[ltt-dev] [rp] [PATCH RFC urcu 2/2] Map symbols to allow multiple RCU flavors to be used in one binary
Mathieu Desnoyers
mathieu.desnoyers at polymtl.ca
Fri Apr 1 16:59:09 EDT 2011
* Paul E. McKenney (paulmck at linux.vnet.ibm.com) wrote:
> 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 <paulmck at linux.vnet.ibm.com>
> ---
> Makefile.am | 3 +-
> tests/Makefile.am | 33 ++--
> tests/rcutorture.h | 1 -
> tests/urcutorture.c | 13 +-
> urcu-bp.c | 4 +
> urcu-bp.h | 8 +-
> urcu-call-rcu-impl.h | 618 +++++++++++++++++++++++++++++++++++++++++++++++++
> urcu-call-rcu.c | 620 --------------------------------------------------
> urcu-qsbr.c | 36 ++--
> urcu-qsbr.h | 18 +-
> urcu.c | 5 +
> urcu.h | 20 ++-
> 12 files changed, 704 insertions(+), 675 deletions(-)
> create mode 100644 urcu-call-rcu-impl.h
> delete mode 100644 urcu-call-rcu.c
>
> diff --git a/Makefile.am b/Makefile.am
> index 7956e7e..ef3bfef 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 <stdlib.h>
> -#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 <urcu.h>
> #endif
> -#ifdef TORTURE_URCU_SIGNAL
> -#define RCU_SIGNAL
> +#ifdef RCU_SIGNAL
> #include <urcu.h>
> #endif
> -#ifdef TORTURE_URCU_MB
> -#define RCU_MB
> +#ifdef RCU_MB
> #include <urcu.h>
> #endif
> -#ifdef TORTURE_QSBR
> +#ifdef RCU_QSBR
> #include <urcu-qsbr.h>
> #endif
> -#ifdef TORTURE_URCU_BP
> +#ifdef RCU_BP
> #include <urcu-bp.h>
> #endif
>
> 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 <unistd.h>
> #include <sys/mman.h>
>
> +#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()
It apply to _bp and all other flavors:
I would prefer a
#define rcu_read_lock_bp() _rcu_read_lock_bp()
so we don't go through the "map" file mapping too maping times,
otherwise things get confusing.
Thanks,
Mathieu
> +#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..68dbbdd
> --- /dev/null
> +++ b/urcu-call-rcu-impl.h
> @@ -0,0 +1,618 @@
> +/*
> + * urcu-call-rcu.c
> + *
> + * Userspace RCU library - batch memory reclamation with kernel API
> + *
> + * Copyright (c) 2010 Paul E. McKenney <paulmck at linux.vnet.ibm.com>
> + *
> + * 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 <stdio.h>
> +#include <pthread.h>
> +#include <signal.h>
> +#include <assert.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <errno.h>
> +#include <poll.h>
> +#include <sys/time.h>
> +#include <syscall.h>
> +#include <unistd.h>
> +
> +#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;
> +
> + /* Re-initialize the mutex. */
> + if (pthread_mutex_init(&call_rcu_mutex, NULL) != 0) {
> + perror("pthread_mutex_init");
> + exit(-1);
> + }
> +
> + /*
> + * 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 665f20c..0000000
> --- a/urcu-call-rcu.c
> +++ /dev/null
> @@ -1,620 +0,0 @@
> -/*
> - * urcu-call-rcu.c
> - *
> - * Userspace RCU library - batch memory reclamation with kernel API
> - *
> - * Copyright (c) 2010 Paul E. McKenney <paulmck at linux.vnet.ibm.com>
> - *
> - * 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 <stdio.h>
> -#include <pthread.h>
> -#include <signal.h>
> -#include <assert.h>
> -#include <stdlib.h>
> -#include <string.h>
> -#include <errno.h>
> -#include <poll.h>
> -#include <sys/time.h>
> -#include <syscall.h>
> -#include <unistd.h>
> -
> -#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;
> -
> - /* Re-initialize the mutex. */
> - if (pthread_mutex_init(&call_rcu_mutex, NULL) != 0) {
> - perror("pthread_mutex_init");
> - exit(-1);
> - }
> -
> - /*
> - * 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-qsbr.c b/urcu-qsbr.c
> index 69effd5..8dcad33 100644
> --- a/urcu-qsbr.c
> +++ b/urcu-qsbr.c
> @@ -32,6 +32,8 @@
> #include <errno.h>
> #include <poll.h>
>
> +#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 <errno.h>
> #include <poll.h>
>
> +#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 */
> --
> 1.7.3.2
>
>
> _______________________________________________
> rp mailing list
> rp at svcs.cs.pdx.edu
> http://svcs.cs.pdx.edu/mailman/listinfo/rp
--
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com
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