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rcu: use coroutine TLS macros

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RCU may be used from coroutines. Standard __thread variables cannot be
used by coroutines. Use the coroutine TLS macros instead.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20220222140150.27240-4-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2022-02-22 14:01:49 +00:00 committed by Kevin Wolf
parent 47b7446456
commit 17c78154b0
4 changed files with 16 additions and 15 deletions
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7
include/qemu/rcu.h
View File

@ -29,6 +29,7 @@
#include "qemu/atomic.h"
#include "qemu/notify.h"
#include "qemu/sys_membarrier.h"
#include "qemu/coroutine-tls.h"
#ifdef __cplusplus
extern "C" {
@ -76,11 +77,11 @@ struct rcu_reader_data {
NotifierList force_rcu;
};
extern __thread struct rcu_reader_data rcu_reader;
QEMU_DECLARE_CO_TLS(struct rcu_reader_data, rcu_reader)
static inline void rcu_read_lock(void)
{
struct rcu_reader_data *p_rcu_reader = &rcu_reader;
struct rcu_reader_data *p_rcu_reader = get_ptr_rcu_reader();
unsigned ctr;
if (p_rcu_reader->depth++ > 0) {
@ -96,7 +97,7 @@ static inline void rcu_read_lock(void)
static inline void rcu_read_unlock(void)
{
struct rcu_reader_data *p_rcu_reader = &rcu_reader;
struct rcu_reader_data *p_rcu_reader = get_ptr_rcu_reader();
assert(p_rcu_reader->depth != 0);
if (--p_rcu_reader->depth > 0) {

10
tests/unit/rcutorture.c
View File

@ -122,7 +122,7 @@ static void *rcu_read_perf_test(void *arg)
rcu_register_thread();
*(struct rcu_reader_data **)arg = &rcu_reader;
*(struct rcu_reader_data **)arg = get_ptr_rcu_reader();
qatomic_inc(&nthreadsrunning);
while (goflag == GOFLAG_INIT) {
g_usleep(1000);
@ -148,7 +148,7 @@ static void *rcu_update_perf_test(void *arg)
rcu_register_thread();
*(struct rcu_reader_data **)arg = &rcu_reader;
*(struct rcu_reader_data **)arg = get_ptr_rcu_reader();
qatomic_inc(&nthreadsrunning);
while (goflag == GOFLAG_INIT) {
g_usleep(1000);
@ -253,7 +253,7 @@ static void *rcu_read_stress_test(void *arg)
rcu_register_thread();
*(struct rcu_reader_data **)arg = &rcu_reader;
*(struct rcu_reader_data **)arg = get_ptr_rcu_reader();
while (goflag == GOFLAG_INIT) {
g_usleep(1000);
}
@ -304,7 +304,7 @@ static void *rcu_update_stress_test(void *arg)
struct rcu_stress *cp = qatomic_read(&rcu_stress_current);
rcu_register_thread();
*(struct rcu_reader_data **)arg = &rcu_reader;
*(struct rcu_reader_data **)arg = get_ptr_rcu_reader();
while (goflag == GOFLAG_INIT) {
g_usleep(1000);
@ -347,7 +347,7 @@ static void *rcu_fake_update_stress_test(void *arg)
{
rcu_register_thread();
*(struct rcu_reader_data **)arg = &rcu_reader;
*(struct rcu_reader_data **)arg = get_ptr_rcu_reader();
while (goflag == GOFLAG_INIT) {
g_usleep(1000);
}

4
tests/unit/test-rcu-list.c
View File

@ -171,7 +171,7 @@ static void *rcu_q_reader(void *arg)
rcu_register_thread();
*(struct rcu_reader_data **)arg = &rcu_reader;
*(struct rcu_reader_data **)arg = get_ptr_rcu_reader();
qatomic_inc(&nthreadsrunning);
while (qatomic_read(&goflag) == GOFLAG_INIT) {
g_usleep(1000);
@ -206,7 +206,7 @@ static void *rcu_q_updater(void *arg)
long long n_removed_local = 0;
struct list_element *el, *prev_el;
*(struct rcu_reader_data **)arg = &rcu_reader;
*(struct rcu_reader_data **)arg = get_ptr_rcu_reader();
qatomic_inc(&nthreadsrunning);
while (qatomic_read(&goflag) == GOFLAG_INIT) {
g_usleep(1000);

10
util/rcu.c
View File

@ -65,7 +65,7 @@ static inline int rcu_gp_ongoing(unsigned long *ctr)
/* Written to only by each individual reader. Read by both the reader and the
* writers.
*/
__thread struct rcu_reader_data rcu_reader;
QEMU_DEFINE_CO_TLS(struct rcu_reader_data, rcu_reader)
/* Protected by rcu_registry_lock. */
typedef QLIST_HEAD(, rcu_reader_data) ThreadList;
@ -355,23 +355,23 @@ void drain_call_rcu(void)
void rcu_register_thread(void)
{
assert(rcu_reader.ctr == 0);
assert(get_ptr_rcu_reader()->ctr == 0);
qemu_mutex_lock(&rcu_registry_lock);
QLIST_INSERT_HEAD(&registry, &rcu_reader, node);
QLIST_INSERT_HEAD(&registry, get_ptr_rcu_reader(), node);
qemu_mutex_unlock(&rcu_registry_lock);
}
void rcu_unregister_thread(void)
{
qemu_mutex_lock(&rcu_registry_lock);
QLIST_REMOVE(&rcu_reader, node);
QLIST_REMOVE(get_ptr_rcu_reader(), node);
qemu_mutex_unlock(&rcu_registry_lock);
}
void rcu_add_force_rcu_notifier(Notifier *n)
{
qemu_mutex_lock(&rcu_registry_lock);
notifier_list_add(&rcu_reader.force_rcu, n);
notifier_list_add(&get_ptr_rcu_reader()->force_rcu, n);
qemu_mutex_unlock(&rcu_registry_lock);
}