openkylin
/
qemu
mirror of https://gitee.com/openkylin/qemu.git
9
0
Fork 0
Code Issues Projects Releases Wiki Activity

test-coroutine: Add rwlock downgrade test 

Test that downgrading an rwlock does not result in a failure to
schedule coroutines queued on the rwlock.

The diagram associated with test_co_rwlock_downgrade() describes the
intended behaviour, but what was observed previously corresponds to:

| c1     | c2         | c3         | c4       |
|--------+------------+------------+----------|
| rdlock |            |            |          |
| yield  |            |            |          |
|        | wrlock     |            |          |
|        | <queued>   |            |          |
|        |            | rdlock     |          |
|        |            | <queued>   |          |
|        |            |            | wrlock   |
|        |            |            | <queued> |
| unlock |            |            |          |
| yield  |            |            |          |
|        | <dequeued> |            |          |
|        | downgrade  |            |          |
|        | ...        |            |          |
|        | unlock     |            |          |
|        |            | <dequeued> |          |
|        |            | <queued>   |          |

This results in a failure...

ERROR:../tests/test-coroutine.c:369:test_co_rwlock_downgrade: assertion failed: (c3_done)
Bail out! ERROR:../tests/test-coroutine.c:369:test_co_rwlock_downgrade: assertion failed: (c3_done)

...as a result of the c3 coroutine failing to run to completion.

Signed-off-by: David Edmondson <david.edmondson@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20210325112941.365238-7-pbonzini@redhat.com
Message-Id: <20210309144015.557477-5-david.edmondson@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
David Edmondson 2021-03-25 12:29:41 +01:00 committed by Stefan Hajnoczi
parent 25bc2daed0
commit b6489ac066
1 changed files with 99 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

99
tests/unit/test-coroutine.c
View File

@ -325,6 +325,104 @@ static void test_co_rwlock_upgrade(void)
g_assert(c2_done);
}
static void coroutine_fn rwlock_rdlock_yield(void *opaque)
{
qemu_co_rwlock_rdlock(&rwlock);
qemu_coroutine_yield();
qemu_co_rwlock_unlock(&rwlock);
qemu_coroutine_yield();
*(bool *)opaque = true;
}
static void coroutine_fn rwlock_wrlock_downgrade(void *opaque)
{
qemu_co_rwlock_wrlock(&rwlock);
qemu_co_rwlock_downgrade(&rwlock);
qemu_co_rwlock_unlock(&rwlock);
*(bool *)opaque = true;
}
static void coroutine_fn rwlock_rdlock(void *opaque)
{
qemu_co_rwlock_rdlock(&rwlock);
qemu_co_rwlock_unlock(&rwlock);
*(bool *)opaque = true;
}
static void coroutine_fn rwlock_wrlock(void *opaque)
{
qemu_co_rwlock_wrlock(&rwlock);
qemu_co_rwlock_unlock(&rwlock);
*(bool *)opaque = true;
}
/*
* Check that downgrading a reader-writer lock does not cause a hang.
*
* Four coroutines are used to produce a situation where there are
* both reader and writer hopefuls waiting to acquire an rwlock that
* is held by a reader.
*
* The correct sequence of operations we aim to provoke can be
* represented as:
*
* | c1 | c2 | c3 | c4 |
* |--------+------------+------------+------------|
* | rdlock | | | |
* | yield | | | |
* | | wrlock | | |
* | | <queued> | | |
* | | | rdlock | |
* | | | <queued> | |
* | | | | wrlock |
* | | | | <queued> |
* | unlock | | | |
* | yield | | | |
* | | <dequeued> | | |
* | | downgrade | | |
* | | | <dequeued> | |
* | | | unlock | |
* | | ... | | |
* | | unlock | | |
* | | | | <dequeued> |
* | | | | unlock |
*/
static void test_co_rwlock_downgrade(void)
{
bool c1_done = false;
bool c2_done = false;
bool c3_done = false;
bool c4_done = false;
Coroutine *c1, *c2, *c3, *c4;
qemu_co_rwlock_init(&rwlock);
c1 = qemu_coroutine_create(rwlock_rdlock_yield, &c1_done);
c2 = qemu_coroutine_create(rwlock_wrlock_downgrade, &c2_done);
c3 = qemu_coroutine_create(rwlock_rdlock, &c3_done);
c4 = qemu_coroutine_create(rwlock_wrlock, &c4_done);
qemu_coroutine_enter(c1);
qemu_coroutine_enter(c2);
qemu_coroutine_enter(c3);
qemu_coroutine_enter(c4);
qemu_coroutine_enter(c1);
g_assert(c2_done);
g_assert(c3_done);
g_assert(c4_done);
qemu_coroutine_enter(c1);
g_assert(c1_done);
}
/*
* Check that creation, enter, and return work
*/
@ -563,6 +661,7 @@ int main(int argc, char **argv)
g_test_add_func("/locking/co-mutex", test_co_mutex);
g_test_add_func("/locking/co-mutex/lockable", test_co_mutex_lockable);
g_test_add_func("/locking/co-rwlock/upgrade", test_co_rwlock_upgrade);
g_test_add_func("/locking/co-rwlock/downgrade", test_co_rwlock_downgrade);
if (g_test_perf()) {
g_test_add_func("/perf/lifecycle", perf_lifecycle);
g_test_add_func("/perf/nesting", perf_nesting);