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39297ba455
the command set (only so long as the module is present): o add db_command_register and db_command_unregister to add and remove commands, respectively o replace linker sets with SYSINIT's (and SYSUINIT's) that register commands o expose 3 list heads: db_cmd_table, db_show_table, and db_show_all_table for registering top-level commands, show operands, and show all operands, respectively While here also: o sort command lists o add DB_ALIAS, DB_SHOW_ALIAS, and DB_SHOW_ALL_ALIAS to add aliases for existing commands o add "show all trace" as an alias for "show alltrace" o add "show all locks" as an alias for "show alllocks" Submitted by: Guillaume Ballet <gballet@gmail.com> (original version) Reviewed by: jhb MFC after: 1 month
1300 lines
35 KiB
C
1300 lines
35 KiB
C
/*-
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* Copyright (c) 1998 Berkeley Software Design, Inc. All rights reserved.
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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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* 3. Berkeley Software Design Inc's name may not be used to endorse or
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* promote products derived from this software without specific prior
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* written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``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 BERKELEY SOFTWARE DESIGN INC 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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* from BSDI $Id: mutex_witness.c,v 1.1.2.20 2000/04/27 03:10:27 cp Exp $
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* and BSDI $Id: synch_machdep.c,v 2.3.2.39 2000/04/27 03:10:25 cp Exp $
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*/
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/*
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* Implementation of turnstiles used to hold queue of threads blocked on
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* non-sleepable locks. Sleepable locks use condition variables to
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* implement their queues. Turnstiles differ from a sleep queue in that
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* turnstile queue's are assigned to a lock held by an owning thread. Thus,
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* when one thread is enqueued onto a turnstile, it can lend its priority
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* to the owning thread.
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*
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* We wish to avoid bloating locks with an embedded turnstile and we do not
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* want to use back-pointers in the locks for the same reason. Thus, we
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* use a similar approach to that of Solaris 7 as described in Solaris
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* Internals by Jim Mauro and Richard McDougall. Turnstiles are looked up
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* in a hash table based on the address of the lock. Each entry in the
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* hash table is a linked-lists of turnstiles and is called a turnstile
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* chain. Each chain contains a spin mutex that protects all of the
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* turnstiles in the chain.
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*
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* Each time a thread is created, a turnstile is allocated from a UMA zone
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* and attached to that thread. When a thread blocks on a lock, if it is the
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* first thread to block, it lends its turnstile to the lock. If the lock
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* already has a turnstile, then it gives its turnstile to the lock's
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* turnstile's free list. When a thread is woken up, it takes a turnstile from
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* the free list if there are any other waiters. If it is the only thread
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* blocked on the lock, then it reclaims the turnstile associated with the lock
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* and removes it from the hash table.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_ddb.h"
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#include "opt_turnstile_profiling.h"
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#include "opt_sched.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/ktr.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/queue.h>
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#include <sys/sched.h>
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#include <sys/sysctl.h>
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#include <sys/turnstile.h>
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#include <vm/uma.h>
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#ifdef DDB
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#include <sys/kdb.h>
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#include <ddb/ddb.h>
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#include <sys/lockmgr.h>
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#include <sys/sx.h>
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#endif
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/*
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* Constants for the hash table of turnstile chains. TC_SHIFT is a magic
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* number chosen because the sleep queue's use the same value for the
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* shift. Basically, we ignore the lower 8 bits of the address.
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* TC_TABLESIZE must be a power of two for TC_MASK to work properly.
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*/
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#define TC_TABLESIZE 128 /* Must be power of 2. */
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#define TC_MASK (TC_TABLESIZE - 1)
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#define TC_SHIFT 8
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#define TC_HASH(lock) (((uintptr_t)(lock) >> TC_SHIFT) & TC_MASK)
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#define TC_LOOKUP(lock) &turnstile_chains[TC_HASH(lock)]
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/*
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* There are three different lists of turnstiles as follows. The list
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* connected by ts_link entries is a per-thread list of all the turnstiles
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* attached to locks that we own. This is used to fixup our priority when
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* a lock is released. The other two lists use the ts_hash entries. The
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* first of these two is the turnstile chain list that a turnstile is on
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* when it is attached to a lock. The second list to use ts_hash is the
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* free list hung off of a turnstile that is attached to a lock.
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*
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* Each turnstile contains three lists of threads. The two ts_blocked lists
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* are linked list of threads blocked on the turnstile's lock. One list is
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* for exclusive waiters, and the other is for shared waiters. The
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* ts_pending list is a linked list of threads previously awakened by
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* turnstile_signal() or turnstile_wait() that are waiting to be put on
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* the run queue.
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*
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* Locking key:
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* c - turnstile chain lock
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* q - td_contested lock
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*/
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struct turnstile {
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struct mtx ts_lock; /* Spin lock for self. */
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struct threadqueue ts_blocked[2]; /* (c + q) Blocked threads. */
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struct threadqueue ts_pending; /* (c) Pending threads. */
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LIST_ENTRY(turnstile) ts_hash; /* (c) Chain and free list. */
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LIST_ENTRY(turnstile) ts_link; /* (q) Contested locks. */
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LIST_HEAD(, turnstile) ts_free; /* (c) Free turnstiles. */
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struct lock_object *ts_lockobj; /* (c) Lock we reference. */
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struct thread *ts_owner; /* (c + q) Who owns the lock. */
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};
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struct turnstile_chain {
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LIST_HEAD(, turnstile) tc_turnstiles; /* List of turnstiles. */
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struct mtx tc_lock; /* Spin lock for this chain. */
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#ifdef TURNSTILE_PROFILING
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u_int tc_depth; /* Length of tc_queues. */
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u_int tc_max_depth; /* Max length of tc_queues. */
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#endif
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};
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#ifdef TURNSTILE_PROFILING
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u_int turnstile_max_depth;
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SYSCTL_NODE(_debug, OID_AUTO, turnstile, CTLFLAG_RD, 0, "turnstile profiling");
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SYSCTL_NODE(_debug_turnstile, OID_AUTO, chains, CTLFLAG_RD, 0,
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"turnstile chain stats");
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SYSCTL_UINT(_debug_turnstile, OID_AUTO, max_depth, CTLFLAG_RD,
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&turnstile_max_depth, 0, "maxmimum depth achieved of a single chain");
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#endif
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static struct mtx td_contested_lock;
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static struct turnstile_chain turnstile_chains[TC_TABLESIZE];
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static uma_zone_t turnstile_zone;
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/*
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* Prototypes for non-exported routines.
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*/
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static void init_turnstile0(void *dummy);
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#ifdef TURNSTILE_PROFILING
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static void init_turnstile_profiling(void *arg);
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#endif
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static void propagate_priority(struct thread *td);
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static int turnstile_adjust_thread(struct turnstile *ts,
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struct thread *td);
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static struct thread *turnstile_first_waiter(struct turnstile *ts);
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static void turnstile_setowner(struct turnstile *ts, struct thread *owner);
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#ifdef INVARIANTS
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static void turnstile_dtor(void *mem, int size, void *arg);
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#endif
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static int turnstile_init(void *mem, int size, int flags);
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static void turnstile_fini(void *mem, int size);
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/*
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* Walks the chain of turnstiles and their owners to propagate the priority
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* of the thread being blocked to all the threads holding locks that have to
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* release their locks before this thread can run again.
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*/
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static void
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propagate_priority(struct thread *td)
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{
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struct turnstile *ts;
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int pri;
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THREAD_LOCK_ASSERT(td, MA_OWNED);
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pri = td->td_priority;
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ts = td->td_blocked;
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THREAD_LOCKPTR_ASSERT(td, &ts->ts_lock);
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/*
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* Grab a recursive lock on this turnstile chain so it stays locked
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* for the whole operation. The caller expects us to return with
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* the original lock held. We only ever lock down the chain so
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* the lock order is constant.
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*/
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mtx_lock_spin(&ts->ts_lock);
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for (;;) {
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td = ts->ts_owner;
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if (td == NULL) {
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/*
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* This might be a read lock with no owner. There's
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* not much we can do, so just bail.
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*/
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mtx_unlock_spin(&ts->ts_lock);
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return;
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}
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thread_lock_flags(td, MTX_DUPOK);
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mtx_unlock_spin(&ts->ts_lock);
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MPASS(td->td_proc != NULL);
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MPASS(td->td_proc->p_magic == P_MAGIC);
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/*
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* If the thread is asleep, then we are probably about
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* to deadlock. To make debugging this easier, just
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* panic and tell the user which thread misbehaved so
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* they can hopefully get a stack trace from the truly
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* misbehaving thread.
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*/
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if (TD_IS_SLEEPING(td)) {
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printf(
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"Sleeping thread (tid %d, pid %d) owns a non-sleepable lock\n",
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td->td_tid, td->td_proc->p_pid);
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#ifdef DDB
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db_trace_thread(td, -1);
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#endif
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panic("sleeping thread");
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}
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/*
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* If this thread already has higher priority than the
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* thread that is being blocked, we are finished.
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*/
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if (td->td_priority <= pri) {
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thread_unlock(td);
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return;
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}
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/*
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* Bump this thread's priority.
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*/
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sched_lend_prio(td, pri);
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/*
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* If lock holder is actually running or on the run queue
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* then we are done.
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*/
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if (TD_IS_RUNNING(td) || TD_ON_RUNQ(td)) {
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MPASS(td->td_blocked == NULL);
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thread_unlock(td);
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return;
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}
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#ifndef SMP
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/*
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* For UP, we check to see if td is curthread (this shouldn't
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* ever happen however as it would mean we are in a deadlock.)
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*/
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KASSERT(td != curthread, ("Deadlock detected"));
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#endif
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/*
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* If we aren't blocked on a lock, we should be.
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*/
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KASSERT(TD_ON_LOCK(td), (
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"thread %d(%s):%d holds %s but isn't blocked on a lock\n",
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td->td_tid, td->td_name, td->td_state,
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ts->ts_lockobj->lo_name));
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/*
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* Pick up the lock that td is blocked on.
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*/
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ts = td->td_blocked;
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MPASS(ts != NULL);
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THREAD_LOCKPTR_ASSERT(td, &ts->ts_lock);
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/* Resort td on the list if needed. */
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if (!turnstile_adjust_thread(ts, td)) {
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mtx_unlock_spin(&ts->ts_lock);
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return;
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}
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/* The thread lock is released as ts lock above. */
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}
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}
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/*
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* Adjust the thread's position on a turnstile after its priority has been
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* changed.
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*/
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static int
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turnstile_adjust_thread(struct turnstile *ts, struct thread *td)
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{
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struct thread *td1, *td2;
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int queue;
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THREAD_LOCK_ASSERT(td, MA_OWNED);
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MPASS(TD_ON_LOCK(td));
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/*
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* This thread may not be blocked on this turnstile anymore
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* but instead might already be woken up on another CPU
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* that is waiting on the thread lock in turnstile_unpend() to
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* finish waking this thread up. We can detect this case
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* by checking to see if this thread has been given a
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* turnstile by either turnstile_signal() or
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* turnstile_broadcast(). In this case, treat the thread as
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* if it was already running.
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*/
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if (td->td_turnstile != NULL)
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return (0);
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/*
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* Check if the thread needs to be moved on the blocked chain.
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* It needs to be moved if either its priority is lower than
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* the previous thread or higher than the next thread.
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*/
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THREAD_LOCKPTR_ASSERT(td, &ts->ts_lock);
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td1 = TAILQ_PREV(td, threadqueue, td_lockq);
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td2 = TAILQ_NEXT(td, td_lockq);
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if ((td1 != NULL && td->td_priority < td1->td_priority) ||
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(td2 != NULL && td->td_priority > td2->td_priority)) {
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/*
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* Remove thread from blocked chain and determine where
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* it should be moved to.
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*/
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queue = td->td_tsqueue;
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MPASS(queue == TS_EXCLUSIVE_QUEUE || queue == TS_SHARED_QUEUE);
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mtx_lock_spin(&td_contested_lock);
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TAILQ_REMOVE(&ts->ts_blocked[queue], td, td_lockq);
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TAILQ_FOREACH(td1, &ts->ts_blocked[queue], td_lockq) {
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MPASS(td1->td_proc->p_magic == P_MAGIC);
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if (td1->td_priority > td->td_priority)
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break;
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}
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if (td1 == NULL)
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TAILQ_INSERT_TAIL(&ts->ts_blocked[queue], td, td_lockq);
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else
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TAILQ_INSERT_BEFORE(td1, td, td_lockq);
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mtx_unlock_spin(&td_contested_lock);
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if (td1 == NULL)
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CTR3(KTR_LOCK,
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"turnstile_adjust_thread: td %d put at tail on [%p] %s",
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td->td_tid, ts->ts_lockobj, ts->ts_lockobj->lo_name);
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else
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CTR4(KTR_LOCK,
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"turnstile_adjust_thread: td %d moved before %d on [%p] %s",
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td->td_tid, td1->td_tid, ts->ts_lockobj,
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ts->ts_lockobj->lo_name);
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}
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return (1);
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}
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/*
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* Early initialization of turnstiles. This is not done via a SYSINIT()
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* since this needs to be initialized very early when mutexes are first
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* initialized.
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*/
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void
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init_turnstiles(void)
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{
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int i;
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for (i = 0; i < TC_TABLESIZE; i++) {
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LIST_INIT(&turnstile_chains[i].tc_turnstiles);
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mtx_init(&turnstile_chains[i].tc_lock, "turnstile chain",
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NULL, MTX_SPIN);
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}
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mtx_init(&td_contested_lock, "td_contested", NULL, MTX_SPIN);
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LIST_INIT(&thread0.td_contested);
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thread0.td_turnstile = NULL;
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}
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#ifdef TURNSTILE_PROFILING
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static void
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init_turnstile_profiling(void *arg)
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{
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struct sysctl_oid *chain_oid;
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char chain_name[10];
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int i;
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for (i = 0; i < TC_TABLESIZE; i++) {
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snprintf(chain_name, sizeof(chain_name), "%d", i);
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chain_oid = SYSCTL_ADD_NODE(NULL,
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SYSCTL_STATIC_CHILDREN(_debug_turnstile_chains), OID_AUTO,
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chain_name, CTLFLAG_RD, NULL, "turnstile chain stats");
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SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO,
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"depth", CTLFLAG_RD, &turnstile_chains[i].tc_depth, 0,
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NULL);
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SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO,
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"max_depth", CTLFLAG_RD, &turnstile_chains[i].tc_max_depth,
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0, NULL);
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}
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}
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SYSINIT(turnstile_profiling, SI_SUB_LOCK, SI_ORDER_ANY,
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init_turnstile_profiling, NULL);
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#endif
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static void
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init_turnstile0(void *dummy)
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{
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turnstile_zone = uma_zcreate("TURNSTILE", sizeof(struct turnstile),
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NULL,
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#ifdef INVARIANTS
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turnstile_dtor,
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#else
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NULL,
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#endif
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turnstile_init, turnstile_fini, UMA_ALIGN_CACHE, UMA_ZONE_NOFREE);
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thread0.td_turnstile = turnstile_alloc();
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}
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SYSINIT(turnstile0, SI_SUB_LOCK, SI_ORDER_ANY, init_turnstile0, NULL);
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|
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/*
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* Update a thread on the turnstile list after it's priority has been changed.
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* The old priority is passed in as an argument.
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*/
|
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void
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turnstile_adjust(struct thread *td, u_char oldpri)
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|
{
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struct turnstile *ts;
|
|
|
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MPASS(TD_ON_LOCK(td));
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|
|
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/*
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* Pick up the lock that td is blocked on.
|
|
*/
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ts = td->td_blocked;
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MPASS(ts != NULL);
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THREAD_LOCKPTR_ASSERT(td, &ts->ts_lock);
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mtx_assert(&ts->ts_lock, MA_OWNED);
|
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|
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/* Resort the turnstile on the list. */
|
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if (!turnstile_adjust_thread(ts, td))
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return;
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/*
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|
* If our priority was lowered and we are at the head of the
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* turnstile, then propagate our new priority up the chain.
|
|
* Note that we currently don't try to revoke lent priorities
|
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* when our priority goes up.
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|
*/
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MPASS(td->td_tsqueue == TS_EXCLUSIVE_QUEUE ||
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td->td_tsqueue == TS_SHARED_QUEUE);
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if (td == TAILQ_FIRST(&ts->ts_blocked[td->td_tsqueue]) &&
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td->td_priority < oldpri) {
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propagate_priority(td);
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}
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}
|
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|
|
/*
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|
* Set the owner of the lock this turnstile is attached to.
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|
*/
|
|
static void
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turnstile_setowner(struct turnstile *ts, struct thread *owner)
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{
|
|
|
|
mtx_assert(&td_contested_lock, MA_OWNED);
|
|
MPASS(ts->ts_owner == NULL);
|
|
|
|
/* A shared lock might not have an owner. */
|
|
if (owner == NULL)
|
|
return;
|
|
|
|
MPASS(owner->td_proc->p_magic == P_MAGIC);
|
|
ts->ts_owner = owner;
|
|
LIST_INSERT_HEAD(&owner->td_contested, ts, ts_link);
|
|
}
|
|
|
|
#ifdef INVARIANTS
|
|
/*
|
|
* UMA zone item deallocator.
|
|
*/
|
|
static void
|
|
turnstile_dtor(void *mem, int size, void *arg)
|
|
{
|
|
struct turnstile *ts;
|
|
|
|
ts = mem;
|
|
MPASS(TAILQ_EMPTY(&ts->ts_blocked[TS_EXCLUSIVE_QUEUE]));
|
|
MPASS(TAILQ_EMPTY(&ts->ts_blocked[TS_SHARED_QUEUE]));
|
|
MPASS(TAILQ_EMPTY(&ts->ts_pending));
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* UMA zone item initializer.
|
|
*/
|
|
static int
|
|
turnstile_init(void *mem, int size, int flags)
|
|
{
|
|
struct turnstile *ts;
|
|
|
|
bzero(mem, size);
|
|
ts = mem;
|
|
TAILQ_INIT(&ts->ts_blocked[TS_EXCLUSIVE_QUEUE]);
|
|
TAILQ_INIT(&ts->ts_blocked[TS_SHARED_QUEUE]);
|
|
TAILQ_INIT(&ts->ts_pending);
|
|
LIST_INIT(&ts->ts_free);
|
|
mtx_init(&ts->ts_lock, "turnstile lock", NULL, MTX_SPIN | MTX_RECURSE);
|
|
return (0);
|
|
}
|
|
|
|
static void
|
|
turnstile_fini(void *mem, int size)
|
|
{
|
|
struct turnstile *ts;
|
|
|
|
ts = mem;
|
|
mtx_destroy(&ts->ts_lock);
|
|
}
|
|
|
|
/*
|
|
* Get a turnstile for a new thread.
|
|
*/
|
|
struct turnstile *
|
|
turnstile_alloc(void)
|
|
{
|
|
|
|
return (uma_zalloc(turnstile_zone, M_WAITOK));
|
|
}
|
|
|
|
/*
|
|
* Free a turnstile when a thread is destroyed.
|
|
*/
|
|
void
|
|
turnstile_free(struct turnstile *ts)
|
|
{
|
|
|
|
uma_zfree(turnstile_zone, ts);
|
|
}
|
|
|
|
/*
|
|
* Lock the turnstile chain associated with the specified lock.
|
|
*/
|
|
void
|
|
turnstile_chain_lock(struct lock_object *lock)
|
|
{
|
|
struct turnstile_chain *tc;
|
|
|
|
tc = TC_LOOKUP(lock);
|
|
mtx_lock_spin(&tc->tc_lock);
|
|
}
|
|
|
|
struct turnstile *
|
|
turnstile_trywait(struct lock_object *lock)
|
|
{
|
|
struct turnstile_chain *tc;
|
|
struct turnstile *ts;
|
|
|
|
tc = TC_LOOKUP(lock);
|
|
mtx_lock_spin(&tc->tc_lock);
|
|
LIST_FOREACH(ts, &tc->tc_turnstiles, ts_hash)
|
|
if (ts->ts_lockobj == lock) {
|
|
mtx_lock_spin(&ts->ts_lock);
|
|
return (ts);
|
|
}
|
|
|
|
ts = curthread->td_turnstile;
|
|
MPASS(ts != NULL);
|
|
mtx_lock_spin(&ts->ts_lock);
|
|
KASSERT(ts->ts_lockobj == NULL, ("stale ts_lockobj pointer"));
|
|
ts->ts_lockobj = lock;
|
|
|
|
return (ts);
|
|
}
|
|
|
|
void
|
|
turnstile_cancel(struct turnstile *ts)
|
|
{
|
|
struct turnstile_chain *tc;
|
|
struct lock_object *lock;
|
|
|
|
mtx_assert(&ts->ts_lock, MA_OWNED);
|
|
|
|
mtx_unlock_spin(&ts->ts_lock);
|
|
lock = ts->ts_lockobj;
|
|
if (ts == curthread->td_turnstile)
|
|
ts->ts_lockobj = NULL;
|
|
tc = TC_LOOKUP(lock);
|
|
mtx_unlock_spin(&tc->tc_lock);
|
|
}
|
|
|
|
/*
|
|
* Look up the turnstile for a lock in the hash table locking the associated
|
|
* turnstile chain along the way. If no turnstile is found in the hash
|
|
* table, NULL is returned.
|
|
*/
|
|
struct turnstile *
|
|
turnstile_lookup(struct lock_object *lock)
|
|
{
|
|
struct turnstile_chain *tc;
|
|
struct turnstile *ts;
|
|
|
|
tc = TC_LOOKUP(lock);
|
|
mtx_assert(&tc->tc_lock, MA_OWNED);
|
|
LIST_FOREACH(ts, &tc->tc_turnstiles, ts_hash)
|
|
if (ts->ts_lockobj == lock) {
|
|
mtx_lock_spin(&ts->ts_lock);
|
|
return (ts);
|
|
}
|
|
return (NULL);
|
|
}
|
|
|
|
/*
|
|
* Unlock the turnstile chain associated with a given lock.
|
|
*/
|
|
void
|
|
turnstile_chain_unlock(struct lock_object *lock)
|
|
{
|
|
struct turnstile_chain *tc;
|
|
|
|
tc = TC_LOOKUP(lock);
|
|
mtx_unlock_spin(&tc->tc_lock);
|
|
}
|
|
|
|
/*
|
|
* Return a pointer to the thread waiting on this turnstile with the
|
|
* most important priority or NULL if the turnstile has no waiters.
|
|
*/
|
|
static struct thread *
|
|
turnstile_first_waiter(struct turnstile *ts)
|
|
{
|
|
struct thread *std, *xtd;
|
|
|
|
std = TAILQ_FIRST(&ts->ts_blocked[TS_SHARED_QUEUE]);
|
|
xtd = TAILQ_FIRST(&ts->ts_blocked[TS_EXCLUSIVE_QUEUE]);
|
|
if (xtd == NULL || (std != NULL && std->td_priority < xtd->td_priority))
|
|
return (std);
|
|
return (xtd);
|
|
}
|
|
|
|
/*
|
|
* Take ownership of a turnstile and adjust the priority of the new
|
|
* owner appropriately.
|
|
*/
|
|
void
|
|
turnstile_claim(struct turnstile *ts)
|
|
{
|
|
struct thread *td, *owner;
|
|
struct turnstile_chain *tc;
|
|
|
|
mtx_assert(&ts->ts_lock, MA_OWNED);
|
|
MPASS(ts != curthread->td_turnstile);
|
|
|
|
owner = curthread;
|
|
mtx_lock_spin(&td_contested_lock);
|
|
turnstile_setowner(ts, owner);
|
|
mtx_unlock_spin(&td_contested_lock);
|
|
|
|
td = turnstile_first_waiter(ts);
|
|
MPASS(td != NULL);
|
|
MPASS(td->td_proc->p_magic == P_MAGIC);
|
|
THREAD_LOCKPTR_ASSERT(td, &ts->ts_lock);
|
|
|
|
/*
|
|
* Update the priority of the new owner if needed.
|
|
*/
|
|
thread_lock(owner);
|
|
if (td->td_priority < owner->td_priority)
|
|
sched_lend_prio(owner, td->td_priority);
|
|
thread_unlock(owner);
|
|
tc = TC_LOOKUP(ts->ts_lockobj);
|
|
mtx_unlock_spin(&ts->ts_lock);
|
|
mtx_unlock_spin(&tc->tc_lock);
|
|
}
|
|
|
|
/*
|
|
* Block the current thread on the turnstile assicated with 'lock'. This
|
|
* function will context switch and not return until this thread has been
|
|
* woken back up. This function must be called with the appropriate
|
|
* turnstile chain locked and will return with it unlocked.
|
|
*/
|
|
void
|
|
turnstile_wait(struct turnstile *ts, struct thread *owner, int queue)
|
|
{
|
|
struct turnstile_chain *tc;
|
|
struct thread *td, *td1;
|
|
struct lock_object *lock;
|
|
|
|
td = curthread;
|
|
mtx_assert(&ts->ts_lock, MA_OWNED);
|
|
if (owner)
|
|
MPASS(owner->td_proc->p_magic == P_MAGIC);
|
|
MPASS(queue == TS_SHARED_QUEUE || queue == TS_EXCLUSIVE_QUEUE);
|
|
|
|
/*
|
|
* If the lock does not already have a turnstile, use this thread's
|
|
* turnstile. Otherwise insert the current thread into the
|
|
* turnstile already in use by this lock.
|
|
*/
|
|
tc = TC_LOOKUP(ts->ts_lockobj);
|
|
if (ts == td->td_turnstile) {
|
|
mtx_assert(&tc->tc_lock, MA_OWNED);
|
|
#ifdef TURNSTILE_PROFILING
|
|
tc->tc_depth++;
|
|
if (tc->tc_depth > tc->tc_max_depth) {
|
|
tc->tc_max_depth = tc->tc_depth;
|
|
if (tc->tc_max_depth > turnstile_max_depth)
|
|
turnstile_max_depth = tc->tc_max_depth;
|
|
}
|
|
#endif
|
|
tc = TC_LOOKUP(ts->ts_lockobj);
|
|
LIST_INSERT_HEAD(&tc->tc_turnstiles, ts, ts_hash);
|
|
KASSERT(TAILQ_EMPTY(&ts->ts_pending),
|
|
("thread's turnstile has pending threads"));
|
|
KASSERT(TAILQ_EMPTY(&ts->ts_blocked[TS_EXCLUSIVE_QUEUE]),
|
|
("thread's turnstile has exclusive waiters"));
|
|
KASSERT(TAILQ_EMPTY(&ts->ts_blocked[TS_SHARED_QUEUE]),
|
|
("thread's turnstile has shared waiters"));
|
|
KASSERT(LIST_EMPTY(&ts->ts_free),
|
|
("thread's turnstile has a non-empty free list"));
|
|
MPASS(ts->ts_lockobj != NULL);
|
|
mtx_lock_spin(&td_contested_lock);
|
|
TAILQ_INSERT_TAIL(&ts->ts_blocked[queue], td, td_lockq);
|
|
turnstile_setowner(ts, owner);
|
|
mtx_unlock_spin(&td_contested_lock);
|
|
} else {
|
|
TAILQ_FOREACH(td1, &ts->ts_blocked[queue], td_lockq)
|
|
if (td1->td_priority > td->td_priority)
|
|
break;
|
|
mtx_lock_spin(&td_contested_lock);
|
|
if (td1 != NULL)
|
|
TAILQ_INSERT_BEFORE(td1, td, td_lockq);
|
|
else
|
|
TAILQ_INSERT_TAIL(&ts->ts_blocked[queue], td, td_lockq);
|
|
MPASS(owner == ts->ts_owner);
|
|
mtx_unlock_spin(&td_contested_lock);
|
|
MPASS(td->td_turnstile != NULL);
|
|
LIST_INSERT_HEAD(&ts->ts_free, td->td_turnstile, ts_hash);
|
|
}
|
|
thread_lock(td);
|
|
thread_lock_set(td, &ts->ts_lock);
|
|
td->td_turnstile = NULL;
|
|
|
|
/* Save who we are blocked on and switch. */
|
|
lock = ts->ts_lockobj;
|
|
td->td_tsqueue = queue;
|
|
td->td_blocked = ts;
|
|
td->td_lockname = lock->lo_name;
|
|
TD_SET_LOCK(td);
|
|
mtx_unlock_spin(&tc->tc_lock);
|
|
propagate_priority(td);
|
|
|
|
if (LOCK_LOG_TEST(lock, 0))
|
|
CTR4(KTR_LOCK, "%s: td %d blocked on [%p] %s", __func__,
|
|
td->td_tid, lock, lock->lo_name);
|
|
|
|
THREAD_LOCKPTR_ASSERT(td, &ts->ts_lock);
|
|
mi_switch(SW_VOL | SWT_TURNSTILE, NULL);
|
|
|
|
if (LOCK_LOG_TEST(lock, 0))
|
|
CTR4(KTR_LOCK, "%s: td %d free from blocked on [%p] %s",
|
|
__func__, td->td_tid, lock, lock->lo_name);
|
|
thread_unlock(td);
|
|
}
|
|
|
|
/*
|
|
* Pick the highest priority thread on this turnstile and put it on the
|
|
* pending list. This must be called with the turnstile chain locked.
|
|
*/
|
|
int
|
|
turnstile_signal(struct turnstile *ts, int queue)
|
|
{
|
|
struct turnstile_chain *tc;
|
|
struct thread *td;
|
|
int empty;
|
|
|
|
MPASS(ts != NULL);
|
|
mtx_assert(&ts->ts_lock, MA_OWNED);
|
|
MPASS(curthread->td_proc->p_magic == P_MAGIC);
|
|
MPASS(ts->ts_owner == curthread || ts->ts_owner == NULL);
|
|
MPASS(queue == TS_SHARED_QUEUE || queue == TS_EXCLUSIVE_QUEUE);
|
|
|
|
/*
|
|
* Pick the highest priority thread blocked on this lock and
|
|
* move it to the pending list.
|
|
*/
|
|
td = TAILQ_FIRST(&ts->ts_blocked[queue]);
|
|
MPASS(td->td_proc->p_magic == P_MAGIC);
|
|
mtx_lock_spin(&td_contested_lock);
|
|
TAILQ_REMOVE(&ts->ts_blocked[queue], td, td_lockq);
|
|
mtx_unlock_spin(&td_contested_lock);
|
|
TAILQ_INSERT_TAIL(&ts->ts_pending, td, td_lockq);
|
|
|
|
/*
|
|
* If the turnstile is now empty, remove it from its chain and
|
|
* give it to the about-to-be-woken thread. Otherwise take a
|
|
* turnstile from the free list and give it to the thread.
|
|
*/
|
|
empty = TAILQ_EMPTY(&ts->ts_blocked[TS_EXCLUSIVE_QUEUE]) &&
|
|
TAILQ_EMPTY(&ts->ts_blocked[TS_SHARED_QUEUE]);
|
|
if (empty) {
|
|
tc = TC_LOOKUP(ts->ts_lockobj);
|
|
mtx_assert(&tc->tc_lock, MA_OWNED);
|
|
MPASS(LIST_EMPTY(&ts->ts_free));
|
|
#ifdef TURNSTILE_PROFILING
|
|
tc->tc_depth--;
|
|
#endif
|
|
} else
|
|
ts = LIST_FIRST(&ts->ts_free);
|
|
MPASS(ts != NULL);
|
|
LIST_REMOVE(ts, ts_hash);
|
|
td->td_turnstile = ts;
|
|
|
|
return (empty);
|
|
}
|
|
|
|
/*
|
|
* Put all blocked threads on the pending list. This must be called with
|
|
* the turnstile chain locked.
|
|
*/
|
|
void
|
|
turnstile_broadcast(struct turnstile *ts, int queue)
|
|
{
|
|
struct turnstile_chain *tc;
|
|
struct turnstile *ts1;
|
|
struct thread *td;
|
|
|
|
MPASS(ts != NULL);
|
|
mtx_assert(&ts->ts_lock, MA_OWNED);
|
|
MPASS(curthread->td_proc->p_magic == P_MAGIC);
|
|
MPASS(ts->ts_owner == curthread || ts->ts_owner == NULL);
|
|
/*
|
|
* We must have the chain locked so that we can remove the empty
|
|
* turnstile from the hash queue.
|
|
*/
|
|
tc = TC_LOOKUP(ts->ts_lockobj);
|
|
mtx_assert(&tc->tc_lock, MA_OWNED);
|
|
MPASS(queue == TS_SHARED_QUEUE || queue == TS_EXCLUSIVE_QUEUE);
|
|
|
|
/*
|
|
* Transfer the blocked list to the pending list.
|
|
*/
|
|
mtx_lock_spin(&td_contested_lock);
|
|
TAILQ_CONCAT(&ts->ts_pending, &ts->ts_blocked[queue], td_lockq);
|
|
mtx_unlock_spin(&td_contested_lock);
|
|
|
|
/*
|
|
* Give a turnstile to each thread. The last thread gets
|
|
* this turnstile if the turnstile is empty.
|
|
*/
|
|
TAILQ_FOREACH(td, &ts->ts_pending, td_lockq) {
|
|
if (LIST_EMPTY(&ts->ts_free)) {
|
|
MPASS(TAILQ_NEXT(td, td_lockq) == NULL);
|
|
ts1 = ts;
|
|
#ifdef TURNSTILE_PROFILING
|
|
tc->tc_depth--;
|
|
#endif
|
|
} else
|
|
ts1 = LIST_FIRST(&ts->ts_free);
|
|
MPASS(ts1 != NULL);
|
|
LIST_REMOVE(ts1, ts_hash);
|
|
td->td_turnstile = ts1;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Wakeup all threads on the pending list and adjust the priority of the
|
|
* current thread appropriately. This must be called with the turnstile
|
|
* chain locked.
|
|
*/
|
|
void
|
|
turnstile_unpend(struct turnstile *ts, int owner_type)
|
|
{
|
|
TAILQ_HEAD( ,thread) pending_threads;
|
|
struct turnstile *nts;
|
|
struct thread *td;
|
|
u_char cp, pri;
|
|
|
|
MPASS(ts != NULL);
|
|
mtx_assert(&ts->ts_lock, MA_OWNED);
|
|
MPASS(ts->ts_owner == curthread || ts->ts_owner == NULL);
|
|
MPASS(!TAILQ_EMPTY(&ts->ts_pending));
|
|
|
|
/*
|
|
* Move the list of pending threads out of the turnstile and
|
|
* into a local variable.
|
|
*/
|
|
TAILQ_INIT(&pending_threads);
|
|
TAILQ_CONCAT(&pending_threads, &ts->ts_pending, td_lockq);
|
|
#ifdef INVARIANTS
|
|
if (TAILQ_EMPTY(&ts->ts_blocked[TS_EXCLUSIVE_QUEUE]) &&
|
|
TAILQ_EMPTY(&ts->ts_blocked[TS_SHARED_QUEUE]))
|
|
ts->ts_lockobj = NULL;
|
|
#endif
|
|
/*
|
|
* Adjust the priority of curthread based on other contested
|
|
* locks it owns. Don't lower the priority below the base
|
|
* priority however.
|
|
*/
|
|
td = curthread;
|
|
pri = PRI_MAX;
|
|
thread_lock(td);
|
|
mtx_lock_spin(&td_contested_lock);
|
|
/*
|
|
* Remove the turnstile from this thread's list of contested locks
|
|
* since this thread doesn't own it anymore. New threads will
|
|
* not be blocking on the turnstile until it is claimed by a new
|
|
* owner. There might not be a current owner if this is a shared
|
|
* lock.
|
|
*/
|
|
if (ts->ts_owner != NULL) {
|
|
ts->ts_owner = NULL;
|
|
LIST_REMOVE(ts, ts_link);
|
|
}
|
|
LIST_FOREACH(nts, &td->td_contested, ts_link) {
|
|
cp = turnstile_first_waiter(nts)->td_priority;
|
|
if (cp < pri)
|
|
pri = cp;
|
|
}
|
|
mtx_unlock_spin(&td_contested_lock);
|
|
sched_unlend_prio(td, pri);
|
|
thread_unlock(td);
|
|
/*
|
|
* Wake up all the pending threads. If a thread is not blocked
|
|
* on a lock, then it is currently executing on another CPU in
|
|
* turnstile_wait() or sitting on a run queue waiting to resume
|
|
* in turnstile_wait(). Set a flag to force it to try to acquire
|
|
* the lock again instead of blocking.
|
|
*/
|
|
while (!TAILQ_EMPTY(&pending_threads)) {
|
|
td = TAILQ_FIRST(&pending_threads);
|
|
TAILQ_REMOVE(&pending_threads, td, td_lockq);
|
|
thread_lock(td);
|
|
THREAD_LOCKPTR_ASSERT(td, &ts->ts_lock);
|
|
MPASS(td->td_proc->p_magic == P_MAGIC);
|
|
MPASS(TD_ON_LOCK(td));
|
|
TD_CLR_LOCK(td);
|
|
MPASS(TD_CAN_RUN(td));
|
|
td->td_blocked = NULL;
|
|
td->td_lockname = NULL;
|
|
#ifdef INVARIANTS
|
|
td->td_tsqueue = 0xff;
|
|
#endif
|
|
sched_add(td, SRQ_BORING);
|
|
thread_unlock(td);
|
|
}
|
|
mtx_unlock_spin(&ts->ts_lock);
|
|
}
|
|
|
|
/*
|
|
* Give up ownership of a turnstile. This must be called with the
|
|
* turnstile chain locked.
|
|
*/
|
|
void
|
|
turnstile_disown(struct turnstile *ts)
|
|
{
|
|
struct thread *td;
|
|
u_char cp, pri;
|
|
|
|
MPASS(ts != NULL);
|
|
mtx_assert(&ts->ts_lock, MA_OWNED);
|
|
MPASS(ts->ts_owner == curthread);
|
|
MPASS(TAILQ_EMPTY(&ts->ts_pending));
|
|
MPASS(!TAILQ_EMPTY(&ts->ts_blocked[TS_EXCLUSIVE_QUEUE]) ||
|
|
!TAILQ_EMPTY(&ts->ts_blocked[TS_SHARED_QUEUE]));
|
|
|
|
/*
|
|
* Remove the turnstile from this thread's list of contested locks
|
|
* since this thread doesn't own it anymore. New threads will
|
|
* not be blocking on the turnstile until it is claimed by a new
|
|
* owner.
|
|
*/
|
|
mtx_lock_spin(&td_contested_lock);
|
|
ts->ts_owner = NULL;
|
|
LIST_REMOVE(ts, ts_link);
|
|
mtx_unlock_spin(&td_contested_lock);
|
|
|
|
/*
|
|
* Adjust the priority of curthread based on other contested
|
|
* locks it owns. Don't lower the priority below the base
|
|
* priority however.
|
|
*/
|
|
td = curthread;
|
|
pri = PRI_MAX;
|
|
thread_lock(td);
|
|
mtx_unlock_spin(&ts->ts_lock);
|
|
mtx_lock_spin(&td_contested_lock);
|
|
LIST_FOREACH(ts, &td->td_contested, ts_link) {
|
|
cp = turnstile_first_waiter(ts)->td_priority;
|
|
if (cp < pri)
|
|
pri = cp;
|
|
}
|
|
mtx_unlock_spin(&td_contested_lock);
|
|
sched_unlend_prio(td, pri);
|
|
thread_unlock(td);
|
|
}
|
|
|
|
/*
|
|
* Return the first thread in a turnstile.
|
|
*/
|
|
struct thread *
|
|
turnstile_head(struct turnstile *ts, int queue)
|
|
{
|
|
#ifdef INVARIANTS
|
|
|
|
MPASS(ts != NULL);
|
|
MPASS(queue == TS_SHARED_QUEUE || queue == TS_EXCLUSIVE_QUEUE);
|
|
mtx_assert(&ts->ts_lock, MA_OWNED);
|
|
#endif
|
|
return (TAILQ_FIRST(&ts->ts_blocked[queue]));
|
|
}
|
|
|
|
/*
|
|
* Returns true if a sub-queue of a turnstile is empty.
|
|
*/
|
|
int
|
|
turnstile_empty(struct turnstile *ts, int queue)
|
|
{
|
|
#ifdef INVARIANTS
|
|
|
|
MPASS(ts != NULL);
|
|
MPASS(queue == TS_SHARED_QUEUE || queue == TS_EXCLUSIVE_QUEUE);
|
|
mtx_assert(&ts->ts_lock, MA_OWNED);
|
|
#endif
|
|
return (TAILQ_EMPTY(&ts->ts_blocked[queue]));
|
|
}
|
|
|
|
#ifdef DDB
|
|
static void
|
|
print_thread(struct thread *td, const char *prefix)
|
|
{
|
|
|
|
db_printf("%s%p (tid %d, pid %d, \"%s\")\n", prefix, td, td->td_tid,
|
|
td->td_proc->p_pid, td->td_name[0] != '\0' ? td->td_name :
|
|
td->td_name);
|
|
}
|
|
|
|
static void
|
|
print_queue(struct threadqueue *queue, const char *header, const char *prefix)
|
|
{
|
|
struct thread *td;
|
|
|
|
db_printf("%s:\n", header);
|
|
if (TAILQ_EMPTY(queue)) {
|
|
db_printf("%sempty\n", prefix);
|
|
return;
|
|
}
|
|
TAILQ_FOREACH(td, queue, td_lockq) {
|
|
print_thread(td, prefix);
|
|
}
|
|
}
|
|
|
|
DB_SHOW_COMMAND(turnstile, db_show_turnstile)
|
|
{
|
|
struct turnstile_chain *tc;
|
|
struct turnstile *ts;
|
|
struct lock_object *lock;
|
|
int i;
|
|
|
|
if (!have_addr)
|
|
return;
|
|
|
|
/*
|
|
* First, see if there is an active turnstile for the lock indicated
|
|
* by the address.
|
|
*/
|
|
lock = (struct lock_object *)addr;
|
|
tc = TC_LOOKUP(lock);
|
|
LIST_FOREACH(ts, &tc->tc_turnstiles, ts_hash)
|
|
if (ts->ts_lockobj == lock)
|
|
goto found;
|
|
|
|
/*
|
|
* Second, see if there is an active turnstile at the address
|
|
* indicated.
|
|
*/
|
|
for (i = 0; i < TC_TABLESIZE; i++)
|
|
LIST_FOREACH(ts, &turnstile_chains[i].tc_turnstiles, ts_hash) {
|
|
if (ts == (struct turnstile *)addr)
|
|
goto found;
|
|
}
|
|
|
|
db_printf("Unable to locate a turnstile via %p\n", (void *)addr);
|
|
return;
|
|
found:
|
|
lock = ts->ts_lockobj;
|
|
db_printf("Lock: %p - (%s) %s\n", lock, LOCK_CLASS(lock)->lc_name,
|
|
lock->lo_name);
|
|
if (ts->ts_owner)
|
|
print_thread(ts->ts_owner, "Lock Owner: ");
|
|
else
|
|
db_printf("Lock Owner: none\n");
|
|
print_queue(&ts->ts_blocked[TS_SHARED_QUEUE], "Shared Waiters", "\t");
|
|
print_queue(&ts->ts_blocked[TS_EXCLUSIVE_QUEUE], "Exclusive Waiters",
|
|
"\t");
|
|
print_queue(&ts->ts_pending, "Pending Threads", "\t");
|
|
|
|
}
|
|
|
|
/*
|
|
* Show all the threads a particular thread is waiting on based on
|
|
* non-sleepable and non-spin locks.
|
|
*/
|
|
static void
|
|
print_lockchain(struct thread *td, const char *prefix)
|
|
{
|
|
struct lock_object *lock;
|
|
struct lock_class *class;
|
|
struct turnstile *ts;
|
|
|
|
/*
|
|
* Follow the chain. We keep walking as long as the thread is
|
|
* blocked on a turnstile that has an owner.
|
|
*/
|
|
while (!db_pager_quit) {
|
|
db_printf("%sthread %d (pid %d, %s) ", prefix, td->td_tid,
|
|
td->td_proc->p_pid, td->td_name[0] != '\0' ? td->td_name :
|
|
td->td_name);
|
|
switch (td->td_state) {
|
|
case TDS_INACTIVE:
|
|
db_printf("is inactive\n");
|
|
return;
|
|
case TDS_CAN_RUN:
|
|
db_printf("can run\n");
|
|
return;
|
|
case TDS_RUNQ:
|
|
db_printf("is on a run queue\n");
|
|
return;
|
|
case TDS_RUNNING:
|
|
db_printf("running on CPU %d\n", td->td_oncpu);
|
|
return;
|
|
case TDS_INHIBITED:
|
|
if (TD_ON_LOCK(td)) {
|
|
ts = td->td_blocked;
|
|
lock = ts->ts_lockobj;
|
|
class = LOCK_CLASS(lock);
|
|
db_printf("blocked on lock %p (%s) \"%s\"\n",
|
|
lock, class->lc_name, lock->lo_name);
|
|
if (ts->ts_owner == NULL)
|
|
return;
|
|
td = ts->ts_owner;
|
|
break;
|
|
}
|
|
db_printf("inhibited\n");
|
|
return;
|
|
default:
|
|
db_printf("??? (%#x)\n", td->td_state);
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
DB_SHOW_COMMAND(lockchain, db_show_lockchain)
|
|
{
|
|
struct thread *td;
|
|
|
|
/* Figure out which thread to start with. */
|
|
if (have_addr)
|
|
td = db_lookup_thread(addr, TRUE);
|
|
else
|
|
td = kdb_thread;
|
|
|
|
print_lockchain(td, "");
|
|
}
|
|
|
|
DB_SHOW_ALL_COMMAND(chains, db_show_allchains)
|
|
{
|
|
struct thread *td;
|
|
struct proc *p;
|
|
int i;
|
|
|
|
i = 1;
|
|
FOREACH_PROC_IN_SYSTEM(p) {
|
|
FOREACH_THREAD_IN_PROC(p, td) {
|
|
if (TD_ON_LOCK(td) && LIST_EMPTY(&td->td_contested)) {
|
|
db_printf("chain %d:\n", i++);
|
|
print_lockchain(td, " ");
|
|
}
|
|
if (db_pager_quit)
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
DB_SHOW_ALIAS(allchains, db_show_allchains)
|
|
|
|
/*
|
|
* Show all the threads a particular thread is waiting on based on
|
|
* sleepable locks.
|
|
*/
|
|
static void
|
|
print_sleepchain(struct thread *td, const char *prefix)
|
|
{
|
|
struct thread *owner;
|
|
|
|
/*
|
|
* Follow the chain. We keep walking as long as the thread is
|
|
* blocked on a sleep lock that has an owner.
|
|
*/
|
|
while (!db_pager_quit) {
|
|
db_printf("%sthread %d (pid %d, %s) ", prefix, td->td_tid,
|
|
td->td_proc->p_pid, td->td_name[0] != '\0' ? td->td_name :
|
|
td->td_name);
|
|
switch (td->td_state) {
|
|
case TDS_INACTIVE:
|
|
db_printf("is inactive\n");
|
|
return;
|
|
case TDS_CAN_RUN:
|
|
db_printf("can run\n");
|
|
return;
|
|
case TDS_RUNQ:
|
|
db_printf("is on a run queue\n");
|
|
return;
|
|
case TDS_RUNNING:
|
|
db_printf("running on CPU %d\n", td->td_oncpu);
|
|
return;
|
|
case TDS_INHIBITED:
|
|
if (TD_ON_SLEEPQ(td)) {
|
|
if (lockmgr_chain(td, &owner) ||
|
|
sx_chain(td, &owner)) {
|
|
if (owner == NULL)
|
|
return;
|
|
td = owner;
|
|
break;
|
|
}
|
|
db_printf("sleeping on %p \"%s\"\n",
|
|
td->td_wchan, td->td_wmesg);
|
|
return;
|
|
}
|
|
db_printf("inhibited\n");
|
|
return;
|
|
default:
|
|
db_printf("??? (%#x)\n", td->td_state);
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
DB_SHOW_COMMAND(sleepchain, db_show_sleepchain)
|
|
{
|
|
struct thread *td;
|
|
|
|
/* Figure out which thread to start with. */
|
|
if (have_addr)
|
|
td = db_lookup_thread(addr, TRUE);
|
|
else
|
|
td = kdb_thread;
|
|
|
|
print_sleepchain(td, "");
|
|
}
|
|
|
|
static void print_waiters(struct turnstile *ts, int indent);
|
|
|
|
static void
|
|
print_waiter(struct thread *td, int indent)
|
|
{
|
|
struct turnstile *ts;
|
|
int i;
|
|
|
|
if (db_pager_quit)
|
|
return;
|
|
for (i = 0; i < indent; i++)
|
|
db_printf(" ");
|
|
print_thread(td, "thread ");
|
|
LIST_FOREACH(ts, &td->td_contested, ts_link)
|
|
print_waiters(ts, indent + 1);
|
|
}
|
|
|
|
static void
|
|
print_waiters(struct turnstile *ts, int indent)
|
|
{
|
|
struct lock_object *lock;
|
|
struct lock_class *class;
|
|
struct thread *td;
|
|
int i;
|
|
|
|
if (db_pager_quit)
|
|
return;
|
|
lock = ts->ts_lockobj;
|
|
class = LOCK_CLASS(lock);
|
|
for (i = 0; i < indent; i++)
|
|
db_printf(" ");
|
|
db_printf("lock %p (%s) \"%s\"\n", lock, class->lc_name, lock->lo_name);
|
|
TAILQ_FOREACH(td, &ts->ts_blocked[TS_EXCLUSIVE_QUEUE], td_lockq)
|
|
print_waiter(td, indent + 1);
|
|
TAILQ_FOREACH(td, &ts->ts_blocked[TS_SHARED_QUEUE], td_lockq)
|
|
print_waiter(td, indent + 1);
|
|
TAILQ_FOREACH(td, &ts->ts_pending, td_lockq)
|
|
print_waiter(td, indent + 1);
|
|
}
|
|
|
|
DB_SHOW_COMMAND(locktree, db_show_locktree)
|
|
{
|
|
struct lock_object *lock;
|
|
struct lock_class *class;
|
|
struct turnstile_chain *tc;
|
|
struct turnstile *ts;
|
|
|
|
if (!have_addr)
|
|
return;
|
|
lock = (struct lock_object *)addr;
|
|
tc = TC_LOOKUP(lock);
|
|
LIST_FOREACH(ts, &tc->tc_turnstiles, ts_hash)
|
|
if (ts->ts_lockobj == lock)
|
|
break;
|
|
if (ts == NULL) {
|
|
class = LOCK_CLASS(lock);
|
|
db_printf("lock %p (%s) \"%s\"\n", lock, class->lc_name,
|
|
lock->lo_name);
|
|
} else
|
|
print_waiters(ts, 0);
|
|
}
|
|
#endif
|