+++ /dev/null
-/*
- * GPL HEADER START
- *
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 only,
- * as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License version 2 for more details (a copy is included
- * in the LICENSE file that accompanied this code).
- *
- * You should have received a copy of the GNU General Public License
- * version 2 along with this program; If not, see
- * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
- *
- * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
- * CA 95054 USA or visit www.sun.com if you need additional information or
- * have any questions.
- *
- * GPL HEADER END
- */
-/*
- * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
- * Use is subject to license terms.
- *
- * Copyright (c) 2012, Intel Corporation.
- */
-/*
- * This file is part of Lustre, http://www.lustre.org/
- * Lustre is a trademark of Sun Microsystems, Inc.
- *
- * lnet/lnet/lib-eq.c
- *
- * Library level Event queue management routines
- */
-
-#define DEBUG_SUBSYSTEM S_LNET
-#include <lnet/lib-lnet.h>
-
-/**
- * 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)
-{
- lnet_eq_t *eq;
-
- LASSERT (the_lnet.ln_refcount > 0);
-
- /* 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
- * apparent capacity at all times */
-
- count = roundup_pow_of_two(count);
-
- if (callback != LNET_EQ_HANDLER_NONE && count != 0) {
- CWARN("EQ callback is guaranteed to get every event, "
- "do you still want to set eqcount %d for polling "
- "event which will have locking overhead? "
- "Please contact with developer to confirm\n", count);
- }
-
- /* count can be 0 if only need callback, we can eliminate
- * overhead of enqueue event */
- if (count == 0 && callback == LNET_EQ_HANDLER_NONE)
- return -EINVAL;
-
- eq = lnet_eq_alloc();
- if (eq == NULL)
- return -ENOMEM;
-
- if (count != 0) {
- LIBCFS_ALLOC(eq->eq_events, count * sizeof(lnet_event_t));
- if (eq->eq_events == NULL)
- goto failed;
- /* NB allocator has set all event sequence numbers to 0,
- * so all them should be earlier than eq_deq_seq */
- }
-
- eq->eq_deq_seq = 1;
- eq->eq_enq_seq = 1;
- eq->eq_size = count;
- eq->eq_callback = callback;
-
- eq->eq_refs = cfs_percpt_alloc(lnet_cpt_table(),
- sizeof(*eq->eq_refs[0]));
- if (eq->eq_refs == NULL)
- goto failed;
-
- /* MUST hold both exclusive lnet_res_lock */
- lnet_res_lock(LNET_LOCK_EX);
- /* NB: hold lnet_eq_wait_lock for EQ link/unlink, so we can do
- * both EQ lookup and poll event with only lnet_eq_wait_lock */
- lnet_eq_wait_lock();
-
- lnet_res_lh_initialize(&the_lnet.ln_eq_container, &eq->eq_lh);
- list_add(&eq->eq_list, &the_lnet.ln_eq_container.rec_active);
-
- lnet_eq_wait_unlock();
- lnet_res_unlock(LNET_LOCK_EX);
-
- lnet_eq2handle(handle, eq);
- return 0;
-
-failed:
- if (eq->eq_events != NULL)
- LIBCFS_FREE(eq->eq_events, count * sizeof(lnet_event_t));
-
- if (eq->eq_refs != NULL)
- cfs_percpt_free(eq->eq_refs);
-
- lnet_eq_free(eq);
- return -ENOMEM;
-}
-EXPORT_SYMBOL(LNetEQAlloc);
-
-/**
- * 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)
-{
- struct lnet_eq *eq;
- lnet_event_t *events = NULL;
- int **refs = NULL;
- int *ref;
- int rc = 0;
- int size = 0;
- int i;
-
- LASSERT(the_lnet.ln_refcount > 0);
-
- lnet_res_lock(LNET_LOCK_EX);
- /* NB: hold lnet_eq_wait_lock for EQ link/unlink, so we can do
- * both EQ lookup and poll event with only lnet_eq_wait_lock */
- lnet_eq_wait_lock();
-
- eq = lnet_handle2eq(&eqh);
- if (eq == NULL) {
- rc = -ENOENT;
- goto out;
- }
-
- cfs_percpt_for_each(ref, i, eq->eq_refs) {
- LASSERT(*ref >= 0);
- if (*ref == 0)
- continue;
-
- CDEBUG(D_NET, "Event equeue (%d: %d) busy on destroy.\n",
- i, *ref);
- rc = -EBUSY;
- goto out;
- }
-
- /* stash for free after lock dropped */
- events = eq->eq_events;
- size = eq->eq_size;
- refs = eq->eq_refs;
-
- lnet_res_lh_invalidate(&eq->eq_lh);
- list_del(&eq->eq_list);
- lnet_eq_free(eq);
- out:
- lnet_eq_wait_unlock();
- lnet_res_unlock(LNET_LOCK_EX);
-
- if (events != NULL)
- LIBCFS_FREE(events, size * sizeof(lnet_event_t));
- if (refs != NULL)
- cfs_percpt_free(refs);
-
- return rc;
-}
-EXPORT_SYMBOL(LNetEQFree);
-
-void
-lnet_eq_enqueue_event(lnet_eq_t *eq, lnet_event_t *ev)
-{
- /* MUST called with resource lock hold but w/o lnet_eq_wait_lock */
- int index;
-
- if (eq->eq_size == 0) {
- LASSERT(eq->eq_callback != LNET_EQ_HANDLER_NONE);
- eq->eq_callback(ev);
- return;
- }
-
- lnet_eq_wait_lock();
- ev->sequence = eq->eq_enq_seq++;
-
- LASSERT(eq->eq_size == LOWEST_BIT_SET(eq->eq_size));
- index = ev->sequence & (eq->eq_size - 1);
-
- eq->eq_events[index] = *ev;
-
- if (eq->eq_callback != LNET_EQ_HANDLER_NONE)
- eq->eq_callback(ev);
-
- /* Wake anyone waiting in LNetEQPoll() */
- if (waitqueue_active(&the_lnet.ln_eq_waitq))
- wake_up_all(&the_lnet.ln_eq_waitq);
- lnet_eq_wait_unlock();
-}
-
-static int
-lnet_eq_dequeue_event(lnet_eq_t *eq, lnet_event_t *ev)
-{
- int new_index = eq->eq_deq_seq & (eq->eq_size - 1);
- lnet_event_t *new_event = &eq->eq_events[new_index];
- int rc;
- ENTRY;
-
- /* must called with lnet_eq_wait_lock hold */
- if (LNET_SEQ_GT(eq->eq_deq_seq, new_event->sequence))
- RETURN(0);
-
- /* We've got a new event... */
- *ev = *new_event;
-
- CDEBUG(D_INFO, "event: %p, sequence: %lu, eq->size: %u\n",
- new_event, eq->eq_deq_seq, eq->eq_size);
-
- /* ...but did it overwrite an event we've not seen yet? */
- if (eq->eq_deq_seq == new_event->sequence) {
- rc = 1;
- } else {
- /* don't complain with CERROR: some EQs are sized small
- * anyway; if it's important, the caller should complain */
- CDEBUG(D_NET, "Event Queue Overflow: eq seq %lu ev seq %lu\n",
- eq->eq_deq_seq, new_event->sequence);
- rc = -EOVERFLOW;
- }
-
- eq->eq_deq_seq = new_event->sequence + 1;
- 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)
-{
- int which;
-
- return LNetEQPoll(&eventq, 1, 0,
- event, &which);
-}
-EXPORT_SYMBOL(LNetEQGet);
-
-/**
- * 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)
-{
- int which;
-
- return LNetEQPoll(&eventq, 1, LNET_TIME_FOREVER,
- event, &which);
-}
-EXPORT_SYMBOL(LNetEQWait);
-
-static int
-lnet_eq_wait_locked(int *timeout_ms)
-__must_hold(&the_lnet.ln_eq_wait_lock)
-{
- int tms = *timeout_ms;
- int wait;
- wait_queue_t wl;
- cfs_time_t now;
-
- if (tms == 0)
- return -ENXIO; /* don't want to wait and no new event */
-
- init_waitqueue_entry(&wl, current);
- set_current_state(TASK_INTERRUPTIBLE);
- add_wait_queue(&the_lnet.ln_eq_waitq, &wl);
-
- lnet_eq_wait_unlock();
-
- if (tms < 0) {
- schedule();
- } else {
- struct timeval tv;
-
- now = cfs_time_current();
- schedule_timeout(cfs_time_seconds(tms) / 1000);
- cfs_duration_usec(cfs_time_sub(cfs_time_current(), now), &tv);
- tms -= (int)(tv.tv_sec * 1000 + tv.tv_usec / 1000);
- if (tms < 0) /* no more wait but may have new event */
- tms = 0;
- }
-
- wait = tms != 0; /* might need to call here again */
- *timeout_ms = tms;
-
- lnet_eq_wait_lock();
- remove_wait_queue(&the_lnet.ln_eq_waitq, &wl);
-
- return wait;
-}
-
-/**
- * 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)
-{
- int wait = 1;
- int rc;
- int i;
- ENTRY;
-
- LASSERT (the_lnet.ln_refcount > 0);
-
- if (neq < 1)
- RETURN(-ENOENT);
-
- lnet_eq_wait_lock();
-
- for (;;) {
- for (i = 0; i < neq; i++) {
- lnet_eq_t *eq = lnet_handle2eq(&eventqs[i]);
-
- if (eq == NULL) {
- lnet_eq_wait_unlock();
- RETURN(-ENOENT);
- }
-
- rc = lnet_eq_dequeue_event(eq, event);
- if (rc != 0) {
- lnet_eq_wait_unlock();
- *which = i;
- RETURN(rc);
- }
- }
-
- if (wait == 0)
- break;
-
- /*
- * return value of lnet_eq_wait_locked:
- * -1 : did nothing and it's sure no new event
- * 1 : sleep inside and wait until new event
- * 0 : don't want to wait anymore, but might have new event
- * so need to call dequeue again
- */
- wait = lnet_eq_wait_locked(&timeout_ms);
- if (wait < 0) /* no new event */
- break;
- }
-
- lnet_eq_wait_unlock();
- RETURN(0);
-}
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