lnet_event_t *ev) RETURN(rc); } - +/** + * A nonblocking function that can be used to get the next event in an EQ. + * If an event handler is associated with the EQ, the handler will run before + * this function returns successfully. The event is removed from the queue. + * + * \param eventq A handle for the event queue. + * \param event On successful return (1 or -EOVERFLOW), this location will + * hold the next event in the EQ. + * + * \retval 0 No pending event in the EQ. + * \retval 1 Indicates success. + * \retval -ENOENT If \a eventq does not point to a valid EQ. + * \retval -EOVERFLOW Indicates success (i.e., an event is returned) and that + * at least one event between this event and the last event obtained from the + * EQ has been dropped due to limited space in the EQ. + */ int LNetEQGet (lnet_handle_eq_t eventq, lnet_event_t *event) { @@ -182,6 +232,22 @@ LNetEQGet (lnet_handle_eq_t eventq, lnet_event_t *event) event, &which); } +/** + * Block the calling process until there is an event in the EQ. + * If an event handler is associated with the EQ, the handler will run before + * this function returns successfully. This function returns the next event + * in the EQ and removes it from the EQ. + * + * \param eventq A handle for the event queue. + * \param event On successful return (1 or -EOVERFLOW), this location will + * hold the next event in the EQ. + * + * \retval 1 Indicates success. + * \retval -ENOENT If \a eventq does not point to a valid EQ. + * \retval -EOVERFLOW Indicates success (i.e., an event is returned) and that + * at least one event between this event and the last event obtained from the + * EQ has been dropped due to limited space in the EQ. + */ int LNetEQWait (lnet_handle_eq_t eventq, lnet_event_t *event) { @@ -191,6 +257,32 @@ LNetEQWait (lnet_handle_eq_t eventq, lnet_event_t *event) event, &which); } +/** + * Block the calling process until there's an event from a set of EQs or + * timeout happens. + * + * If an event handler is associated with the EQ, the handler will run before + * this function returns successfully, in which case the corresponding event + * is consumed. + * + * LNetEQPoll() provides a timeout to allow applications to poll, block for a + * fixed period, or block indefinitely. + * + * \param eventqs,neq An array of EQ handles, and size of the array. + * \param timeout_ms Time in milliseconds to wait for an event to occur on + * one of the EQs. The constant LNET_TIME_FOREVER can be used to indicate an + * infinite timeout. + * \param event,which On successful return (1 or -EOVERFLOW), \a event will + * hold the next event in the EQs, and \a which will contain the index of the + * EQ from which the event was taken. + * + * \retval 0 No pending event in the EQs after timeout. + * \retval 1 Indicates success. + * \retval -EOVERFLOW Indicates success (i.e., an event is returned) and that + * at least one event between this event and the last event obtained from the + * EQ indicated by \a which has been dropped due to limited space in the EQ. + * \retval -ENOENT If there's an invalid handle in \a eventqs. + */ int LNetEQPoll (lnet_handle_eq_t *eventqs, int neq, int timeout_ms, lnet_event_t *event, int *which)