From: Paul E. McKenney Date: Fri, 3 Jun 2011 16:43:17 +0000 (-0400) Subject: Map symbols to allow multiple RCU flavors to be used in one binary X-Git-Tag: v0.6.0~44 X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=5e77fc1f94c3572fca067d37667d74f8165e2434;p=userspace-rcu.git Map symbols to allow multiple RCU flavors to be used in one binary Probably need similar mapping for rcu_defer(). Definitely need backwards-compatibility mapping for programs compiled against old versions of the library. Signed-off-by: Paul E. McKenney Signed-off-by: Mathieu Desnoyers --- diff --git a/Makefile.am b/Makefile.am index 776fa2b..4b70644 100644 --- a/Makefile.am +++ b/Makefile.am @@ -30,7 +30,7 @@ COMPAT+=compat_futex.c endif lib_LTLIBRARIES = liburcu.la liburcu-qsbr.la liburcu-mb.la liburcu-signal.la \ - liburcu-bp.la liburcu-defer.la liburcu-call.la \ + liburcu-bp.la liburcu-defer.la \ libwfqueue.la libwfstack.la librculfqueue.la librculfstack.la liburcu_la_SOURCES = urcu.c urcu-pointer.c $(COMPAT) @@ -45,7 +45,6 @@ liburcu_signal_la_CFLAGS = -DRCU_SIGNAL liburcu_bp_la_SOURCES = urcu-bp.c urcu-pointer.c $(COMPAT) -liburcu_call_la_SOURCES = urcu-call-rcu.c $(COMPAT) liburcu_defer_la_SOURCES = urcu-defer.c $(COMPAT) libwfqueue_la_SOURCES = wfqueue.c $(COMPAT) diff --git a/tests/Makefile.am b/tests/Makefile.am index 3c025a4..8dacb11 100644 --- a/tests/Makefile.am +++ b/tests/Makefile.am @@ -28,21 +28,20 @@ if COMPAT_FUTEX COMPAT+=$(top_srcdir)/compat_futex.c endif -URCU=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/urcu-call-rcu.c $(top_srcdir)/wfqueue.c $(COMPAT) -URCU_QSBR=$(top_srcdir)/urcu-qsbr.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/urcu-call-rcu.c $(top_srcdir)/wfqueue.c $(COMPAT) +URCU=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT) +URCU_QSBR=$(top_srcdir)/urcu-qsbr.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT) # URCU_MB uses urcu.c but -DRCU_MB must be defined -URCU_MB=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/urcu-call-rcu.c $(top_srcdir)/wfqueue.c $(COMPAT) +URCU_MB=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT) # URCU_SIGNAL uses urcu.c but -DRCU_SIGNAL must be defined -URCU_SIGNAL=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/urcu-call-rcu.c $(top_srcdir)/wfqueue.c $(COMPAT) -URCU_BP=$(top_srcdir)/urcu-bp.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/urcu-call-rcu.c $(top_srcdir)/wfqueue.c $(COMPAT) -URCU_DEFER=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-defer.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/urcu-call-rcu.c $(top_srcdir)/wfqueue.c $(COMPAT) +URCU_SIGNAL=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT) +URCU_BP=$(top_srcdir)/urcu-bp.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT) +URCU_DEFER=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-defer.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT) URCU_LIB=$(top_builddir)/liburcu.la URCU_QSBR_LIB=$(top_builddir)/liburcu-qsbr.la URCU_MB_LIB=$(top_builddir)/liburcu-mb.la URCU_SIGNAL_LIB=$(top_builddir)/liburcu-signal.la URCU_BP_LIB=$(top_builddir)/liburcu-bp.la -URCU_CALL_LIB=$(top_builddir)/liburcu-call.la WFQUEUE_LIB=$(top_builddir)/libwfqueue.la WFSTACK_LIB=$(top_builddir)/libwfstack.la RCULFQUEUE_LIB=$(top_builddir)/librculfqueue.la @@ -95,24 +94,24 @@ test_perthreadlock_SOURCES = test_perthreadlock.c $(URCU_SIGNAL) rcutorture_urcu_SOURCES = urcutorture.c -rcutorture_urcu_CFLAGS = -DTORTURE_URCU $(AM_CFLAGS) -rcutorture_urcu_LDADD = $(URCU) $(URCU_CALL_LIB) $(WFQUEUE_LIB) +rcutorture_urcu_CFLAGS = -DRCU_MEMBARRIER $(AM_CFLAGS) +rcutorture_urcu_LDADD = $(URCU) $(WFQUEUE_LIB) rcutorture_urcu_mb_SOURCES = urcutorture.c -rcutorture_urcu_mb_CFLAGS = -DTORTURE_URCU_MB $(AM_CFLAGS) -rcutorture_urcu_mb_LDADD = $(URCU_MB_LIB) $(URCU_CALL_LIB) $(WFQUEUE_LIB) +rcutorture_urcu_mb_CFLAGS = -DRCU_MB $(AM_CFLAGS) +rcutorture_urcu_mb_LDADD = $(URCU_MB_LIB) $(WFQUEUE_LIB) rcutorture_qsbr_SOURCES = urcutorture.c -rcutorture_qsbr_CFLAGS = -DTORTURE_QSBR $(AM_CFLAGS) -rcutorture_qsbr_LDADD = $(URCU_QSBR_LIB) $(URCU_CALL_LIB) $(WFQUEUE_LIB) +rcutorture_qsbr_CFLAGS = -DRCU_QSBR $(AM_CFLAGS) +rcutorture_qsbr_LDADD = $(URCU_QSBR_LIB) $(WFQUEUE_LIB) rcutorture_urcu_signal_SOURCES = urcutorture.c -rcutorture_urcu_signal_CFLAGS = -DTORTURE_URCU_SIGNAL $(AM_CFLAGS) -rcutorture_urcu_signal_LDADD = $(URCU_SIGNAL_LIB) $(URCU_CALL_LIB) $(WFQUEUE_LIB) +rcutorture_urcu_signal_CFLAGS = -DRCU_SIGNAL $(AM_CFLAGS) +rcutorture_urcu_signal_LDADD = $(URCU_SIGNAL_LIB) $(WFQUEUE_LIB) rcutorture_urcu_bp_SOURCES = urcutorture.c -rcutorture_urcu_bp_CFLAGS = -DTORTURE_URCU_BP $(AM_CFLAGS) -rcutorture_urcu_bp_LDADD = $(URCU_BP_LIB) $(URCU_CALL_LIB) $(WFQUEUE_LIB) +rcutorture_urcu_bp_CFLAGS = -DRCU_BP $(AM_CFLAGS) +rcutorture_urcu_bp_LDADD = $(URCU_BP_LIB) $(WFQUEUE_LIB) test_mutex_SOURCES = test_mutex.c $(URCU) diff --git a/tests/rcutorture.h b/tests/rcutorture.h index 66fdd7f..aba74b0 100644 --- a/tests/rcutorture.h +++ b/tests/rcutorture.h @@ -66,7 +66,6 @@ */ #include -#include "../urcu-call-rcu.h" DEFINE_PER_THREAD(long long, n_reads_pt); DEFINE_PER_THREAD(long long, n_updates_pt); diff --git a/tests/urcutorture.c b/tests/urcutorture.c index 63fa386..a098d87 100644 --- a/tests/urcutorture.c +++ b/tests/urcutorture.c @@ -8,22 +8,19 @@ #include "api.h" #define _LGPL_SOURCE -#ifdef TORTURE_RCU_MEMBARRIER -#define RCU_MEMBARRIER +#ifdef RCU_MEMBARRIER #include #endif -#ifdef TORTURE_URCU_SIGNAL -#define RCU_SIGNAL +#ifdef RCU_SIGNAL #include #endif -#ifdef TORTURE_URCU_MB -#define RCU_MB +#ifdef RCU_MB #include #endif -#ifdef TORTURE_QSBR +#ifdef RCU_QSBR #include #endif -#ifdef TORTURE_URCU_BP +#ifdef RCU_BP #include #endif diff --git a/urcu-bp-map.h b/urcu-bp-map.h new file mode 100644 index 0000000..6321802 --- /dev/null +++ b/urcu-bp-map.h @@ -0,0 +1,61 @@ +#ifndef _URCU_BP_MAP_H +#define _URCU_BP_MAP_H + +/* + * urcu-map.h + * + * Userspace RCU header -- name mapping to allow multiple flavors to be + * used in the same executable. + * + * Copyright (c) 2009 Mathieu Desnoyers + * Copyright (c) 2009 Paul E. McKenney, IBM Corporation. + * + * LGPL-compatible code should include this header with : + * + * #define _LGPL_SOURCE + * #include + * + * 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. + */ + +/* Mapping macros to allow multiple flavors in a single binary. */ + +#define rcu_read_lock rcu_read_lock_bp +#define _rcu_read_lock _rcu_read_lock_bp +#define rcu_read_unlock rcu_read_unlock_bp +#define _rcu_read_unlock _rcu_read_unlock_bp +#define rcu_register_thread rcu_register_thread_bp +#define rcu_unregister_thread rcu_unregister_thread_bp +#define rcu_init rcu_init_bp +#define rcu_exit rcu_exit_bp +#define synchronize_rcu synchronize_rcu_bp +#define rcu_reader rcu_reader_bp +#define rcu_gp_ctr rcu_gp_ctr_bp + +#define get_cpu_call_rcu_data get_cpu_call_rcu_data_bp +#define get_call_rcu_thread get_call_rcu_thread_bp +#define create_call_rcu_data create_call_rcu_data_bp +#define set_cpu_call_rcu_data set_cpu_call_rcu_data_bp +#define get_default_call_rcu_data get_default_call_rcu_data_bp +#define get_call_rcu_data get_call_rcu_data_bp +#define get_thread_call_rcu_data get_thread_call_rcu_data_bp +#define set_thread_call_rcu_data set_thread_call_rcu_data_bp +#define create_all_cpu_call_rcu_data create_all_cpu_call_rcu_data_bp +#define free_all_cpu_call_rcu_data free_all_cpu_call_rcu_data_bp +#define call_rcu call_rcu_bp + +#endif /* _URCU_BP_MAP_H */ diff --git a/urcu-bp.c b/urcu-bp.c index 04bb675..5474f9f 100644 --- a/urcu-bp.c +++ b/urcu-bp.c @@ -35,6 +35,8 @@ #include #include +#include "urcu-bp-map.h" + #include "urcu-bp-static.h" /* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */ #include "urcu-bp.h" @@ -375,3 +377,5 @@ void rcu_bp_after_fork_child(void) ret = pthread_sigmask(SIG_SETMASK, &oldmask, NULL); assert(!ret); } + +#include "urcu-call-rcu-impl.h" diff --git a/urcu-bp.h b/urcu-bp.h index d92fbd1..fdf885c 100644 --- a/urcu-bp.h +++ b/urcu-bp.h @@ -46,6 +46,8 @@ extern "C" { #endif +#include "urcu-bp-map.h" + /* * Important ! * @@ -69,8 +71,8 @@ extern "C" { * * Mark the beginning and end of a read-side critical section. */ -#define rcu_read_lock() _rcu_read_lock() -#define rcu_read_unlock() _rcu_read_unlock() +#define rcu_read_lock_bp() _rcu_read_lock() +#define rcu_read_unlock_bp() _rcu_read_unlock() #else /* !_LGPL_SOURCE */ @@ -115,4 +117,6 @@ static inline void rcu_init(void) } #endif +#include "urcu-call-rcu.h" + #endif /* _URCU_BP_H */ diff --git a/urcu-call-rcu-impl.h b/urcu-call-rcu-impl.h new file mode 100644 index 0000000..9fa6aa6 --- /dev/null +++ b/urcu-call-rcu-impl.h @@ -0,0 +1,615 @@ +/* + * urcu-call-rcu.c + * + * Userspace RCU library - batch memory reclamation with kernel API + * + * Copyright (c) 2010 Paul E. McKenney + * + * 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 + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "config.h" +#include "urcu/wfqueue.h" +#include "urcu-call-rcu.h" +#include "urcu-pointer.h" +#include "urcu/list.h" + +/* Data structure that identifies a call_rcu thread. */ + +struct call_rcu_data { + struct cds_wfq_queue cbs; + unsigned long flags; + pthread_mutex_t mtx; + pthread_cond_t cond; + unsigned long qlen; + pthread_t tid; + struct cds_list_head list; +} __attribute__((aligned(CAA_CACHE_LINE_SIZE))); + +/* + * List of all call_rcu_data structures to keep valgrind happy. + * Protected by call_rcu_mutex. + */ + +CDS_LIST_HEAD(call_rcu_data_list); + +/* Link a thread using call_rcu() to its call_rcu thread. */ + +static __thread struct call_rcu_data *thread_call_rcu_data; + +/* Guard call_rcu thread creation. */ + +static pthread_mutex_t call_rcu_mutex = PTHREAD_MUTEX_INITIALIZER; + +/* If a given thread does not have its own call_rcu thread, this is default. */ + +static struct call_rcu_data *default_call_rcu_data; + +/* + * If the sched_getcpu() and sysconf(_SC_NPROCESSORS_CONF) calls are + * available, then we can have call_rcu threads assigned to individual + * CPUs rather than only to specific threads. + */ + +#if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) + +/* + * Pointer to array of pointers to per-CPU call_rcu_data structures + * and # CPUs. + */ + +static struct call_rcu_data **per_cpu_call_rcu_data; +static long maxcpus; + +/* Allocate the array if it has not already been allocated. */ + +static void alloc_cpu_call_rcu_data(void) +{ + struct call_rcu_data **p; + static int warned = 0; + + if (maxcpus != 0) + return; + maxcpus = sysconf(_SC_NPROCESSORS_CONF); + if (maxcpus <= 0) { + return; + } + p = malloc(maxcpus * sizeof(*per_cpu_call_rcu_data)); + if (p != NULL) { + memset(p, '\0', maxcpus * sizeof(*per_cpu_call_rcu_data)); + per_cpu_call_rcu_data = p; + } else { + if (!warned) { + fprintf(stderr, "[error] liburcu: unable to allocate per-CPU pointer array\n"); + } + warned = 1; + } +} + +#else /* #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */ + +static const struct call_rcu_data **per_cpu_call_rcu_data = NULL; +static const long maxcpus = -1; + +static void alloc_cpu_call_rcu_data(void) +{ +} + +static int sched_getcpu(void) +{ + return -1; +} + +#endif /* #else #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */ + +/* Acquire the specified pthread mutex. */ + +static void call_rcu_lock(pthread_mutex_t *pmp) +{ + if (pthread_mutex_lock(pmp) != 0) { + perror("pthread_mutex_lock"); + exit(-1); + } +} + +/* Release the specified pthread mutex. */ + +static void call_rcu_unlock(pthread_mutex_t *pmp) +{ + if (pthread_mutex_unlock(pmp) != 0) { + perror("pthread_mutex_unlock"); + exit(-1); + } +} + +/* This is the code run by each call_rcu thread. */ + +static void *call_rcu_thread(void *arg) +{ + unsigned long cbcount; + struct cds_wfq_node *cbs; + struct cds_wfq_node **cbs_tail; + struct call_rcu_data *crdp = (struct call_rcu_data *)arg; + struct rcu_head *rhp; + + thread_call_rcu_data = crdp; + for (;;) { + if (&crdp->cbs.head != _CMM_LOAD_SHARED(crdp->cbs.tail)) { + while ((cbs = _CMM_LOAD_SHARED(crdp->cbs.head)) == NULL) + poll(NULL, 0, 1); + _CMM_STORE_SHARED(crdp->cbs.head, NULL); + cbs_tail = (struct cds_wfq_node **) + uatomic_xchg(&crdp->cbs.tail, &crdp->cbs.head); + synchronize_rcu(); + cbcount = 0; + do { + while (cbs->next == NULL && + &cbs->next != cbs_tail) + poll(NULL, 0, 1); + if (cbs == &crdp->cbs.dummy) { + cbs = cbs->next; + continue; + } + rhp = (struct rcu_head *)cbs; + cbs = cbs->next; + rhp->func(rhp); + cbcount++; + } while (cbs != NULL); + uatomic_sub(&crdp->qlen, cbcount); + } + if (crdp->flags & URCU_CALL_RCU_STOP) + break; + if (crdp->flags & URCU_CALL_RCU_RT) + poll(NULL, 0, 10); + else { + call_rcu_lock(&crdp->mtx); + _CMM_STORE_SHARED(crdp->flags, + crdp->flags & ~URCU_CALL_RCU_RUNNING); + if (&crdp->cbs.head == + _CMM_LOAD_SHARED(crdp->cbs.tail) && + pthread_cond_wait(&crdp->cond, &crdp->mtx) != 0) { + perror("pthread_cond_wait"); + exit(-1); + } + _CMM_STORE_SHARED(crdp->flags, + crdp->flags | URCU_CALL_RCU_RUNNING); + poll(NULL, 0, 10); + call_rcu_unlock(&crdp->mtx); + } + } + call_rcu_lock(&crdp->mtx); + crdp->flags |= URCU_CALL_RCU_STOPPED; + call_rcu_unlock(&crdp->mtx); + return NULL; +} + +/* + * Create both a call_rcu thread and the corresponding call_rcu_data + * structure, linking the structure in as specified. Caller must hold + * call_rcu_mutex. + */ + +static void call_rcu_data_init(struct call_rcu_data **crdpp, + unsigned long flags) +{ + struct call_rcu_data *crdp; + + crdp = malloc(sizeof(*crdp)); + if (crdp == NULL) { + fprintf(stderr, "Out of memory.\n"); + exit(-1); + } + memset(crdp, '\0', sizeof(*crdp)); + cds_wfq_init(&crdp->cbs); + crdp->qlen = 0; + if (pthread_mutex_init(&crdp->mtx, NULL) != 0) { + perror("pthread_mutex_init"); + exit(-1); + } + if (pthread_cond_init(&crdp->cond, NULL) != 0) { + perror("pthread_cond_init"); + exit(-1); + } + crdp->flags = flags | URCU_CALL_RCU_RUNNING; + cds_list_add(&crdp->list, &call_rcu_data_list); + cmm_smp_mb(); /* Structure initialized before pointer is planted. */ + *crdpp = crdp; + if (pthread_create(&crdp->tid, NULL, call_rcu_thread, crdp) != 0) { + perror("pthread_create"); + exit(-1); + } +} + +/* + * Return a pointer to the call_rcu_data structure for the specified + * CPU, returning NULL if there is none. We cannot automatically + * created it because the platform we are running on might not define + * sched_getcpu(). + */ + +struct call_rcu_data *get_cpu_call_rcu_data(int cpu) +{ + static int warned = 0; + + if (per_cpu_call_rcu_data == NULL) + return NULL; + if (!warned && maxcpus > 0 && (cpu < 0 || maxcpus <= cpu)) { + fprintf(stderr, "[error] liburcu: get CPU # out of range\n"); + warned = 1; + } + if (cpu < 0 || maxcpus <= cpu) + return NULL; + return per_cpu_call_rcu_data[cpu]; +} + +/* + * Return the tid corresponding to the call_rcu thread whose + * call_rcu_data structure is specified. + */ + +pthread_t get_call_rcu_thread(struct call_rcu_data *crdp) +{ + return crdp->tid; +} + +/* + * Create a call_rcu_data structure (with thread) and return a pointer. + */ + +static struct call_rcu_data *__create_call_rcu_data(unsigned long flags) +{ + struct call_rcu_data *crdp; + + call_rcu_data_init(&crdp, flags); + return crdp; +} + +struct call_rcu_data *create_call_rcu_data(unsigned long flags) +{ + struct call_rcu_data *crdp; + + call_rcu_lock(&call_rcu_mutex); + crdp = __create_call_rcu_data(flags); + call_rcu_unlock(&call_rcu_mutex); + return crdp; +} + +/* + * Set the specified CPU to use the specified call_rcu_data structure. + * + * Use NULL to remove a CPU's call_rcu_data structure, but it is + * the caller's responsibility to dispose of the removed structure. + * Use get_cpu_call_rcu_data() to obtain a pointer to the old structure + * (prior to NULLing it out, of course). + */ + +int set_cpu_call_rcu_data(int cpu, struct call_rcu_data *crdp) +{ + int warned = 0; + + call_rcu_lock(&call_rcu_mutex); + if (cpu < 0 || maxcpus <= cpu) { + if (!warned) { + fprintf(stderr, "[error] liburcu: set CPU # out of range\n"); + warned = 1; + } + call_rcu_unlock(&call_rcu_mutex); + errno = EINVAL; + return -EINVAL; + } + alloc_cpu_call_rcu_data(); + call_rcu_unlock(&call_rcu_mutex); + if (per_cpu_call_rcu_data == NULL) { + errno = ENOMEM; + return -ENOMEM; + } + per_cpu_call_rcu_data[cpu] = crdp; + return 0; +} + +/* + * Return a pointer to the default call_rcu_data structure, creating + * one if need be. Because we never free call_rcu_data structures, + * we don't need to be in an RCU read-side critical section. + */ + +struct call_rcu_data *get_default_call_rcu_data(void) +{ + if (default_call_rcu_data != NULL) + return rcu_dereference(default_call_rcu_data); + call_rcu_lock(&call_rcu_mutex); + if (default_call_rcu_data != NULL) { + call_rcu_unlock(&call_rcu_mutex); + return default_call_rcu_data; + } + call_rcu_data_init(&default_call_rcu_data, 0); + call_rcu_unlock(&call_rcu_mutex); + return default_call_rcu_data; +} + +/* + * Return the call_rcu_data structure that applies to the currently + * running thread. Any call_rcu_data structure assigned specifically + * to this thread has first priority, followed by any call_rcu_data + * structure assigned to the CPU on which the thread is running, + * followed by the default call_rcu_data structure. If there is not + * yet a default call_rcu_data structure, one will be created. + */ +struct call_rcu_data *get_call_rcu_data(void) +{ + int curcpu; + static int warned = 0; + + if (thread_call_rcu_data != NULL) + return thread_call_rcu_data; + if (maxcpus <= 0) + return get_default_call_rcu_data(); + curcpu = sched_getcpu(); + if (!warned && (curcpu < 0 || maxcpus <= curcpu)) { + fprintf(stderr, "[error] liburcu: gcrd CPU # out of range\n"); + warned = 1; + } + if (curcpu >= 0 && maxcpus > curcpu && + per_cpu_call_rcu_data != NULL && + per_cpu_call_rcu_data[curcpu] != NULL) + return per_cpu_call_rcu_data[curcpu]; + return get_default_call_rcu_data(); +} + +/* + * Return a pointer to this task's call_rcu_data if there is one. + */ + +struct call_rcu_data *get_thread_call_rcu_data(void) +{ + return thread_call_rcu_data; +} + +/* + * Set this task's call_rcu_data structure as specified, regardless + * of whether or not this task already had one. (This allows switching + * to and from real-time call_rcu threads, for example.) + * + * Use NULL to remove a thread's call_rcu_data structure, but it is + * the caller's responsibility to dispose of the removed structure. + * Use get_thread_call_rcu_data() to obtain a pointer to the old structure + * (prior to NULLing it out, of course). + */ + +void set_thread_call_rcu_data(struct call_rcu_data *crdp) +{ + thread_call_rcu_data = crdp; +} + +/* + * Create a separate call_rcu thread for each CPU. This does not + * replace a pre-existing call_rcu thread -- use the set_cpu_call_rcu_data() + * function if you want that behavior. + */ + +int create_all_cpu_call_rcu_data(unsigned long flags) +{ + int i; + struct call_rcu_data *crdp; + int ret; + + call_rcu_lock(&call_rcu_mutex); + alloc_cpu_call_rcu_data(); + call_rcu_unlock(&call_rcu_mutex); + if (maxcpus <= 0) { + errno = EINVAL; + return -EINVAL; + } + if (per_cpu_call_rcu_data == NULL) { + errno = ENOMEM; + return -ENOMEM; + } + for (i = 0; i < maxcpus; i++) { + call_rcu_lock(&call_rcu_mutex); + if (get_cpu_call_rcu_data(i)) { + call_rcu_unlock(&call_rcu_mutex); + continue; + } + crdp = __create_call_rcu_data(flags); + if (crdp == NULL) { + call_rcu_unlock(&call_rcu_mutex); + errno = ENOMEM; + return -ENOMEM; + } + call_rcu_unlock(&call_rcu_mutex); + if ((ret = set_cpu_call_rcu_data(i, crdp)) != 0) { + /* FIXME: Leaks crdp for now. */ + return ret; /* Can happen on race. */ + } + } + return 0; +} + +/* + * Wake up the call_rcu thread corresponding to the specified + * call_rcu_data structure. + */ +static void wake_call_rcu_thread(struct call_rcu_data *crdp) +{ + if (!(_CMM_LOAD_SHARED(crdp->flags) & URCU_CALL_RCU_RT)) { + call_rcu_lock(&crdp->mtx); + if (!(_CMM_LOAD_SHARED(crdp->flags) & URCU_CALL_RCU_RUNNING)) { + if (pthread_cond_signal(&crdp->cond) != 0) { + perror("pthread_cond_signal"); + exit(-1); + } + } + call_rcu_unlock(&crdp->mtx); + } +} + +/* + * Schedule a function to be invoked after a following grace period. + * This is the only function that must be called -- the others are + * only present to allow applications to tune their use of RCU for + * maximum performance. + * + * Note that unless a call_rcu thread has not already been created, + * the first invocation of call_rcu() will create one. So, if you + * need the first invocation of call_rcu() to be fast, make sure + * to create a call_rcu thread first. One way to accomplish this is + * "get_call_rcu_data();", and another is create_all_cpu_call_rcu_data(). + */ + +void call_rcu(struct rcu_head *head, + void (*func)(struct rcu_head *head)) +{ + struct call_rcu_data *crdp; + + cds_wfq_node_init(&head->next); + head->func = func; + crdp = get_call_rcu_data(); + cds_wfq_enqueue(&crdp->cbs, &head->next); + uatomic_inc(&crdp->qlen); + wake_call_rcu_thread(crdp); +} + +/* + * Free up the specified call_rcu_data structure, terminating the + * associated call_rcu thread. The caller must have previously + * removed the call_rcu_data structure from per-thread or per-CPU + * usage. For example, set_cpu_call_rcu_data(cpu, NULL) for per-CPU + * call_rcu_data structures or set_thread_call_rcu_data(NULL) for + * per-thread call_rcu_data structures. + * + * We silently refuse to free up the default call_rcu_data structure + * because that is where we put any leftover callbacks. Note that + * the possibility of self-spawning callbacks makes it impossible + * to execute all the callbacks in finite time without putting any + * newly spawned callbacks somewhere else. The "somewhere else" of + * last resort is the default call_rcu_data structure. + * + * We also silently refuse to free NULL pointers. This simplifies + * the calling code. + */ +void call_rcu_data_free(struct call_rcu_data *crdp) +{ + struct cds_wfq_node *cbs; + struct cds_wfq_node **cbs_tail; + struct cds_wfq_node **cbs_endprev; + + if (crdp == NULL || crdp == default_call_rcu_data) { + return; + } + if ((crdp->flags & URCU_CALL_RCU_STOPPED) == 0) { + call_rcu_lock(&crdp->mtx); + crdp->flags |= URCU_CALL_RCU_STOP; + call_rcu_unlock(&crdp->mtx); + wake_call_rcu_thread(crdp); + while ((crdp->flags & URCU_CALL_RCU_STOPPED) == 0) + poll(NULL, 0, 1); + } + if (&crdp->cbs.head != _CMM_LOAD_SHARED(crdp->cbs.tail)) { + while ((cbs = _CMM_LOAD_SHARED(crdp->cbs.head)) == NULL) + poll(NULL, 0, 1); + _CMM_STORE_SHARED(crdp->cbs.head, NULL); + cbs_tail = (struct cds_wfq_node **) + uatomic_xchg(&crdp->cbs.tail, &crdp->cbs.head); + cbs_endprev = (struct cds_wfq_node **) + uatomic_xchg(&default_call_rcu_data, cbs_tail); + *cbs_endprev = cbs; + uatomic_add(&default_call_rcu_data->qlen, + uatomic_read(&crdp->qlen)); + cds_list_del(&crdp->list); + free(crdp); + } +} + +/* + * Clean up all the per-CPU call_rcu threads. + */ +void free_all_cpu_call_rcu_data(void) +{ + int cpu; + struct call_rcu_data *crdp; + + if (maxcpus <= 0) + return; + for (cpu = 0; cpu < maxcpus; cpu++) { + crdp = get_cpu_call_rcu_data(cpu); + if (crdp == NULL) + continue; + set_cpu_call_rcu_data(cpu, NULL); + call_rcu_data_free(crdp); + } +} + +/* + * Acquire the call_rcu_mutex in order to ensure that the child sees + * all of the call_rcu() data structures in a consistent state. + * Suitable for pthread_atfork() and friends. + */ +void call_rcu_before_fork(void) +{ + call_rcu_lock(&call_rcu_mutex); +} + +/* + * Clean up call_rcu data structures in the parent of a successful fork() + * that is not followed by exec() in the child. Suitable for + * pthread_atfork() and friends. + */ +void call_rcu_after_fork_parent(void) +{ + call_rcu_unlock(&call_rcu_mutex); +} + +/* + * Clean up call_rcu data structures in the child of a successful fork() + * that is not followed by exec(). Suitable for pthread_atfork() and + * friends. + */ +void call_rcu_after_fork_child(void) +{ + struct call_rcu_data *crdp; + + /* Release the mutex. */ + call_rcu_unlock(&call_rcu_mutex); + + /* + * Allocate a new default call_rcu_data structure in order + * to get a working call_rcu thread to go with it. + */ + default_call_rcu_data = NULL; + (void)get_default_call_rcu_data(); + + /* Dispose of all of the rest of the call_rcu_data structures. */ + while (call_rcu_data_list.next != call_rcu_data_list.prev) { + crdp = cds_list_entry(call_rcu_data_list.prev, + struct call_rcu_data, list); + if (crdp == default_call_rcu_data) + crdp = cds_list_entry(crdp->list.prev, + struct call_rcu_data, list); + crdp->flags = URCU_CALL_RCU_STOPPED; + call_rcu_data_free(crdp); + } +} diff --git a/urcu-call-rcu.c b/urcu-call-rcu.c deleted file mode 100644 index 9cc56c5..0000000 --- a/urcu-call-rcu.c +++ /dev/null @@ -1,617 +0,0 @@ -/* - * urcu-call-rcu.c - * - * Userspace RCU library - batch memory reclamation with kernel API - * - * Copyright (c) 2010 Paul E. McKenney - * - * 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 - */ - -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include - -#include "config.h" -#include "urcu/wfqueue.h" -#include "urcu-call-rcu.h" -#include "urcu-pointer.h" -#include "urcu/list.h" - -/* Data structure that identifies a call_rcu thread. */ - -struct call_rcu_data { - struct cds_wfq_queue cbs; - unsigned long flags; - pthread_mutex_t mtx; - pthread_cond_t cond; - unsigned long qlen; - pthread_t tid; - struct cds_list_head list; -} __attribute__((aligned(CAA_CACHE_LINE_SIZE))); - -/* - * List of all call_rcu_data structures to keep valgrind happy. - * Protected by call_rcu_mutex. - */ - -CDS_LIST_HEAD(call_rcu_data_list); - -/* Link a thread using call_rcu() to its call_rcu thread. */ - -static __thread struct call_rcu_data *thread_call_rcu_data; - -/* Guard call_rcu thread creation. */ - -static pthread_mutex_t call_rcu_mutex = PTHREAD_MUTEX_INITIALIZER; - -/* If a given thread does not have its own call_rcu thread, this is default. */ - -static struct call_rcu_data *default_call_rcu_data; - -extern void synchronize_rcu(void); - -/* - * If the sched_getcpu() and sysconf(_SC_NPROCESSORS_CONF) calls are - * available, then we can have call_rcu threads assigned to individual - * CPUs rather than only to specific threads. - */ - -#if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) - -/* - * Pointer to array of pointers to per-CPU call_rcu_data structures - * and # CPUs. - */ - -static struct call_rcu_data **per_cpu_call_rcu_data; -static long maxcpus; - -/* Allocate the array if it has not already been allocated. */ - -static void alloc_cpu_call_rcu_data(void) -{ - struct call_rcu_data **p; - static int warned = 0; - - if (maxcpus != 0) - return; - maxcpus = sysconf(_SC_NPROCESSORS_CONF); - if (maxcpus <= 0) { - return; - } - p = malloc(maxcpus * sizeof(*per_cpu_call_rcu_data)); - if (p != NULL) { - memset(p, '\0', maxcpus * sizeof(*per_cpu_call_rcu_data)); - per_cpu_call_rcu_data = p; - } else { - if (!warned) { - fprintf(stderr, "[error] liburcu: unable to allocate per-CPU pointer array\n"); - } - warned = 1; - } -} - -#else /* #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */ - -static const struct call_rcu_data **per_cpu_call_rcu_data = NULL; -static const long maxcpus = -1; - -static void alloc_cpu_call_rcu_data(void) -{ -} - -static int sched_getcpu(void) -{ - return -1; -} - -#endif /* #else #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */ - -/* Acquire the specified pthread mutex. */ - -static void call_rcu_lock(pthread_mutex_t *pmp) -{ - if (pthread_mutex_lock(pmp) != 0) { - perror("pthread_mutex_lock"); - exit(-1); - } -} - -/* Release the specified pthread mutex. */ - -static void call_rcu_unlock(pthread_mutex_t *pmp) -{ - if (pthread_mutex_unlock(pmp) != 0) { - perror("pthread_mutex_unlock"); - exit(-1); - } -} - -/* This is the code run by each call_rcu thread. */ - -static void *call_rcu_thread(void *arg) -{ - unsigned long cbcount; - struct cds_wfq_node *cbs; - struct cds_wfq_node **cbs_tail; - struct call_rcu_data *crdp = (struct call_rcu_data *)arg; - struct rcu_head *rhp; - - thread_call_rcu_data = crdp; - for (;;) { - if (&crdp->cbs.head != _CMM_LOAD_SHARED(crdp->cbs.tail)) { - while ((cbs = _CMM_LOAD_SHARED(crdp->cbs.head)) == NULL) - poll(NULL, 0, 1); - _CMM_STORE_SHARED(crdp->cbs.head, NULL); - cbs_tail = (struct cds_wfq_node **) - uatomic_xchg(&crdp->cbs.tail, &crdp->cbs.head); - synchronize_rcu(); - cbcount = 0; - do { - while (cbs->next == NULL && - &cbs->next != cbs_tail) - poll(NULL, 0, 1); - if (cbs == &crdp->cbs.dummy) { - cbs = cbs->next; - continue; - } - rhp = (struct rcu_head *)cbs; - cbs = cbs->next; - rhp->func(rhp); - cbcount++; - } while (cbs != NULL); - uatomic_sub(&crdp->qlen, cbcount); - } - if (crdp->flags & URCU_CALL_RCU_STOP) - break; - if (crdp->flags & URCU_CALL_RCU_RT) - poll(NULL, 0, 10); - else { - call_rcu_lock(&crdp->mtx); - _CMM_STORE_SHARED(crdp->flags, - crdp->flags & ~URCU_CALL_RCU_RUNNING); - if (&crdp->cbs.head == - _CMM_LOAD_SHARED(crdp->cbs.tail) && - pthread_cond_wait(&crdp->cond, &crdp->mtx) != 0) { - perror("pthread_cond_wait"); - exit(-1); - } - _CMM_STORE_SHARED(crdp->flags, - crdp->flags | URCU_CALL_RCU_RUNNING); - poll(NULL, 0, 10); - call_rcu_unlock(&crdp->mtx); - } - } - call_rcu_lock(&crdp->mtx); - crdp->flags |= URCU_CALL_RCU_STOPPED; - call_rcu_unlock(&crdp->mtx); - return NULL; -} - -/* - * Create both a call_rcu thread and the corresponding call_rcu_data - * structure, linking the structure in as specified. Caller must hold - * call_rcu_mutex. - */ - -static void call_rcu_data_init(struct call_rcu_data **crdpp, - unsigned long flags) -{ - struct call_rcu_data *crdp; - - crdp = malloc(sizeof(*crdp)); - if (crdp == NULL) { - fprintf(stderr, "Out of memory.\n"); - exit(-1); - } - memset(crdp, '\0', sizeof(*crdp)); - cds_wfq_init(&crdp->cbs); - crdp->qlen = 0; - if (pthread_mutex_init(&crdp->mtx, NULL) != 0) { - perror("pthread_mutex_init"); - exit(-1); - } - if (pthread_cond_init(&crdp->cond, NULL) != 0) { - perror("pthread_cond_init"); - exit(-1); - } - crdp->flags = flags | URCU_CALL_RCU_RUNNING; - cds_list_add(&crdp->list, &call_rcu_data_list); - cmm_smp_mb(); /* Structure initialized before pointer is planted. */ - *crdpp = crdp; - if (pthread_create(&crdp->tid, NULL, call_rcu_thread, crdp) != 0) { - perror("pthread_create"); - exit(-1); - } -} - -/* - * Return a pointer to the call_rcu_data structure for the specified - * CPU, returning NULL if there is none. We cannot automatically - * created it because the platform we are running on might not define - * sched_getcpu(). - */ - -struct call_rcu_data *get_cpu_call_rcu_data(int cpu) -{ - static int warned = 0; - - if (per_cpu_call_rcu_data == NULL) - return NULL; - if (!warned && maxcpus > 0 && (cpu < 0 || maxcpus <= cpu)) { - fprintf(stderr, "[error] liburcu: get CPU # out of range\n"); - warned = 1; - } - if (cpu < 0 || maxcpus <= cpu) - return NULL; - return per_cpu_call_rcu_data[cpu]; -} - -/* - * Return the tid corresponding to the call_rcu thread whose - * call_rcu_data structure is specified. - */ - -pthread_t get_call_rcu_thread(struct call_rcu_data *crdp) -{ - return crdp->tid; -} - -/* - * Create a call_rcu_data structure (with thread) and return a pointer. - */ - -static struct call_rcu_data *__create_call_rcu_data(unsigned long flags) -{ - struct call_rcu_data *crdp; - - call_rcu_data_init(&crdp, flags); - return crdp; -} - -struct call_rcu_data *create_call_rcu_data(unsigned long flags) -{ - struct call_rcu_data *crdp; - - call_rcu_lock(&call_rcu_mutex); - crdp = __create_call_rcu_data(flags); - call_rcu_unlock(&call_rcu_mutex); - return crdp; -} - -/* - * Set the specified CPU to use the specified call_rcu_data structure. - * - * Use NULL to remove a CPU's call_rcu_data structure, but it is - * the caller's responsibility to dispose of the removed structure. - * Use get_cpu_call_rcu_data() to obtain a pointer to the old structure - * (prior to NULLing it out, of course). - */ - -int set_cpu_call_rcu_data(int cpu, struct call_rcu_data *crdp) -{ - int warned = 0; - - call_rcu_lock(&call_rcu_mutex); - if (cpu < 0 || maxcpus <= cpu) { - if (!warned) { - fprintf(stderr, "[error] liburcu: set CPU # out of range\n"); - warned = 1; - } - call_rcu_unlock(&call_rcu_mutex); - errno = EINVAL; - return -EINVAL; - } - alloc_cpu_call_rcu_data(); - call_rcu_unlock(&call_rcu_mutex); - if (per_cpu_call_rcu_data == NULL) { - errno = ENOMEM; - return -ENOMEM; - } - per_cpu_call_rcu_data[cpu] = crdp; - return 0; -} - -/* - * Return a pointer to the default call_rcu_data structure, creating - * one if need be. Because we never free call_rcu_data structures, - * we don't need to be in an RCU read-side critical section. - */ - -struct call_rcu_data *get_default_call_rcu_data(void) -{ - if (default_call_rcu_data != NULL) - return rcu_dereference(default_call_rcu_data); - call_rcu_lock(&call_rcu_mutex); - if (default_call_rcu_data != NULL) { - call_rcu_unlock(&call_rcu_mutex); - return default_call_rcu_data; - } - call_rcu_data_init(&default_call_rcu_data, 0); - call_rcu_unlock(&call_rcu_mutex); - return default_call_rcu_data; -} - -/* - * Return the call_rcu_data structure that applies to the currently - * running thread. Any call_rcu_data structure assigned specifically - * to this thread has first priority, followed by any call_rcu_data - * structure assigned to the CPU on which the thread is running, - * followed by the default call_rcu_data structure. If there is not - * yet a default call_rcu_data structure, one will be created. - */ -struct call_rcu_data *get_call_rcu_data(void) -{ - int curcpu; - static int warned = 0; - - if (thread_call_rcu_data != NULL) - return thread_call_rcu_data; - if (maxcpus <= 0) - return get_default_call_rcu_data(); - curcpu = sched_getcpu(); - if (!warned && (curcpu < 0 || maxcpus <= curcpu)) { - fprintf(stderr, "[error] liburcu: gcrd CPU # out of range\n"); - warned = 1; - } - if (curcpu >= 0 && maxcpus > curcpu && - per_cpu_call_rcu_data != NULL && - per_cpu_call_rcu_data[curcpu] != NULL) - return per_cpu_call_rcu_data[curcpu]; - return get_default_call_rcu_data(); -} - -/* - * Return a pointer to this task's call_rcu_data if there is one. - */ - -struct call_rcu_data *get_thread_call_rcu_data(void) -{ - return thread_call_rcu_data; -} - -/* - * Set this task's call_rcu_data structure as specified, regardless - * of whether or not this task already had one. (This allows switching - * to and from real-time call_rcu threads, for example.) - * - * Use NULL to remove a thread's call_rcu_data structure, but it is - * the caller's responsibility to dispose of the removed structure. - * Use get_thread_call_rcu_data() to obtain a pointer to the old structure - * (prior to NULLing it out, of course). - */ - -void set_thread_call_rcu_data(struct call_rcu_data *crdp) -{ - thread_call_rcu_data = crdp; -} - -/* - * Create a separate call_rcu thread for each CPU. This does not - * replace a pre-existing call_rcu thread -- use the set_cpu_call_rcu_data() - * function if you want that behavior. - */ - -int create_all_cpu_call_rcu_data(unsigned long flags) -{ - int i; - struct call_rcu_data *crdp; - int ret; - - call_rcu_lock(&call_rcu_mutex); - alloc_cpu_call_rcu_data(); - call_rcu_unlock(&call_rcu_mutex); - if (maxcpus <= 0) { - errno = EINVAL; - return -EINVAL; - } - if (per_cpu_call_rcu_data == NULL) { - errno = ENOMEM; - return -ENOMEM; - } - for (i = 0; i < maxcpus; i++) { - call_rcu_lock(&call_rcu_mutex); - if (get_cpu_call_rcu_data(i)) { - call_rcu_unlock(&call_rcu_mutex); - continue; - } - crdp = __create_call_rcu_data(flags); - if (crdp == NULL) { - call_rcu_unlock(&call_rcu_mutex); - errno = ENOMEM; - return -ENOMEM; - } - call_rcu_unlock(&call_rcu_mutex); - if ((ret = set_cpu_call_rcu_data(i, crdp)) != 0) { - /* FIXME: Leaks crdp for now. */ - return ret; /* Can happen on race. */ - } - } - return 0; -} - -/* - * Wake up the call_rcu thread corresponding to the specified - * call_rcu_data structure. - */ -static void wake_call_rcu_thread(struct call_rcu_data *crdp) -{ - if (!(_CMM_LOAD_SHARED(crdp->flags) & URCU_CALL_RCU_RT)) { - call_rcu_lock(&crdp->mtx); - if (!(_CMM_LOAD_SHARED(crdp->flags) & URCU_CALL_RCU_RUNNING)) { - if (pthread_cond_signal(&crdp->cond) != 0) { - perror("pthread_cond_signal"); - exit(-1); - } - } - call_rcu_unlock(&crdp->mtx); - } -} - -/* - * Schedule a function to be invoked after a following grace period. - * This is the only function that must be called -- the others are - * only present to allow applications to tune their use of RCU for - * maximum performance. - * - * Note that unless a call_rcu thread has not already been created, - * the first invocation of call_rcu() will create one. So, if you - * need the first invocation of call_rcu() to be fast, make sure - * to create a call_rcu thread first. One way to accomplish this is - * "get_call_rcu_data();", and another is create_all_cpu_call_rcu_data(). - */ - -void call_rcu(struct rcu_head *head, - void (*func)(struct rcu_head *head)) -{ - struct call_rcu_data *crdp; - - cds_wfq_node_init(&head->next); - head->func = func; - crdp = get_call_rcu_data(); - cds_wfq_enqueue(&crdp->cbs, &head->next); - uatomic_inc(&crdp->qlen); - wake_call_rcu_thread(crdp); -} - -/* - * Free up the specified call_rcu_data structure, terminating the - * associated call_rcu thread. The caller must have previously - * removed the call_rcu_data structure from per-thread or per-CPU - * usage. For example, set_cpu_call_rcu_data(cpu, NULL) for per-CPU - * call_rcu_data structures or set_thread_call_rcu_data(NULL) for - * per-thread call_rcu_data structures. - * - * We silently refuse to free up the default call_rcu_data structure - * because that is where we put any leftover callbacks. Note that - * the possibility of self-spawning callbacks makes it impossible - * to execute all the callbacks in finite time without putting any - * newly spawned callbacks somewhere else. The "somewhere else" of - * last resort is the default call_rcu_data structure. - * - * We also silently refuse to free NULL pointers. This simplifies - * the calling code. - */ -void call_rcu_data_free(struct call_rcu_data *crdp) -{ - struct cds_wfq_node *cbs; - struct cds_wfq_node **cbs_tail; - struct cds_wfq_node **cbs_endprev; - - if (crdp == NULL || crdp == default_call_rcu_data) { - return; - } - if ((crdp->flags & URCU_CALL_RCU_STOPPED) == 0) { - call_rcu_lock(&crdp->mtx); - crdp->flags |= URCU_CALL_RCU_STOP; - call_rcu_unlock(&crdp->mtx); - wake_call_rcu_thread(crdp); - while ((crdp->flags & URCU_CALL_RCU_STOPPED) == 0) - poll(NULL, 0, 1); - } - if (&crdp->cbs.head != _CMM_LOAD_SHARED(crdp->cbs.tail)) { - while ((cbs = _CMM_LOAD_SHARED(crdp->cbs.head)) == NULL) - poll(NULL, 0, 1); - _CMM_STORE_SHARED(crdp->cbs.head, NULL); - cbs_tail = (struct cds_wfq_node **) - uatomic_xchg(&crdp->cbs.tail, &crdp->cbs.head); - cbs_endprev = (struct cds_wfq_node **) - uatomic_xchg(&default_call_rcu_data, cbs_tail); - *cbs_endprev = cbs; - uatomic_add(&default_call_rcu_data->qlen, - uatomic_read(&crdp->qlen)); - cds_list_del(&crdp->list); - free(crdp); - } -} - -/* - * Clean up all the per-CPU call_rcu threads. - */ -void free_all_cpu_call_rcu_data(void) -{ - int cpu; - struct call_rcu_data *crdp; - - if (maxcpus <= 0) - return; - for (cpu = 0; cpu < maxcpus; cpu++) { - crdp = get_cpu_call_rcu_data(cpu); - if (crdp == NULL) - continue; - set_cpu_call_rcu_data(cpu, NULL); - call_rcu_data_free(crdp); - } -} - -/* - * Acquire the call_rcu_mutex in order to ensure that the child sees - * all of the call_rcu() data structures in a consistent state. - * Suitable for pthread_atfork() and friends. - */ -void call_rcu_before_fork(void) -{ - call_rcu_lock(&call_rcu_mutex); -} - -/* - * Clean up call_rcu data structures in the parent of a successful fork() - * that is not followed by exec() in the child. Suitable for - * pthread_atfork() and friends. - */ -void call_rcu_after_fork_parent(void) -{ - call_rcu_unlock(&call_rcu_mutex); -} - -/* - * Clean up call_rcu data structures in the child of a successful fork() - * that is not followed by exec(). Suitable for pthread_atfork() and - * friends. - */ -void call_rcu_after_fork_child(void) -{ - struct call_rcu_data *crdp; - - /* Release the mutex. */ - call_rcu_unlock(&call_rcu_mutex); - - /* - * Allocate a new default call_rcu_data structure in order - * to get a working call_rcu thread to go with it. - */ - default_call_rcu_data = NULL; - (void)get_default_call_rcu_data(); - - /* Dispose of all of the rest of the call_rcu_data structures. */ - while (call_rcu_data_list.next != call_rcu_data_list.prev) { - crdp = cds_list_entry(call_rcu_data_list.prev, - struct call_rcu_data, list); - if (crdp == default_call_rcu_data) - crdp = cds_list_entry(crdp->list.prev, - struct call_rcu_data, list); - crdp->flags = URCU_CALL_RCU_STOPPED; - call_rcu_data_free(crdp); - } -} diff --git a/urcu-map.h b/urcu-map.h new file mode 100644 index 0000000..eccaac2 --- /dev/null +++ b/urcu-map.h @@ -0,0 +1,117 @@ +#ifndef _URCU_MAP_H +#define _URCU_MAP_H + +/* + * urcu-map.h + * + * Userspace RCU header -- name mapping to allow multiple flavors to be + * used in the same executable. + * + * Copyright (c) 2009 Mathieu Desnoyers + * Copyright (c) 2009 Paul E. McKenney, IBM Corporation. + * + * LGPL-compatible code should include this header with : + * + * #define _LGPL_SOURCE + * #include + * + * 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. + */ + +/* Mapping macros to allow multiple flavors in a single binary. */ + +#ifdef RCU_MEMBARRIER + +#define rcu_read_lock rcu_read_lock_memb +#define _rcu_read_lock _rcu_read_lock_memb +#define rcu_read_unlock rcu_read_unlock_memb +#define _rcu_read_unlock _rcu_read_unlock_memb +#define rcu_register_thread rcu_register_thread_memb +#define rcu_unregister_thread rcu_unregister_thread_memb +#define rcu_init rcu_init_memb +#define rcu_exit rcu_exit_memb +#define synchronize_rcu synchronize_rcu_memb +#define rcu_reader rcu_reader_memb +#define rcu_gp_ctr rcu_gp_ctr_memb + +#define get_cpu_call_rcu_data get_cpu_call_rcu_data_memb +#define get_call_rcu_thread get_call_rcu_thread_memb +#define create_call_rcu_data create_call_rcu_data_memb +#define set_cpu_call_rcu_data set_cpu_call_rcu_data_memb +#define get_default_call_rcu_data get_default_call_rcu_data_memb +#define get_call_rcu_data get_call_rcu_data_memb +#define get_thread_call_rcu_data get_thread_call_rcu_data_memb +#define set_thread_call_rcu_data set_thread_call_rcu_data_memb +#define create_all_cpu_call_rcu_data create_all_cpu_call_rcu_data_memb +#define free_all_cpu_call_rcu_data free_all_cpu_call_rcu_data_memb +#define call_rcu call_rcu_memb + +#elif defined(RCU_SIGNAL) + +#define rcu_read_lock rcu_read_lock_sig +#define _rcu_read_lock _rcu_read_lock_sig +#define rcu_read_unlock rcu_read_unlock_sig +#define _rcu_read_unlock _rcu_read_unlock_sig +#define rcu_register_thread rcu_register_thread_sig +#define rcu_unregister_thread rcu_unregister_thread_sig +#define rcu_init rcu_init_sig +#define rcu_exit rcu_exit_sig +#define synchronize_rcu synchronize_rcu_sig +#define rcu_reader rcu_reader_sig +#define rcu_gp_ctr rcu_gp_ctr_sig + +#define get_cpu_call_rcu_data get_cpu_call_rcu_data_sig +#define get_call_rcu_thread get_call_rcu_thread_sig +#define create_call_rcu_data create_call_rcu_data_sig +#define set_cpu_call_rcu_data set_cpu_call_rcu_data_sig +#define get_default_call_rcu_data get_default_call_rcu_data_sig +#define get_call_rcu_data get_call_rcu_data_sig +#define get_thread_call_rcu_data get_thread_call_rcu_data_sig +#define set_thread_call_rcu_data set_thread_call_rcu_data_sig +#define create_all_cpu_call_rcu_data create_all_cpu_call_rcu_data_sig +#define free_all_cpu_call_rcu_data free_all_cpu_call_rcu_data_sig +#define call_rcu call_rcu_sig + +#elif defined(RCU_MB) + +#define rcu_read_lock rcu_read_lock_mb +#define _rcu_read_lock _rcu_read_lock_mb +#define rcu_read_unlock rcu_read_unlock_mb +#define _rcu_read_unlock _rcu_read_unlock_mb +#define rcu_register_thread rcu_register_thread_mb +#define rcu_unregister_thread rcu_unregister_thread_mb +#define rcu_init rcu_init_mb +#define rcu_exit rcu_exit_mb +#define synchronize_rcu synchronize_rcu_mb +#define rcu_reader rcu_reader_mb +#define rcu_gp_ctr rcu_gp_ctr_mb + +#define get_cpu_call_rcu_data get_cpu_call_rcu_data_mb +#define get_call_rcu_thread get_call_rcu_thread_mb +#define create_call_rcu_data create_call_rcu_data_mb +#define set_cpu_call_rcu_data set_cpu_call_rcu_data_mb +#define get_default_call_rcu_data get_default_call_rcu_data_mb +#define get_call_rcu_data get_call_rcu_data_mb +#define get_thread_call_rcu_data get_thread_call_rcu_data_mb +#define set_thread_call_rcu_data set_thread_call_rcu_data_mb +#define create_all_cpu_call_rcu_data create_all_cpu_call_rcu_data_mb +#define free_all_cpu_call_rcu_data free_all_cpu_call_rcu_data_mb +#define call_rcu call_rcu_mb + +#endif + +#endif /* _URCU_MAP_H */ diff --git a/urcu-qsbr-map.h b/urcu-qsbr-map.h new file mode 100644 index 0000000..2bce1b6 --- /dev/null +++ b/urcu-qsbr-map.h @@ -0,0 +1,63 @@ +#ifndef _URCU_QSBR_MAP_H +#define _URCU_QSBR_MAP_H + +/* + * urcu-map.h + * + * Userspace RCU header -- name mapping to allow multiple flavors to be + * used in the same executable. + * + * Copyright (c) 2009 Mathieu Desnoyers + * Copyright (c) 2009 Paul E. McKenney, IBM Corporation. + * + * LGPL-compatible code should include this header with : + * + * #define _LGPL_SOURCE + * #include + * + * 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. + */ + +/* Mapping macros to allow multiple flavors in a single binary. */ + +#define rcu_read_lock rcu_read_lock_qsbr +#define _rcu_read_lock _rcu_read_lock_qsbr +#define rcu_read_unlock rcu_read_unlock_qsbr +#define _rcu_read_unlock _rcu_read_unlock_qsbr +#define rcu_quiescent_state rcu_quiescent_state_qsbr +#define _rcu_quiescent_state _rcu_quiescent_state_qsbr +#define rcu_thread_offline rcu_thread_offline_qsbr +#define rcu_thread_online rcu_thread_online_qsbr +#define rcu_register_thread rcu_register_thread_qsbr +#define rcu_unregister_thread rcu_unregister_thread_qsbr +#define rcu_exit rcu_exit_qsbr +#define synchronize_rcu synchronize_rcu_qsbr +#define rcu_reader rcu_reader_qsbr +#define rcu_gp_ctr rcu_gp_ctr_qsbr + +#define get_cpu_call_rcu_data get_cpu_call_rcu_data_qsbr +#define get_call_rcu_thread get_call_rcu_thread_qsbr +#define create_call_rcu_data create_call_rcu_data_qsbr +#define set_cpu_call_rcu_data set_cpu_call_rcu_data_qsbr +#define get_default_call_rcu_data get_default_call_rcu_data_qsbr +#define get_call_rcu_data get_call_rcu_data_qsbr +#define get_thread_call_rcu_data get_thread_call_rcu_data_qsbr +#define set_thread_call_rcu_data set_thread_call_rcu_data_qsbr +#define create_all_cpu_call_rcu_data create_all_cpu_call_rcu_data_qsbr +#define call_rcu call_rcu_qsbr + +#endif /* _URCU_QSBR_MAP_H */ diff --git a/urcu-qsbr.c b/urcu-qsbr.c index 69effd5..8dcad33 100644 --- a/urcu-qsbr.c +++ b/urcu-qsbr.c @@ -32,6 +32,8 @@ #include #include +#include "urcu-qsbr-map.h" + #define BUILD_QSBR_LIB #include "urcu-qsbr-static.h" /* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */ @@ -121,10 +123,11 @@ static void update_counter_and_wait(void) #endif /* !(CAA_BITS_PER_LONG < 64) */ /* - * Must commit rcu_gp_ctr update to memory before waiting for quiescent - * state. Failure to do so could result in the writer waiting forever - * while new readers are always accessing data (no progress). Enforce - * compiler-order of store to rcu_gp_ctr before load rcu_reader ctr. + * Must commit rcu_gp_ctr update to memory before waiting for + * quiescent state. Failure to do so could result in the writer + * waiting forever while new readers are always accessing data + * (no progress). Enforce compiler-order of store to rcu_gp_ctr + * before load rcu_reader ctr. */ cmm_barrier(); @@ -194,8 +197,8 @@ void synchronize_rcu(void) /* * Mark the writer thread offline to make sure we don't wait for - * our own quiescent state. This allows using synchronize_rcu() in - * threads registered as readers. + * our own quiescent state. This allows using synchronize_rcu() + * in threads registered as readers. */ if (was_online) CMM_STORE_SHARED(rcu_reader.ctr, 0); @@ -212,10 +215,11 @@ void synchronize_rcu(void) /* * Must finish waiting for quiescent state for parity 0 before - * 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. + * 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. */ cmm_barrier(); @@ -238,7 +242,8 @@ out: * freed. */ if (was_online) - _CMM_STORE_SHARED(rcu_reader.ctr, CMM_LOAD_SHARED(rcu_gp_ctr)); + _CMM_STORE_SHARED(rcu_reader.ctr, + CMM_LOAD_SHARED(rcu_gp_ctr)); cmm_smp_mb(); } #else /* !(CAA_BITS_PER_LONG < 64) */ @@ -250,8 +255,8 @@ void synchronize_rcu(void) /* * Mark the writer thread offline to make sure we don't wait for - * our own quiescent state. This allows using synchronize_rcu() in - * threads registered as readers. + * our own quiescent state. This allows using synchronize_rcu() + * in threads registered as readers. */ cmm_smp_mb(); if (was_online) @@ -265,7 +270,8 @@ out: mutex_unlock(&rcu_gp_lock); if (was_online) - _CMM_STORE_SHARED(rcu_reader.ctr, CMM_LOAD_SHARED(rcu_gp_ctr)); + _CMM_STORE_SHARED(rcu_reader.ctr, + CMM_LOAD_SHARED(rcu_gp_ctr)); cmm_smp_mb(); } #endif /* !(CAA_BITS_PER_LONG < 64) */ @@ -326,3 +332,5 @@ void rcu_exit(void) { assert(cds_list_empty(®istry)); } + +#include "urcu-call-rcu-impl.h" diff --git a/urcu-qsbr.h b/urcu-qsbr.h index 116fd77..984d70c 100644 --- a/urcu-qsbr.h +++ b/urcu-qsbr.h @@ -40,6 +40,8 @@ extern "C" { #endif +#include "urcu-qsbr-map.h" + /* * Important ! * @@ -62,15 +64,15 @@ extern "C" { * rcu_read_unlock() * * Mark the beginning and end of a read-side critical section. - * DON'T FORGET TO USE rcu_register_thread/rcu_unregister_thread() FOR EACH - * THREAD WITH READ-SIDE CRITICAL SECTION. + * DON'T FORGET TO USE rcu_register_thread/rcu_unregister_thread() + * FOR EACH THREAD WITH READ-SIDE CRITICAL SECTION. */ -#define rcu_read_lock() _rcu_read_lock() -#define rcu_read_unlock() _rcu_read_unlock() +#define rcu_read_lock_qsbr() _rcu_read_lock() +#define rcu_read_unlock_qsbr() _rcu_read_unlock() -#define rcu_quiescent_state() _rcu_quiescent_state() -#define rcu_thread_offline() _rcu_thread_offline() -#define rcu_thread_online() _rcu_thread_online() +#define rcu_quiescent_state_qsbr() _rcu_quiescent_state() +#define rcu_thread_offline_qsbr() _rcu_thread_offline() +#define rcu_thread_online_qsbr() _rcu_thread_online() #else /* !_LGPL_SOURCE */ @@ -122,4 +124,6 @@ extern void rcu_unregister_thread(void); } #endif +#include "urcu-call-rcu.h" + #endif /* _URCU_QSBR_H */ diff --git a/urcu.c b/urcu.c index e529ac0..4ee9e3b 100644 --- a/urcu.c +++ b/urcu.c @@ -33,6 +33,8 @@ #include #include +#include "urcu-map.h" + #include "urcu-static.h" /* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */ #include "urcu.h" @@ -428,4 +430,7 @@ void rcu_exit(void) assert(act.sa_sigaction == sigrcu_handler); assert(cds_list_empty(®istry)); } + #endif /* #ifdef RCU_SIGNAL */ + +#include "urcu-call-rcu-impl.h" diff --git a/urcu.h b/urcu.h index c6c54e7..00d9b75 100644 --- a/urcu.h +++ b/urcu.h @@ -43,12 +43,14 @@ extern "C" { #endif +#include "urcu-map.h" + /* * Important ! * * Each thread containing read-side critical sections must be registered - * with rcu_register_thread() before calling rcu_read_lock(). - * rcu_unregister_thread() should be called before the thread exits. + * with rcu_register_thread_mb() before calling rcu_read_lock_mb(). + * rcu_unregister_thread_mb() should be called before the thread exits. */ #ifdef _LGPL_SOURCE @@ -68,8 +70,16 @@ extern "C" { * DON'T FORGET TO USE RCU_REGISTER/UNREGISTER_THREAD() FOR EACH THREAD WITH * READ-SIDE CRITICAL SECTION. */ -#define rcu_read_lock() _rcu_read_lock() -#define rcu_read_unlock() _rcu_read_unlock() +#ifdef RCU_MEMBARRIER +#define rcu_read_lock_memb() _rcu_read_lock() +#define rcu_read_unlock_memb() _rcu_read_unlock() +#elif defined(RCU_SIGNAL) +#define rcu_read_lock_sig() _rcu_read_lock() +#define rcu_read_unlock_sig() _rcu_read_unlock() +#elif defined(RCU_MB) +#define rcu_read_lock_mb() _rcu_read_lock() +#define rcu_read_unlock_mb() _rcu_read_unlock() +#endif #else /* !_LGPL_SOURCE */ @@ -100,4 +110,6 @@ extern void rcu_init(void); } #endif +#include "urcu-call-rcu.h" + #endif /* _URCU_H */