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bdev: make QoS channel management thread safe

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We must hold bdev->mutex around all QoS channel manipulations, not just
channel_count; otherwise, there are race conditions.

Change-Id: I6183aef83f4d5789bded426a1832e3faaa688363
Signed-off-by: Daniel Verkamp <daniel.verkamp@intel.com>
Reviewed-on: https://review.gerrithub.io/403367
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: GangCao <gang.cao@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
This commit is contained in:
Daniel Verkamp 2018-03-09 14:46:47 -07:00
parent e45c36ffb3
commit d4ef1338b0
3 changed files with 43 additions and 98 deletions
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3
include/spdk_internal/bdev.h
View File

@ -230,9 +230,6 @@ struct spdk_bdev {
/** QoS thread for this bdev */
struct spdk_thread *qos_thread;
/** Indicate an async destroying event is on going */
bool qos_channel_destroying;
/** write cache enabled, not used at the moment */
int write_cache;

136
lib/bdev/bdev.c
View File

@ -1052,9 +1052,13 @@ _spdk_bdev_channel_destroy_resource(struct spdk_bdev_channel *ch)
}
}
/* Caller must hold bdev->mutex. */
static int
_spdk_bdev_qos_channel_create(struct spdk_bdev *bdev)
spdk_bdev_qos_channel_create(struct spdk_bdev *bdev)
{
assert(bdev->qos_channel == NULL);
assert(bdev->qos_thread == NULL);
bdev->qos_channel = calloc(1, sizeof(struct spdk_bdev_channel));
if (!bdev->qos_channel) {
return -1;
@ -1062,10 +1066,15 @@ _spdk_bdev_qos_channel_create(struct spdk_bdev *bdev)
bdev->qos_thread = spdk_get_thread();
if (!bdev->qos_thread) {
free(bdev->qos_channel);
bdev->qos_channel = NULL;
return -1;
}
if (_spdk_bdev_channel_create(bdev->qos_channel, __bdev_to_io_dev(bdev)) != 0) {
free(bdev->qos_channel);
bdev->qos_channel = NULL;
bdev->qos_thread = NULL;
return -1;
}
@ -1079,67 +1088,6 @@ _spdk_bdev_qos_channel_create(struct spdk_bdev *bdev)
return 0;
}
static void
_spdk_bdev_qos_channel_destroy(void *ctx)
{
struct spdk_bdev_channel *qos_channel = ctx;
struct spdk_bdev *bdev = NULL;
if (!qos_channel) {
SPDK_DEBUGLOG(SPDK_LOG_BDEV, "QoS channel already NULL\n");
return;
}
spdk_poller_unregister(&qos_channel->qos_poller);
bdev = qos_channel->bdev;
assert(bdev->qos_thread == spdk_get_thread());
assert(bdev->qos_channel == qos_channel);
free(bdev->qos_channel);
bdev->qos_channel = NULL;
bdev->qos_thread = NULL;
}
static void
spdk_bdev_qos_channel_create_async(void *ctx)
{
struct spdk_bdev *bdev = ctx;
if (!bdev->qos_channel) {
if (_spdk_bdev_qos_channel_create(bdev) != 0) {
SPDK_ERRLOG("QoS channel failed to create\n");
_spdk_bdev_channel_destroy_resource(bdev->qos_channel);
_spdk_bdev_qos_channel_destroy(bdev->qos_channel);
}
}
}
static int
spdk_bdev_qos_channel_create(void *ctx)
{
struct spdk_bdev *bdev = ctx;
struct spdk_thread *qos_thread = bdev->qos_thread;
/*
* There is an async destroying on going.
* Send a message to that thread to defer the creation.
*/
if (bdev->qos_channel_destroying == true) {
if (qos_thread) {
spdk_thread_send_msg(qos_thread,
spdk_bdev_qos_channel_create_async, bdev);
return 0;
}
}
if (!bdev->qos_channel) {
return _spdk_bdev_qos_channel_create(bdev);
} else {
return 0;
}
}
static int
spdk_bdev_channel_create(void *io_device, void *ctx_buf)
{
@ -1151,20 +1099,6 @@ spdk_bdev_channel_create(void *io_device, void *ctx_buf)
return -1;
}
/* Rate limiting on this bdev enabled */
if (bdev->ios_per_sec > 0) {
if (spdk_bdev_qos_channel_create(bdev) != 0) {
_spdk_bdev_channel_destroy_resource(ch);
_spdk_bdev_channel_destroy_resource(bdev->qos_channel);
_spdk_bdev_qos_channel_destroy(bdev->qos_channel);
return -1;
}
}
pthread_mutex_lock(&bdev->mutex);
bdev->channel_count++;
pthread_mutex_unlock(&bdev->mutex);
#ifdef SPDK_CONFIG_VTUNE
{
char *name;
@ -1172,8 +1106,6 @@ spdk_bdev_channel_create(void *io_device, void *ctx_buf)
name = spdk_sprintf_alloc("spdk_bdev_%s_%p", ch->bdev->name, ch);
if (!name) {
_spdk_bdev_channel_destroy_resource(ch);
_spdk_bdev_channel_destroy_resource(bdev->qos_channel);
_spdk_bdev_qos_channel_destroy(bdev->qos_channel);
return -1;
}
ch->handle = __itt_string_handle_create(name);
@ -1183,6 +1115,21 @@ spdk_bdev_channel_create(void *io_device, void *ctx_buf)
}
#endif
pthread_mutex_lock(&bdev->mutex);
/* Rate limiting on this bdev enabled */
if (bdev->ios_per_sec > 0 && bdev->qos_channel == NULL) {
if (spdk_bdev_qos_channel_create(bdev) != 0) {
_spdk_bdev_channel_destroy_resource(ch);
pthread_mutex_unlock(&bdev->mutex);
return -1;
}
}
bdev->channel_count++;
pthread_mutex_unlock(&bdev->mutex);
return 0;
}
@ -1257,12 +1204,12 @@ _spdk_bdev_channel_destroy(struct spdk_bdev_channel *ch)
static void
spdk_bdev_qos_channel_destroy(void *ctx)
{
struct spdk_bdev *bdev = ctx;
struct spdk_bdev_channel *qos_channel = ctx;
bdev->qos_channel_destroying = false;
_spdk_bdev_channel_destroy(qos_channel);
_spdk_bdev_channel_destroy(bdev->qos_channel);
_spdk_bdev_qos_channel_destroy(bdev->qos_channel);
spdk_poller_unregister(&qos_channel->qos_poller);
free(qos_channel);
}
static void
@ -1270,25 +1217,26 @@ spdk_bdev_channel_destroy(void *io_device, void *ctx_buf)
{
struct spdk_bdev_channel *ch = ctx_buf;
struct spdk_bdev *bdev = ch->bdev;
uint32_t channel_count = 0;
_spdk_bdev_channel_destroy(ch);
pthread_mutex_lock(&bdev->mutex);
bdev->channel_count--;
channel_count = bdev->channel_count;
pthread_mutex_unlock(&bdev->mutex);
if (bdev->channel_count == 0 && bdev->qos_channel != NULL) {
/* All I/O channels for this bdev have been destroyed - destroy the QoS channel. */
spdk_thread_send_msg(bdev->qos_thread, spdk_bdev_qos_channel_destroy,
bdev->qos_channel);
/* Destroy QoS channel as no active bdev channels there */
if (channel_count == 0 && bdev->ios_per_sec > 0 && bdev->qos_thread) {
if (bdev->qos_thread == spdk_get_thread()) {
spdk_bdev_qos_channel_destroy(bdev);
} else {
bdev->qos_channel_destroying = true;
spdk_thread_send_msg(bdev->qos_thread,
spdk_bdev_qos_channel_destroy, bdev);
}
/*
* Set qos_channel to NULL within the critical section so that
* if another channel is created, it will see qos_channel == NULL and
* re-create the QoS channel even if the asynchronous qos_channel_destroy
* isn't finished yet.
*/
bdev->qos_channel = NULL;
bdev->qos_thread = NULL;
}
pthread_mutex_unlock(&bdev->mutex);
}
int

2
test/unit/lib/bdev/mt/bdev.c/bdev_ut.c
View File

@ -697,7 +697,7 @@ basic_qos(void)
CU_ASSERT(qos_bdev_ch != NULL);
module_ch = qos_bdev_ch->module_ch;
CU_ASSERT(module_ch->io_outstanding == 0);
CU_ASSERT(g_ut_threads[1].thread == bdev->qos_thread);
CU_ASSERT(g_ut_threads[2].thread == bdev->qos_thread);
/*
* Destroy the last I/O channel so that the QoS bdev channel