1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
2 * vim:expandtab:shiftwidth=8:tabstop=8:
6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 only,
10 * as published by the Free Software Foundation.
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * General Public License version 2 for more details (a copy is included
16 * in the LICENSE file that accompanied this code).
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19 * version 2 along with this program; If not, see
20 * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
22 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
23 * CA 95054 USA or visit www.sun.com if you need additional information or
29 * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
30 * Use is subject to license terms.
33 * This file is part of Lustre, http://www.lustre.org/
34 * Lustre is a trademark of Sun Microsystems, Inc.
38 * Library level Event queue management routines
41 #define DEBUG_SUBSYSTEM S_LNET
42 #include <lnet/lib-lnet.h>
45 * Create an event queue that has room for \a count number of events.
47 * The event queue is circular and older events will be overwritten by new
48 * ones if they are not removed in time by the user using the functions
49 * LNetEQGet(), LNetEQWait(), or LNetEQPoll(). It is up to the user to
50 * determine the appropriate size of the event queue to prevent this loss
51 * of events. Note that when EQ handler is specified in \a callback, no
52 * event loss can happen, since the handler is run for each event deposited
55 * \param count The number of events to be stored in the event queue. It
56 * will be rounded up to the next power of two.
57 * \param callback A handler function that runs when an event is deposited
58 * into the EQ. The constant value LNET_EQ_HANDLER_NONE can be used to
59 * indicate that no event handler is desired.
60 * \param handle On successful return, this location will hold a handle for
61 * the newly created EQ.
63 * \retval 0 On success.
64 * \retval -EINVAL If an parameter is not valid.
65 * \retval -ENOMEM If memory for the EQ can't be allocated.
67 * \see lnet_eq_handler_t for the discussion on EQ handler semantics.
70 LNetEQAlloc(unsigned int count, lnet_eq_handler_t callback,
71 lnet_handle_eq_t *handle)
75 LASSERT (the_lnet.ln_init);
76 LASSERT (the_lnet.ln_refcount > 0);
78 /* We need count to be a power of 2 so that when eq_{enq,deq}_seq
79 * overflow, they don't skip entries, so the queue has the same
80 * apparent capacity at all times */
82 if (count != LOWEST_BIT_SET(count)) { /* not a power of 2 already */
83 do { /* knock off all but the top bit... */
84 count &= ~LOWEST_BIT_SET (count);
85 } while (count != LOWEST_BIT_SET(count));
87 count <<= 1; /* ...and round up */
90 if (count == 0) /* catch bad parameter / overflow on roundup */
97 LIBCFS_ALLOC(eq->eq_events, count * sizeof(lnet_event_t));
98 if (eq->eq_events == NULL) {
106 /* NB this resets all event sequence numbers to 0, to be earlier
108 memset(eq->eq_events, 0, count * sizeof(lnet_event_t));
114 eq->eq_callback = callback;
118 lnet_initialise_handle (&eq->eq_lh, LNET_COOKIE_TYPE_EQ);
119 cfs_list_add (&eq->eq_list, &the_lnet.ln_active_eqs);
123 lnet_eq2handle(handle, eq);
128 * Release the resources associated with an event queue if it's idle;
129 * otherwise do nothing and it's up to the user to try again.
131 * \param eqh A handle for the event queue to be released.
133 * \retval 0 If the EQ is not in use and freed.
134 * \retval -ENOENT If \a eqh does not point to a valid EQ.
135 * \retval -EBUSY If the EQ is still in use by some MDs.
138 LNetEQFree(lnet_handle_eq_t eqh)
142 lnet_event_t *events;
144 LASSERT (the_lnet.ln_init);
145 LASSERT (the_lnet.ln_refcount > 0);
149 eq = lnet_handle2eq(&eqh);
155 if (eq->eq_refcount != 0) {
156 CDEBUG(D_NET, "Event queue (%d) busy on destroy.\n",
162 /* stash for free after lock dropped */
163 events = eq->eq_events;
166 lnet_invalidate_handle (&eq->eq_lh);
167 cfs_list_del (&eq->eq_list);
172 LIBCFS_FREE(events, size * sizeof (lnet_event_t));
178 lib_get_event (lnet_eq_t *eq, lnet_event_t *ev)
180 int new_index = eq->eq_deq_seq & (eq->eq_size - 1);
181 lnet_event_t *new_event = &eq->eq_events[new_index];
185 CDEBUG(D_INFO, "event: %p, sequence: %lu, eq->size: %u\n",
186 new_event, eq->eq_deq_seq, eq->eq_size);
188 if (LNET_SEQ_GT (eq->eq_deq_seq, new_event->sequence)) {
192 /* We've got a new event... */
195 /* ...but did it overwrite an event we've not seen yet? */
196 if (eq->eq_deq_seq == new_event->sequence) {
199 /* don't complain with CERROR: some EQs are sized small
200 * anyway; if it's important, the caller should complain */
201 CDEBUG(D_NET, "Event Queue Overflow: eq seq %lu ev seq %lu\n",
202 eq->eq_deq_seq, new_event->sequence);
206 eq->eq_deq_seq = new_event->sequence + 1;
211 * A nonblocking function that can be used to get the next event in an EQ.
212 * If an event handler is associated with the EQ, the handler will run before
213 * this function returns successfully. The event is removed from the queue.
215 * \param eventq A handle for the event queue.
216 * \param event On successful return (1 or -EOVERFLOW), this location will
217 * hold the next event in the EQ.
219 * \retval 0 No pending event in the EQ.
220 * \retval 1 Indicates success.
221 * \retval -ENOENT If \a eventq does not point to a valid EQ.
222 * \retval -EOVERFLOW Indicates success (i.e., an event is returned) and that
223 * at least one event between this event and the last event obtained from the
224 * EQ has been dropped due to limited space in the EQ.
227 LNetEQGet (lnet_handle_eq_t eventq, lnet_event_t *event)
231 return LNetEQPoll(&eventq, 1, 0,
236 * Block the calling process until there is an event in the EQ.
237 * If an event handler is associated with the EQ, the handler will run before
238 * this function returns successfully. This function returns the next event
239 * in the EQ and removes it from the EQ.
241 * \param eventq A handle for the event queue.
242 * \param event On successful return (1 or -EOVERFLOW), this location will
243 * hold the next event in the EQ.
245 * \retval 1 Indicates success.
246 * \retval -ENOENT If \a eventq does not point to a valid EQ.
247 * \retval -EOVERFLOW Indicates success (i.e., an event is returned) and that
248 * at least one event between this event and the last event obtained from the
249 * EQ has been dropped due to limited space in the EQ.
252 LNetEQWait (lnet_handle_eq_t eventq, lnet_event_t *event)
256 return LNetEQPoll(&eventq, 1, LNET_TIME_FOREVER,
261 * Block the calling process until there's an event from a set of EQs or
264 * If an event handler is associated with the EQ, the handler will run before
265 * this function returns successfully, in which case the corresponding event
268 * LNetEQPoll() provides a timeout to allow applications to poll, block for a
269 * fixed period, or block indefinitely.
271 * \param eventqs,neq An array of EQ handles, and size of the array.
272 * \param timeout_ms Time in milliseconds to wait for an event to occur on
273 * one of the EQs. The constant LNET_TIME_FOREVER can be used to indicate an
275 * \param event,which On successful return (1 or -EOVERFLOW), \a event will
276 * hold the next event in the EQs, and \a which will contain the index of the
277 * EQ from which the event was taken.
279 * \retval 0 No pending event in the EQs after timeout.
280 * \retval 1 Indicates success.
281 * \retval -EOVERFLOW Indicates success (i.e., an event is returned) and that
282 * at least one event between this event and the last event obtained from the
283 * EQ indicated by \a which has been dropped due to limited space in the EQ.
284 * \retval -ENOENT If there's an invalid handle in \a eventqs.
287 LNetEQPoll (lnet_handle_eq_t *eventqs, int neq, int timeout_ms,
288 lnet_event_t *event, int *which)
298 # ifdef HAVE_LIBPTHREAD
301 lnet_ni_t *eqwaitni = the_lnet.ln_eqwaitni;
305 LASSERT (the_lnet.ln_init);
306 LASSERT (the_lnet.ln_refcount > 0);
317 /* Recursion breaker */
318 if (the_lnet.ln_rc_state == LNET_RC_STATE_RUNNING &&
319 !LNetHandleIsEqual(eventqs[0], the_lnet.ln_rc_eqh))
320 lnet_router_checker();
324 for (i = 0; i < neq; i++) {
325 lnet_eq_t *eq = lnet_handle2eq(&eventqs[i]);
332 rc = lib_get_event (eq, event);
341 if (timeout_ms == 0) {
346 cfs_waitlink_init(&wl);
347 cfs_set_current_state(CFS_TASK_INTERRUPTIBLE);
348 cfs_waitq_add(&the_lnet.ln_waitq, &wl);
352 if (timeout_ms < 0) {
353 cfs_waitq_wait (&wl, CFS_TASK_INTERRUPTIBLE);
357 now = cfs_time_current();
358 cfs_waitq_timedwait(&wl, CFS_TASK_INTERRUPTIBLE,
359 cfs_time_seconds(timeout_ms)/1000);
360 cfs_duration_usec(cfs_time_sub(cfs_time_current(), now),
362 timeout_ms -= (int)(tv.tv_sec * 1000 + tv.tv_usec / 1000);
368 cfs_waitq_del(&the_lnet.ln_waitq, &wl);
370 if (eqwaitni != NULL) {
371 /* I have a single NI that I have to call into, to get
372 * events queued, or to block. */
373 lnet_ni_addref_locked(eqwaitni);
376 if (timeout_ms <= 0) {
377 (eqwaitni->ni_lnd->lnd_wait)(eqwaitni, timeout_ms);
379 gettimeofday(&then, NULL);
381 (eqwaitni->ni_lnd->lnd_wait)(eqwaitni, timeout_ms);
383 gettimeofday(&now, NULL);
384 timeout_ms -= (now.tv_sec - then.tv_sec) * 1000 +
385 (now.tv_usec - then.tv_usec) / 1000;
391 lnet_ni_decref_locked(eqwaitni);
393 /* don't call into eqwaitni again if timeout has
398 continue; /* go back and check for events */
401 if (timeout_ms == 0) {
406 # ifndef HAVE_LIBPTHREAD
407 /* If I'm single-threaded, LNET fails at startup if it can't
408 * set the_lnet.ln_eqwaitni correctly. */
411 if (timeout_ms < 0) {
412 pthread_cond_wait(&the_lnet.ln_cond,
415 gettimeofday(&then, NULL);
417 ts.tv_sec = then.tv_sec + timeout_ms/1000;
418 ts.tv_nsec = then.tv_usec * 1000 +
419 (timeout_ms%1000) * 1000000;
420 if (ts.tv_nsec >= 1000000000) {
422 ts.tv_nsec -= 1000000000;
425 pthread_cond_timedwait(&the_lnet.ln_cond,
426 &the_lnet.ln_lock, &ts);
428 gettimeofday(&now, NULL);
429 timeout_ms -= (now.tv_sec - then.tv_sec) * 1000 +
430 (now.tv_usec - then.tv_usec) / 1000;