* net-next-2.6 [PATCH 0/4] dccp: CCID packet dequeueing interface [not found] <dccp_packet_dequeueing_interface_set_of_4> @ 2010-10-28 5:16 ` Gerrit Renker 2010-10-28 5:16 ` [PATCH 1/4] dccp: Return-value convention of hc_tx_send_packet() Gerrit Renker 2010-10-28 17:28 ` net-next-2.6 [PATCH 0/4] dccp: CCID packet dequeueing interface David Miller 0 siblings, 2 replies; 6+ messages in thread From: Gerrit Renker @ 2010-10-28 5:16 UTC (permalink / raw) To: davem; +Cc: dccp, netdev Dave, can you please consider the following set of 4, which solves several problems of the CCID packet-dequeueing interface. This set has been tested for about 3 years. Patch #1: sets up a return code convention to handle both rate-based and window-based congestion-control IDs (CCIDs) with one function. Patch #2: generalizes the xmit interface: rate-based CCIDs continue to use timers, whereas window-based ones use a tasklet. Patch #3: fixes issues in cleaning up CCID state when closing a connection, like patch #2 this also divides into rate-based/window-based. Patch #4: using the previous patches, takes CCID-2 out of its polling mode (that was the problem of the xmit interface - CCID-2 kept on abusing it by faking a small timeout, constantly polling until its internal congestion state allowed it to send again). The set has also been placed into a fresh (today's) copy of net-next-2.6, on git://eden-feed.erg.abdn.ac.uk/net-next-2.6 [subtree 'dccp'] The set is fully bisectable. --- include/linux/dccp.h | 4 +- net/dccp/ccid.h | 34 +++++++- net/dccp/ccids/ccid2.c | 23 ++++-- net/dccp/ccids/ccid2.h | 5 + net/dccp/ccids/ccid3.c | 12 ++-- net/dccp/dccp.h | 5 +- net/dccp/output.c | 209 +++++++++++++++++++++++++++++------------------- net/dccp/proto.c | 21 +++++- net/dccp/timer.c | 27 ++++--- 9 files changed, 223 insertions(+), 117 deletions(-) ^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 1/4] dccp: Return-value convention of hc_tx_send_packet() 2010-10-28 5:16 ` net-next-2.6 [PATCH 0/4] dccp: CCID packet dequeueing interface Gerrit Renker @ 2010-10-28 5:16 ` Gerrit Renker 2010-10-28 5:16 ` [PATCH 2/4] dccp: Extend CCID packet dequeueing interface Gerrit Renker 2010-10-28 17:28 ` net-next-2.6 [PATCH 0/4] dccp: CCID packet dequeueing interface David Miller 1 sibling, 1 reply; 6+ messages in thread From: Gerrit Renker @ 2010-10-28 5:16 UTC (permalink / raw) To: davem; +Cc: dccp, netdev, Gerrit Renker This patch reorganises the return value convention of the CCID TX sending function, to permit more flexible schemes, as required by subsequent patches. Currently the convention is * values < 0 mean error, * a value == 0 means "send now", and * a value x > 0 means "send in x milliseconds". The patch provides symbolic constants and a function to interpret return values. In addition, it caps the maximum positive return value to 0xFFFF milliseconds, corresponding to 65.535 seconds. This is possible since in CCID-3/4 the maximum possible inter-packet gap is fixed at t_mbi = 64 sec. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> --- net/dccp/ccid.h | 34 +++++++++++++++++++++++++++++++--- net/dccp/ccids/ccid3.c | 12 ++++++------ 2 files changed, 37 insertions(+), 9 deletions(-) --- a/net/dccp/ccid.h +++ b/net/dccp/ccid.h @@ -134,13 +134,41 @@ static inline int ccid_get_current_tx_ccid(struct dccp_sock *dp) extern void ccid_hc_rx_delete(struct ccid *ccid, struct sock *sk); extern void ccid_hc_tx_delete(struct ccid *ccid, struct sock *sk); +/* + * Congestion control of queued data packets via CCID decision. + * + * The TX CCID performs its congestion-control by indicating whether and when a + * queued packet may be sent, using the return code of ccid_hc_tx_send_packet(). + * The following modes are supported via the symbolic constants below: + * - timer-based pacing (CCID returns a delay value in milliseconds); + * - autonomous dequeueing (CCID internally schedules dccps_xmitlet). + */ + +enum ccid_dequeueing_decision { + CCID_PACKET_SEND_AT_ONCE = 0x00000, /* "green light": no delay */ + CCID_PACKET_DELAY_MAX = 0x0FFFF, /* maximum delay in msecs */ + CCID_PACKET_DELAY = 0x10000, /* CCID msec-delay mode */ + CCID_PACKET_WILL_DEQUEUE_LATER = 0x20000, /* CCID autonomous mode */ + CCID_PACKET_ERR = 0xF0000, /* error condition */ +}; + +static inline int ccid_packet_dequeue_eval(const int return_code) +{ + if (return_code < 0) + return CCID_PACKET_ERR; + if (return_code == 0) + return CCID_PACKET_SEND_AT_ONCE; + if (return_code <= CCID_PACKET_DELAY_MAX) + return CCID_PACKET_DELAY; + return return_code; +} + static inline int ccid_hc_tx_send_packet(struct ccid *ccid, struct sock *sk, struct sk_buff *skb) { - int rc = 0; if (ccid->ccid_ops->ccid_hc_tx_send_packet != NULL) - rc = ccid->ccid_ops->ccid_hc_tx_send_packet(sk, skb); - return rc; + return ccid->ccid_ops->ccid_hc_tx_send_packet(sk, skb); + return CCID_PACKET_SEND_AT_ONCE; } static inline void ccid_hc_tx_packet_sent(struct ccid *ccid, struct sock *sk, --- a/net/dccp/ccids/ccid3.c +++ b/net/dccp/ccids/ccid3.c @@ -268,11 +268,11 @@ out: sock_put(sk); } -/* - * returns - * > 0: delay (in msecs) that should pass before actually sending - * = 0: can send immediately - * < 0: error condition; do not send packet +/** + * ccid3_hc_tx_send_packet - Delay-based dequeueing of TX packets + * @skb: next packet candidate to send on @sk + * This function uses the convention of ccid_packet_dequeue_eval() and + * returns a millisecond-delay value between 0 and t_mbi = 64000 msec. */ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb) { @@ -348,7 +348,7 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb) /* set the nominal send time for the next following packet */ hc->tx_t_nom = ktime_add_us(hc->tx_t_nom, hc->tx_t_ipi); - return 0; + return CCID_PACKET_SEND_AT_ONCE; } static void ccid3_hc_tx_packet_sent(struct sock *sk, unsigned int len) ^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 2/4] dccp: Extend CCID packet dequeueing interface 2010-10-28 5:16 ` [PATCH 1/4] dccp: Return-value convention of hc_tx_send_packet() Gerrit Renker @ 2010-10-28 5:16 ` Gerrit Renker 2010-10-28 5:16 ` [PATCH 3/4] dccp: Refine the wait-for-ccid mechanism Gerrit Renker 0 siblings, 1 reply; 6+ messages in thread From: Gerrit Renker @ 2010-10-28 5:16 UTC (permalink / raw) To: davem; +Cc: dccp, netdev, Gerrit Renker This extends the packet dequeuing interface of dccp_write_xmit() to allow 1. CCIDs to take care of timing when the next packet may be sent; 2. delayed sending (as before, with an inter-packet gap up to 65.535 seconds). The main purpose is to take CCID-2 out of its polling mode (when it is network- limited, it tries every millisecond to send, without interruption). The mode of operation for (2) is as follows: * new packet is enqueued via dccp_sendmsg() => dccp_write_xmit(), * ccid_hc_tx_send_packet() detects that it may not send (e.g. window full), * it signals this condition via `CCID_PACKET_WILL_DEQUEUE_LATER', * dccp_write_xmit() returns without further action; * after some time the wait-condition for CCID becomes true, * that CCID schedules the tasklet, * tasklet function calls ccid_hc_tx_send_packet() via dccp_write_xmit(), * since the wait-condition is now true, ccid_hc_tx_packet() returns "send now", * packet is sent, and possibly more (since dccp_write_xmit() loops). Code reuse: the taskled function calls dccp_write_xmit(), the timer function reduces to a wrapper around the same code. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> --- include/linux/dccp.h | 4 +- net/dccp/output.c | 118 ++++++++++++++++++++++++++++++------------------- net/dccp/timer.c | 25 ++++++----- 3 files changed, 89 insertions(+), 58 deletions(-) --- a/include/linux/dccp.h +++ b/include/linux/dccp.h @@ -462,7 +462,8 @@ struct dccp_ackvec; * @dccps_hc_rx_insert_options - receiver wants to add options when acking * @dccps_hc_tx_insert_options - sender wants to add options when sending * @dccps_server_timewait - server holds timewait state on close (RFC 4340, 8.3) - * @dccps_xmit_timer - timer for when CCID is not ready to send + * @dccps_xmitlet - tasklet scheduled by the TX CCID to dequeue data packets + * @dccps_xmit_timer - used by the TX CCID to delay sending (rate-based pacing) * @dccps_syn_rtt - RTT sample from Request/Response exchange (in usecs) */ struct dccp_sock { @@ -502,6 +503,7 @@ struct dccp_sock { __u8 dccps_hc_rx_insert_options:1; __u8 dccps_hc_tx_insert_options:1; __u8 dccps_server_timewait:1; + struct tasklet_struct dccps_xmitlet; struct timer_list dccps_xmit_timer; }; --- a/net/dccp/output.c +++ b/net/dccp/output.c @@ -254,63 +254,89 @@ do_interrupted: goto out; } +/** + * dccp_xmit_packet - Send data packet under control of CCID + * Transmits next-queued payload and informs CCID to account for the packet. + */ +static void dccp_xmit_packet(struct sock *sk) +{ + int err, len; + struct dccp_sock *dp = dccp_sk(sk); + struct sk_buff *skb = skb_dequeue(&sk->sk_write_queue); + + if (unlikely(skb == NULL)) + return; + len = skb->len; + + if (sk->sk_state == DCCP_PARTOPEN) { + const u32 cur_mps = dp->dccps_mss_cache - DCCP_FEATNEG_OVERHEAD; + /* + * See 8.1.5 - Handshake Completion. + * + * For robustness we resend Confirm options until the client has + * entered OPEN. During the initial feature negotiation, the MPS + * is smaller than usual, reduced by the Change/Confirm options. + */ + if (!list_empty(&dp->dccps_featneg) && len > cur_mps) { + DCCP_WARN("Payload too large (%d) for featneg.\n", len); + dccp_send_ack(sk); + dccp_feat_list_purge(&dp->dccps_featneg); + } + + inet_csk_schedule_ack(sk); + inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, + inet_csk(sk)->icsk_rto, + DCCP_RTO_MAX); + DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_DATAACK; + } else if (dccp_ack_pending(sk)) { + DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_DATAACK; + } else { + DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_DATA; + } + + err = dccp_transmit_skb(sk, skb); + if (err) + dccp_pr_debug("transmit_skb() returned err=%d\n", err); + /* + * Register this one as sent even if an error occurred. To the remote + * end a local packet drop is indistinguishable from network loss, i.e. + * any local drop will eventually be reported via receiver feedback. + */ + ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, len); +} + void dccp_write_xmit(struct sock *sk, int block) { struct dccp_sock *dp = dccp_sk(sk); struct sk_buff *skb; while ((skb = skb_peek(&sk->sk_write_queue))) { - int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb); + int rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb); - if (err > 0) { + switch (ccid_packet_dequeue_eval(rc)) { + case CCID_PACKET_WILL_DEQUEUE_LATER: + return; + case CCID_PACKET_DELAY: if (!block) { sk_reset_timer(sk, &dp->dccps_xmit_timer, - msecs_to_jiffies(err)+jiffies); + msecs_to_jiffies(rc)+jiffies); + return; + } + rc = dccp_wait_for_ccid(sk, skb, rc); + if (rc && rc != -EINTR) { + DCCP_BUG("err=%d after dccp_wait_for_ccid", rc); + skb_dequeue(&sk->sk_write_queue); + kfree_skb(skb); break; - } else - err = dccp_wait_for_ccid(sk, skb, err); - if (err && err != -EINTR) - DCCP_BUG("err=%d after dccp_wait_for_ccid", err); - } - - skb_dequeue(&sk->sk_write_queue); - if (err == 0) { - struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); - const int len = skb->len; - - if (sk->sk_state == DCCP_PARTOPEN) { - const u32 cur_mps = dp->dccps_mss_cache - DCCP_FEATNEG_OVERHEAD; - /* - * See 8.1.5 - Handshake Completion. - * - * For robustness we resend Confirm options until the client has - * entered OPEN. During the initial feature negotiation, the MPS - * is smaller than usual, reduced by the Change/Confirm options. - */ - if (!list_empty(&dp->dccps_featneg) && len > cur_mps) { - DCCP_WARN("Payload too large (%d) for featneg.\n", len); - dccp_send_ack(sk); - dccp_feat_list_purge(&dp->dccps_featneg); - } - - inet_csk_schedule_ack(sk); - inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, - inet_csk(sk)->icsk_rto, - DCCP_RTO_MAX); - dcb->dccpd_type = DCCP_PKT_DATAACK; - } else if (dccp_ack_pending(sk)) - dcb->dccpd_type = DCCP_PKT_DATAACK; - else - dcb->dccpd_type = DCCP_PKT_DATA; - - err = dccp_transmit_skb(sk, skb); - ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, len); - if (err) - DCCP_BUG("err=%d after ccid_hc_tx_packet_sent", - err); - } else { - dccp_pr_debug("packet discarded due to err=%d\n", err); + } + /* fall through */ + case CCID_PACKET_SEND_AT_ONCE: + dccp_xmit_packet(sk); + break; + case CCID_PACKET_ERR: + skb_dequeue(&sk->sk_write_queue); kfree_skb(skb); + dccp_pr_debug("packet discarded due to err=%d\n", rc); } } } --- a/net/dccp/timer.c +++ b/net/dccp/timer.c @@ -237,32 +237,35 @@ out: sock_put(sk); } -/* Transmit-delay timer: used by the CCIDs to delay actual send time */ -static void dccp_write_xmit_timer(unsigned long data) +/** + * dccp_write_xmitlet - Workhorse for CCID packet dequeueing interface + * See the comments above %ccid_dequeueing_decision for supported modes. + */ +static void dccp_write_xmitlet(unsigned long data) { struct sock *sk = (struct sock *)data; - struct dccp_sock *dp = dccp_sk(sk); bh_lock_sock(sk); if (sock_owned_by_user(sk)) - sk_reset_timer(sk, &dp->dccps_xmit_timer, jiffies+1); + sk_reset_timer(sk, &dccp_sk(sk)->dccps_xmit_timer, jiffies + 1); else dccp_write_xmit(sk, 0); bh_unlock_sock(sk); - sock_put(sk); } -static void dccp_init_write_xmit_timer(struct sock *sk) +static void dccp_write_xmit_timer(unsigned long data) { - struct dccp_sock *dp = dccp_sk(sk); - - setup_timer(&dp->dccps_xmit_timer, dccp_write_xmit_timer, - (unsigned long)sk); + dccp_write_xmitlet(data); + sock_put((struct sock *)data); } void dccp_init_xmit_timers(struct sock *sk) { - dccp_init_write_xmit_timer(sk); + struct dccp_sock *dp = dccp_sk(sk); + + tasklet_init(&dp->dccps_xmitlet, dccp_write_xmitlet, (unsigned long)sk); + setup_timer(&dp->dccps_xmit_timer, dccp_write_xmit_timer, + (unsigned long)sk); inet_csk_init_xmit_timers(sk, &dccp_write_timer, &dccp_delack_timer, &dccp_keepalive_timer); } ^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 3/4] dccp: Refine the wait-for-ccid mechanism 2010-10-28 5:16 ` [PATCH 2/4] dccp: Extend CCID packet dequeueing interface Gerrit Renker @ 2010-10-28 5:16 ` Gerrit Renker 2010-10-28 5:16 ` [PATCH 4/4] dccp ccid-2: Stop polling Gerrit Renker 0 siblings, 1 reply; 6+ messages in thread From: Gerrit Renker @ 2010-10-28 5:16 UTC (permalink / raw) To: davem; +Cc: dccp, netdev, Gerrit Renker This extends the existing wait-for-ccid routine so that it may be used with different types of CCID, addressing the following problems: 1) The queue-drain mechanism only works with rate-based CCIDs. If CCID-2 for example has a full TX queue and becomes network-limited just as the application wants to close, then waiting for CCID-2 to become unblocked could lead to an indefinite delay (i.e., application "hangs"). 2) Since each TX CCID in turn uses a feedback mechanism, there may be changes in its sending policy while the queue is being drained. This can lead to further delays during which the application will not be able to terminate. 3) The minimum wait time for CCID-3/4 can be expected to be the queue length times the current inter-packet delay. For example if tx_qlen=100 and a delay of 15 ms is used for each packet, then the application would have to wait for a minimum of 1.5 seconds before being allowed to exit. 4) There is no way for the user/application to control this behaviour. It would be good to use the timeout argument of dccp_close() as an upper bound. Then the maximum time that an application is willing to wait for its CCIDs to can be set via the SO_LINGER option. These problems are addressed by giving the CCID a grace period of up to the `timeout' value. The wait-for-ccid function is, as before, used when the application (a) has read all the data in its receive buffer and (b) if SO_LINGER was set with a non-zero linger time, or (c) the socket is either in the OPEN (active close) or in the PASSIVE_CLOSEREQ state (client application closes after receiving CloseReq). In addition, there is a catch-all case of __skb_queue_purge() after waiting for the CCID. This is necessary since the write queue may still have data when (a) the host has been passively-closed, (b) abnormal termination (unread data, zero linger time), (c) wait-for-ccid could not finish within the given time limit. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> --- net/dccp/dccp.h | 5 +- net/dccp/output.c | 115 ++++++++++++++++++++++++++++++----------------------- net/dccp/proto.c | 21 +++++++++- net/dccp/timer.c | 2 +- 4 files changed, 89 insertions(+), 54 deletions(-) --- a/net/dccp/dccp.h +++ b/net/dccp/dccp.h @@ -243,8 +243,9 @@ extern void dccp_reqsk_send_ack(struct sock *sk, struct sk_buff *skb, extern void dccp_send_sync(struct sock *sk, const u64 seq, const enum dccp_pkt_type pkt_type); -extern void dccp_write_xmit(struct sock *sk, int block); -extern void dccp_write_space(struct sock *sk); +extern void dccp_write_xmit(struct sock *sk); +extern void dccp_write_space(struct sock *sk); +extern void dccp_flush_write_queue(struct sock *sk, long *time_budget); extern void dccp_init_xmit_timers(struct sock *sk); static inline void dccp_clear_xmit_timers(struct sock *sk) --- a/net/dccp/output.c +++ b/net/dccp/output.c @@ -209,49 +209,29 @@ void dccp_write_space(struct sock *sk) } /** - * dccp_wait_for_ccid - Wait for ccid to tell us we can send a packet + * dccp_wait_for_ccid - Await CCID send permission * @sk: socket to wait for - * @skb: current skb to pass on for waiting - * @delay: sleep timeout in milliseconds (> 0) - * This function is called by default when the socket is closed, and - * when a non-zero linger time is set on the socket. For consistency + * @delay: timeout in jiffies + * This is used by CCIDs which need to delay the send time in process context. */ -static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb, int delay) +static int dccp_wait_for_ccid(struct sock *sk, unsigned long delay) { - struct dccp_sock *dp = dccp_sk(sk); DEFINE_WAIT(wait); - unsigned long jiffdelay; - int rc; - - do { - dccp_pr_debug("delayed send by %d msec\n", delay); - jiffdelay = msecs_to_jiffies(delay); - - prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); + long remaining; - sk->sk_write_pending++; - release_sock(sk); - schedule_timeout(jiffdelay); - lock_sock(sk); - sk->sk_write_pending--; + prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); + sk->sk_write_pending++; + release_sock(sk); - if (sk->sk_err) - goto do_error; - if (signal_pending(current)) - goto do_interrupted; + remaining = schedule_timeout(delay); - rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb); - } while ((delay = rc) > 0); -out: + lock_sock(sk); + sk->sk_write_pending--; finish_wait(sk_sleep(sk), &wait); - return rc; - -do_error: - rc = -EPIPE; - goto out; -do_interrupted: - rc = -EINTR; - goto out; + + if (signal_pending(current) || sk->sk_err) + return -1; + return remaining; } /** @@ -305,7 +285,53 @@ static void dccp_xmit_packet(struct sock *sk) ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, len); } -void dccp_write_xmit(struct sock *sk, int block) +/** + * dccp_flush_write_queue - Drain queue at end of connection + * Since dccp_sendmsg queues packets without waiting for them to be sent, it may + * happen that the TX queue is not empty at the end of a connection. We give the + * HC-sender CCID a grace period of up to @time_budget jiffies. If this function + * returns with a non-empty write queue, it will be purged later. + */ +void dccp_flush_write_queue(struct sock *sk, long *time_budget) +{ + struct dccp_sock *dp = dccp_sk(sk); + struct sk_buff *skb; + long delay, rc; + + while (*time_budget > 0 && (skb = skb_peek(&sk->sk_write_queue))) { + rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb); + + switch (ccid_packet_dequeue_eval(rc)) { + case CCID_PACKET_WILL_DEQUEUE_LATER: + /* + * If the CCID determines when to send, the next sending + * time is unknown or the CCID may not even send again + * (e.g. remote host crashes or lost Ack packets). + */ + DCCP_WARN("CCID did not manage to send all packets\n"); + return; + case CCID_PACKET_DELAY: + delay = msecs_to_jiffies(rc); + if (delay > *time_budget) + return; + rc = dccp_wait_for_ccid(sk, delay); + if (rc < 0) + return; + *time_budget -= (delay - rc); + /* check again if we can send now */ + break; + case CCID_PACKET_SEND_AT_ONCE: + dccp_xmit_packet(sk); + break; + case CCID_PACKET_ERR: + skb_dequeue(&sk->sk_write_queue); + kfree_skb(skb); + dccp_pr_debug("packet discarded due to err=%ld\n", rc); + } + } +} + +void dccp_write_xmit(struct sock *sk) { struct dccp_sock *dp = dccp_sk(sk); struct sk_buff *skb; @@ -317,19 +343,9 @@ void dccp_write_xmit(struct sock *sk, int block) case CCID_PACKET_WILL_DEQUEUE_LATER: return; case CCID_PACKET_DELAY: - if (!block) { - sk_reset_timer(sk, &dp->dccps_xmit_timer, - msecs_to_jiffies(rc)+jiffies); - return; - } - rc = dccp_wait_for_ccid(sk, skb, rc); - if (rc && rc != -EINTR) { - DCCP_BUG("err=%d after dccp_wait_for_ccid", rc); - skb_dequeue(&sk->sk_write_queue); - kfree_skb(skb); - break; - } - /* fall through */ + sk_reset_timer(sk, &dp->dccps_xmit_timer, + jiffies + msecs_to_jiffies(rc)); + return; case CCID_PACKET_SEND_AT_ONCE: dccp_xmit_packet(sk); break; @@ -648,7 +664,6 @@ void dccp_send_close(struct sock *sk, const int active) DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_CLOSE; if (active) { - dccp_write_xmit(sk, 1); dccp_skb_entail(sk, skb); dccp_transmit_skb(sk, skb_clone(skb, prio)); /* --- a/net/dccp/proto.c +++ b/net/dccp/proto.c @@ -726,7 +726,13 @@ int dccp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, goto out_discard; skb_queue_tail(&sk->sk_write_queue, skb); - dccp_write_xmit(sk,0); + /* + * The xmit_timer is set if the TX CCID is rate-based and will expire + * when congestion control permits to release further packets into the + * network. Window-based CCIDs do not use this timer. + */ + if (!timer_pending(&dp->dccps_xmit_timer)) + dccp_write_xmit(sk); out_release: release_sock(sk); return rc ? : len; @@ -951,9 +957,22 @@ void dccp_close(struct sock *sk, long timeout) /* Check zero linger _after_ checking for unread data. */ sk->sk_prot->disconnect(sk, 0); } else if (sk->sk_state != DCCP_CLOSED) { + /* + * Normal connection termination. May need to wait if there are + * still packets in the TX queue that are delayed by the CCID. + */ + dccp_flush_write_queue(sk, &timeout); dccp_terminate_connection(sk); } + /* + * Flush write queue. This may be necessary in several cases: + * - we have been closed by the peer but still have application data; + * - abortive termination (unread data or zero linger time), + * - normal termination but queue could not be flushed within time limit + */ + __skb_queue_purge(&sk->sk_write_queue); + sk_stream_wait_close(sk, timeout); adjudge_to_death: --- a/net/dccp/timer.c +++ b/net/dccp/timer.c @@ -249,7 +249,7 @@ static void dccp_write_xmitlet(unsigned long data) if (sock_owned_by_user(sk)) sk_reset_timer(sk, &dccp_sk(sk)->dccps_xmit_timer, jiffies + 1); else - dccp_write_xmit(sk, 0); + dccp_write_xmit(sk); bh_unlock_sock(sk); } ^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 4/4] dccp ccid-2: Stop polling 2010-10-28 5:16 ` [PATCH 3/4] dccp: Refine the wait-for-ccid mechanism Gerrit Renker @ 2010-10-28 5:16 ` Gerrit Renker 0 siblings, 0 replies; 6+ messages in thread From: Gerrit Renker @ 2010-10-28 5:16 UTC (permalink / raw) To: davem; +Cc: dccp, netdev, Gerrit Renker This updates CCID-2 to use the CCID dequeuing mechanism, converting from previous continuous-polling to a now event-driven mechanism. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> --- net/dccp/ccids/ccid2.c | 23 +++++++++++++++-------- net/dccp/ccids/ccid2.h | 5 +++++ 2 files changed, 20 insertions(+), 8 deletions(-) --- a/net/dccp/ccids/ccid2.h +++ b/net/dccp/ccids/ccid2.h @@ -81,6 +81,11 @@ struct ccid2_hc_tx_sock { u64 tx_high_ack; }; +static inline bool ccid2_cwnd_network_limited(struct ccid2_hc_tx_sock *hc) +{ + return hc->tx_pipe >= hc->tx_cwnd; +} + struct ccid2_hc_rx_sock { int rx_data; }; --- a/net/dccp/ccids/ccid2.c +++ b/net/dccp/ccids/ccid2.c @@ -78,12 +78,9 @@ static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock *hc) static int ccid2_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb) { - struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk); - - if (hc->tx_pipe < hc->tx_cwnd) - return 0; - - return 1; /* XXX CCID should dequeue when ready instead of polling */ + if (ccid2_cwnd_network_limited(ccid2_hc_tx_sk(sk))) + return CCID_PACKET_WILL_DEQUEUE_LATER; + return CCID_PACKET_SEND_AT_ONCE; } static void ccid2_change_l_ack_ratio(struct sock *sk, u32 val) @@ -115,6 +112,7 @@ static void ccid2_hc_tx_rto_expire(unsigned long data) { struct sock *sk = (struct sock *)data; struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk); + const bool sender_was_blocked = ccid2_cwnd_network_limited(hc); bh_lock_sock(sk); if (sock_owned_by_user(sk)) { @@ -129,8 +127,6 @@ static void ccid2_hc_tx_rto_expire(unsigned long data) if (hc->tx_rto > DCCP_RTO_MAX) hc->tx_rto = DCCP_RTO_MAX; - sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto); - /* adjust pipe, cwnd etc */ hc->tx_ssthresh = hc->tx_cwnd / 2; if (hc->tx_ssthresh < 2) @@ -146,6 +142,12 @@ static void ccid2_hc_tx_rto_expire(unsigned long data) hc->tx_rpseq = 0; hc->tx_rpdupack = -1; ccid2_change_l_ack_ratio(sk, 1); + + /* if we were blocked before, we may now send cwnd=1 packet */ + if (sender_was_blocked) + tasklet_schedule(&dccp_sk(sk)->dccps_xmitlet); + /* restart backed-off timer */ + sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto); out: bh_unlock_sock(sk); sock_put(sk); @@ -434,6 +436,7 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) { struct dccp_sock *dp = dccp_sk(sk); struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk); + const bool sender_was_blocked = ccid2_cwnd_network_limited(hc); u64 ackno, seqno; struct ccid2_seq *seqp; unsigned char *vector; @@ -631,6 +634,10 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) sk_stop_timer(sk, &hc->tx_rtotimer); else sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto); + + /* check if incoming Acks allow pending packets to be sent */ + if (sender_was_blocked && !ccid2_cwnd_network_limited(hc)) + tasklet_schedule(&dccp_sk(sk)->dccps_xmitlet); } static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk) ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: net-next-2.6 [PATCH 0/4] dccp: CCID packet dequeueing interface 2010-10-28 5:16 ` net-next-2.6 [PATCH 0/4] dccp: CCID packet dequeueing interface Gerrit Renker 2010-10-28 5:16 ` [PATCH 1/4] dccp: Return-value convention of hc_tx_send_packet() Gerrit Renker @ 2010-10-28 17:28 ` David Miller 1 sibling, 0 replies; 6+ messages in thread From: David Miller @ 2010-10-28 17:28 UTC (permalink / raw) To: gerrit; +Cc: dccp, netdev From: Gerrit Renker <gerrit@erg.abdn.ac.uk> Date: Thu, 28 Oct 2010 07:16:24 +0200 > The set has also been placed into a fresh (today's) copy of net-next-2.6, on > > git://eden-feed.erg.abdn.ac.uk/net-next-2.6 [subtree 'dccp'] > > The set is fully bisectable. All applied, thanks a lot. ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2010-10-28 17:27 UTC | newest]
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2010-10-28 5:16 ` net-next-2.6 [PATCH 0/4] dccp: CCID packet dequeueing interface Gerrit Renker
2010-10-28 5:16 ` [PATCH 1/4] dccp: Return-value convention of hc_tx_send_packet() Gerrit Renker
2010-10-28 5:16 ` [PATCH 2/4] dccp: Extend CCID packet dequeueing interface Gerrit Renker
2010-10-28 5:16 ` [PATCH 3/4] dccp: Refine the wait-for-ccid mechanism Gerrit Renker
2010-10-28 5:16 ` [PATCH 4/4] dccp ccid-2: Stop polling Gerrit Renker
2010-10-28 17:28 ` net-next-2.6 [PATCH 0/4] dccp: CCID packet dequeueing interface David Miller
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