1529 lines
40 KiB
C
1529 lines
40 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 2004 John Baldwin <jhb@FreeBSD.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* Implementation of sleep queues used to hold queue of threads blocked on
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* a wait channel. Sleep queues are different from turnstiles in that wait
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* channels are not owned by anyone, so there is no priority propagation.
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* Sleep queues can also provide a timeout and can also be interrupted by
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* signals. That said, there are several similarities between the turnstile
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* and sleep queue implementations. (Note: turnstiles were implemented
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* first.) For example, both use a hash table of the same size where each
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* bucket is referred to as a "chain" that contains both a spin lock and
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* a linked list of queues. An individual queue is located by using a hash
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* to pick a chain, locking the chain, and then walking the chain searching
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* for the queue. This means that a wait channel object does not need to
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* embed its queue head just as locks do not embed their turnstile queue
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* head. Threads also carry around a sleep queue that they lend to the
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* wait channel when blocking. Just as in turnstiles, the queue includes
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* a free list of the sleep queues of other threads blocked on the same
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* wait channel in the case of multiple waiters.
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*
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* Some additional functionality provided by sleep queues include the
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* ability to set a timeout. The timeout is managed using a per-thread
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* callout that resumes a thread if it is asleep. A thread may also
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* catch signals while it is asleep (aka an interruptible sleep). The
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* signal code uses sleepq_abort() to interrupt a sleeping thread. Finally,
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* sleep queues also provide some extra assertions. One is not allowed to
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* mix the sleep/wakeup and cv APIs for a given wait channel. Also, one
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* must consistently use the same lock to synchronize with a wait channel,
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* though this check is currently only a warning for sleep/wakeup due to
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* pre-existing abuse of that API. The same lock must also be held when
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* awakening threads, though that is currently only enforced for condition
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* variables.
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*/
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#include <sys/cdefs.h>
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#include "opt_sleepqueue_profiling.h"
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#include "opt_ddb.h"
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#include "opt_sched.h"
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#include "opt_stack.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/lock.h>
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#include <sys/kernel.h>
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#include <sys/ktr.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/sbuf.h>
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#include <sys/sched.h>
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#include <sys/sdt.h>
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#include <sys/signalvar.h>
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#include <sys/sleepqueue.h>
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#include <sys/stack.h>
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#include <sys/sysctl.h>
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#include <sys/time.h>
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#ifdef EPOCH_TRACE
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#include <sys/epoch.h>
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#endif
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#include <machine/atomic.h>
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#include <vm/uma.h>
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#ifdef DDB
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#include <ddb/ddb.h>
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#endif
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/*
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* Constants for the hash table of sleep queue chains.
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* SC_TABLESIZE must be a power of two for SC_MASK to work properly.
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*/
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#ifndef SC_TABLESIZE
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#define SC_TABLESIZE 256
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#endif
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CTASSERT(powerof2(SC_TABLESIZE));
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#define SC_MASK (SC_TABLESIZE - 1)
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#define SC_SHIFT 8
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#define SC_HASH(wc) ((((uintptr_t)(wc) >> SC_SHIFT) ^ (uintptr_t)(wc)) & \
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SC_MASK)
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#define SC_LOOKUP(wc) &sleepq_chains[SC_HASH(wc)]
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#define NR_SLEEPQS 2
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/*
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* There are two different lists of sleep queues. Both lists are connected
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* via the sq_hash entries. The first list is the sleep queue chain list
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* that a sleep queue is on when it is attached to a wait channel. The
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* second list is the free list hung off of a sleep queue that is attached
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* to a wait channel.
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*
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* Each sleep queue also contains the wait channel it is attached to, the
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* list of threads blocked on that wait channel, flags specific to the
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* wait channel, and the lock used to synchronize with a wait channel.
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* The flags are used to catch mismatches between the various consumers
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* of the sleep queue API (e.g. sleep/wakeup and condition variables).
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* The lock pointer is only used when invariants are enabled for various
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* debugging checks.
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*
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* Locking key:
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* c - sleep queue chain lock
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*/
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struct sleepqueue {
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struct threadqueue sq_blocked[NR_SLEEPQS]; /* (c) Blocked threads. */
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u_int sq_blockedcnt[NR_SLEEPQS]; /* (c) N. of blocked threads. */
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LIST_ENTRY(sleepqueue) sq_hash; /* (c) Chain and free list. */
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LIST_HEAD(, sleepqueue) sq_free; /* (c) Free queues. */
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const void *sq_wchan; /* (c) Wait channel. */
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int sq_type; /* (c) Queue type. */
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#ifdef INVARIANTS
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struct lock_object *sq_lock; /* (c) Associated lock. */
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#endif
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};
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struct sleepqueue_chain {
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LIST_HEAD(, sleepqueue) sc_queues; /* List of sleep queues. */
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struct mtx sc_lock; /* Spin lock for this chain. */
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#ifdef SLEEPQUEUE_PROFILING
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u_int sc_depth; /* Length of sc_queues. */
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u_int sc_max_depth; /* Max length of sc_queues. */
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#endif
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} __aligned(CACHE_LINE_SIZE);
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#ifdef SLEEPQUEUE_PROFILING
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static SYSCTL_NODE(_debug, OID_AUTO, sleepq, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
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"sleepq profiling");
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static SYSCTL_NODE(_debug_sleepq, OID_AUTO, chains,
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CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
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"sleepq chain stats");
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static u_int sleepq_max_depth;
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SYSCTL_UINT(_debug_sleepq, OID_AUTO, max_depth, CTLFLAG_RD, &sleepq_max_depth,
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0, "maxmimum depth achieved of a single chain");
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static void sleepq_profile(const char *wmesg);
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static int prof_enabled;
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#endif
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static struct sleepqueue_chain sleepq_chains[SC_TABLESIZE];
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static uma_zone_t sleepq_zone;
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/*
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* Prototypes for non-exported routines.
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*/
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static int sleepq_catch_signals(const void *wchan, int pri);
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static inline int sleepq_check_signals(void);
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static inline int sleepq_check_timeout(void);
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#ifdef INVARIANTS
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static void sleepq_dtor(void *mem, int size, void *arg);
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#endif
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static int sleepq_init(void *mem, int size, int flags);
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static int sleepq_resume_thread(struct sleepqueue *sq, struct thread *td,
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int pri, int srqflags);
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static void sleepq_remove_thread(struct sleepqueue *sq, struct thread *td);
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static void sleepq_switch(const void *wchan, int pri);
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static void sleepq_timeout(void *arg);
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SDT_PROBE_DECLARE(sched, , , sleep);
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SDT_PROBE_DECLARE(sched, , , wakeup);
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/*
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* Initialize SLEEPQUEUE_PROFILING specific sysctl nodes.
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* Note that it must happen after sleepinit() has been fully executed, so
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* it must happen after SI_SUB_KMEM SYSINIT() subsystem setup.
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*/
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#ifdef SLEEPQUEUE_PROFILING
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static void
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init_sleepqueue_profiling(void)
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{
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char chain_name[10];
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struct sysctl_oid *chain_oid;
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u_int i;
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for (i = 0; i < SC_TABLESIZE; i++) {
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snprintf(chain_name, sizeof(chain_name), "%u", i);
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chain_oid = SYSCTL_ADD_NODE(NULL,
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SYSCTL_STATIC_CHILDREN(_debug_sleepq_chains), OID_AUTO,
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chain_name, CTLFLAG_RD | CTLFLAG_MPSAFE, NULL,
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"sleepq chain stats");
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SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO,
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"depth", CTLFLAG_RD, &sleepq_chains[i].sc_depth, 0, NULL);
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SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO,
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"max_depth", CTLFLAG_RD, &sleepq_chains[i].sc_max_depth, 0,
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NULL);
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}
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}
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SYSINIT(sleepqueue_profiling, SI_SUB_LOCK, SI_ORDER_ANY,
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init_sleepqueue_profiling, NULL);
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#endif
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/*
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* Early initialization of sleep queues that is called from the sleepinit()
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* SYSINIT.
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*/
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void
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init_sleepqueues(void)
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{
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int i;
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for (i = 0; i < SC_TABLESIZE; i++) {
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LIST_INIT(&sleepq_chains[i].sc_queues);
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mtx_init(&sleepq_chains[i].sc_lock, "sleepq chain", NULL,
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MTX_SPIN);
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}
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sleepq_zone = uma_zcreate("SLEEPQUEUE", sizeof(struct sleepqueue),
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#ifdef INVARIANTS
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NULL, sleepq_dtor, sleepq_init, NULL, UMA_ALIGN_CACHE, 0);
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#else
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NULL, NULL, sleepq_init, NULL, UMA_ALIGN_CACHE, 0);
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#endif
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thread0.td_sleepqueue = sleepq_alloc();
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}
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/*
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* Get a sleep queue for a new thread.
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*/
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struct sleepqueue *
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sleepq_alloc(void)
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{
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return (uma_zalloc(sleepq_zone, M_WAITOK));
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}
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/*
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* Free a sleep queue when a thread is destroyed.
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*/
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void
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sleepq_free(struct sleepqueue *sq)
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{
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uma_zfree(sleepq_zone, sq);
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}
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/*
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* Lock the sleep queue chain associated with the specified wait channel.
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*/
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void
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sleepq_lock(const void *wchan)
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{
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struct sleepqueue_chain *sc;
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sc = SC_LOOKUP(wchan);
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mtx_lock_spin(&sc->sc_lock);
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}
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/*
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* Look up the sleep queue associated with a given wait channel in the hash
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* table locking the associated sleep queue chain. If no queue is found in
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* the table, NULL is returned.
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*/
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struct sleepqueue *
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sleepq_lookup(const void *wchan)
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{
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struct sleepqueue_chain *sc;
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struct sleepqueue *sq;
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KASSERT(wchan != NULL, ("%s: invalid NULL wait channel", __func__));
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sc = SC_LOOKUP(wchan);
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mtx_assert(&sc->sc_lock, MA_OWNED);
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LIST_FOREACH(sq, &sc->sc_queues, sq_hash)
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if (sq->sq_wchan == wchan)
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return (sq);
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return (NULL);
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}
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/*
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* Unlock the sleep queue chain associated with a given wait channel.
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*/
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void
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sleepq_release(const void *wchan)
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{
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struct sleepqueue_chain *sc;
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sc = SC_LOOKUP(wchan);
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mtx_unlock_spin(&sc->sc_lock);
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}
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/*
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* Places the current thread on the sleep queue for the specified wait
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* channel. If INVARIANTS is enabled, then it associates the passed in
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* lock with the sleepq to make sure it is held when that sleep queue is
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* woken up.
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*/
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void
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sleepq_add(const void *wchan, struct lock_object *lock, const char *wmesg,
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int flags, int queue)
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{
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struct sleepqueue_chain *sc;
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struct sleepqueue *sq;
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struct thread *td;
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td = curthread;
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sc = SC_LOOKUP(wchan);
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mtx_assert(&sc->sc_lock, MA_OWNED);
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MPASS(td->td_sleepqueue != NULL);
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MPASS(wchan != NULL);
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MPASS((queue >= 0) && (queue < NR_SLEEPQS));
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/* If this thread is not allowed to sleep, die a horrible death. */
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if (__predict_false(!THREAD_CAN_SLEEP())) {
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#ifdef EPOCH_TRACE
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epoch_trace_list(curthread);
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#endif
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KASSERT(0,
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("%s: td %p to sleep on wchan %p with sleeping prohibited",
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__func__, td, wchan));
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}
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/* Look up the sleep queue associated with the wait channel 'wchan'. */
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sq = sleepq_lookup(wchan);
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/*
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* If the wait channel does not already have a sleep queue, use
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* this thread's sleep queue. Otherwise, insert the current thread
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* into the sleep queue already in use by this wait channel.
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*/
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if (sq == NULL) {
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#ifdef INVARIANTS
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int i;
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sq = td->td_sleepqueue;
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for (i = 0; i < NR_SLEEPQS; i++) {
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KASSERT(TAILQ_EMPTY(&sq->sq_blocked[i]),
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("thread's sleep queue %d is not empty", i));
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KASSERT(sq->sq_blockedcnt[i] == 0,
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("thread's sleep queue %d count mismatches", i));
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}
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KASSERT(LIST_EMPTY(&sq->sq_free),
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("thread's sleep queue has a non-empty free list"));
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KASSERT(sq->sq_wchan == NULL, ("stale sq_wchan pointer"));
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sq->sq_lock = lock;
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#endif
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#ifdef SLEEPQUEUE_PROFILING
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sc->sc_depth++;
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if (sc->sc_depth > sc->sc_max_depth) {
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sc->sc_max_depth = sc->sc_depth;
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if (sc->sc_max_depth > sleepq_max_depth)
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sleepq_max_depth = sc->sc_max_depth;
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}
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#endif
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sq = td->td_sleepqueue;
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LIST_INSERT_HEAD(&sc->sc_queues, sq, sq_hash);
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sq->sq_wchan = wchan;
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sq->sq_type = flags & SLEEPQ_TYPE;
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} else {
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MPASS(wchan == sq->sq_wchan);
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MPASS(lock == sq->sq_lock);
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MPASS((flags & SLEEPQ_TYPE) == sq->sq_type);
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LIST_INSERT_HEAD(&sq->sq_free, td->td_sleepqueue, sq_hash);
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}
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thread_lock(td);
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TAILQ_INSERT_TAIL(&sq->sq_blocked[queue], td, td_slpq);
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sq->sq_blockedcnt[queue]++;
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td->td_sleepqueue = NULL;
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td->td_sqqueue = queue;
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td->td_wchan = wchan;
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td->td_wmesg = wmesg;
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if (flags & SLEEPQ_INTERRUPTIBLE) {
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td->td_intrval = 0;
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td->td_flags |= TDF_SINTR;
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}
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td->td_flags &= ~TDF_TIMEOUT;
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thread_unlock(td);
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}
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/*
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* Sets a timeout that will remove the current thread from the
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* specified sleep queue at the specified time if the thread has not
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* already been awakened. Flags are from C_* (callout) namespace.
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*/
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void
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sleepq_set_timeout_sbt(const void *wchan, sbintime_t sbt, sbintime_t pr,
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int flags)
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{
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struct sleepqueue_chain *sc __unused;
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struct thread *td;
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sbintime_t pr1;
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td = curthread;
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sc = SC_LOOKUP(wchan);
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mtx_assert(&sc->sc_lock, MA_OWNED);
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MPASS(TD_ON_SLEEPQ(td));
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MPASS(td->td_sleepqueue == NULL);
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MPASS(wchan != NULL);
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if (cold && td == &thread0)
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panic("timed sleep before timers are working");
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KASSERT(td->td_sleeptimo == 0, ("td %d %p td_sleeptimo %jx",
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td->td_tid, td, (uintmax_t)td->td_sleeptimo));
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thread_lock(td);
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callout_when(sbt, pr, flags, &td->td_sleeptimo, &pr1);
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thread_unlock(td);
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callout_reset_sbt_on(&td->td_slpcallout, td->td_sleeptimo, pr1,
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sleepq_timeout, td, PCPU_GET(cpuid), flags | C_PRECALC |
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C_DIRECT_EXEC);
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}
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/*
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* Return the number of actual sleepers for the specified queue.
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*/
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u_int
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sleepq_sleepcnt(const void *wchan, int queue)
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{
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struct sleepqueue *sq;
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KASSERT(wchan != NULL, ("%s: invalid NULL wait channel", __func__));
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MPASS((queue >= 0) && (queue < NR_SLEEPQS));
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sq = sleepq_lookup(wchan);
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if (sq == NULL)
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return (0);
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return (sq->sq_blockedcnt[queue]);
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}
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static int
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sleepq_check_ast_sc_locked(struct thread *td, struct sleepqueue_chain *sc)
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{
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struct proc *p;
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int ret;
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mtx_assert(&sc->sc_lock, MA_OWNED);
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if ((td->td_pflags & TDP_WAKEUP) != 0) {
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td->td_pflags &= ~TDP_WAKEUP;
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thread_lock(td);
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return (EINTR);
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}
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/*
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* See if there are any pending signals or suspension requests for this
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* thread. If not, we can switch immediately.
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*/
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thread_lock(td);
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if (!td_ast_pending(td, TDA_SIG) && !td_ast_pending(td, TDA_SUSPEND))
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return (0);
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thread_unlock(td);
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mtx_unlock_spin(&sc->sc_lock);
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p = td->td_proc;
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CTR3(KTR_PROC, "sleepq catching signals: thread %p (pid %ld, %s)",
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(void *)td, (long)p->p_pid, td->td_name);
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PROC_LOCK(p);
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/*
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* Check for suspension first. Checking for signals and then
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* suspending could result in a missed signal, since a signal
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* can be delivered while this thread is suspended.
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*/
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ret = sig_ast_checksusp(td);
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if (ret != 0) {
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PROC_UNLOCK(p);
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mtx_lock_spin(&sc->sc_lock);
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thread_lock(td);
|
|
return (ret);
|
|
}
|
|
|
|
ret = sig_ast_needsigchk(td);
|
|
|
|
/*
|
|
* Lock the per-process spinlock prior to dropping the
|
|
* PROC_LOCK to avoid a signal delivery race.
|
|
* PROC_LOCK, PROC_SLOCK, and thread_lock() are
|
|
* currently held in tdsendsignal() and thread_single().
|
|
*/
|
|
PROC_SLOCK(p);
|
|
mtx_lock_spin(&sc->sc_lock);
|
|
PROC_UNLOCK(p);
|
|
thread_lock(td);
|
|
PROC_SUNLOCK(p);
|
|
|
|
return (ret);
|
|
}
|
|
|
|
/*
|
|
* Marks the pending sleep of the current thread as interruptible and
|
|
* makes an initial check for pending signals before putting a thread
|
|
* to sleep. Enters and exits with the thread lock held. Thread lock
|
|
* may have transitioned from the sleepq lock to a run lock.
|
|
*/
|
|
static int
|
|
sleepq_catch_signals(const void *wchan, int pri)
|
|
{
|
|
struct thread *td;
|
|
struct sleepqueue_chain *sc;
|
|
struct sleepqueue *sq;
|
|
int ret;
|
|
|
|
sc = SC_LOOKUP(wchan);
|
|
mtx_assert(&sc->sc_lock, MA_OWNED);
|
|
MPASS(wchan != NULL);
|
|
td = curthread;
|
|
|
|
ret = sleepq_check_ast_sc_locked(td, sc);
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
mtx_assert(&sc->sc_lock, MA_OWNED);
|
|
|
|
if (ret == 0) {
|
|
/*
|
|
* No pending signals and no suspension requests found.
|
|
* Switch the thread off the cpu.
|
|
*/
|
|
sleepq_switch(wchan, pri);
|
|
} else {
|
|
/*
|
|
* There were pending signals and this thread is still
|
|
* on the sleep queue, remove it from the sleep queue.
|
|
*/
|
|
if (TD_ON_SLEEPQ(td)) {
|
|
sq = sleepq_lookup(wchan);
|
|
sleepq_remove_thread(sq, td);
|
|
}
|
|
MPASS(td->td_lock != &sc->sc_lock);
|
|
mtx_unlock_spin(&sc->sc_lock);
|
|
thread_unlock(td);
|
|
}
|
|
return (ret);
|
|
}
|
|
|
|
/*
|
|
* Switches to another thread if we are still asleep on a sleep queue.
|
|
* Returns with thread lock.
|
|
*/
|
|
static void
|
|
sleepq_switch(const void *wchan, int pri)
|
|
{
|
|
struct sleepqueue_chain *sc;
|
|
struct sleepqueue *sq;
|
|
struct thread *td;
|
|
bool rtc_changed;
|
|
|
|
td = curthread;
|
|
sc = SC_LOOKUP(wchan);
|
|
mtx_assert(&sc->sc_lock, MA_OWNED);
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
|
|
/*
|
|
* If we have a sleep queue, then we've already been woken up, so
|
|
* just return.
|
|
*/
|
|
if (td->td_sleepqueue != NULL) {
|
|
mtx_unlock_spin(&sc->sc_lock);
|
|
thread_unlock(td);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* If TDF_TIMEOUT is set, then our sleep has been timed out
|
|
* already but we are still on the sleep queue, so dequeue the
|
|
* thread and return.
|
|
*
|
|
* Do the same if the real-time clock has been adjusted since this
|
|
* thread calculated its timeout based on that clock. This handles
|
|
* the following race:
|
|
* - The Ts thread needs to sleep until an absolute real-clock time.
|
|
* It copies the global rtc_generation into curthread->td_rtcgen,
|
|
* reads the RTC, and calculates a sleep duration based on that time.
|
|
* See umtxq_sleep() for an example.
|
|
* - The Tc thread adjusts the RTC, bumps rtc_generation, and wakes
|
|
* threads that are sleeping until an absolute real-clock time.
|
|
* See tc_setclock() and the POSIX specification of clock_settime().
|
|
* - Ts reaches the code below. It holds the sleepqueue chain lock,
|
|
* so Tc has finished waking, so this thread must test td_rtcgen.
|
|
* (The declaration of td_rtcgen refers to this comment.)
|
|
*/
|
|
rtc_changed = td->td_rtcgen != 0 && td->td_rtcgen != rtc_generation;
|
|
if ((td->td_flags & TDF_TIMEOUT) || rtc_changed) {
|
|
if (rtc_changed) {
|
|
td->td_rtcgen = 0;
|
|
}
|
|
MPASS(TD_ON_SLEEPQ(td));
|
|
sq = sleepq_lookup(wchan);
|
|
sleepq_remove_thread(sq, td);
|
|
mtx_unlock_spin(&sc->sc_lock);
|
|
thread_unlock(td);
|
|
return;
|
|
}
|
|
#ifdef SLEEPQUEUE_PROFILING
|
|
if (prof_enabled)
|
|
sleepq_profile(td->td_wmesg);
|
|
#endif
|
|
MPASS(td->td_sleepqueue == NULL);
|
|
sched_sleep(td, pri);
|
|
thread_lock_set(td, &sc->sc_lock);
|
|
SDT_PROBE0(sched, , , sleep);
|
|
TD_SET_SLEEPING(td);
|
|
mi_switch(SW_VOL | SWT_SLEEPQ);
|
|
KASSERT(TD_IS_RUNNING(td), ("running but not TDS_RUNNING"));
|
|
CTR3(KTR_PROC, "sleepq resume: thread %p (pid %ld, %s)",
|
|
(void *)td, (long)td->td_proc->p_pid, (void *)td->td_name);
|
|
}
|
|
|
|
/*
|
|
* Check to see if we timed out.
|
|
*/
|
|
static inline int
|
|
sleepq_check_timeout(void)
|
|
{
|
|
struct thread *td;
|
|
int res;
|
|
|
|
res = 0;
|
|
td = curthread;
|
|
if (td->td_sleeptimo != 0) {
|
|
if (td->td_sleeptimo <= sbinuptime())
|
|
res = EWOULDBLOCK;
|
|
td->td_sleeptimo = 0;
|
|
}
|
|
return (res);
|
|
}
|
|
|
|
/*
|
|
* Check to see if we were awoken by a signal.
|
|
*/
|
|
static inline int
|
|
sleepq_check_signals(void)
|
|
{
|
|
struct thread *td;
|
|
|
|
td = curthread;
|
|
KASSERT((td->td_flags & TDF_SINTR) == 0,
|
|
("thread %p still in interruptible sleep?", td));
|
|
|
|
return (td->td_intrval);
|
|
}
|
|
|
|
/*
|
|
* Block the current thread until it is awakened from its sleep queue.
|
|
*/
|
|
void
|
|
sleepq_wait(const void *wchan, int pri)
|
|
{
|
|
struct thread *td;
|
|
|
|
td = curthread;
|
|
MPASS(!(td->td_flags & TDF_SINTR));
|
|
thread_lock(td);
|
|
sleepq_switch(wchan, pri);
|
|
}
|
|
|
|
/*
|
|
* Block the current thread until it is awakened from its sleep queue
|
|
* or it is interrupted by a signal.
|
|
*/
|
|
int
|
|
sleepq_wait_sig(const void *wchan, int pri)
|
|
{
|
|
int rcatch;
|
|
|
|
rcatch = sleepq_catch_signals(wchan, pri);
|
|
if (rcatch)
|
|
return (rcatch);
|
|
return (sleepq_check_signals());
|
|
}
|
|
|
|
/*
|
|
* Block the current thread until it is awakened from its sleep queue
|
|
* or it times out while waiting.
|
|
*/
|
|
int
|
|
sleepq_timedwait(const void *wchan, int pri)
|
|
{
|
|
struct thread *td;
|
|
|
|
td = curthread;
|
|
MPASS(!(td->td_flags & TDF_SINTR));
|
|
|
|
thread_lock(td);
|
|
sleepq_switch(wchan, pri);
|
|
|
|
return (sleepq_check_timeout());
|
|
}
|
|
|
|
/*
|
|
* Block the current thread until it is awakened from its sleep queue,
|
|
* it is interrupted by a signal, or it times out waiting to be awakened.
|
|
*/
|
|
int
|
|
sleepq_timedwait_sig(const void *wchan, int pri)
|
|
{
|
|
int rcatch, rvalt, rvals;
|
|
|
|
rcatch = sleepq_catch_signals(wchan, pri);
|
|
/* We must always call check_timeout() to clear sleeptimo. */
|
|
rvalt = sleepq_check_timeout();
|
|
rvals = sleepq_check_signals();
|
|
if (rcatch)
|
|
return (rcatch);
|
|
if (rvals)
|
|
return (rvals);
|
|
return (rvalt);
|
|
}
|
|
|
|
/*
|
|
* Returns the type of sleepqueue given a waitchannel.
|
|
*/
|
|
int
|
|
sleepq_type(const void *wchan)
|
|
{
|
|
struct sleepqueue *sq;
|
|
int type;
|
|
|
|
MPASS(wchan != NULL);
|
|
|
|
sq = sleepq_lookup(wchan);
|
|
if (sq == NULL)
|
|
return (-1);
|
|
type = sq->sq_type;
|
|
|
|
return (type);
|
|
}
|
|
|
|
/*
|
|
* Removes a thread from a sleep queue and makes it
|
|
* runnable.
|
|
*
|
|
* Requires the sc chain locked on entry. If SRQ_HOLD is specified it will
|
|
* be locked on return. Returns without the thread lock held.
|
|
*/
|
|
static int
|
|
sleepq_resume_thread(struct sleepqueue *sq, struct thread *td, int pri,
|
|
int srqflags)
|
|
{
|
|
struct sleepqueue_chain *sc;
|
|
bool drop;
|
|
|
|
MPASS(td != NULL);
|
|
MPASS(sq->sq_wchan != NULL);
|
|
MPASS(td->td_wchan == sq->sq_wchan);
|
|
|
|
sc = SC_LOOKUP(sq->sq_wchan);
|
|
mtx_assert(&sc->sc_lock, MA_OWNED);
|
|
|
|
/*
|
|
* Avoid recursing on the chain lock. If the locks don't match we
|
|
* need to acquire the thread lock which setrunnable will drop for
|
|
* us. In this case we need to drop the chain lock afterwards.
|
|
*
|
|
* There is no race that will make td_lock equal to sc_lock because
|
|
* we hold sc_lock.
|
|
*/
|
|
drop = false;
|
|
if (!TD_IS_SLEEPING(td)) {
|
|
thread_lock(td);
|
|
drop = true;
|
|
} else
|
|
thread_lock_block_wait(td);
|
|
|
|
/* Remove thread from the sleepq. */
|
|
sleepq_remove_thread(sq, td);
|
|
|
|
/* If we're done with the sleepqueue release it. */
|
|
if ((srqflags & SRQ_HOLD) == 0 && drop)
|
|
mtx_unlock_spin(&sc->sc_lock);
|
|
|
|
/* Adjust priority if requested. */
|
|
MPASS(pri == 0 || (pri >= PRI_MIN && pri <= PRI_MAX));
|
|
if (pri != 0 && td->td_priority > pri &&
|
|
PRI_BASE(td->td_pri_class) == PRI_TIMESHARE)
|
|
sched_prio(td, pri);
|
|
|
|
/*
|
|
* Note that thread td might not be sleeping if it is running
|
|
* sleepq_catch_signals() on another CPU or is blocked on its
|
|
* proc lock to check signals. There's no need to mark the
|
|
* thread runnable in that case.
|
|
*/
|
|
if (TD_IS_SLEEPING(td)) {
|
|
MPASS(!drop);
|
|
TD_CLR_SLEEPING(td);
|
|
return (setrunnable(td, srqflags));
|
|
}
|
|
MPASS(drop);
|
|
thread_unlock(td);
|
|
|
|
return (0);
|
|
}
|
|
|
|
static void
|
|
sleepq_remove_thread(struct sleepqueue *sq, struct thread *td)
|
|
{
|
|
struct sleepqueue_chain *sc __unused;
|
|
|
|
MPASS(td != NULL);
|
|
MPASS(sq->sq_wchan != NULL);
|
|
MPASS(td->td_wchan == sq->sq_wchan);
|
|
MPASS(td->td_sqqueue < NR_SLEEPQS && td->td_sqqueue >= 0);
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
sc = SC_LOOKUP(sq->sq_wchan);
|
|
mtx_assert(&sc->sc_lock, MA_OWNED);
|
|
|
|
SDT_PROBE2(sched, , , wakeup, td, td->td_proc);
|
|
|
|
/* Remove the thread from the queue. */
|
|
sq->sq_blockedcnt[td->td_sqqueue]--;
|
|
TAILQ_REMOVE(&sq->sq_blocked[td->td_sqqueue], td, td_slpq);
|
|
|
|
/*
|
|
* Get a sleep queue for this thread. If this is the last waiter,
|
|
* use the queue itself and take it out of the chain, otherwise,
|
|
* remove a queue from the free list.
|
|
*/
|
|
if (LIST_EMPTY(&sq->sq_free)) {
|
|
td->td_sleepqueue = sq;
|
|
#ifdef INVARIANTS
|
|
sq->sq_wchan = NULL;
|
|
#endif
|
|
#ifdef SLEEPQUEUE_PROFILING
|
|
sc->sc_depth--;
|
|
#endif
|
|
} else
|
|
td->td_sleepqueue = LIST_FIRST(&sq->sq_free);
|
|
LIST_REMOVE(td->td_sleepqueue, sq_hash);
|
|
|
|
if ((td->td_flags & TDF_TIMEOUT) == 0 && td->td_sleeptimo != 0 &&
|
|
td->td_lock == &sc->sc_lock) {
|
|
/*
|
|
* We ignore the situation where timeout subsystem was
|
|
* unable to stop our callout. The struct thread is
|
|
* type-stable, the callout will use the correct
|
|
* memory when running. The checks of the
|
|
* td_sleeptimo value in this function and in
|
|
* sleepq_timeout() ensure that the thread does not
|
|
* get spurious wakeups, even if the callout was reset
|
|
* or thread reused.
|
|
*
|
|
* We also cannot safely stop the callout if a scheduler
|
|
* lock is held since softclock_thread() forces a lock
|
|
* order of callout lock -> scheduler lock. The thread
|
|
* lock will be a scheduler lock only if the thread is
|
|
* preparing to go to sleep, so this is hopefully a rare
|
|
* scenario.
|
|
*/
|
|
callout_stop(&td->td_slpcallout);
|
|
}
|
|
|
|
td->td_wmesg = NULL;
|
|
td->td_wchan = NULL;
|
|
td->td_flags &= ~(TDF_SINTR | TDF_TIMEOUT);
|
|
|
|
CTR3(KTR_PROC, "sleepq_wakeup: thread %p (pid %ld, %s)",
|
|
(void *)td, (long)td->td_proc->p_pid, td->td_name);
|
|
}
|
|
|
|
void
|
|
sleepq_remove_nested(struct thread *td)
|
|
{
|
|
struct sleepqueue_chain *sc;
|
|
struct sleepqueue *sq;
|
|
const void *wchan;
|
|
|
|
MPASS(TD_ON_SLEEPQ(td));
|
|
|
|
wchan = td->td_wchan;
|
|
sc = SC_LOOKUP(wchan);
|
|
mtx_lock_spin(&sc->sc_lock);
|
|
sq = sleepq_lookup(wchan);
|
|
MPASS(sq != NULL);
|
|
thread_lock(td);
|
|
sleepq_remove_thread(sq, td);
|
|
mtx_unlock_spin(&sc->sc_lock);
|
|
/* Returns with the thread lock owned. */
|
|
}
|
|
|
|
#ifdef INVARIANTS
|
|
/*
|
|
* UMA zone item deallocator.
|
|
*/
|
|
static void
|
|
sleepq_dtor(void *mem, int size, void *arg)
|
|
{
|
|
struct sleepqueue *sq;
|
|
int i;
|
|
|
|
sq = mem;
|
|
for (i = 0; i < NR_SLEEPQS; i++) {
|
|
MPASS(TAILQ_EMPTY(&sq->sq_blocked[i]));
|
|
MPASS(sq->sq_blockedcnt[i] == 0);
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* UMA zone item initializer.
|
|
*/
|
|
static int
|
|
sleepq_init(void *mem, int size, int flags)
|
|
{
|
|
struct sleepqueue *sq;
|
|
int i;
|
|
|
|
bzero(mem, size);
|
|
sq = mem;
|
|
for (i = 0; i < NR_SLEEPQS; i++) {
|
|
TAILQ_INIT(&sq->sq_blocked[i]);
|
|
sq->sq_blockedcnt[i] = 0;
|
|
}
|
|
LIST_INIT(&sq->sq_free);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Find thread sleeping on a wait channel and resume it.
|
|
*/
|
|
int
|
|
sleepq_signal(const void *wchan, int flags, int pri, int queue)
|
|
{
|
|
struct sleepqueue_chain *sc;
|
|
struct sleepqueue *sq;
|
|
struct threadqueue *head;
|
|
struct thread *td, *besttd;
|
|
int wakeup_swapper;
|
|
|
|
CTR2(KTR_PROC, "sleepq_signal(%p, %d)", wchan, flags);
|
|
KASSERT(wchan != NULL, ("%s: invalid NULL wait channel", __func__));
|
|
MPASS((queue >= 0) && (queue < NR_SLEEPQS));
|
|
sq = sleepq_lookup(wchan);
|
|
if (sq == NULL) {
|
|
if (flags & SLEEPQ_DROP)
|
|
sleepq_release(wchan);
|
|
return (0);
|
|
}
|
|
KASSERT(sq->sq_type == (flags & SLEEPQ_TYPE),
|
|
("%s: mismatch between sleep/wakeup and cv_*", __func__));
|
|
|
|
head = &sq->sq_blocked[queue];
|
|
if (flags & SLEEPQ_UNFAIR) {
|
|
/*
|
|
* Find the most recently sleeping thread, but try to
|
|
* skip threads still in process of context switch to
|
|
* avoid spinning on the thread lock.
|
|
*/
|
|
sc = SC_LOOKUP(wchan);
|
|
besttd = TAILQ_LAST_FAST(head, thread, td_slpq);
|
|
while (besttd->td_lock != &sc->sc_lock) {
|
|
td = TAILQ_PREV_FAST(besttd, head, thread, td_slpq);
|
|
if (td == NULL)
|
|
break;
|
|
besttd = td;
|
|
}
|
|
} else {
|
|
/*
|
|
* Find the highest priority thread on the queue. If there
|
|
* is a tie, use the thread that first appears in the queue
|
|
* as it has been sleeping the longest since threads are
|
|
* always added to the tail of sleep queues.
|
|
*/
|
|
besttd = td = TAILQ_FIRST(head);
|
|
while ((td = TAILQ_NEXT(td, td_slpq)) != NULL) {
|
|
if (td->td_priority < besttd->td_priority)
|
|
besttd = td;
|
|
}
|
|
}
|
|
MPASS(besttd != NULL);
|
|
wakeup_swapper = sleepq_resume_thread(sq, besttd, pri,
|
|
(flags & SLEEPQ_DROP) ? 0 : SRQ_HOLD);
|
|
return (wakeup_swapper);
|
|
}
|
|
|
|
static bool
|
|
match_any(struct thread *td __unused)
|
|
{
|
|
|
|
return (true);
|
|
}
|
|
|
|
/*
|
|
* Resume all threads sleeping on a specified wait channel.
|
|
*/
|
|
int
|
|
sleepq_broadcast(const void *wchan, int flags, int pri, int queue)
|
|
{
|
|
struct sleepqueue *sq;
|
|
|
|
CTR2(KTR_PROC, "sleepq_broadcast(%p, %d)", wchan, flags);
|
|
KASSERT(wchan != NULL, ("%s: invalid NULL wait channel", __func__));
|
|
MPASS((queue >= 0) && (queue < NR_SLEEPQS));
|
|
sq = sleepq_lookup(wchan);
|
|
if (sq == NULL)
|
|
return (0);
|
|
KASSERT(sq->sq_type == (flags & SLEEPQ_TYPE),
|
|
("%s: mismatch between sleep/wakeup and cv_*", __func__));
|
|
|
|
return (sleepq_remove_matching(sq, queue, match_any, pri));
|
|
}
|
|
|
|
/*
|
|
* Resume threads on the sleep queue that match the given predicate.
|
|
*/
|
|
int
|
|
sleepq_remove_matching(struct sleepqueue *sq, int queue,
|
|
bool (*matches)(struct thread *), int pri)
|
|
{
|
|
struct thread *td, *tdn;
|
|
int wakeup_swapper;
|
|
|
|
/*
|
|
* The last thread will be given ownership of sq and may
|
|
* re-enqueue itself before sleepq_resume_thread() returns,
|
|
* so we must cache the "next" queue item at the beginning
|
|
* of the final iteration.
|
|
*/
|
|
wakeup_swapper = 0;
|
|
TAILQ_FOREACH_SAFE(td, &sq->sq_blocked[queue], td_slpq, tdn) {
|
|
if (matches(td))
|
|
wakeup_swapper |= sleepq_resume_thread(sq, td, pri,
|
|
SRQ_HOLD);
|
|
}
|
|
|
|
return (wakeup_swapper);
|
|
}
|
|
|
|
/*
|
|
* Time sleeping threads out. When the timeout expires, the thread is
|
|
* removed from the sleep queue and made runnable if it is still asleep.
|
|
*/
|
|
static void
|
|
sleepq_timeout(void *arg)
|
|
{
|
|
struct sleepqueue_chain *sc __unused;
|
|
struct sleepqueue *sq;
|
|
struct thread *td;
|
|
const void *wchan;
|
|
int wakeup_swapper;
|
|
|
|
td = arg;
|
|
CTR3(KTR_PROC, "sleepq_timeout: thread %p (pid %ld, %s)",
|
|
(void *)td, (long)td->td_proc->p_pid, (void *)td->td_name);
|
|
|
|
thread_lock(td);
|
|
if (td->td_sleeptimo == 0 ||
|
|
td->td_sleeptimo > td->td_slpcallout.c_time) {
|
|
/*
|
|
* The thread does not want a timeout (yet).
|
|
*/
|
|
} else if (TD_IS_SLEEPING(td) && TD_ON_SLEEPQ(td)) {
|
|
/*
|
|
* See if the thread is asleep and get the wait
|
|
* channel if it is.
|
|
*/
|
|
wchan = td->td_wchan;
|
|
sc = SC_LOOKUP(wchan);
|
|
THREAD_LOCKPTR_ASSERT(td, &sc->sc_lock);
|
|
sq = sleepq_lookup(wchan);
|
|
MPASS(sq != NULL);
|
|
td->td_flags |= TDF_TIMEOUT;
|
|
wakeup_swapper = sleepq_resume_thread(sq, td, 0, 0);
|
|
if (wakeup_swapper)
|
|
kick_proc0();
|
|
return;
|
|
} else if (TD_ON_SLEEPQ(td)) {
|
|
/*
|
|
* If the thread is on the SLEEPQ but isn't sleeping
|
|
* yet, it can either be on another CPU in between
|
|
* sleepq_add() and one of the sleepq_*wait*()
|
|
* routines or it can be in sleepq_catch_signals().
|
|
*/
|
|
td->td_flags |= TDF_TIMEOUT;
|
|
}
|
|
thread_unlock(td);
|
|
}
|
|
|
|
/*
|
|
* Resumes a specific thread from the sleep queue associated with a specific
|
|
* wait channel if it is on that queue.
|
|
*/
|
|
void
|
|
sleepq_remove(struct thread *td, const void *wchan)
|
|
{
|
|
struct sleepqueue_chain *sc;
|
|
struct sleepqueue *sq;
|
|
int wakeup_swapper;
|
|
|
|
/*
|
|
* Look up the sleep queue for this wait channel, then re-check
|
|
* that the thread is asleep on that channel, if it is not, then
|
|
* bail.
|
|
*/
|
|
MPASS(wchan != NULL);
|
|
sc = SC_LOOKUP(wchan);
|
|
mtx_lock_spin(&sc->sc_lock);
|
|
/*
|
|
* We can not lock the thread here as it may be sleeping on a
|
|
* different sleepq. However, holding the sleepq lock for this
|
|
* wchan can guarantee that we do not miss a wakeup for this
|
|
* channel. The asserts below will catch any false positives.
|
|
*/
|
|
if (!TD_ON_SLEEPQ(td) || td->td_wchan != wchan) {
|
|
mtx_unlock_spin(&sc->sc_lock);
|
|
return;
|
|
}
|
|
|
|
/* Thread is asleep on sleep queue sq, so wake it up. */
|
|
sq = sleepq_lookup(wchan);
|
|
MPASS(sq != NULL);
|
|
MPASS(td->td_wchan == wchan);
|
|
wakeup_swapper = sleepq_resume_thread(sq, td, 0, 0);
|
|
if (wakeup_swapper)
|
|
kick_proc0();
|
|
}
|
|
|
|
/*
|
|
* Abort a thread as if an interrupt had occurred. Only abort
|
|
* interruptible waits (unfortunately it isn't safe to abort others).
|
|
*
|
|
* Requires thread lock on entry, releases on return.
|
|
*/
|
|
int
|
|
sleepq_abort(struct thread *td, int intrval)
|
|
{
|
|
struct sleepqueue *sq;
|
|
const void *wchan;
|
|
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
MPASS(TD_ON_SLEEPQ(td));
|
|
MPASS(td->td_flags & TDF_SINTR);
|
|
MPASS((intrval == 0 && (td->td_flags & TDF_SIGWAIT) != 0) ||
|
|
intrval == EINTR || intrval == ERESTART);
|
|
|
|
/*
|
|
* If the TDF_TIMEOUT flag is set, just leave. A
|
|
* timeout is scheduled anyhow.
|
|
*/
|
|
if (td->td_flags & TDF_TIMEOUT) {
|
|
thread_unlock(td);
|
|
return (0);
|
|
}
|
|
|
|
CTR3(KTR_PROC, "sleepq_abort: thread %p (pid %ld, %s)",
|
|
(void *)td, (long)td->td_proc->p_pid, (void *)td->td_name);
|
|
td->td_intrval = intrval;
|
|
|
|
/*
|
|
* If the thread has not slept yet it will find the signal in
|
|
* sleepq_catch_signals() and call sleepq_resume_thread. Otherwise
|
|
* we have to do it here.
|
|
*/
|
|
if (!TD_IS_SLEEPING(td)) {
|
|
thread_unlock(td);
|
|
return (0);
|
|
}
|
|
wchan = td->td_wchan;
|
|
MPASS(wchan != NULL);
|
|
sq = sleepq_lookup(wchan);
|
|
MPASS(sq != NULL);
|
|
|
|
/* Thread is asleep on sleep queue sq, so wake it up. */
|
|
return (sleepq_resume_thread(sq, td, 0, 0));
|
|
}
|
|
|
|
void
|
|
sleepq_chains_remove_matching(bool (*matches)(struct thread *))
|
|
{
|
|
struct sleepqueue_chain *sc;
|
|
struct sleepqueue *sq, *sq1;
|
|
int i, wakeup_swapper;
|
|
|
|
wakeup_swapper = 0;
|
|
for (sc = &sleepq_chains[0]; sc < sleepq_chains + SC_TABLESIZE; ++sc) {
|
|
if (LIST_EMPTY(&sc->sc_queues)) {
|
|
continue;
|
|
}
|
|
mtx_lock_spin(&sc->sc_lock);
|
|
LIST_FOREACH_SAFE(sq, &sc->sc_queues, sq_hash, sq1) {
|
|
for (i = 0; i < NR_SLEEPQS; ++i) {
|
|
wakeup_swapper |= sleepq_remove_matching(sq, i,
|
|
matches, 0);
|
|
}
|
|
}
|
|
mtx_unlock_spin(&sc->sc_lock);
|
|
}
|
|
if (wakeup_swapper) {
|
|
kick_proc0();
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Prints the stacks of all threads presently sleeping on wchan/queue to
|
|
* the sbuf sb. Sets count_stacks_printed to the number of stacks actually
|
|
* printed. Typically, this will equal the number of threads sleeping on the
|
|
* queue, but may be less if sb overflowed before all stacks were printed.
|
|
*/
|
|
#ifdef STACK
|
|
int
|
|
sleepq_sbuf_print_stacks(struct sbuf *sb, const void *wchan, int queue,
|
|
int *count_stacks_printed)
|
|
{
|
|
struct thread *td, *td_next;
|
|
struct sleepqueue *sq;
|
|
struct stack **st;
|
|
struct sbuf **td_infos;
|
|
int i, stack_idx, error, stacks_to_allocate;
|
|
bool finished;
|
|
|
|
error = 0;
|
|
finished = false;
|
|
|
|
KASSERT(wchan != NULL, ("%s: invalid NULL wait channel", __func__));
|
|
MPASS((queue >= 0) && (queue < NR_SLEEPQS));
|
|
|
|
stacks_to_allocate = 10;
|
|
for (i = 0; i < 3 && !finished ; i++) {
|
|
/* We cannot malloc while holding the queue's spinlock, so
|
|
* we do our mallocs now, and hope it is enough. If it
|
|
* isn't, we will free these, drop the lock, malloc more,
|
|
* and try again, up to a point. After that point we will
|
|
* give up and report ENOMEM. We also cannot write to sb
|
|
* during this time since the client may have set the
|
|
* SBUF_AUTOEXTEND flag on their sbuf, which could cause a
|
|
* malloc as we print to it. So we defer actually printing
|
|
* to sb until after we drop the spinlock.
|
|
*/
|
|
|
|
/* Where we will store the stacks. */
|
|
st = malloc(sizeof(struct stack *) * stacks_to_allocate,
|
|
M_TEMP, M_WAITOK);
|
|
for (stack_idx = 0; stack_idx < stacks_to_allocate;
|
|
stack_idx++)
|
|
st[stack_idx] = stack_create(M_WAITOK);
|
|
|
|
/* Where we will store the td name, tid, etc. */
|
|
td_infos = malloc(sizeof(struct sbuf *) * stacks_to_allocate,
|
|
M_TEMP, M_WAITOK);
|
|
for (stack_idx = 0; stack_idx < stacks_to_allocate;
|
|
stack_idx++)
|
|
td_infos[stack_idx] = sbuf_new(NULL, NULL,
|
|
MAXCOMLEN + sizeof(struct thread *) * 2 + 40,
|
|
SBUF_FIXEDLEN);
|
|
|
|
sleepq_lock(wchan);
|
|
sq = sleepq_lookup(wchan);
|
|
if (sq == NULL) {
|
|
/* This sleepq does not exist; exit and return ENOENT. */
|
|
error = ENOENT;
|
|
finished = true;
|
|
sleepq_release(wchan);
|
|
goto loop_end;
|
|
}
|
|
|
|
stack_idx = 0;
|
|
/* Save thread info */
|
|
TAILQ_FOREACH_SAFE(td, &sq->sq_blocked[queue], td_slpq,
|
|
td_next) {
|
|
if (stack_idx >= stacks_to_allocate)
|
|
goto loop_end;
|
|
|
|
/* Note the td_lock is equal to the sleepq_lock here. */
|
|
(void)stack_save_td(st[stack_idx], td);
|
|
|
|
sbuf_printf(td_infos[stack_idx], "%d: %s %p",
|
|
td->td_tid, td->td_name, td);
|
|
|
|
++stack_idx;
|
|
}
|
|
|
|
finished = true;
|
|
sleepq_release(wchan);
|
|
|
|
/* Print the stacks */
|
|
for (i = 0; i < stack_idx; i++) {
|
|
sbuf_finish(td_infos[i]);
|
|
sbuf_printf(sb, "--- thread %s: ---\n", sbuf_data(td_infos[i]));
|
|
stack_sbuf_print(sb, st[i]);
|
|
sbuf_printf(sb, "\n");
|
|
|
|
error = sbuf_error(sb);
|
|
if (error == 0)
|
|
*count_stacks_printed = stack_idx;
|
|
}
|
|
|
|
loop_end:
|
|
if (!finished)
|
|
sleepq_release(wchan);
|
|
for (stack_idx = 0; stack_idx < stacks_to_allocate;
|
|
stack_idx++)
|
|
stack_destroy(st[stack_idx]);
|
|
for (stack_idx = 0; stack_idx < stacks_to_allocate;
|
|
stack_idx++)
|
|
sbuf_delete(td_infos[stack_idx]);
|
|
free(st, M_TEMP);
|
|
free(td_infos, M_TEMP);
|
|
stacks_to_allocate *= 10;
|
|
}
|
|
|
|
if (!finished && error == 0)
|
|
error = ENOMEM;
|
|
|
|
return (error);
|
|
}
|
|
#endif
|
|
|
|
#ifdef SLEEPQUEUE_PROFILING
|
|
#define SLEEPQ_PROF_LOCATIONS 1024
|
|
#define SLEEPQ_SBUFSIZE 512
|
|
struct sleepq_prof {
|
|
LIST_ENTRY(sleepq_prof) sp_link;
|
|
const char *sp_wmesg;
|
|
long sp_count;
|
|
};
|
|
|
|
LIST_HEAD(sqphead, sleepq_prof);
|
|
|
|
struct sqphead sleepq_prof_free;
|
|
struct sqphead sleepq_hash[SC_TABLESIZE];
|
|
static struct sleepq_prof sleepq_profent[SLEEPQ_PROF_LOCATIONS];
|
|
static struct mtx sleepq_prof_lock;
|
|
MTX_SYSINIT(sleepq_prof_lock, &sleepq_prof_lock, "sleepq_prof", MTX_SPIN);
|
|
|
|
static void
|
|
sleepq_profile(const char *wmesg)
|
|
{
|
|
struct sleepq_prof *sp;
|
|
|
|
mtx_lock_spin(&sleepq_prof_lock);
|
|
if (prof_enabled == 0)
|
|
goto unlock;
|
|
LIST_FOREACH(sp, &sleepq_hash[SC_HASH(wmesg)], sp_link)
|
|
if (sp->sp_wmesg == wmesg)
|
|
goto done;
|
|
sp = LIST_FIRST(&sleepq_prof_free);
|
|
if (sp == NULL)
|
|
goto unlock;
|
|
sp->sp_wmesg = wmesg;
|
|
LIST_REMOVE(sp, sp_link);
|
|
LIST_INSERT_HEAD(&sleepq_hash[SC_HASH(wmesg)], sp, sp_link);
|
|
done:
|
|
sp->sp_count++;
|
|
unlock:
|
|
mtx_unlock_spin(&sleepq_prof_lock);
|
|
return;
|
|
}
|
|
|
|
static void
|
|
sleepq_prof_reset(void)
|
|
{
|
|
struct sleepq_prof *sp;
|
|
int enabled;
|
|
int i;
|
|
|
|
mtx_lock_spin(&sleepq_prof_lock);
|
|
enabled = prof_enabled;
|
|
prof_enabled = 0;
|
|
for (i = 0; i < SC_TABLESIZE; i++)
|
|
LIST_INIT(&sleepq_hash[i]);
|
|
LIST_INIT(&sleepq_prof_free);
|
|
for (i = 0; i < SLEEPQ_PROF_LOCATIONS; i++) {
|
|
sp = &sleepq_profent[i];
|
|
sp->sp_wmesg = NULL;
|
|
sp->sp_count = 0;
|
|
LIST_INSERT_HEAD(&sleepq_prof_free, sp, sp_link);
|
|
}
|
|
prof_enabled = enabled;
|
|
mtx_unlock_spin(&sleepq_prof_lock);
|
|
}
|
|
|
|
static int
|
|
enable_sleepq_prof(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
int error, v;
|
|
|
|
v = prof_enabled;
|
|
error = sysctl_handle_int(oidp, &v, v, req);
|
|
if (error)
|
|
return (error);
|
|
if (req->newptr == NULL)
|
|
return (error);
|
|
if (v == prof_enabled)
|
|
return (0);
|
|
if (v == 1)
|
|
sleepq_prof_reset();
|
|
mtx_lock_spin(&sleepq_prof_lock);
|
|
prof_enabled = !!v;
|
|
mtx_unlock_spin(&sleepq_prof_lock);
|
|
|
|
return (0);
|
|
}
|
|
|
|
static int
|
|
reset_sleepq_prof_stats(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
int error, v;
|
|
|
|
v = 0;
|
|
error = sysctl_handle_int(oidp, &v, 0, req);
|
|
if (error)
|
|
return (error);
|
|
if (req->newptr == NULL)
|
|
return (error);
|
|
if (v == 0)
|
|
return (0);
|
|
sleepq_prof_reset();
|
|
|
|
return (0);
|
|
}
|
|
|
|
static int
|
|
dump_sleepq_prof_stats(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
struct sleepq_prof *sp;
|
|
struct sbuf *sb;
|
|
int enabled;
|
|
int error;
|
|
int i;
|
|
|
|
error = sysctl_wire_old_buffer(req, 0);
|
|
if (error != 0)
|
|
return (error);
|
|
sb = sbuf_new_for_sysctl(NULL, NULL, SLEEPQ_SBUFSIZE, req);
|
|
sbuf_printf(sb, "\nwmesg\tcount\n");
|
|
enabled = prof_enabled;
|
|
mtx_lock_spin(&sleepq_prof_lock);
|
|
prof_enabled = 0;
|
|
mtx_unlock_spin(&sleepq_prof_lock);
|
|
for (i = 0; i < SC_TABLESIZE; i++) {
|
|
LIST_FOREACH(sp, &sleepq_hash[i], sp_link) {
|
|
sbuf_printf(sb, "%s\t%ld\n",
|
|
sp->sp_wmesg, sp->sp_count);
|
|
}
|
|
}
|
|
mtx_lock_spin(&sleepq_prof_lock);
|
|
prof_enabled = enabled;
|
|
mtx_unlock_spin(&sleepq_prof_lock);
|
|
|
|
error = sbuf_finish(sb);
|
|
sbuf_delete(sb);
|
|
return (error);
|
|
}
|
|
|
|
SYSCTL_PROC(_debug_sleepq, OID_AUTO, stats,
|
|
CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_NEEDGIANT, NULL, 0,
|
|
dump_sleepq_prof_stats, "A",
|
|
"Sleepqueue profiling statistics");
|
|
SYSCTL_PROC(_debug_sleepq, OID_AUTO, reset,
|
|
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 0,
|
|
reset_sleepq_prof_stats, "I",
|
|
"Reset sleepqueue profiling statistics");
|
|
SYSCTL_PROC(_debug_sleepq, OID_AUTO, enable,
|
|
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 0,
|
|
enable_sleepq_prof, "I",
|
|
"Enable sleepqueue profiling");
|
|
#endif
|
|
|
|
#ifdef DDB
|
|
DB_SHOW_COMMAND(sleepq, db_show_sleepqueue)
|
|
{
|
|
struct sleepqueue_chain *sc;
|
|
struct sleepqueue *sq;
|
|
#ifdef INVARIANTS
|
|
struct lock_object *lock;
|
|
#endif
|
|
struct thread *td;
|
|
void *wchan;
|
|
int i;
|
|
|
|
if (!have_addr)
|
|
return;
|
|
|
|
/*
|
|
* First, see if there is an active sleep queue for the wait channel
|
|
* indicated by the address.
|
|
*/
|
|
wchan = (void *)addr;
|
|
sc = SC_LOOKUP(wchan);
|
|
LIST_FOREACH(sq, &sc->sc_queues, sq_hash)
|
|
if (sq->sq_wchan == wchan)
|
|
goto found;
|
|
|
|
/*
|
|
* Second, see if there is an active sleep queue at the address
|
|
* indicated.
|
|
*/
|
|
for (i = 0; i < SC_TABLESIZE; i++)
|
|
LIST_FOREACH(sq, &sleepq_chains[i].sc_queues, sq_hash) {
|
|
if (sq == (struct sleepqueue *)addr)
|
|
goto found;
|
|
}
|
|
|
|
db_printf("Unable to locate a sleep queue via %p\n", (void *)addr);
|
|
return;
|
|
found:
|
|
db_printf("Wait channel: %p\n", sq->sq_wchan);
|
|
db_printf("Queue type: %d\n", sq->sq_type);
|
|
#ifdef INVARIANTS
|
|
if (sq->sq_lock) {
|
|
lock = sq->sq_lock;
|
|
db_printf("Associated Interlock: %p - (%s) %s\n", lock,
|
|
LOCK_CLASS(lock)->lc_name, lock->lo_name);
|
|
}
|
|
#endif
|
|
db_printf("Blocked threads:\n");
|
|
for (i = 0; i < NR_SLEEPQS; i++) {
|
|
db_printf("\nQueue[%d]:\n", i);
|
|
if (TAILQ_EMPTY(&sq->sq_blocked[i]))
|
|
db_printf("\tempty\n");
|
|
else
|
|
TAILQ_FOREACH(td, &sq->sq_blocked[i],
|
|
td_slpq) {
|
|
db_printf("\t%p (tid %d, pid %d, \"%s\")\n", td,
|
|
td->td_tid, td->td_proc->p_pid,
|
|
td->td_name);
|
|
}
|
|
db_printf("(expected: %u)\n", sq->sq_blockedcnt[i]);
|
|
}
|
|
}
|
|
|
|
/* Alias 'show sleepqueue' to 'show sleepq'. */
|
|
DB_SHOW_ALIAS(sleepqueue, db_show_sleepqueue);
|
|
#endif
|