Fallback mechanism not working on platform where TLS is unsupported
[urcu.git] / urcu.c
diff --git a/urcu.c b/urcu.c
index 2339bc63c872c6a4826d7a52e8d064d85130c0df..c42184656a3a0381b518aa15372b84a365400dea 100644 (file)
--- a/urcu.c
+++ b/urcu.c
@@ -25,6 +25,7 @@
 
 #define _BSD_SOURCE
 #define _GNU_SOURCE
+#define _LGPL_SOURCE
 #include <stdio.h>
 #include <pthread.h>
 #include <signal.h>
 #include <errno.h>
 #include <poll.h>
 
+#include "urcu/wfcqueue.h"
 #include "urcu/map/urcu.h"
-
 #include "urcu/static/urcu.h"
+#include "urcu-pointer.h"
+#include "urcu/tls-compat.h"
+
+#include "urcu-die.h"
+
 /* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */
+#undef _LGPL_SOURCE
 #include "urcu.h"
+#define _LGPL_SOURCE
+
+/*
+ * If a reader is really non-cooperative and refuses to commit its
+ * rcu_active_readers count to memory (there is no barrier in the reader
+ * per-se), kick it after a few loops waiting for it.
+ */
+#define KICK_READER_LOOPS 10000
+
+/*
+ * Active attempts to check for reader Q.S. before calling futex().
+ */
+#define RCU_QS_ACTIVE_ATTEMPTS 100
 
 #ifdef RCU_MEMBARRIER
 static int init_done;
-int has_sys_membarrier;
+int rcu_has_sys_membarrier;
 
 void __attribute__((constructor)) rcu_init(void);
 #endif
@@ -63,7 +83,7 @@ void __attribute__((destructor)) rcu_exit(void);
 
 static pthread_mutex_t rcu_gp_lock = PTHREAD_MUTEX_INITIALIZER;
 
-int32_t gp_futex;
+int32_t rcu_gp_futex;
 
 /*
  * Global grace period counter.
@@ -77,11 +97,11 @@ unsigned long rcu_gp_ctr = RCU_GP_COUNT;
  * Written to only by each individual reader. Read by both the reader and the
  * writers.
  */
-struct rcu_reader __thread rcu_reader;
+DEFINE_URCU_TLS(struct rcu_reader, rcu_reader);
 
 #ifdef DEBUG_YIELD
-unsigned int yield_active;
-unsigned int __thread rand_yield;
+unsigned int rcu_yield_active;
+DEFINE_URCU_TLS(unsigned int, rcu_rand_yield);
 #endif
 
 static CDS_LIST_HEAD(registry);
@@ -92,20 +112,15 @@ static void mutex_lock(pthread_mutex_t *mutex)
 
 #ifndef DISTRUST_SIGNALS_EXTREME
        ret = pthread_mutex_lock(mutex);
-       if (ret) {
-               perror("Error in pthread mutex lock");
-               exit(-1);
-       }
+       if (ret)
+               urcu_die(ret);
 #else /* #ifndef DISTRUST_SIGNALS_EXTREME */
        while ((ret = pthread_mutex_trylock(mutex)) != 0) {
-               if (ret != EBUSY && ret != EINTR) {
-                       printf("ret = %d, errno = %d\n", ret, errno);
-                       perror("Error in pthread mutex lock");
-                       exit(-1);
-               }
-               if (CMM_LOAD_SHARED(rcu_reader.need_mb)) {
+               if (ret != EBUSY && ret != EINTR)
+                       urcu_die(ret);
+               if (CMM_LOAD_SHARED(URCU_TLS(rcu_reader).need_mb)) {
                        cmm_smp_mb();
-                       _CMM_STORE_SHARED(rcu_reader.need_mb, 0);
+                       _CMM_STORE_SHARED(URCU_TLS(rcu_reader).need_mb, 0);
                        cmm_smp_mb();
                }
                poll(NULL,0,10);
@@ -118,16 +133,14 @@ static void mutex_unlock(pthread_mutex_t *mutex)
        int ret;
 
        ret = pthread_mutex_unlock(mutex);
-       if (ret) {
-               perror("Error in pthread mutex unlock");
-               exit(-1);
-       }
+       if (ret)
+               urcu_die(ret);
 }
 
 #ifdef RCU_MEMBARRIER
 static void smp_mb_master(int group)
 {
-       if (likely(has_sys_membarrier))
+       if (caa_likely(rcu_has_sys_membarrier))
                membarrier(MEMBARRIER_EXPEDITED);
        else
                cmm_smp_mb();
@@ -197,12 +210,12 @@ static void wait_gp(void)
 {
        /* Read reader_gp before read futex */
        smp_mb_master(RCU_MB_GROUP);
-       if (uatomic_read(&gp_futex) == -1)
-               futex_async(&gp_futex, FUTEX_WAIT, -1,
+       if (uatomic_read(&rcu_gp_futex) == -1)
+               futex_async(&rcu_gp_futex, FUTEX_WAIT, -1,
                      NULL, NULL, 0);
 }
 
-void update_counter_and_wait(void)
+static void update_counter_and_wait(void)
 {
        CDS_LIST_HEAD(qsreaders);
        int wait_loops = 0;
@@ -228,12 +241,12 @@ void update_counter_and_wait(void)
        cmm_smp_mb();
 
        /*
-        * Wait for each thread rcu_reader.ctr count to become 0.
+        * Wait for each thread URCU_TLS(rcu_reader).ctr count to become 0.
         */
        for (;;) {
                wait_loops++;
                if (wait_loops == RCU_QS_ACTIVE_ATTEMPTS) {
-                       uatomic_dec(&gp_futex);
+                       uatomic_dec(&rcu_gp_futex);
                        /* Write futex before read reader_gp */
                        smp_mb_master(RCU_MB_GROUP);
                }
@@ -248,7 +261,7 @@ void update_counter_and_wait(void)
                        if (wait_loops == RCU_QS_ACTIVE_ATTEMPTS) {
                                /* Read reader_gp before write futex */
                                smp_mb_master(RCU_MB_GROUP);
-                               uatomic_set(&gp_futex, 0);
+                               uatomic_set(&rcu_gp_futex, 0);
                        }
                        break;
                } else {
@@ -260,13 +273,14 @@ void update_counter_and_wait(void)
 #else /* #ifndef HAS_INCOHERENT_CACHES */
                /*
                 * BUSY-LOOP. Force the reader thread to commit its
-                * rcu_reader.ctr update to memory if we wait for too long.
+                * URCU_TLS(rcu_reader).ctr update to memory if we wait
+                * for too long.
                 */
                if (cds_list_empty(&registry)) {
                        if (wait_loops == RCU_QS_ACTIVE_ATTEMPTS) {
                                /* Read reader_gp before write futex */
                                smp_mb_master(RCU_MB_GROUP);
-                               uatomic_set(&gp_futex, 0);
+                               uatomic_set(&rcu_gp_futex, 0);
                        }
                        break;
                } else {
@@ -311,7 +325,7 @@ void synchronize_rcu(void)
         * committing next rcu_gp_ctr update to memory. Failure to do so could
         * result in the writer waiting forever while new readers are always
         * accessing data (no progress).  Enforce compiler-order of load
-        * rcu_reader ctr before store to rcu_gp_ctr.
+        * URCU_TLS(rcu_reader).ctr before store to rcu_gp_ctr.
         */
        cmm_barrier();
 
@@ -351,20 +365,20 @@ void rcu_read_unlock(void)
 
 void rcu_register_thread(void)
 {
-       rcu_reader.tid = pthread_self();
-       assert(rcu_reader.need_mb == 0);
-       assert(!(rcu_reader.ctr & RCU_GP_CTR_NEST_MASK));
+       URCU_TLS(rcu_reader).tid = pthread_self();
+       assert(URCU_TLS(rcu_reader).need_mb == 0);
+       assert(!(URCU_TLS(rcu_reader).ctr & RCU_GP_CTR_NEST_MASK));
 
        mutex_lock(&rcu_gp_lock);
        rcu_init();     /* In case gcc does not support constructor attribute */
-       cds_list_add(&rcu_reader.node, &registry);
+       cds_list_add(&URCU_TLS(rcu_reader).node, &registry);
        mutex_unlock(&rcu_gp_lock);
 }
 
 void rcu_unregister_thread(void)
 {
        mutex_lock(&rcu_gp_lock);
-       cds_list_del(&rcu_reader.node);
+       cds_list_del(&URCU_TLS(rcu_reader).node);
        mutex_unlock(&rcu_gp_lock);
 }
 
@@ -375,7 +389,7 @@ void rcu_init(void)
                return;
        init_done = 1;
        if (!membarrier(MEMBARRIER_EXPEDITED | MEMBARRIER_QUERY))
-               has_sys_membarrier = 1;
+               rcu_has_sys_membarrier = 1;
 }
 #endif
 
@@ -388,7 +402,7 @@ static void sigrcu_handler(int signo, siginfo_t *siginfo, void *context)
         * executed on.
         */
        cmm_smp_mb();
-       _CMM_STORE_SHARED(rcu_reader.need_mb, 0);
+       _CMM_STORE_SHARED(URCU_TLS(rcu_reader).need_mb, 0);
        cmm_smp_mb();
 }
 
@@ -413,10 +427,8 @@ void rcu_init(void)
        act.sa_flags = SA_SIGINFO | SA_RESTART;
        sigemptyset(&act.sa_mask);
        ret = sigaction(SIGRCU, &act, NULL);
-       if (ret) {
-               perror("Error in sigaction");
-               exit(-1);
-       }
+       if (ret)
+               urcu_die(errno);
 }
 
 void rcu_exit(void)
@@ -425,15 +437,15 @@ void rcu_exit(void)
        int ret;
 
        ret = sigaction(SIGRCU, NULL, &act);
-       if (ret) {
-               perror("Error in sigaction");
-               exit(-1);
-       }
+       if (ret)
+               urcu_die(errno);
        assert(act.sa_sigaction == sigrcu_handler);
        assert(cds_list_empty(&registry));
 }
 
 #endif /* #ifdef RCU_SIGNAL */
 
+DEFINE_RCU_FLAVOR(rcu_flavor);
+
 #include "urcu-call-rcu-impl.h"
 #include "urcu-defer-impl.h"
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