[PATCHv3 net 0/3] sctp: a bunch of fixes for prsctp polices

[PATCHv3 net 0/3] sctp: a bunch of fixes for prsctp polices

[Xin Long]

This patchset is to fix 2 issues for prsctp polices:

  1. patch 1 and 2 fix "netperf-Throughput_Mbps -37.2% regression" issue
     when overloading the CPU.

  2. patch 3 fix "prsctp polices should check both sides' prsctp_capable,
     instead of only local side".

Xin Long (3):
  sctp: move sent_count to the memory hole in sctp_chunk
  sctp: remove prsctp_param from sctp_chunk
  sctp: change to check peer prsctp_capable when using prsctp polices

 include/net/sctp/structs.h | 13 +++----------
 net/sctp/chunk.c           | 11 ++++++++---
 net/sctp/outqueue.c        | 12 ++++++------
 net/sctp/sm_make_chunk.c   | 15 ---------------
 4 files changed, 17 insertions(+), 34 deletions(-)

-- 
2.1.0

[PATCHv3 net 1/3] sctp: move sent_count to the memory hole in sctp_chunk

[Xin Long]

Now pahole sctp_chunk, it has 2 memory holes:
   struct sctp_chunk {
	struct list_head           list;
	atomic_t                   refcnt;
	/* XXX 4 bytes hole, try to pack */
	...
	long unsigned int          prsctp_param;
	int                        sent_count;
	/* XXX 4 bytes hole, try to pack */

This patch is to move up sent_count to fill the 1st one and eliminate
the 2nd one.

It's not just another struct compaction, it also fixes the "netperf-
Throughput_Mbps -37.2% regression" issue when overloading the CPU.

Fixes: a6c2f792873a ("sctp: implement prsctp TTL policy")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
---
 include/net/sctp/structs.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index ce93c4b..4f097f5 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -554,6 +554,9 @@ struct sctp_chunk {
 
 	atomic_t refcnt;
 
+	/* How many times this chunk have been sent, for prsctp RTX policy */
+	int sent_count;
+
 	/* This is our link to the per-transport transmitted list.  */
 	struct list_head transmitted_list;
 
@@ -610,9 +613,6 @@ struct sctp_chunk {
 	 */
 	unsigned long prsctp_param;
 
-	/* How many times this chunk have been sent, for prsctp RTX policy */
-	int sent_count;
-
 	/* Which association does this belong to?  */
 	struct sctp_association *asoc;
 
-- 
2.1.0

[PATCHv3 net 2/3] sctp: remove prsctp_param from sctp_chunk

[Xin Long]

Now sctp uses chunk->prsctp_param to save the prsctp param for all the
prsctp polices, we didn't need to introduce prsctp_param to sctp_chunk.
We can just use chunk->sinfo.sinfo_timetolive for RTX and BUF polices,
and reuse msg->expires_at for TTL policy, as the prsctp polices and old
expires policy are mutual exclusive.

This patch is to remove prsctp_param from sctp_chunk, and reuse msg's
expires_at for TTL and chunk's sinfo.sinfo_timetolive for RTX and BUF
polices.

Note that sctp can't use chunk's sinfo.sinfo_timetolive for TTL policy,
as it needs a u64 variables to save the expires_at time.

This one also fixes the "netperf-Throughput_Mbps -37.2% regression"
issue.

Fixes: a6c2f792873a ("sctp: implement prsctp TTL policy")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
---
 include/net/sctp/structs.h |  7 -------
 net/sctp/chunk.c           |  9 +++++++--
 net/sctp/outqueue.c        |  4 ++--
 net/sctp/sm_make_chunk.c   | 15 ---------------
 4 files changed, 9 insertions(+), 26 deletions(-)

diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 4f097f5..ced0df3 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -606,13 +606,6 @@ struct sctp_chunk {
 	/* This needs to be recoverable for SCTP_SEND_FAILED events. */
 	struct sctp_sndrcvinfo sinfo;
 
-	/* We use this field to record param for prsctp policies,
-	 * for TTL policy, it is the time_to_drop of this chunk,
-	 * for RTX policy, it is the max_sent_count of this chunk,
-	 * for PRIO policy, it is the priority of this chunk.
-	 */
-	unsigned long prsctp_param;
-
 	/* Which association does this belong to?  */
 	struct sctp_association *asoc;
 
diff --git a/net/sctp/chunk.c b/net/sctp/chunk.c
index a55e547..14990e2 100644
--- a/net/sctp/chunk.c
+++ b/net/sctp/chunk.c
@@ -179,6 +179,11 @@ struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
 			 msg, msg->expires_at, jiffies);
 	}
 
+	if (asoc->prsctp_enable &&
+	    SCTP_PR_TTL_ENABLED(sinfo->sinfo_flags))
+		msg->expires_at +			jiffies + msecs_to_jiffies(sinfo->sinfo_timetolive);
+
 	/* This is the biggest possible DATA chunk that can fit into
 	 * the packet
 	 */
@@ -349,14 +354,14 @@ int sctp_chunk_abandoned(struct sctp_chunk *chunk)
 	}
 
 	if (SCTP_PR_TTL_ENABLED(chunk->sinfo.sinfo_flags) &&
-	    time_after(jiffies, chunk->prsctp_param)) {
+	    time_after(jiffies, chunk->msg->expires_at)) {
 		if (chunk->sent_count)
 			chunk->asoc->abandoned_sent[SCTP_PR_INDEX(TTL)]++;
 		else
 			chunk->asoc->abandoned_unsent[SCTP_PR_INDEX(TTL)]++;
 		return 1;
 	} else if (SCTP_PR_RTX_ENABLED(chunk->sinfo.sinfo_flags) &&
-		   chunk->sent_count > chunk->prsctp_param) {
+		   chunk->sent_count > chunk->sinfo.sinfo_timetolive) {
 		chunk->asoc->abandoned_sent[SCTP_PR_INDEX(RTX)]++;
 		return 1;
 	}
diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index 72e54a4..e084f35 100644
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -383,7 +383,7 @@ static int sctp_prsctp_prune_sent(struct sctp_association *asoc,
 
 	list_for_each_entry_safe(chk, temp, queue, transmitted_list) {
 		if (!SCTP_PR_PRIO_ENABLED(chk->sinfo.sinfo_flags) ||
-		    chk->prsctp_param <= sinfo->sinfo_timetolive)
+		    chk->sinfo.sinfo_timetolive <= sinfo->sinfo_timetolive)
 			continue;
 
 		list_del_init(&chk->transmitted_list);
@@ -418,7 +418,7 @@ static int sctp_prsctp_prune_unsent(struct sctp_association *asoc,
 
 	list_for_each_entry_safe(chk, temp, queue, list) {
 		if (!SCTP_PR_PRIO_ENABLED(chk->sinfo.sinfo_flags) ||
-		    chk->prsctp_param <= sinfo->sinfo_timetolive)
+		    chk->sinfo.sinfo_timetolive <= sinfo->sinfo_timetolive)
 			continue;
 
 		list_del_init(&chk->list);
diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 8c77b87..46ffecc 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -706,20 +706,6 @@ nodata:
 	return retval;
 }
 
-static void sctp_set_prsctp_policy(struct sctp_chunk *chunk,
-				   const struct sctp_sndrcvinfo *sinfo)
-{
-	if (!chunk->asoc->prsctp_enable)
-		return;
-
-	if (SCTP_PR_TTL_ENABLED(sinfo->sinfo_flags))
-		chunk->prsctp_param -			jiffies + msecs_to_jiffies(sinfo->sinfo_timetolive);
-	else if (SCTP_PR_RTX_ENABLED(sinfo->sinfo_flags) ||
-		 SCTP_PR_PRIO_ENABLED(sinfo->sinfo_flags))
-		chunk->prsctp_param = sinfo->sinfo_timetolive;
-}
-
 /* Make a DATA chunk for the given association from the provided
  * parameters.  However, do not populate the data payload.
  */
@@ -753,7 +739,6 @@ struct sctp_chunk *sctp_make_datafrag_empty(struct sctp_association *asoc,
 
 	retval->subh.data_hdr = sctp_addto_chunk(retval, sizeof(dp), &dp);
 	memcpy(&retval->sinfo, sinfo, sizeof(struct sctp_sndrcvinfo));
-	sctp_set_prsctp_policy(retval, sinfo);
 
 nodata:
 	return retval;
-- 
2.1.0

[PATCHv3 net 3/3] sctp: change to check peer prsctp_capable when using prsctp polices

[Xin Long]

Now before using prsctp polices, sctp uses asoc->prsctp_enable to
check if prsctp is enabled. However asoc->prsctp_enable is set only
means local host support prsctp, sctp should not abandon packet if
peer host doesn't enable prsctp.

So this patch is to use asoc->peer.prsctp_capable to check if prsctp
is enabled on both side, instead of asoc->prsctp_enable, as asoc's
peer.prsctp_capable is set only when local and peer both enable prsctp.

Fixes: a6c2f792873a ("sctp: implement prsctp TTL policy")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
---
 net/sctp/chunk.c    | 4 ++--
 net/sctp/outqueue.c | 8 ++++----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/net/sctp/chunk.c b/net/sctp/chunk.c
index 14990e2..0a3dbec 100644
--- a/net/sctp/chunk.c
+++ b/net/sctp/chunk.c
@@ -179,7 +179,7 @@ struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
 			 msg, msg->expires_at, jiffies);
 	}
 
-	if (asoc->prsctp_enable &&
+	if (asoc->peer.prsctp_capable &&
 	    SCTP_PR_TTL_ENABLED(sinfo->sinfo_flags))
 		msg->expires_at  			jiffies + msecs_to_jiffies(sinfo->sinfo_timetolive);
@@ -340,7 +340,7 @@ errout:
 /* Check whether this message has expired. */
 int sctp_chunk_abandoned(struct sctp_chunk *chunk)
 {
-	if (!chunk->asoc->prsctp_enable ||
+	if (!chunk->asoc->peer.prsctp_capable ||
 	    !SCTP_PR_POLICY(chunk->sinfo.sinfo_flags)) {
 		struct sctp_datamsg *msg = chunk->msg;
 
diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index e084f35..107233d 100644
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -326,7 +326,7 @@ int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk, gfp_t gfp)
 
 			sctp_chunk_hold(chunk);
 			sctp_outq_tail_data(q, chunk);
-			if (chunk->asoc->prsctp_enable &&
+			if (chunk->asoc->peer.prsctp_capable &&
 			    SCTP_PR_PRIO_ENABLED(chunk->sinfo.sinfo_flags))
 				chunk->asoc->sent_cnt_removable++;
 			if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)
@@ -442,7 +442,7 @@ void sctp_prsctp_prune(struct sctp_association *asoc,
 {
 	struct sctp_transport *transport;
 
-	if (!asoc->prsctp_enable || !asoc->sent_cnt_removable)
+	if (!asoc->peer.prsctp_capable || !asoc->sent_cnt_removable)
 		return;
 
 	msg_len = sctp_prsctp_prune_sent(asoc, sinfo,
@@ -1055,7 +1055,7 @@ static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout, gfp_t gfp)
 
 				/* Mark as failed send. */
 				sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM);
-				if (asoc->prsctp_enable &&
+				if (asoc->peer.prsctp_capable &&
 				    SCTP_PR_PRIO_ENABLED(chunk->sinfo.sinfo_flags))
 					asoc->sent_cnt_removable--;
 				sctp_chunk_free(chunk);
@@ -1347,7 +1347,7 @@ int sctp_outq_sack(struct sctp_outq *q, struct sctp_chunk *chunk)
 		tsn = ntohl(tchunk->subh.data_hdr->tsn);
 		if (TSN_lte(tsn, ctsn)) {
 			list_del_init(&tchunk->transmitted_list);
-			if (asoc->prsctp_enable &&
+			if (asoc->peer.prsctp_capable &&
 			    SCTP_PR_PRIO_ENABLED(chunk->sinfo.sinfo_flags))
 				asoc->sent_cnt_removable--;
 			sctp_chunk_free(tchunk);
-- 
2.1.0

Re: [PATCHv3 net 0/3] sctp: a bunch of fixes for prsctp polices

[David Miller]

From: Xin Long <lucien.xin@gmail.com>
Date: Thu, 29 Sep 2016 02:37:25 +0800

> This patchset is to fix 2 issues for prsctp polices:
> 
>   1. patch 1 and 2 fix "netperf-Throughput_Mbps -37.2% regression" issue
>      when overloading the CPU.
> 
>   2. patch 3 fix "prsctp polices should check both sides' prsctp_capable,
>      instead of only local side".

Series applied, thanks.