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Update.
2000-06-26 Ulrich Drepper <drepper@redhat.com> * Makefile (tests): Add ex11. Add rules to build it. * Examples/ex11.c: New file. * rwlock.c: Fix complete braindamaged previous try to implement timedout functions. * spinlock.c: Pretty print.
This commit is contained in:
Ulrich Drepper
parent
d82e4c7bb2
commit
c49ebf7645
@ -1,3 +1,12 @@
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2000-06-26 Ulrich Drepper <drepper@redhat.com>
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* Makefile (tests): Add ex11. Add rules to build it.
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* Examples/ex11.c: New file.
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* rwlock.c: Fix complete braindamaged previous try to implement
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timedout functions.
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* spinlock.c: Pretty print.
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2000-06-25 Ulrich Drepper <drepper@redhat.com>
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* Makefile (tests): Add ex10. Add rules to build it.
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152
linuxthreads/Examples/ex11.c
Normal file
152
linuxthreads/Examples/ex11.c
Normal file
@ -0,0 +1,152 @@
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/* Test program for timedout read/write lock functions.
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Copyright (C) 2000 Free Software Foundation, Inc.
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Contributed by Ulrich Drepper <drepper@redhat.com>, 2000.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <errno.h>
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#include <error.h>
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#include <pthread.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <time.h>
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#include <unistd.h>
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#define NWRITERS 15
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#define WRITETRIES 10
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#define NREADERS 15
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#define READTRIES 15
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#define TIMEOUT 1000000
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#define DELAY 1000000
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static pthread_rwlock_t lock = PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP;
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static void *
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writer_thread (void *nr)
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{
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struct timespec ts;
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struct timespec delay;
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int n;
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ts.tv_sec = 0;
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ts.tv_nsec = TIMEOUT;
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delay.tv_sec = 0;
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delay.tv_nsec = DELAY;
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for (n = 0; n < WRITETRIES; ++n)
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{
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do
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{
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clock_gettime (CLOCK_REALTIME, &ts);
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ts.tv_nsec += 2 * TIMEOUT;
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printf ("writer thread %ld tries again\n", (long int) nr);
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}
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//while (pthread_rwlock_wrlock (&lock), 0);
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while (pthread_rwlock_timedwrlock (&lock, &ts) == ETIMEDOUT);
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printf ("writer thread %ld succeeded\n", (long int) nr);
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nanosleep (&delay, NULL);
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pthread_rwlock_unlock (&lock);
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printf ("writer thread %ld released\n", (long int) nr);
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}
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return NULL;
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}
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static void *
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reader_thread (void *nr)
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{
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struct timespec ts;
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struct timespec delay;
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int n;
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delay.tv_sec = 0;
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delay.tv_nsec = DELAY;
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for (n = 0; n < READTRIES; ++n)
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{
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do
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{
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clock_gettime (CLOCK_REALTIME, &ts);
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ts.tv_nsec += TIMEOUT;
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printf ("reader thread %ld tries again\n", (long int) nr);
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}
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//while (pthread_rwlock_rdlock (&lock), 0);
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while (pthread_rwlock_timedrdlock (&lock, &ts) == ETIMEDOUT);
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printf ("reader thread %ld succeeded\n", (long int) nr);
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nanosleep (&delay, NULL);
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pthread_rwlock_unlock (&lock);
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printf ("reader thread %ld released\n", (long int) nr);
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}
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return NULL;
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}
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int
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main (void)
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{
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pthread_t thwr[NWRITERS];
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pthread_t thrd[NREADERS];
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int n;
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void *res;
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/* Make standard error the same as standard output. */
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dup2 (1, 2);
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/* Make sure we see all message, even those on stdout. */
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setvbuf (stdout, NULL, _IONBF, 0);
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for (n = 0; n < NWRITERS; ++n)
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{
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int err = pthread_create (&thwr[n], NULL, writer_thread, (void *) n);
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if (err != 0)
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error (EXIT_FAILURE, err, "cannot create writer thread");
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}
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for (n = 0; n < NREADERS; ++n)
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{
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int err = pthread_create (&thrd[n], NULL, reader_thread, (void *) n);
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if (err != 0)
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error (EXIT_FAILURE, err, "cannot create reader thread");
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}
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/* Wait for all the threads. */
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for (n = 0; n < NWRITERS; ++n)
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pthread_join (thwr[n], &res);
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for (n = 0; n < NREADERS; ++n)
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pthread_join (thrd[n], &res);
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return 0;
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}
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@ -38,7 +38,7 @@ libpthread-routines := attr cancel condvar join manager mutex ptfork \
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oldsemaphore events getcpuclockid pspinlock barrier
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vpath %.c Examples
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tests = ex1 ex2 ex3 ex4 ex5 ex6 ex7 ex8 ex9 ex10 joinrace
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tests = ex1 ex2 ex3 ex4 ex5 ex6 ex7 ex8 ex9 ex10 ex11 joinrace
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include ../Rules
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@ -72,4 +72,5 @@ $(objpfx)ex7: $(libpthread)
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$(objpfx)ex8: $(libpthread)
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$(objpfx)ex9: $(libpthread)
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$(objpfx)ex10: $(libpthread) $(librt)
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$(objpfx)ex11: $(libpthread) $(librt)
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$(objpfx)joinrace: $(libpthread)
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@ -27,6 +27,35 @@
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#include "spinlock.h"
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#include "restart.h"
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/* Function called by pthread_cancel to remove the thread from
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waiting inside pthread_rwlock_timedrdlock or pthread_rwlock_timedwrlock. */
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static int rwlock_rd_extricate_func(void *obj, pthread_descr th)
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{
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volatile pthread_descr self = thread_self();
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pthread_rwlock_t *rwlock = obj;
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int did_remove = 0;
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__pthread_lock((struct _pthread_fastlock *) &rwlock->__rw_lock, self);
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did_remove = remove_from_queue(&rwlock->__rw_read_waiting, th);
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__pthread_unlock((struct _pthread_fastlock *) &rwlock->__rw_lock);
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return did_remove;
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}
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static int rwlock_wr_extricate_func(void *obj, pthread_descr th)
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{
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volatile pthread_descr self = thread_self();
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pthread_rwlock_t *rwlock = obj;
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int did_remove = 0;
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__pthread_lock((struct _pthread_fastlock *) &rwlock->__rw_lock, self);
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did_remove = remove_from_queue(&rwlock->__rw_write_waiting, th);
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__pthread_unlock((struct _pthread_fastlock *) &rwlock->__rw_lock);
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return did_remove;
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}
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/*
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* Check whether the calling thread already owns one or more read locks on the
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* specified lock. If so, return a pointer to the read lock info structure
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@ -214,10 +243,10 @@ __pthread_rwlock_destroy (pthread_rwlock_t *rwlock)
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int readers;
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_pthread_descr writer;
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__pthread_alt_lock (&rwlock->__rw_lock, NULL);
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__pthread_lock (&rwlock->__rw_lock, NULL);
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readers = rwlock->__rw_readers;
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writer = rwlock->__rw_writer;
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__pthread_alt_unlock (&rwlock->__rw_lock);
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__pthread_unlock (&rwlock->__rw_lock);
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if (readers > 0 || writer != NULL)
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return EBUSY;
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@ -241,18 +270,18 @@ __pthread_rwlock_rdlock (pthread_rwlock_t *rwlock)
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for (;;)
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{
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__pthread_alt_lock (&rwlock->__rw_lock, self);
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__pthread_lock (&rwlock->__rw_lock, self);
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if (rwlock_can_rdlock(rwlock, have_lock_already))
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break;
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enqueue (&rwlock->__rw_read_waiting, self);
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__pthread_alt_unlock (&rwlock->__rw_lock);
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__pthread_unlock (&rwlock->__rw_lock);
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suspend (self); /* This is not a cancellation point */
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}
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++rwlock->__rw_readers;
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__pthread_alt_unlock (&rwlock->__rw_lock);
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__pthread_unlock (&rwlock->__rw_lock);
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if (have_lock_already || out_of_mem)
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{
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@ -273,6 +302,7 @@ __pthread_rwlock_timedrdlock (pthread_rwlock_t *rwlock,
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pthread_descr self = NULL;
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pthread_readlock_info *existing;
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int out_of_mem, have_lock_already;
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pthread_extricate_if extr;
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if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
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return EINVAL;
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@ -283,21 +313,46 @@ __pthread_rwlock_timedrdlock (pthread_rwlock_t *rwlock,
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if (self == NULL)
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self = thread_self ();
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/* Set up extrication interface */
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extr.pu_object = rwlock;
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extr.pu_extricate_func = rwlock_rd_extricate_func;
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/* Register extrication interface */
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__pthread_set_own_extricate_if (self, &extr);
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for (;;)
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{
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if (__pthread_alt_timedlock (&rwlock->__rw_lock, self, abstime) == 0)
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return ETIMEDOUT;
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__pthread_lock (&rwlock->__rw_lock, self);
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if (rwlock_can_rdlock(rwlock, have_lock_already))
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break;
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enqueue (&rwlock->__rw_read_waiting, self);
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__pthread_alt_unlock (&rwlock->__rw_lock);
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suspend (self); /* This is not a cancellation point */
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__pthread_unlock (&rwlock->__rw_lock);
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/* This is not a cancellation point */
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if (timedsuspend (self, abstime) == 0)
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{
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int was_on_queue;
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__pthread_lock (&rwlock->__rw_lock, self);
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was_on_queue = remove_from_queue (&rwlock->__rw_read_waiting, self);
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__pthread_unlock (&rwlock->__rw_lock);
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if (was_on_queue)
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{
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__pthread_set_own_extricate_if (self, 0);
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return ETIMEDOUT;
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}
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/* Eat the outstanding restart() from the signaller */
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suspend (self);
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}
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}
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__pthread_set_own_extricate_if (self, 0);
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++rwlock->__rw_readers;
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__pthread_alt_unlock (&rwlock->__rw_lock);
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__pthread_unlock (&rwlock->__rw_lock);
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if (have_lock_already || out_of_mem)
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{
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@ -322,7 +377,7 @@ __pthread_rwlock_tryrdlock (pthread_rwlock_t *rwlock)
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have_lock_already = rwlock_have_already(&self, rwlock,
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&existing, &out_of_mem);
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__pthread_alt_lock (&rwlock->__rw_lock, self);
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__pthread_lock (&rwlock->__rw_lock, self);
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/* 0 is passed to here instead of have_lock_already.
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This is to meet Single Unix Spec requirements:
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@ -336,7 +391,7 @@ __pthread_rwlock_tryrdlock (pthread_rwlock_t *rwlock)
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retval = 0;
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}
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__pthread_alt_unlock (&rwlock->__rw_lock);
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__pthread_unlock (&rwlock->__rw_lock);
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if (retval == 0)
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{
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@ -361,17 +416,17 @@ __pthread_rwlock_wrlock (pthread_rwlock_t *rwlock)
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while(1)
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{
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__pthread_alt_lock (&rwlock->__rw_lock, self);
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__pthread_lock (&rwlock->__rw_lock, self);
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if (rwlock->__rw_readers == 0 && rwlock->__rw_writer == NULL)
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{
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rwlock->__rw_writer = self;
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__pthread_alt_unlock (&rwlock->__rw_lock);
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__pthread_unlock (&rwlock->__rw_lock);
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return 0;
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}
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/* Suspend ourselves, then try again */
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enqueue (&rwlock->__rw_write_waiting, self);
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__pthread_alt_unlock (&rwlock->__rw_lock);
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__pthread_unlock (&rwlock->__rw_lock);
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suspend (self); /* This is not a cancellation point */
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}
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}
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@ -383,28 +438,53 @@ __pthread_rwlock_timedwrlock (pthread_rwlock_t *rwlock,
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const struct timespec *abstime)
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{
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pthread_descr self;
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pthread_extricate_if extr;
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if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
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return EINVAL;
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self = thread_self ();
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/* Set up extrication interface */
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extr.pu_object = rwlock;
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extr.pu_extricate_func = rwlock_wr_extricate_func;
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/* Register extrication interface */
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__pthread_set_own_extricate_if (self, &extr);
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while(1)
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{
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if (__pthread_alt_timedlock (&rwlock->__rw_lock, self, abstime) == 0)
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return ETIMEDOUT;
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__pthread_lock (&rwlock->__rw_lock, self);
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if (rwlock->__rw_readers == 0 && rwlock->__rw_writer == NULL)
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{
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rwlock->__rw_writer = self;
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__pthread_alt_unlock (&rwlock->__rw_lock);
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__pthread_set_own_extricate_if (self, 0);
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__pthread_unlock (&rwlock->__rw_lock);
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return 0;
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}
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/* Suspend ourselves, then try again */
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enqueue (&rwlock->__rw_write_waiting, self);
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__pthread_alt_unlock (&rwlock->__rw_lock);
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suspend (self); /* This is not a cancellation point */
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__pthread_unlock (&rwlock->__rw_lock);
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/* This is not a cancellation point */
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if (timedsuspend (self, abstime) == 0)
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{
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int was_on_queue;
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__pthread_lock (&rwlock->__rw_lock, self);
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was_on_queue = remove_from_queue (&rwlock->__rw_write_waiting, self);
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__pthread_unlock (&rwlock->__rw_lock);
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if (was_on_queue)
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{
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__pthread_set_own_extricate_if (self, 0);
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return ETIMEDOUT;
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}
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/* Eat the outstanding restart() from the signaller */
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suspend (self);
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}
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}
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}
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strong_alias (__pthread_rwlock_timedwrlock, pthread_rwlock_timedwrlock)
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@ -415,13 +495,13 @@ __pthread_rwlock_trywrlock (pthread_rwlock_t *rwlock)
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{
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int result = EBUSY;
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__pthread_alt_lock (&rwlock->__rw_lock, NULL);
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__pthread_lock (&rwlock->__rw_lock, NULL);
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if (rwlock->__rw_readers == 0 && rwlock->__rw_writer == NULL)
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{
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rwlock->__rw_writer = thread_self ();
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result = 0;
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}
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__pthread_alt_unlock (&rwlock->__rw_lock);
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__pthread_unlock (&rwlock->__rw_lock);
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return result;
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}
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@ -434,13 +514,13 @@ __pthread_rwlock_unlock (pthread_rwlock_t *rwlock)
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pthread_descr torestart;
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pthread_descr th;
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__pthread_alt_lock (&rwlock->__rw_lock, NULL);
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__pthread_lock (&rwlock->__rw_lock, NULL);
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if (rwlock->__rw_writer != NULL)
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{
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/* Unlocking a write lock. */
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if (rwlock->__rw_writer != thread_self ())
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{
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__pthread_alt_unlock (&rwlock->__rw_lock);
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__pthread_unlock (&rwlock->__rw_lock);
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return EPERM;
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}
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rwlock->__rw_writer = NULL;
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@ -452,14 +532,14 @@ __pthread_rwlock_unlock (pthread_rwlock_t *rwlock)
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/* Restart all waiting readers. */
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torestart = rwlock->__rw_read_waiting;
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rwlock->__rw_read_waiting = NULL;
|
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__pthread_alt_unlock (&rwlock->__rw_lock);
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__pthread_unlock (&rwlock->__rw_lock);
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while ((th = dequeue (&torestart)) != NULL)
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restart (th);
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}
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else
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{
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/* Restart one waiting writer. */
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__pthread_alt_unlock (&rwlock->__rw_lock);
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__pthread_unlock (&rwlock->__rw_lock);
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restart (th);
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}
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||||
}
|
||||
@ -468,7 +548,7 @@ __pthread_rwlock_unlock (pthread_rwlock_t *rwlock)
|
||||
/* Unlocking a read lock. */
|
||||
if (rwlock->__rw_readers == 0)
|
||||
{
|
||||
__pthread_alt_unlock (&rwlock->__rw_lock);
|
||||
__pthread_unlock (&rwlock->__rw_lock);
|
||||
return EPERM;
|
||||
}
|
||||
|
||||
@ -479,7 +559,7 @@ __pthread_rwlock_unlock (pthread_rwlock_t *rwlock)
|
||||
else
|
||||
th = NULL;
|
||||
|
||||
__pthread_alt_unlock (&rwlock->__rw_lock);
|
||||
__pthread_unlock (&rwlock->__rw_lock);
|
||||
if (th != NULL)
|
||||
restart (th);
|
||||
|
||||
|
||||
@ -149,7 +149,7 @@ again:
|
||||
return 0;
|
||||
}
|
||||
|
||||
/*
|
||||
/*
|
||||
* Alternate fastlocks do not queue threads directly. Instead, they queue
|
||||
* these wait queue node structures. When a timed wait wakes up due to
|
||||
* a timeout, it can leave its wait node in the queue (because there
|
||||
@ -191,7 +191,7 @@ static struct wait_node *wait_node_alloc(void)
|
||||
return (struct wait_node *) oldvalue;
|
||||
}
|
||||
|
||||
/* Return a node to the head of the free list using an atomic
|
||||
/* Return a node to the head of the free list using an atomic
|
||||
operation. */
|
||||
|
||||
static void wait_node_free(struct wait_node *wn)
|
||||
@ -210,7 +210,7 @@ static void wait_node_free(struct wait_node *wn)
|
||||
/* Remove a wait node from the specified queue. It is assumed
|
||||
that the removal takes place concurrently with only atomic insertions at the
|
||||
head of the queue. */
|
||||
|
||||
|
||||
static void wait_node_dequeue(struct wait_node **pp_head,
|
||||
struct wait_node **pp_node,
|
||||
struct wait_node *p_node,
|
||||
@ -281,7 +281,7 @@ int __pthread_alt_timedlock(struct _pthread_fastlock * lock,
|
||||
{
|
||||
struct wait_node *p_wait_node = wait_node_alloc();
|
||||
long oldstatus, newstatus;
|
||||
|
||||
|
||||
/* Out of memory, just give up and do ordinary lock. */
|
||||
if (p_wait_node == 0) {
|
||||
__pthread_alt_lock(lock, self);
|
||||
@ -342,13 +342,13 @@ void __pthread_alt_unlock(struct _pthread_fastlock *lock)
|
||||
|
||||
oldstatus = lock->__status;
|
||||
if (oldstatus == 0 || oldstatus == 1) {
|
||||
if (compare_and_swap_with_release_semantics (&lock->__status,
|
||||
oldstatus, 0, &lock->__spinlock))
|
||||
if (compare_and_swap_with_release_semantics (&lock->__status, oldstatus,
|
||||
0, &lock->__spinlock))
|
||||
return;
|
||||
else
|
||||
continue;
|
||||
}
|
||||
|
||||
|
||||
/* Process the entire queue of wait nodes. Remove all abandoned
|
||||
wait nodes and put them into the global free queue, and
|
||||
remember the one unabandoned node which refers to the thread
|
||||
|
||||
Loading…
Reference in New Issue
Block a user