From: Sukadev Bhattiprolu <[email protected]> Date: Fri, 8 Jan 2010 10:56:38 -0800 Subject: [PATCH] pthread4: Ensure mutexes are consistent across C/R
Pthread mutex (not) held at checkpoint must continue to be (not) held after restart. Signed-off-by: Sukadev Bhattiprolu <[email protected]> --- process-tree/Makefile | 2 +- process-tree/pthread4.c | 285 +++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 286 insertions(+), 1 deletions(-) create mode 100644 process-tree/pthread4.c diff --git a/process-tree/Makefile b/process-tree/Makefile index b043394..64fdd20 100644 --- a/process-tree/Makefile +++ b/process-tree/Makefile @@ -1,5 +1,5 @@ -targets = ptree1 pthread1 pthread2 pthread3 +targets = ptree1 pthread1 pthread2 pthread3 pthread4 INCLUDE = ../libcrtest LIBCRTEST = ../libcrtest/common.o diff --git a/process-tree/pthread4.c b/process-tree/pthread4.c new file mode 100644 index 0000000..b7afcab --- /dev/null +++ b/process-tree/pthread4.c @@ -0,0 +1,285 @@ +#include <stdio.h> +#include <unistd.h> +#include <wait.h> +#include <errno.h> +#include <string.h> +#include <stdlib.h> +#include <libcrtest.h> +#define __USE_UNIX98 +#include <pthread.h> + + +#define ERROR_EXIT ((void *)1) +#define MIN_STACK_SIZE (64 *1024) +#define LOG_PREFIX "logs.d/pthread4" + +FILE *logfp; +int num_threads = 4; +int *tstatus; +pthread_barrier_t cr_ready; +pthread_barrier_t threads_created; +pthread_mutex_t mutex; + +static void usage(char *argv[]) +{ + printf("%s [h] [-n num-threads]\n", argv[0]); + printf("\t <num-threads> # of threads, default 5\n"); + do_exit(1); +} + +void * do_work(void *arg) +{ + int tnum = (int)arg; + int rc; + int lock_acquired; + + /* + * Wait for all threads to be created, so a random thread can + * get the lock. + */ + rc = pthread_barrier_wait(&threads_created); + if (rc != PTHREAD_BARRIER_SERIAL_THREAD && rc != 0) { + fprintf(logfp, "%d: pthread_barrier_wait() failed, rc %d, " + "error %s\n", tnum, rc, strerror(errno)); + do_exit(1); + } + + rc = pthread_mutex_trylock(&mutex); + if (rc && rc != EBUSY) { + fprintf(logfp, "%d: pthread_mutex_trylock() failed, rc %d, " + "error %s\n", tnum, rc, strerror(errno)); + do_exit(1); + } + + lock_acquired = 0; + if (!rc) + lock_acquired++; + + fprintf(logfp, "%d: Thread %lu: lock_acquired %d waiting for " + "checkpoint\n", tnum, pthread_self(), lock_acquired); + fflush(logfp); + + /* + * Inform main-thread we are ready for checkpoint. + */ + rc = pthread_barrier_wait(&cr_ready); + if (rc != PTHREAD_BARRIER_SERIAL_THREAD && rc != 0) { + fprintf(logfp, "%d: pthread_barrier_wait() failed, rc %d, " + "error %s\n", tnum, rc, strerror(errno)); + do_exit(1); + } + + /* + * Wait for checkpoint/restart. + */ + while(!test_done()) + sleep(1); + + rc = pthread_mutex_trylock(&mutex); + if (rc && rc != EBUSY) { + fprintf(logfp, "%d: pthread_mutex_trylock() failed, rc %d, " + "error %s\n", tnum, rc, strerror(errno)); + do_exit(1); + } + + /* + * If I already hold the lock, this trylock better fail :-) + */ + tstatus[tnum] = 0; + if (lock_acquired && !rc) { + fprintf(logfp, "%d: FAIL: I no longer hold the lock held " + "before checkpoint/restart !!! rc %d " + "lock_acquired %d\n", tnum, rc, lock_acquired); + tstatus[tnum] = 1; + } + + if (lock_acquired || !rc) + pthread_mutex_unlock(&mutex); + + fprintf(logfp, "%d: Thread %lu: exiting, rc 0\n", tnum, + pthread_self()); + fflush(logfp); + + pthread_exit((void *)&tstatus[tnum]); + +} + +pthread_t *create_threads(int n) +{ + int i; + int rc; + pthread_t *tid_list; + pthread_t tid; + pthread_attr_t *attr = NULL; + + tid_list = (pthread_t *)malloc(n * sizeof(pthread_t)); + tstatus = malloc(sizeof(int) * n); + + if (!tid_list || !tstatus) { + fprintf(logfp, "malloc() failed, n %d, error %s\n", + n, strerror(errno)); + do_exit(1); + } + + attr = NULL; + for (i = 0; i < n; i++) { + rc = pthread_create(&tid, attr, do_work, (void *)i); + if (rc < 0) { + fprintf(logfp, "pthread_create(): i %d, rc %d, " + "error %s\n", i, rc, strerror(errno)); + do_exit(1); + } + + tid_list[i] = tid; + } + + fprintf(logfp, "Created %d threads\n", n); + fflush(logfp); + + return tid_list; +} + +int wait_for_threads(pthread_t *tid_list, int n) +{ + int i; + int rc; + int status; + int *statusp; + int exit_status; + + exit_status = 0; + for (i = 0; i < n; i++) { + rc = pthread_join(tid_list[i], (void **)&statusp); + if (rc < 0) { + fprintf(logfp, "pthread_join() failed, i %d, rc %d " + "error %s\n", i, rc, strerror(errno)); + do_exit(1); + } + + fprintf(logfp, "i %d: *statusp %x\n", i, *statusp); + fflush(logfp); + + if (*statusp) + exit_status = 1; + } + + return exit_status; +} + +init_mutex(pthread_mutex_t *mutex) +{ + int rc; + pthread_mutexattr_t mutex_attr; + + rc = pthread_mutexattr_init(&mutex_attr); + if (rc) { + fprintf(logfp, "pthread_mutexattr_init() failed, rc %d, " + "error %s\n", rc, strerror(errno)); + do_exit(1); + } + + rc = pthread_mutexattr_settype(&mutex_attr, PTHREAD_MUTEX_ERRORCHECK); + if (rc) { + fprintf(logfp, "pthread_mutexattr_settype() failed, rc %d, " + "error %s\n", rc, strerror(errno)); + do_exit(1); + } + + /* + * TODO: Change other attributes of the mutex to non-default values ? + */ + + rc = pthread_mutex_init(mutex, &mutex_attr); + if (rc) { + fprintf(logfp, "pthread_mutex_init() failed, rc %d, error %s\n", + rc, strerror(errno)); + do_exit(1); + } +} + +main(int argc, char *argv[]) +{ + int c; + int i; + int rc; + int status; + pthread_t *tid_list; + char log_file[256]; + + sprintf(log_file, "%s.log", LOG_PREFIX); + + if (test_done()) { + fprintf(stderr, "Remove %s before running test\n", TEST_DONE); + do_exit(1); + } + + while ((c = getopt(argc, argv, "hn:")) != EOF) { + switch (c) { + case 'n': num_threads = atoi(optarg); break; + case 'h': + default: + usage(argv); + } + }; + + logfp = fopen(log_file, "w"); + if (!logfp) { + fprintf(stderr, "fopen(%s) failed, %s\n", log_file, + strerror(errno)); + fflush(stderr); + do_exit(1); + } + + fprintf(stderr, "Redirecting output to %s\n", log_file); + fflush(stderr); + + for (i=0; i<100; i++) { + if (fileno(logfp) != i) + close(i); + } + + + /* + * Create a barrier which the main-thread can use to determine + * when all threads are ready for checkpoint. + */ + rc = pthread_barrier_init(&cr_ready, NULL, num_threads+1); + if (rc < 0) { + fprintf(logfp, "pthread_barrier_init() failed, rc %d, " + "error %s\n", rc, strerror(errno)); + do_exit(1); + } + + rc = pthread_barrier_init(&threads_created, NULL, num_threads); + if (rc < 0) { + fprintf(logfp, "pthread_barrier_init() failed, rc %d, " + "error %s\n", rc, strerror(errno)); + do_exit(1); + } + + init_mutex(&mutex); + + tid_list = create_threads(num_threads); + + /* + * Wait for everyone to be ready for checkpoint + */ + pthread_barrier_wait(&cr_ready); + if (rc != PTHREAD_BARRIER_SERIAL_THREAD && rc != 0) { + fprintf(logfp, "main: pthread_barrier_wait() failed, rc %d, " + "error %s\n", rc, strerror(errno)); + do_exit(1); + } + + /* + * Now that we closed the special files and created the threads, + * tell any wrapper scripts, we are ready for checkpoint + */ + set_checkpoint_ready(); + + rc = wait_for_threads(tid_list, num_threads); + + fprintf(logfp, "Exiting with status %d\n", rc); + + do_exit(rc); +} -- 1.6.0.4 _______________________________________________ Containers mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/containers _______________________________________________ Devel mailing list [email protected] https://openvz.org/mailman/listinfo/devel
