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iscsi: Assign connections to cores using round robin

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Previously, this searched the list of cores for the one
with the fewest connections and scheduled there. iSCSI
is being migrated to a new threading model where the
threads themselves will float, so simplify this part
of the code while that's implemented.

Change-Id: I05a1ff51a45df9c176c0e57d7f1ae9e97928adcd
Signed-off-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/452780
Tested-by: SPDK CI Jenkins <sys_sgci@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:
Ben Walker 2019-04-30 13:42:59 -07:00 committed by Jim Harris
parent af8affd1a9
commit 07c9541082
1 changed files with 15 additions and 34 deletions
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49
lib/iscsi/conn.c
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@ -62,8 +62,6 @@
memset(&(conn)->portal, 0, sizeof(*(conn)) - \
offsetof(struct spdk_iscsi_conn, portal));
static uint32_t *g_num_connections;
struct spdk_iscsi_conn *g_conns_array = MAP_FAILED;
static int g_conns_array_fd = -1;
static char g_shm_name[64];
@ -121,7 +119,7 @@ find_iscsi_connection_by_id(int cid)
int spdk_initialize_iscsi_conns(void)
{
size_t conns_size = sizeof(struct spdk_iscsi_conn) * MAX_ISCSI_CONNECTIONS;
uint32_t i, last_core;
uint32_t i;
SPDK_DEBUGLOG(SPDK_LOG_ISCSI, "spdk_iscsi_init\n");
@ -150,14 +148,6 @@ int spdk_initialize_iscsi_conns(void)
g_conns_array[i].id = i;
}
last_core = spdk_env_get_last_core();
g_num_connections = calloc(last_core + 1, sizeof(uint32_t));
if (!g_num_connections) {
SPDK_ERRLOG("Could not allocate array size=%u for g_num_connections\n",
last_core + 1);
goto err;
}
return 0;
err:
@ -324,7 +314,6 @@ spdk_iscsi_conn_construct(struct spdk_iscsi_portal *portal,
conn->pending_task_cnt = 0;
conn->lcore = spdk_env_get_current_core();
__sync_fetch_and_add(&g_num_connections[conn->lcore], 1);
iscsi_poll_group_add_conn(conn);
return 0;
@ -582,7 +571,6 @@ spdk_iscsi_get_active_conns(struct spdk_iscsi_tgt_node *target)
static void
iscsi_conns_cleanup(void)
{
free(g_num_connections);
munmap(g_conns_array, sizeof(struct spdk_iscsi_conn) *
MAX_ISCSI_CONNECTIONS);
g_conns_array = MAP_FAILED;
@ -743,8 +731,6 @@ iscsi_conn_stop(struct spdk_iscsi_conn *conn)
}
assert(conn->lcore == spdk_env_get_current_core());
__sync_fetch_and_sub(&g_num_connections[conn->lcore], 1);
}
void
@ -1479,43 +1465,38 @@ spdk_iscsi_conn_schedule(struct spdk_iscsi_conn *conn)
pthread_mutex_unlock(&target->mutex);
}
__sync_fetch_and_sub(&g_num_connections[conn->lcore], 1);
iscsi_poll_group_remove_conn(conn);
__sync_fetch_and_add(&g_num_connections[lcore], 1);
conn->last_nopin = spdk_get_ticks();
event = spdk_event_allocate(lcore, iscsi_conn_full_feature_migrate,
conn, NULL);
spdk_event_call(event);
}
static uint32_t g_next_core = SPDK_ENV_LCORE_ID_ANY;
static uint32_t
iscsi_conn_allocate_reactor(const struct spdk_cpuset *cpumask)
{
uint32_t i, selected_core;
int32_t num_pollers, min_pollers;
uint32_t i, core;
min_pollers = INT_MAX;
selected_core = spdk_env_get_first_core();
for (i = 0; i < spdk_env_get_core_count(); i++) {
if (g_next_core > spdk_env_get_last_core()) {
g_next_core = spdk_env_get_first_core();
}
SPDK_ENV_FOREACH_CORE(i) {
if (!spdk_cpuset_get_cpu(cpumask, i)) {
core = g_next_core;
g_next_core = spdk_env_get_next_core(g_next_core);
if (!spdk_cpuset_get_cpu(cpumask, core)) {
continue;
}
/* This core is running. Check how many pollers it already has. */
num_pollers = g_num_connections[i];
if (num_pollers < min_pollers) {
/* Track the core that has the minimum number of pollers
* to be used if no cores meet our criteria
*/
selected_core = i;
min_pollers = num_pollers;
}
return core;
}
return selected_core;
SPDK_ERRLOG("Unable to schedule connection on allowed CPU core. Scheduling on first core instead.\n");
return spdk_env_get_first_core();
}
static int