/* * Sally Floyd's High Speed TCP (RFC 3649) congestion control * * See http://www.icir.org/floyd/hstcp.html * * John Heffner */ #include #include /* From AIMD tables from RFC 3649 appendix B, * with fixed-point MD scaled <<8. */ static const struct hstcp_aimd_val { unsigned int cwnd; unsigned int md; } hstcp_aimd_vals[] = { { 38, 128, /* 0.50 */ }, { 118, 112, /* 0.44 */ }, { 221, 104, /* 0.41 */ }, { 347, 98, /* 0.38 */ }, { 495, 93, /* 0.37 */ }, { 663, 89, /* 0.35 */ }, { 851, 86, /* 0.34 */ }, { 1058, 83, /* 0.33 */ }, { 1284, 81, /* 0.32 */ }, { 1529, 78, /* 0.31 */ }, { 1793, 76, /* 0.30 */ }, { 2076, 74, /* 0.29 */ }, { 2378, 72, /* 0.28 */ }, { 2699, 71, /* 0.28 */ }, { 3039, 69, /* 0.27 */ }, { 3399, 68, /* 0.27 */ }, { 3778, 66, /* 0.26 */ }, { 4177, 65, /* 0.26 */ }, { 4596, 64, /* 0.25 */ }, { 5036, 62, /* 0.25 */ }, { 5497, 61, /* 0.24 */ }, { 5979, 60, /* 0.24 */ }, { 6483, 59, /* 0.23 */ }, { 7009, 58, /* 0.23 */ }, { 7558, 57, /* 0.22 */ }, { 8130, 56, /* 0.22 */ }, { 8726, 55, /* 0.22 */ }, { 9346, 54, /* 0.21 */ }, { 9991, 53, /* 0.21 */ }, { 10661, 52, /* 0.21 */ }, { 11358, 52, /* 0.20 */ }, { 12082, 51, /* 0.20 */ }, { 12834, 50, /* 0.20 */ }, { 13614, 49, /* 0.19 */ }, { 14424, 48, /* 0.19 */ }, { 15265, 48, /* 0.19 */ }, { 16137, 47, /* 0.19 */ }, { 17042, 46, /* 0.18 */ }, { 17981, 45, /* 0.18 */ }, { 18955, 45, /* 0.18 */ }, { 19965, 44, /* 0.17 */ }, { 21013, 43, /* 0.17 */ }, { 22101, 43, /* 0.17 */ }, { 23230, 42, /* 0.17 */ }, { 24402, 41, /* 0.16 */ }, { 25618, 41, /* 0.16 */ }, { 26881, 40, /* 0.16 */ }, { 28193, 39, /* 0.16 */ }, { 29557, 39, /* 0.15 */ }, { 30975, 38, /* 0.15 */ }, { 32450, 38, /* 0.15 */ }, { 33986, 37, /* 0.15 */ }, { 35586, 36, /* 0.14 */ }, { 37253, 36, /* 0.14 */ }, { 38992, 35, /* 0.14 */ }, { 40808, 35, /* 0.14 */ }, { 42707, 34, /* 0.13 */ }, { 44694, 33, /* 0.13 */ }, { 46776, 33, /* 0.13 */ }, { 48961, 32, /* 0.13 */ }, { 51258, 32, /* 0.13 */ }, { 53677, 31, /* 0.12 */ }, { 56230, 30, /* 0.12 */ }, { 58932, 30, /* 0.12 */ }, { 61799, 29, /* 0.12 */ }, { 64851, 28, /* 0.11 */ }, { 68113, 28, /* 0.11 */ }, { 71617, 27, /* 0.11 */ }, { 75401, 26, /* 0.10 */ }, { 79517, 26, /* 0.10 */ }, { 84035, 25, /* 0.10 */ }, { 89053, 24, /* 0.10 */ }, }; #define HSTCP_AIMD_MAX ARRAY_SIZE(hstcp_aimd_vals) struct hstcp { u32 ai; u32 loss_cwnd; }; static void hstcp_init(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); struct hstcp *ca = inet_csk_ca(sk); ca->ai = 0; /* Ensure the MD arithmetic works. This is somewhat pedantic, * since I don't think we will see a cwnd this large. :) */ tp->snd_cwnd_clamp = min_t(u32, tp->snd_cwnd_clamp, 0xffffffff/128); } static void hstcp_cong_avoid(struct sock *sk, u32 ack, u32 acked) { struct tcp_sock *tp = tcp_sk(sk); struct hstcp *ca = inet_csk_ca(sk); if (!tcp_is_cwnd_limited(sk)) return; if (tcp_in_slow_start(tp)) tcp_slow_start(tp, acked); else { /* Update AIMD parameters. * * We want to guarantee that: * hstcp_aimd_vals[ca->ai-1].cwnd < * snd_cwnd <= * hstcp_aimd_vals[ca->ai].cwnd */ if (tp->snd_cwnd > hstcp_aimd_vals[ca->ai].cwnd) { while (tp->snd_cwnd > hstcp_aimd_vals[ca->ai].cwnd && ca->ai < HSTCP_AIMD_MAX - 1) ca->ai++; } else if (ca->ai && tp->snd_cwnd <= hstcp_aimd_vals[ca->ai-1].cwnd) { while (ca->ai && tp->snd_cwnd <= hstcp_aimd_vals[ca->ai-1].cwnd) ca->ai--; } /* Do additive increase */ if (tp->snd_cwnd < tp->snd_cwnd_clamp) { /* cwnd = cwnd + a(w) / cwnd */ tp->snd_cwnd_cnt += ca->ai + 1; if (tp->snd_cwnd_cnt >= tp->snd_cwnd) { tp->snd_cwnd_cnt -= tp->snd_cwnd; tp->snd_cwnd++; } } } } static u32 hstcp_ssthresh(struct sock *sk) { const struct tcp_sock *tp = tcp_sk(sk); struct hstcp *ca = inet_csk_ca(sk); ca->loss_cwnd = tp->snd_cwnd; /* Do multiplicative decrease */ return max(tp->snd_cwnd - ((tp->snd_cwnd * hstcp_aimd_vals[ca->ai].md) >> 8), 2U); } static u32 hstcp_cwnd_undo(struct sock *sk) { const struct hstcp *ca = inet_csk_ca(sk); return max(tcp_sk(sk)->snd_cwnd, ca->loss_cwnd); } static struct tcp_congestion_ops tcp_highspeed __read_mostly = { .init = hstcp_init, .ssthresh = hstcp_ssthresh, .undo_cwnd = hstcp_cwnd_undo, .cong_avoid = hstcp_cong_avoid, .owner = THIS_MODULE, .name = "highspeed" }; static int __init hstcp_register(void) { BUILD_BUG_ON(sizeof(struct hstcp) > ICSK_CA_PRIV_SIZE); return tcp_register_congestion_control(&tcp_highspeed); } static void __exit hstcp_unregister(void) { tcp_unregister_congestion_control(&tcp_highspeed); } module_init(hstcp_register); module_exit(hstcp_unregister); MODULE_AUTHOR("John Heffner"); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("High Speed TCP"); 24c2503255d35c269b67162c397a1a1c1e02f6ce (diff)
x86/mce: Make timer handling more robust
Erik reported that on a preproduction hardware a CMCI storm triggers the BUG_ON in add_timer_on(). The reason is that the per CPU MCE timer is started by the CMCI logic before the MCE CPU hotplug callback starts the timer with add_timer_on(). So the timer is already queued which triggers the BUG. Using add_timer_on() is pretty pointless in this code because the timer is strictlty per CPU, initialized as pinned and all operations which arm the timer happen on the CPU to which the timer belongs. Simplify the whole machinery by using mod_timer() instead of add_timer_on() which avoids the problem because mod_timer() can handle already queued timers. Use __start_timer() everywhere so the earliest armed expiry time is preserved. Reported-by: Erik Veijola <erik.veijola@intel.com> Tested-by: Borislav Petkov <bp@alien8.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@alien8.de> Cc: Tony Luck <tony.luck@intel.com> Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1701310936080.3457@nanos Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'net/l2tp')