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[Qemu-devel] [PATCH v2 05/12] test-rcu-list: access n_reclaims and n_nod
From: |
Emilio G. Cota |
Subject: |
[Qemu-devel] [PATCH v2 05/12] test-rcu-list: access n_reclaims and n_nodes_removed with atomic64 |
Date: |
Mon, 10 Sep 2018 19:27:45 -0400 |
To avoid undefined behaviour.
Note that these "atomics" are atomic in the "access once" sense.
The variables are updated by a single thread at a time, so no
"full" atomics are necessary.
Signed-off-by: Emilio G. Cota <address@hidden>
---
tests/test-rcu-list.c | 20 +++++++++++---------
1 file changed, 11 insertions(+), 9 deletions(-)
diff --git a/tests/test-rcu-list.c b/tests/test-rcu-list.c
index 192bfbf02e..2e6f70bd59 100644
--- a/tests/test-rcu-list.c
+++ b/tests/test-rcu-list.c
@@ -33,8 +33,8 @@
static QemuMutex counts_mutex;
static long long n_reads = 0LL;
static long long n_updates = 0LL;
-static long long n_reclaims = 0LL;
-static long long n_nodes_removed = 0LL;
+static int64_t n_reclaims;
+static int64_t n_nodes_removed;
static long long n_nodes = 0LL;
static int g_test_in_charge = 0;
@@ -104,7 +104,7 @@ static void reclaim_list_el(struct rcu_head *prcu)
struct list_element *el = container_of(prcu, struct list_element, rcu);
g_free(el);
/* Accessed only from call_rcu thread. */
- n_reclaims++;
+ atomic_set_i64(&n_reclaims, n_reclaims + 1);
}
#if TEST_LIST_TYPE == 1
@@ -232,7 +232,7 @@ static void *rcu_q_updater(void *arg)
qemu_mutex_lock(&counts_mutex);
n_nodes += n_nodes_local;
n_updates += n_updates_local;
- n_nodes_removed += n_removed_local;
+ atomic_set_i64(&n_nodes_removed, n_nodes_removed + n_removed_local);
qemu_mutex_unlock(&counts_mutex);
return NULL;
}
@@ -286,19 +286,21 @@ static void rcu_qtest(const char *test, int duration, int
nreaders)
n_removed_local++;
}
qemu_mutex_lock(&counts_mutex);
- n_nodes_removed += n_removed_local;
+ atomic_set_i64(&n_nodes_removed, n_nodes_removed + n_removed_local);
qemu_mutex_unlock(&counts_mutex);
synchronize_rcu();
- while (n_nodes_removed > n_reclaims) {
+ while (atomic_read_i64(&n_nodes_removed) > atomic_read_i64(&n_reclaims)) {
g_usleep(100);
synchronize_rcu();
}
if (g_test_in_charge) {
- g_assert_cmpint(n_nodes_removed, ==, n_reclaims);
+ g_assert_cmpint(atomic_read_i64(&n_nodes_removed), ==,
+ atomic_read_i64(&n_reclaims));
} else {
printf("%s: %d readers; 1 updater; nodes read: " \
- "%lld, nodes removed: %lld; nodes reclaimed: %lld\n",
- test, nthreadsrunning - 1, n_reads, n_nodes_removed,
n_reclaims);
+ "%lld, nodes removed: %"PRIi64"; nodes reclaimed: %"PRIi64"\n",
+ test, nthreadsrunning - 1, n_reads,
+ atomic_read_i64(&n_nodes_removed),
atomic_read_i64(&n_reclaims));
exit(0);
}
}
--
2.17.1
- Re: [Qemu-devel] [PATCH v2 02/12] util: add atomic64, (continued)
- Re: [Qemu-devel] [PATCH v2 02/12] util: add atomic64, Richard Henderson, 2018/09/11
- Re: [Qemu-devel] [PATCH v2 02/12] util: add atomic64, Peter Maydell, 2018/09/18
- Re: [Qemu-devel] [PATCH v2 02/12] util: add atomic64, Emilio G. Cota, 2018/09/18
- Re: [Qemu-devel] [PATCH v2 02/12] util: add atomic64, Peter Maydell, 2018/09/18
- Re: [Qemu-devel] [PATCH v2 02/12] util: add atomic64, Richard Henderson, 2018/09/18
[Qemu-devel] [PATCH v2 06/12] atomic: fix comment s/x64_64/x86_64/, Emilio G. Cota, 2018/09/10
[Qemu-devel] [PATCH v2 05/12] test-rcu-list: access n_reclaims and n_nodes_removed with atomic64,
Emilio G. Cota <=
[Qemu-devel] [PATCH v2 07/12] cpus: initialize timers_state.vm_clock_lock, Emilio G. Cota, 2018/09/10
[Qemu-devel] [PATCH v2 04/12] qsp: use atomic64 accessors, Emilio G. Cota, 2018/09/10
[Qemu-devel] [PATCH v2 03/12] tests: add atomic64-bench, Emilio G. Cota, 2018/09/10
[Qemu-devel] [PATCH v2 08/12] cpus: always call seqlock_write in cpu_update_icount, Emilio G. Cota, 2018/09/10