llc_queue: Refactor to handle codel_state per prio queue internally
A CoDel state per prio queue is needed, otherwise the sojourn time state
is not properly reset when a high prio packet is dequeued.
If we have a global codel state shared for all prio queues of an MS, then
basically high prio (GMM) packets will "never" be dropped because they are
handled/dequeued way quicker, so it's sojourn time will be below the
threshold most probably, stopping the "dropping" state for the rest of
lower prio packets.
The handling of different codel states is moved from MS object to the
llc_queue, also offloading already loaded dl_tbf.cpp in the process.
This will also allow in the future setting different CoDel parameters
for different priority queues if needed.
Tests need to be adapted since now the CoDel and PDU lifetime are
incorporated into the llc_queue_dequeue(). Also because dequeue now also
accesses related MS fields.
Related: OS#5508
Change-Id: I2bce2e82ab6389d8a70130a5c26a966a316b0fa4
diff --git a/src/llc.c b/src/llc.c
index c8d74d8..ddc1e03 100644
--- a/src/llc.c
+++ b/src/llc.c
@@ -21,6 +21,7 @@
#include <osmocom/core/msgb.h>
#include "bts.h"
+#include "gprs_ms.h"
#include "pcu_utils.h"
#include "llc.h"
@@ -94,17 +95,32 @@
return true;
}
-void llc_queue_init(struct gprs_llc_queue *q)
+void llc_queue_init(struct gprs_llc_queue *q, struct GprsMs *ms)
{
unsigned int i;
+ q->ms = ms;
q->queue_size = 0;
q->queue_octets = 0;
q->avg_queue_delay = 0;
- for (i = 0; i < ARRAY_SIZE(q->queue); i++)
- INIT_LLIST_HEAD(&q->queue[i]);
+ for (i = 0; i < ARRAY_SIZE(q->pq); i++) {
+ INIT_LLIST_HEAD(&q->pq[i].queue);
+ gprs_codel_init(&q->pq[i].codel_state);
+ }
}
+/* interval=0 -> don't use codel in the LLC queue */
+void llc_queue_set_codel_interval(struct gprs_llc_queue *q, unsigned int interval)
+{
+ unsigned int i;
+ if (interval == LLC_CODEL_DISABLE) {
+ q->use_codel = false;
+ return;
+ }
+ q->use_codel = true;
+ for (i = 0; i < ARRAY_SIZE(q->pq); i++)
+ gprs_codel_set_interval(&q->pq[i].codel_state, interval);
+}
static enum gprs_llc_queue_prio llc_sapi2prio(uint8_t sapi)
{
@@ -137,7 +153,7 @@
osmo_clock_gettime(CLOCK_MONOTONIC, &meta_storage->recv_time);
meta_storage->expire_time = *expire_time;
- msgb_enqueue(&q->queue[prio], llc_msg);
+ msgb_enqueue(&q->pq[prio].queue, llc_msg);
}
void llc_queue_clear(struct gprs_llc_queue *q, struct gprs_rlcmac_bts *bts)
@@ -145,8 +161,8 @@
struct msgb *msg;
unsigned int i;
- for (i = 0; i < ARRAY_SIZE(q->queue); i++) {
- while ((msg = msgb_dequeue(&q->queue[i]))) {
+ for (i = 0; i < ARRAY_SIZE(q->pq); i++) {
+ while ((msg = msgb_dequeue(&q->pq[i].queue))) {
if (bts)
bts_do_rate_ctr_inc(bts, CTR_LLC_FRAME_DROPPED);
msgb_free(msg);
@@ -166,13 +182,13 @@
size_t queue_octets = 0;
INIT_LLIST_HEAD(&new_queue);
- for (i = 0; i < ARRAY_SIZE(q->queue); i++) {
+ for (i = 0; i < ARRAY_SIZE(q->pq); i++) {
while (1) {
if (msg1 == NULL)
- msg1 = msgb_dequeue(&q->queue[i]);
+ msg1 = msgb_dequeue(&q->pq[i].queue);
if (msg2 == NULL)
- msg2 = msgb_dequeue(&o->queue[i]);
+ msg2 = msgb_dequeue(&o->pq[i].queue);
if (msg1 == NULL && msg2 == NULL)
break;
@@ -201,9 +217,9 @@
queue_octets += msgb_length(msg);
}
- OSMO_ASSERT(llist_empty(&q->queue[i]));
- OSMO_ASSERT(llist_empty(&o->queue[i]));
- llist_splice_init(&new_queue, &q->queue[i]);
+ OSMO_ASSERT(llist_empty(&q->pq[i].queue));
+ OSMO_ASSERT(llist_empty(&o->pq[i].queue));
+ llist_splice_init(&new_queue, &q->pq[i].queue);
}
o->queue_size = 0;
@@ -214,7 +230,7 @@
#define ALPHA 0.5f
-struct msgb *llc_queue_dequeue(struct gprs_llc_queue *q, const struct MetaInfo **info)
+static struct msgb *llc_queue_pick_msg(struct gprs_llc_queue *q, enum gprs_llc_queue_prio *prio)
{
struct msgb *msg;
struct timespec *tv, tv_now, tv_result;
@@ -222,18 +238,17 @@
unsigned int i;
const struct MetaInfo *meta_storage;
- for (i = 0; i < ARRAY_SIZE(q->queue); i++) {
- if ((msg = msgb_dequeue(&q->queue[i])))
+ for (i = 0; i < ARRAY_SIZE(q->pq); i++) {
+ if ((msg = msgb_dequeue(&q->pq[i].queue))) {
+ *prio = (enum gprs_llc_queue_prio)i;
break;
+ }
}
if (!msg)
return NULL;
meta_storage = (struct MetaInfo *)&msg->cb[0];
- if (info)
- *info = meta_storage;
-
q->queue_size -= 1;
q->queue_octets -= msgb_length(msg);
@@ -248,6 +263,85 @@
return msg;
}
+struct msgb *llc_queue_dequeue(struct gprs_llc_queue *q)
+{
+ struct msgb *msg;
+ struct timespec tv_now, tv_now2;
+ uint32_t octets = 0, frames = 0;
+ struct gprs_rlcmac_bts *bts = q->ms->bts;
+ struct gprs_pcu *pcu = bts->pcu;
+ struct timespec hyst_delta = {0, 0};
+ const unsigned keep_small_thresh = 60;
+ enum gprs_llc_queue_prio prio;
+
+ if (pcu->vty.llc_discard_csec)
+ csecs_to_timespec(pcu->vty.llc_discard_csec, &hyst_delta);
+
+ osmo_clock_gettime(CLOCK_MONOTONIC, &tv_now);
+ timespecadd(&tv_now, &hyst_delta, &tv_now2);
+
+ while ((msg = llc_queue_pick_msg(q, &prio))) {
+ const struct MetaInfo *info = (const struct MetaInfo *)&msg->cb[0];
+ const struct timespec *tv_disc = &info->expire_time;
+ const struct timespec *tv_recv = &info->recv_time;
+
+ gprs_bssgp_update_queue_delay(tv_recv, &tv_now);
+
+ if (q->use_codel) {
+ int bytes = llc_queue_octets(q);
+ if (gprs_codel_control(&q->pq[prio].codel_state, tv_recv, &tv_now, bytes))
+ goto drop_frame;
+ }
+
+ /* Is the age below the low water mark? */
+ if (!llc_queue_is_frame_expired(&tv_now2, tv_disc))
+ break;
+
+ /* Is the age below the high water mark */
+ if (!llc_queue_is_frame_expired(&tv_now, tv_disc)) {
+ /* Has the previous message not been dropped? */
+ if (frames == 0)
+ break;
+
+ /* Hysteresis mode, try to discard LLC messages until
+ * the low water mark has been reached */
+
+ /* Check whether to abort the hysteresis mode */
+
+ /* Is the frame small, perhaps only a TCP ACK? */
+ if (msg->len <= keep_small_thresh)
+ break;
+
+ /* Is it a GMM message? */
+ if (!llc_is_user_data_frame(msg->data, msg->len))
+ break;
+ }
+
+ bts_do_rate_ctr_inc(bts, CTR_LLC_FRAME_TIMEDOUT);
+drop_frame:
+ frames++;
+ octets += msg->len;
+ msgb_free(msg);
+ bts_do_rate_ctr_inc(bts, CTR_LLC_FRAME_DROPPED);
+ continue;
+ }
+
+ if (frames) {
+ LOGPMS(q->ms, DTBFDL, LOGL_NOTICE, "Discarding LLC PDU "
+ "because lifetime limit reached, "
+ "count=%u new_queue_size=%zu\n",
+ frames, llc_queue_size(q));
+ if (frames > 0xff)
+ frames = 0xff;
+ if (octets > 0xffffff)
+ octets = 0xffffff;
+ if (pcu->bssgp.bctx)
+ bssgp_tx_llc_discarded(pcu->bssgp.bctx, ms_tlli(q->ms), frames, octets);
+ }
+
+ return msg;
+}
+
void llc_queue_calc_pdu_lifetime(struct gprs_rlcmac_bts *bts, const uint16_t pdu_delay_csec, struct timespec *tv)
{
uint16_t delay_csec;