From 07978aabd52ce67f59971872c80f76d6e3ca18ae Mon Sep 17 00:00:00 2001 From: Andrea Bittau Date: Tue, 19 Sep 2006 13:13:37 -0700 Subject: [PATCH] [DCCP] CCID2: Allocate seq records on demand Allocate more sequence state on demand. Each time a packet is sent out by CCID2, a record of it needs to be kept. This list of records grows proportionally to cwnd. Previously, the length of this list was hardcored and therefore the cwnd could only grow to this value (of 128). Now, records are allocated on demand as necessary---cwnd may grow as it wishes. The exceptional case of when memory is not available is not handled gracefully. Perhaps, cwnd should be capped at that point. Signed-off-by: Andrea Bittau Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: David S. Miller --- net/dccp/ccids/ccid2.c | 96 ++++++++++++++++++++++++++++-------------- net/dccp/ccids/ccid2.h | 6 ++- 2 files changed, 70 insertions(+), 32 deletions(-) diff --git a/net/dccp/ccids/ccid2.c b/net/dccp/ccids/ccid2.c index dbcda7e868b7..93a30ae8d07a 100644 --- a/net/dccp/ccids/ccid2.c +++ b/net/dccp/ccids/ccid2.c @@ -44,8 +44,6 @@ static int ccid2_debug; #define ccid2_pr_debug(format, a...) #endif -static const int ccid2_seq_len = 128; - #ifdef CONFIG_IP_DCCP_CCID2_DEBUG static void ccid2_hc_tx_check_sanity(const struct ccid2_hc_tx_sock *hctx) { @@ -71,7 +69,6 @@ static void ccid2_hc_tx_check_sanity(const struct ccid2_hc_tx_sock *hctx) BUG_ON(seqp->ccid2s_seq <= prev->ccid2s_seq); BUG_ON(time_before(seqp->ccid2s_sent, prev->ccid2s_sent)); - BUG_ON(len > ccid2_seq_len); seqp = prev; } @@ -83,16 +80,57 @@ static void ccid2_hc_tx_check_sanity(const struct ccid2_hc_tx_sock *hctx) do { seqp = seqp->ccid2s_prev; len++; - BUG_ON(len > ccid2_seq_len); } while (seqp != hctx->ccid2hctx_seqh); - BUG_ON(len != ccid2_seq_len); ccid2_pr_debug("total len=%d\n", len); + BUG_ON(len != hctx->ccid2hctx_seqbufc * CCID2_SEQBUF_LEN); } #else #define ccid2_hc_tx_check_sanity(hctx) do {} while (0) #endif +static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock *hctx, int num, + gfp_t gfp) +{ + struct ccid2_seq *seqp; + int i; + + /* check if we have space to preserve the pointer to the buffer */ + if (hctx->ccid2hctx_seqbufc >= (sizeof(hctx->ccid2hctx_seqbuf) / + sizeof(struct ccid2_seq*))) + return -ENOMEM; + + /* allocate buffer and initialize linked list */ + seqp = kmalloc(sizeof(*seqp) * num, gfp); + if (seqp == NULL) + return -ENOMEM; + + for (i = 0; i < (num - 1); i++) { + seqp[i].ccid2s_next = &seqp[i + 1]; + seqp[i + 1].ccid2s_prev = &seqp[i]; + } + seqp[num - 1].ccid2s_next = seqp; + seqp->ccid2s_prev = &seqp[num - 1]; + + /* This is the first allocation. Initiate the head and tail. */ + if (hctx->ccid2hctx_seqbufc == 0) + hctx->ccid2hctx_seqh = hctx->ccid2hctx_seqt = seqp; + else { + /* link the existing list with the one we just created */ + hctx->ccid2hctx_seqh->ccid2s_next = seqp; + seqp->ccid2s_prev = hctx->ccid2hctx_seqh; + + hctx->ccid2hctx_seqt->ccid2s_prev = &seqp[num - 1]; + seqp[num - 1].ccid2s_next = hctx->ccid2hctx_seqt; + } + + /* store the original pointer to the buffer so we can free it */ + hctx->ccid2hctx_seqbuf[hctx->ccid2hctx_seqbufc] = seqp; + hctx->ccid2hctx_seqbufc++; + + return 0; +} + static int ccid2_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb, int len) { @@ -231,6 +269,7 @@ static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, int len) { struct dccp_sock *dp = dccp_sk(sk); struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); + struct ccid2_seq *next; u64 seq; ccid2_hc_tx_check_sanity(hctx); @@ -250,16 +289,24 @@ static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, int len) hctx->ccid2hctx_seqh->ccid2s_seq = seq; hctx->ccid2hctx_seqh->ccid2s_acked = 0; hctx->ccid2hctx_seqh->ccid2s_sent = jiffies; - hctx->ccid2hctx_seqh = hctx->ccid2hctx_seqh->ccid2s_next; + + next = hctx->ccid2hctx_seqh->ccid2s_next; + /* check if we need to alloc more space */ + if (next == hctx->ccid2hctx_seqt) { + int rc; + + ccid2_pr_debug("allocating more space in history\n"); + rc = ccid2_hc_tx_alloc_seq(hctx, CCID2_SEQBUF_LEN, GFP_KERNEL); + BUG_ON(rc); /* XXX what do we do? */ + + next = hctx->ccid2hctx_seqh->ccid2s_next; + BUG_ON(next == hctx->ccid2hctx_seqt); + } + hctx->ccid2hctx_seqh = next; ccid2_pr_debug("cwnd=%d pipe=%d\n", hctx->ccid2hctx_cwnd, hctx->ccid2hctx_pipe); - if (hctx->ccid2hctx_seqh == hctx->ccid2hctx_seqt) { - /* XXX allocate more space */ - WARN_ON(1); - } - hctx->ccid2hctx_sent++; /* Ack Ratio. Need to maintain a concept of how many windows we sent */ @@ -674,8 +721,6 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk) { struct ccid2_hc_tx_sock *hctx = ccid_priv(ccid); - int seqcount = ccid2_seq_len; - int i; hctx->ccid2hctx_cwnd = 1; /* Initialize ssthresh to infinity. This means that we will exit the @@ -684,26 +729,12 @@ static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk) */ hctx->ccid2hctx_ssthresh = ~0; hctx->ccid2hctx_numdupack = 3; + hctx->ccid2hctx_seqbufc = 0; /* XXX init ~ to window size... */ - hctx->ccid2hctx_seqbuf = kmalloc(sizeof(*hctx->ccid2hctx_seqbuf) * - seqcount, gfp_any()); - if (hctx->ccid2hctx_seqbuf == NULL) + if (ccid2_hc_tx_alloc_seq(hctx, CCID2_SEQBUF_LEN, GFP_ATOMIC) != 0) return -ENOMEM; - for (i = 0; i < (seqcount - 1); i++) { - hctx->ccid2hctx_seqbuf[i].ccid2s_next = - &hctx->ccid2hctx_seqbuf[i + 1]; - hctx->ccid2hctx_seqbuf[i + 1].ccid2s_prev = - &hctx->ccid2hctx_seqbuf[i]; - } - hctx->ccid2hctx_seqbuf[seqcount - 1].ccid2s_next = - hctx->ccid2hctx_seqbuf; - hctx->ccid2hctx_seqbuf->ccid2s_prev = - &hctx->ccid2hctx_seqbuf[seqcount - 1]; - - hctx->ccid2hctx_seqh = hctx->ccid2hctx_seqbuf; - hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqh; hctx->ccid2hctx_sent = 0; hctx->ccid2hctx_rto = 3 * HZ; hctx->ccid2hctx_srtt = -1; @@ -722,10 +753,13 @@ static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk) static void ccid2_hc_tx_exit(struct sock *sk) { struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); + int i; ccid2_hc_tx_kill_rto_timer(sk); - kfree(hctx->ccid2hctx_seqbuf); - hctx->ccid2hctx_seqbuf = NULL; + + for (i = 0; i < hctx->ccid2hctx_seqbufc; i++) + kfree(hctx->ccid2hctx_seqbuf[i]); + hctx->ccid2hctx_seqbufc = 0; } static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) diff --git a/net/dccp/ccids/ccid2.h b/net/dccp/ccids/ccid2.h index b4cc6c0bf020..2a02ce04ba85 100644 --- a/net/dccp/ccids/ccid2.h +++ b/net/dccp/ccids/ccid2.h @@ -35,6 +35,9 @@ struct ccid2_seq { struct ccid2_seq *ccid2s_next; }; +#define CCID2_SEQBUF_LEN 256 +#define CCID2_SEQBUF_MAX 128 + /** struct ccid2_hc_tx_sock - CCID2 TX half connection * * @ccid2hctx_ssacks - ACKs recv in slow start @@ -53,7 +56,8 @@ struct ccid2_hc_tx_sock { unsigned int ccid2hctx_ssthresh; int ccid2hctx_pipe; int ccid2hctx_numdupack; - struct ccid2_seq *ccid2hctx_seqbuf; + struct ccid2_seq *ccid2hctx_seqbuf[CCID2_SEQBUF_MAX]; + int ccid2hctx_seqbufc; struct ccid2_seq *ccid2hctx_seqh; struct ccid2_seq *ccid2hctx_seqt; long ccid2hctx_rto;