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Commit ac1ed8b8 authored by Marcelo Ricardo Leitner's avatar Marcelo Ricardo Leitner Committed by David S. Miller
Browse files

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: default avatarXin Long <lucien.xin@gmail.com>
Signed-off-by: default avatarMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 637784ad

include/net/sctp/structs.h

+11 −0
Original line number Diff line number Diff line
@@ -1348,6 +1348,10 @@ struct sctp_stream_out_ext { 
			struct list_head prio_list;

			struct sctp_stream_priorities *prio_head;

		};

		/* Fields used by RR scheduler */

		struct {

			struct list_head rr_list;

		};

	};

};
@@ -1374,6 +1378,13 @@ struct sctp_stream { 
			/* List of priorities scheduled */

			struct list_head prio_list;

		};

		/* Fields used by RR scheduler */

		struct {

			/* List of streams scheduled */

			struct list_head rr_list;

			/* The next stream stream in line */

			struct sctp_stream_out_ext *rr_next;

		};

	};

};

include/uapi/linux/sctp.h

+2 −1
Original line number Diff line number Diff line
@@ -1100,7 +1100,8 @@ struct sctp_add_streams { 
enum sctp_sched_type {

	SCTP_SS_FCFS,

	SCTP_SS_PRIO,

	SCTP_SS_MAX = SCTP_SS_PRIO

	SCTP_SS_RR,

	SCTP_SS_MAX = SCTP_SS_RR

};



#endif /* _UAPI_SCTP_H */

net/sctp/Makefile

+2 −1
Original line number Diff line number Diff line
@@ -12,7 +12,8 @@ sctp-y := sm_statetable.o sm_statefuns.o sm_sideeffect.o \ 
	  inqueue.o outqueue.o ulpqueue.o \

	  tsnmap.o bind_addr.o socket.o primitive.o \

	  output.o input.o debug.o stream.o auth.o \

	  offload.o stream_sched.o stream_sched_prio.o

	  offload.o stream_sched.o stream_sched_prio.o \

	  stream_sched_rr.o



sctp_probe-y := probe.o

net/sctp/stream_sched.c

+2 −0
Original line number Diff line number Diff line
@@ -122,10 +122,12 @@ static struct sctp_sched_ops sctp_sched_fcfs = { 
/* API to other parts of the stack */



extern struct sctp_sched_ops sctp_sched_prio;

extern struct sctp_sched_ops sctp_sched_rr;



struct sctp_sched_ops *sctp_sched_ops[] = {

	&sctp_sched_fcfs,

	&sctp_sched_prio,

	&sctp_sched_rr,

};



int sctp_sched_set_sched(struct sctp_association *asoc,

net/sctp/stream_sched_rr.c

0 → 100644
+201 −0
Original line number Diff line number Diff line 
/* 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,

};