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-rw-r--r--include/net/tcp.h28
1 files changed, 28 insertions, 0 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 14d45661a84d..6b814e788f00 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -2140,6 +2140,34 @@ extern void tcp_rack_advance(struct tcp_sock *tp, u8 sacked, u32 end_seq,
extern void tcp_rack_reo_timeout(struct sock *sk);
extern void tcp_rack_update_reo_wnd(struct sock *sk, struct rate_sample *rs);
+/* tcp_plb.c */
+
+/*
+ * Scaling factor for fractions in PLB. For example, tcp_plb_update_state
+ * expects cong_ratio which represents fraction of traffic that experienced
+ * congestion over a single RTT. In order to avoid floating point operations,
+ * this fraction should be mapped to (1 << TCP_PLB_SCALE) and passed in.
+ */
+#define TCP_PLB_SCALE 8
+
+/* State for PLB (Protective Load Balancing) for a single TCP connection. */
+struct tcp_plb_state {
+ u8 consec_cong_rounds:5, /* consecutive congested rounds */
+ unused:3;
+ u32 pause_until; /* jiffies32 when PLB can resume rerouting */
+};
+
+static inline void tcp_plb_init(const struct sock *sk,
+ struct tcp_plb_state *plb)
+{
+ plb->consec_cong_rounds = 0;
+ plb->pause_until = 0;
+}
+void tcp_plb_update_state(const struct sock *sk, struct tcp_plb_state *plb,
+ const int cong_ratio);
+void tcp_plb_check_rehash(struct sock *sk, struct tcp_plb_state *plb);
+void tcp_plb_update_state_upon_rto(struct sock *sk, struct tcp_plb_state *plb);
+
/* At how many usecs into the future should the RTO fire? */
static inline s64 tcp_rto_delta_us(const struct sock *sk)
{