Fix: make benchmark test run in oot build

[urcu.git] / urcu-call-rcu-impl.h

diff --git a/urcu-call-rcu-impl.h b/urcu-call-rcu-impl.h
index c4a78752b5c383e4ade261c85051e18793bafa87..f02405ddd698ca684901a3d68c2534b9e9295b9e 100644 (file)
--- a/urcu-call-rcu-impl.h
+++ b/urcu-call-rcu-impl.h
@@ -45,6 +45,9 @@
 #include "urcu/ref.h"
 #include "urcu-die.h"
 
+#define SET_AFFINITY_CHECK_PERIOD              (1U << 8)       /* 256 */
+#define SET_AFFINITY_CHECK_PERIOD_MASK         (SET_AFFINITY_CHECK_PERIOD - 1)
+
 /* Data structure that identifies a call_rcu thread. */
 
 struct call_rcu_data {
@@ -62,6 +65,7 @@ struct call_rcu_data {
        unsigned long qlen; /* maintained for debugging. */
        pthread_t tid;
        int cpu_affinity;
+       unsigned long gp_count;
        struct cds_list_head list;
 } __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
 
@@ -203,22 +207,42 @@ static void call_rcu_unlock(pthread_mutex_t *pmp)
                urcu_die(ret);
 }
 
+/*
+ * Periodically retry setting CPU affinity if we migrate.
+ * Losing affinity can be caused by CPU hotunplug/hotplug, or by
+ * cpuset(7).
+ */
 #if HAVE_SCHED_SETAFFINITY
 static
 int set_thread_cpu_affinity(struct call_rcu_data *crdp)
 {
        cpu_set_t mask;
+       int ret;
 
        if (crdp->cpu_affinity < 0)
                return 0;
+       if (++crdp->gp_count & SET_AFFINITY_CHECK_PERIOD_MASK)
+               return 0;
+       if (urcu_sched_getcpu() == crdp->cpu_affinity)
+               return 0;
 
        CPU_ZERO(&mask);
        CPU_SET(crdp->cpu_affinity, &mask);
 #if SCHED_SETAFFINITY_ARGS == 2
-       return sched_setaffinity(0, &mask);
+       ret = sched_setaffinity(0, &mask);
 #else
-       return sched_setaffinity(0, sizeof(mask), &mask);
+       ret = sched_setaffinity(0, sizeof(mask), &mask);
 #endif
+       /*
+        * EINVAL is fine: can be caused by hotunplugged CPUs, or by
+        * cpuset(7). This is why we should always retry if we detect
+        * migration.
+        */
+       if (ret && errno == EINVAL) {
+               ret = 0;
+               errno = 0;
+       }
+       return ret;
 }
 #else
 static
@@ -275,10 +299,8 @@ static void *call_rcu_thread(void *arg)
        unsigned long cbcount;
        struct call_rcu_data *crdp = (struct call_rcu_data *) arg;
        int rt = !!(uatomic_read(&crdp->flags) & URCU_CALL_RCU_RT);
-       int ret;
 
-       ret = set_thread_cpu_affinity(crdp);
-       if (ret)
+       if (set_thread_cpu_affinity(crdp))
                urcu_die(errno);
 
        /*
@@ -298,6 +320,9 @@ static void *call_rcu_thread(void *arg)
                struct cds_wfcq_node *cbs, *cbs_tmp_n;
                enum cds_wfcq_ret splice_ret;
 
+               if (set_thread_cpu_affinity(crdp))
+                       urcu_die(errno);
+
                if (uatomic_read(&crdp->flags) & URCU_CALL_RCU_PAUSE) {
                        /*
                         * Pause requested. Become quiescent: remove
@@ -309,7 +334,7 @@ static void *call_rcu_thread(void *arg)
                        cmm_smp_mb__before_uatomic_or();
                        uatomic_or(&crdp->flags, URCU_CALL_RCU_PAUSED);
                        while ((uatomic_read(&crdp->flags) & URCU_CALL_RCU_PAUSE) != 0)
-                               poll(NULL, 0, 1);
+                               (void) poll(NULL, 0, 1);
                        uatomic_and(&crdp->flags, ~URCU_CALL_RCU_PAUSED);
                        cmm_smp_mb__after_uatomic_and();
                        rcu_register_thread();
@@ -341,7 +366,7 @@ static void *call_rcu_thread(void *arg)
                        if (cds_wfcq_empty(&crdp->cbs_head,
                                        &crdp->cbs_tail)) {
                                call_rcu_wait(crdp);
-                               poll(NULL, 0, 10);
+                               (void) poll(NULL, 0, 10);
                                uatomic_dec(&crdp->futex);
                                /*
                                 * Decrement futex before reading
@@ -349,10 +374,10 @@ static void *call_rcu_thread(void *arg)
                                 */
                                cmm_smp_mb();
                        } else {
-                               poll(NULL, 0, 10);
+                               (void) poll(NULL, 0, 10);
                        }
                } else {
-                       poll(NULL, 0, 10);
+                       (void) poll(NULL, 0, 10);
                }
                rcu_thread_online();
        }
@@ -391,6 +416,7 @@ static void call_rcu_data_init(struct call_rcu_data **crdpp,
        crdp->flags = flags;
        cds_list_add(&crdp->list, &call_rcu_data_list);
        crdp->cpu_affinity = cpu_affinity;
+       crdp->gp_count = 0;
        cmm_smp_mb();  /* Structure initialized before pointer is planted. */
        *crdpp = crdp;
        ret = pthread_create(&crdp->tid, NULL, call_rcu_thread, crdp);
@@ -710,7 +736,7 @@ void call_rcu_data_free(struct call_rcu_data *crdp)
                uatomic_or(&crdp->flags, URCU_CALL_RCU_STOP);
                wake_call_rcu_thread(crdp);
                while ((uatomic_read(&crdp->flags) & URCU_CALL_RCU_STOPPED) == 0)
-                       poll(NULL, 0, 1);
+                       (void) poll(NULL, 0, 1);
        }
        if (!cds_wfcq_empty(&crdp->cbs_head, &crdp->cbs_tail)) {
                /* Create default call rcu data if need be */
@@ -880,7 +906,7 @@ void call_rcu_before_fork(void)
        }
        cds_list_for_each_entry(crdp, &call_rcu_data_list, list) {
                while ((uatomic_read(&crdp->flags) & URCU_CALL_RCU_PAUSED) == 0)
-                       poll(NULL, 0, 1);
+                       (void) poll(NULL, 0, 1);
        }
 }
 
@@ -897,7 +923,7 @@ void call_rcu_after_fork_parent(void)
                uatomic_and(&crdp->flags, ~URCU_CALL_RCU_PAUSE);
        cds_list_for_each_entry(crdp, &call_rcu_data_list, list) {
                while ((uatomic_read(&crdp->flags) & URCU_CALL_RCU_PAUSED) != 0)
-                       poll(NULL, 0, 1);
+                       (void) poll(NULL, 0, 1);
        }
        call_rcu_unlock(&call_rcu_mutex);
 }