X-Git-Url: https://git.lttng.org/?p=urcu.git;a=blobdiff_plain;f=src%2Furcu-defer-impl.h;h=8b5ad972421d52f523f18146a3a1a068c2bcb661;hp=b2e1b3cab6c72428c138e45fb800ebdedd0e0a53;hb=HEAD;hpb=6fd172f599e8d798e68974a786dd930d876f182e diff --git a/src/urcu-defer-impl.h b/src/urcu-defer-impl.h index b2e1b3c..a180c48 100644 --- a/src/urcu-defer-impl.h +++ b/src/urcu-defer-impl.h @@ -1,31 +1,17 @@ +// SPDX-FileCopyrightText: 2009 Mathieu Desnoyers +// SPDX-FileCopyrightText: 2009 Paul E. McKenney, IBM Corporation. +// +// SPDX-License-Identifier: LGPL-2.1-or-later + #ifndef _URCU_DEFER_IMPL_H #define _URCU_DEFER_IMPL_H /* - * urcu-defer-impl.h - * * Userspace RCU header - memory reclamation. * * TO BE INCLUDED ONLY FROM URCU LIBRARY CODE. See urcu-defer.h for linking * dynamically with the userspace rcu reclamation library. * - * Copyright (c) 2009 Mathieu Desnoyers - * Copyright (c) 2009 Paul E. McKenney, IBM Corporation. - * - * This library is free software; you can redistribute it and/or - * modify it under the terms of the GNU Lesser General Public - * License as published by the Free Software Foundation; either - * version 2.1 of the License, or (at your option) any later version. - * - * This library is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * Lesser General Public License for more details. - * - * You should have received a copy of the GNU Lesser General Public - * License along with this library; if not, write to the Free Software - * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA - * * IBM's contributions to this file may be relicensed under LGPLv2 or later. */ @@ -33,7 +19,6 @@ #include #include #include -#include #include #include #include @@ -43,6 +28,7 @@ #include "urcu/futex.h" +#include #include #include #include @@ -50,6 +36,7 @@ #include #include #include "urcu-die.h" +#include "urcu-utils.h" /* * Number of entries in the per-thread defer queue. Must be power of 2. @@ -107,7 +94,7 @@ struct defer_queue { }; /* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */ -#include "urcu-defer.h" +#include void __attribute__((destructor)) rcu_defer_exit(void); @@ -126,7 +113,7 @@ static int32_t defer_thread_stop; * Written to only by each individual deferer. Read by both the deferer and * the reclamation tread. */ -static DEFINE_URCU_TLS_IE(struct defer_queue, defer_queue); +static DEFINE_URCU_TLS(struct defer_queue, defer_queue); static CDS_LIST_HEAD(registry_defer); static pthread_t tid_defer; @@ -193,17 +180,25 @@ static void wait_defer(void) uatomic_set(&defer_thread_futex, 0); } else { cmm_smp_rmb(); /* Read queue before read futex */ - if (uatomic_read(&defer_thread_futex) != -1) - return; - while (futex_noasync(&defer_thread_futex, FUTEX_WAIT, -1, - NULL, NULL, 0)) { + while (uatomic_read(&defer_thread_futex) == -1) { + if (!futex_noasync(&defer_thread_futex, FUTEX_WAIT, -1, NULL, NULL, 0)) { + /* + * Prior queued wakeups queued by unrelated code + * using the same address can cause futex wait to + * return 0 even through the futex value is still + * -1 (spurious wakeups). Check the value again + * in user-space to validate whether it really + * differs from -1. + */ + continue; + } switch (errno) { - case EWOULDBLOCK: + case EAGAIN: /* Value already changed. */ return; case EINTR: /* Retry if interrupted by signal. */ - break; /* Get out of switch. */ + break; /* Get out of switch. Check again. */ default: /* Unexpected error. */ urcu_die(errno); @@ -324,9 +319,9 @@ static void _defer_rcu(void (*fct)(void *p), void *p) * Worse-case: must allow 2 supplementary entries for fct pointer. */ if (caa_unlikely(head - tail >= DEFER_QUEUE_SIZE - 2)) { - assert(head - tail <= DEFER_QUEUE_SIZE); + urcu_posix_assert(head - tail <= DEFER_QUEUE_SIZE); rcu_defer_barrier_thread(); - assert(head - CMM_LOAD_SHARED(URCU_TLS(defer_queue).tail) == 0); + urcu_posix_assert(head - CMM_LOAD_SHARED(URCU_TLS(defer_queue).tail) == 0); } /* @@ -371,7 +366,7 @@ static void _defer_rcu(void (*fct)(void *p), void *p) wake_up_defer(); } -static void *thr_defer(void *args) +static void *thr_defer(void *args __attribute__((unused))) { for (;;) { /* @@ -400,9 +395,19 @@ void defer_rcu(void (*fct)(void *p), void *p) static void start_defer_thread(void) { int ret; + sigset_t newmask, oldmask; + + ret = sigfillset(&newmask); + urcu_posix_assert(!ret); + ret = pthread_sigmask(SIG_BLOCK, &newmask, &oldmask); + urcu_posix_assert(!ret); ret = pthread_create(&tid_defer, NULL, thr_defer, NULL); - assert(!ret); + if (ret) + urcu_die(ret); + + ret = pthread_sigmask(SIG_SETMASK, &oldmask, NULL); + urcu_posix_assert(!ret); } static void stop_defer_thread(void) @@ -416,19 +421,19 @@ static void stop_defer_thread(void) wake_up_defer(); ret = pthread_join(tid_defer, &tret); - assert(!ret); + urcu_posix_assert(!ret); CMM_STORE_SHARED(defer_thread_stop, 0); /* defer thread should always exit when futex value is 0 */ - assert(uatomic_read(&defer_thread_futex) == 0); + urcu_posix_assert(uatomic_read(&defer_thread_futex) == 0); } int rcu_defer_register_thread(void) { int was_empty; - assert(URCU_TLS(defer_queue).last_head == 0); - assert(URCU_TLS(defer_queue).q == NULL); + urcu_posix_assert(URCU_TLS(defer_queue).last_head == 0); + urcu_posix_assert(URCU_TLS(defer_queue).q == NULL); URCU_TLS(defer_queue).q = malloc(sizeof(void *) * DEFER_QUEUE_SIZE); if (!URCU_TLS(defer_queue).q) return -ENOMEM; @@ -465,7 +470,7 @@ void rcu_defer_unregister_thread(void) void rcu_defer_exit(void) { - assert(cds_list_empty(®istry_defer)); + urcu_posix_assert(cds_list_empty(®istry_defer)); } #endif /* _URCU_DEFER_IMPL_H */