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authorMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>2017-10-04 01:20:17 +0300
committerDavid S. Miller <davem@davemloft.net>2017-10-04 02:27:29 +0300
commitac1ed8b82cd60ba8e7d84103ac1414b8c577c485 (patch)
tree23144fff13a5bb0ac5a84f429fd8ac768b49a214 /net/sctp/stream_sched_rr.c
parent637784ade221a3c8a7ecd0f583eddd95d6276b9a (diff)
downloadlinux-ac1ed8b82cd60ba8e7d84103ac1414b8c577c485.tar.xz
sctp: introduce round robin stream scheduler
This patch introduces RFC Draft ndata section 3.2 Priority Based Scheduler (SCTP_SS_RR). Works by maintaining a list of enqueued streams and tracking the last one used to send data. When the datamsg is done, it switches to the next stream. See-also: https://tools.ietf.org/html/draft-ietf-tsvwg-sctp-ndata-13 Tested-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sctp/stream_sched_rr.c')
-rw-r--r--net/sctp/stream_sched_rr.c201
1 files changed, 201 insertions, 0 deletions
diff --git a/net/sctp/stream_sched_rr.c b/net/sctp/stream_sched_rr.c
new file mode 100644
index 000000000000..7612a438c5b9
--- /dev/null
+++ b/net/sctp/stream_sched_rr.c
@@ -0,0 +1,201 @@
+/* SCTP kernel implementation
+ * (C) Copyright Red Hat Inc. 2017
+ *
+ * This file is part of the SCTP kernel implementation
+ *
+ * These functions manipulate sctp stream queue/scheduling.
+ *
+ * This SCTP implementation is free software;
+ * you can redistribute it and/or modify it under the terms of
+ * the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This SCTP implementation is distributed in the hope that it
+ * will be useful, but WITHOUT ANY WARRANTY; without even the implied
+ * ************************
+ * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU CC; see the file COPYING. If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * Please send any bug reports or fixes you make to the
+ * email addresched(es):
+ * lksctp developers <linux-sctp@vger.kernel.org>
+ *
+ * Written or modified by:
+ * Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
+ */
+
+#include <linux/list.h>
+#include <net/sctp/sctp.h>
+#include <net/sctp/sm.h>
+#include <net/sctp/stream_sched.h>
+
+/* Priority handling
+ * RFC DRAFT ndata section 3.2
+ */
+static void sctp_sched_rr_unsched_all(struct sctp_stream *stream);
+
+static void sctp_sched_rr_next_stream(struct sctp_stream *stream)
+{
+ struct list_head *pos;
+
+ pos = stream->rr_next->rr_list.next;
+ if (pos == &stream->rr_list)
+ pos = pos->next;
+ stream->rr_next = list_entry(pos, struct sctp_stream_out_ext, rr_list);
+}
+
+static void sctp_sched_rr_unsched(struct sctp_stream *stream,
+ struct sctp_stream_out_ext *soute)
+{
+ if (stream->rr_next == soute)
+ /* Try to move to the next stream */
+ sctp_sched_rr_next_stream(stream);
+
+ list_del_init(&soute->rr_list);
+
+ /* If we have no other stream queued, clear next */
+ if (list_empty(&stream->rr_list))
+ stream->rr_next = NULL;
+}
+
+static void sctp_sched_rr_sched(struct sctp_stream *stream,
+ struct sctp_stream_out_ext *soute)
+{
+ if (!list_empty(&soute->rr_list))
+ /* Already scheduled. */
+ return;
+
+ /* Schedule the stream */
+ list_add_tail(&soute->rr_list, &stream->rr_list);
+
+ if (!stream->rr_next)
+ stream->rr_next = soute;
+}
+
+static int sctp_sched_rr_set(struct sctp_stream *stream, __u16 sid,
+ __u16 prio, gfp_t gfp)
+{
+ return 0;
+}
+
+static int sctp_sched_rr_get(struct sctp_stream *stream, __u16 sid,
+ __u16 *value)
+{
+ return 0;
+}
+
+static int sctp_sched_rr_init(struct sctp_stream *stream)
+{
+ INIT_LIST_HEAD(&stream->rr_list);
+ stream->rr_next = NULL;
+
+ return 0;
+}
+
+static int sctp_sched_rr_init_sid(struct sctp_stream *stream, __u16 sid,
+ gfp_t gfp)
+{
+ INIT_LIST_HEAD(&stream->out[sid].ext->rr_list);
+
+ return 0;
+}
+
+static void sctp_sched_rr_free(struct sctp_stream *stream)
+{
+ sctp_sched_rr_unsched_all(stream);
+}
+
+static void sctp_sched_rr_enqueue(struct sctp_outq *q,
+ struct sctp_datamsg *msg)
+{
+ struct sctp_stream *stream;
+ struct sctp_chunk *ch;
+ __u16 sid;
+
+ ch = list_first_entry(&msg->chunks, struct sctp_chunk, frag_list);
+ sid = sctp_chunk_stream_no(ch);
+ stream = &q->asoc->stream;
+ sctp_sched_rr_sched(stream, stream->out[sid].ext);
+}
+
+static struct sctp_chunk *sctp_sched_rr_dequeue(struct sctp_outq *q)
+{
+ struct sctp_stream *stream = &q->asoc->stream;
+ struct sctp_stream_out_ext *soute;
+ struct sctp_chunk *ch = NULL;
+
+ /* Bail out quickly if queue is empty */
+ if (list_empty(&q->out_chunk_list))
+ goto out;
+
+ /* Find which chunk is next */
+ if (stream->out_curr)
+ soute = stream->out_curr->ext;
+ else
+ soute = stream->rr_next;
+ ch = list_entry(soute->outq.next, struct sctp_chunk, stream_list);
+
+ sctp_sched_dequeue_common(q, ch);
+
+out:
+ return ch;
+}
+
+static void sctp_sched_rr_dequeue_done(struct sctp_outq *q,
+ struct sctp_chunk *ch)
+{
+ struct sctp_stream_out_ext *soute;
+ __u16 sid;
+
+ /* Last chunk on that msg, move to the next stream */
+ sid = sctp_chunk_stream_no(ch);
+ soute = q->asoc->stream.out[sid].ext;
+
+ sctp_sched_rr_next_stream(&q->asoc->stream);
+
+ if (list_empty(&soute->outq))
+ sctp_sched_rr_unsched(&q->asoc->stream, soute);
+}
+
+static void sctp_sched_rr_sched_all(struct sctp_stream *stream)
+{
+ struct sctp_association *asoc;
+ struct sctp_stream_out_ext *soute;
+ struct sctp_chunk *ch;
+
+ asoc = container_of(stream, struct sctp_association, stream);
+ list_for_each_entry(ch, &asoc->outqueue.out_chunk_list, list) {
+ __u16 sid;
+
+ sid = sctp_chunk_stream_no(ch);
+ soute = stream->out[sid].ext;
+ if (soute)
+ sctp_sched_rr_sched(stream, soute);
+ }
+}
+
+static void sctp_sched_rr_unsched_all(struct sctp_stream *stream)
+{
+ struct sctp_stream_out_ext *soute, *tmp;
+
+ list_for_each_entry_safe(soute, tmp, &stream->rr_list, rr_list)
+ sctp_sched_rr_unsched(stream, soute);
+}
+
+struct sctp_sched_ops sctp_sched_rr = {
+ .set = sctp_sched_rr_set,
+ .get = sctp_sched_rr_get,
+ .init = sctp_sched_rr_init,
+ .init_sid = sctp_sched_rr_init_sid,
+ .free = sctp_sched_rr_free,
+ .enqueue = sctp_sched_rr_enqueue,
+ .dequeue = sctp_sched_rr_dequeue,
+ .dequeue_done = sctp_sched_rr_dequeue_done,
+ .sched_all = sctp_sched_rr_sched_all,
+ .unsched_all = sctp_sched_rr_unsched_all,
+};