kernel.git/net/sctp/outqueue.c, branch linux-4.8.y

sctp: change to check peer prsctp_capable when using prsctp polices

2016-09-30T06:07:05Z

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 Signed-off-by: David S. Miller

sctp: remove prsctp_param from sctp_chunk

2016-09-30T06:07:05Z

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 Signed-off-by: David S. Miller

sctp: implement prsctp PRIO policy

2016-07-11T20:25:39Z

prsctp PRIO policy is a policy to abandon lower priority chunks when asoc doesn't have enough snd buffer, so that the current chunk with higher priority can be queued successfully. Similar to TTL/RTX policy, we will set the priority of the chunk to prsctp_param with sinfo->sinfo_timetolive in sctp_set_prsctp_policy(). So if PRIO policy is enabled, msg->expire_at won't work. asoc->sent_cnt_removable will record how many chunks can be checked to remove. If priority policy is enabled, when the chunk is queued into the out_queue, we will increase sent_cnt_removable. When the chunk is moved to abandon_queue or dequeue and free, we will decrease sent_cnt_removable. In sctp_sendmsg, we will check if there is enough snd buffer for current msg and if sent_cnt_removable is not 0. Then try to abandon chunks in sctp_prune_prsctp when sendmsg from the retransmit/transmited queue, and free chunks from out_queue in right order until the abandon+free size > msg_len - sctp_wfree. For the abandon size, we have to wait until it sends FORWARD TSN, receives the sack and the chunks are really freed. Signed-off-by: Xin Long Signed-off-by: David S. Miller

sctp: avoid refreshing heartbeat timer too often

2016-04-11T02:22:34Z

Currently on high rate SCTP streams the heartbeat timer refresh can consume quite a lot of resources as timer updates are costly and it contains a random factor, which a) is also costly and b) invalidates mod_timer() optimization for not editing a timer to the same value. It may even cause the timer to be slightly advanced, for no good reason. As suggested by David Laight this patch now removes this timer update from hot path by leaving the timer on and re-evaluating upon its expiration if the heartbeat is still needed or not, similarly to what is done for TCP. If it's not needed anymore the timer is re-scheduled to the new timeout, considering the time already elapsed. For this, we now record the last tx timestamp per transport, updated in the same spots as hb timer was restarted on tx. Also split up sctp_transport_reset_timers into sctp_transport_reset_t3_rtx and sctp_transport_reset_hb_timer, so we can re-arm T3 without re-arming the heartbeat one. On loopback with MTU of 65535 and data chunks with 1636, so that we have a considerable amount of chunks without stressing system calls, netperf -t SCTP_STREAM -l 30, perf looked like this before: Samples: 103K of event 'cpu-clock', Event count (approx.): 25833000000 Overhead Command Shared Object Symbol + 6,15% netperf [kernel.vmlinux] [k] copy_user_enhanced_fast_string - 5,43% netperf [kernel.vmlinux] [k] _raw_write_unlock_irqrestore - _raw_write_unlock_irqrestore - 96,54% _raw_spin_unlock_irqrestore - 36,14% mod_timer + 97,24% sctp_transport_reset_timers + 2,76% sctp_do_sm + 33,65% __wake_up_sync_key + 28,77% sctp_ulpq_tail_event + 1,40% del_timer - 1,84% mod_timer + 99,03% sctp_transport_reset_timers + 0,97% sctp_do_sm + 1,50% sctp_ulpq_tail_event And after this patch, now with netperf -l 60: Samples: 230K of event 'cpu-clock', Event count (approx.): 57707250000 Overhead Command Shared Object Symbol + 5,65% netperf [kernel.vmlinux] [k] memcpy_erms + 5,59% netperf [kernel.vmlinux] [k] copy_user_enhanced_fast_string - 5,05% netperf [kernel.vmlinux] [k] _raw_spin_unlock_irqrestore - _raw_spin_unlock_irqrestore + 49,89% __wake_up_sync_key + 45,68% sctp_ulpq_tail_event - 2,85% mod_timer + 76,51% sctp_transport_reset_t3_rtx + 23,49% sctp_do_sm + 1,55% del_timer + 2,50% netperf [sctp] [k] sctp_datamsg_from_user + 2,26% netperf [sctp] [k] sctp_sendmsg Throughput-wise, from 6800mbps without the patch to 7050mbps with it, ~3.7%. Signed-off-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller

sctp: do not leak chunks that are sent to unconfirmed paths

2016-03-20T20:31:12Z

Currently, if a chunk is scheduled to be sent through a transport that is currently unconfirmed, it will be leaked as it is dequeued from outq and is not re-queued nor freed. As I'm not aware of any situation that may lead to this situation, I'm fixing this by freeing the chunk and also logging a trace so that we can fix the other bug if it ever happens. Signed-off-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller

sctp: allow sctp_transmit_packet and others to use gfp

2016-03-14T02:29:07Z

Currently sctp_sendmsg() triggers some calls that will allocate memory with GFP_ATOMIC even when not necessary. In the case of sctp_packet_transmit it will allocate a linear skb that will be used to construct the packet and this may cause sends to fail due to ENOMEM more often than anticipated specially with big MTUs. This patch thus allows it to inherit gfp flags from upper calls so that it can use GFP_KERNEL if it was triggered by a sctp_sendmsg call or similar. All others, like retransmits or flushes started from BH, are still allocated using GFP_ATOMIC. In netperf tests this didn't result in any performance drawbacks when memory is not too fragmented and made it trigger ENOMEM way less often. Signed-off-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller

sctp: start t5 timer only when peer rwnd is 0 and local state is SHUTDOWN_PENDING

2015-12-07T03:31:51Z

when A sends a data to B, then A close() and enter into SHUTDOWN_PENDING state, if B neither claim his rwnd is 0 nor send SACK for this data, A will keep retransmitting this data until t5 timeout, Max.Retrans times can't work anymore, which is bad. if B's rwnd is not 0, it should send abort after Max.Retrans times, only when B's rwnd == 0 and A's retransmitting beyonds Max.Retrans times, A will start t5 timer, which is also commit f8d960524328 ("sctp: Enforce retransmission limit during shutdown") means, but it lacks the condition peer rwnd == 0. so fix it by adding a bit (zero_window_announced) in peer to record if the last rwnd is 0. If it was, zero_window_announced will be set. and use this bit to decide if start t5 timer when local.state is SHUTDOWN_PENDING. Fixes: commit f8d960524328 ("sctp: Enforce retransmission limit during shutdown") Signed-off-by: Xin Long Signed-off-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller

sctp: hold the chunks only after the chunk is enqueued in outq

2015-12-06T18:25:12Z

When a msg is sent, sctp will hold the chunks of this msg and then try to enqueue them. But if the chunks are not enqueued in sctp_outq_tail() because of the invalid state, sctp_cmd_interpreter() may still return success to sctp_sendmsg() after calling sctp_outq_flush(), these chunks will become orphans and will leak. So we fix them by moving sctp_chunk_hold() to sctp_outq_tail(), where we are sure that the chunk is going to get queued. Signed-off-by: Xin Long Signed-off-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller

net: sctp: Rename SCTP_XMIT_NAGLE_DELAY to SCTP_XMIT_DELAY

2014-07-22T20:32:11Z

MSG_MORE and 'corking' a socket would require that the transmit of a data chunk be delayed. Rename the return value to be less specific. Signed-off-by: David Laight Acked-by: Vlad Yasevich Signed-off-by: David S. Miller

net: sctp: remove unnecessary break after return/goto

2014-07-15T23:27:01Z

Signed-off-by: Fabian Frederick Signed-off-by: David S. Miller