diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 794497c7d7551776755cdb6c79fc4a22db43165a..08027f1d7f31d81836de46fd58f89d1fd5edbcae 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -343,10 +343,7 @@ struct tcp_sock {
struct sk_buff *scoreboard_skb_hint;
struct sk_buff *retransmit_skb_hint;
struct sk_buff *forward_skb_hint;
- struct sk_buff *fastpath_skb_hint;
- int fastpath_cnt_hint; /* Lags behind by current skb's pcount
- * compared to respective fackets_out */
int lost_cnt_hint;
int retransmit_cnt_hint;
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 0ede804b16d4f4559cec5cebd6c254023b28ec33..f0c5e7a2940045fbe80da96c41f1078ea5236e8a 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1081,7 +1081,6 @@ static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp)
static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp)
{
tcp_clear_retrans_hints_partial(tp);
- tp->fastpath_skb_hint = NULL;
}
/* MD5 Signature */
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index a287747e9dd6fe0a3b55bd19501ec8587fac70f6..3ad6a19ad30f027a9245da5455fd7e44c0e8b2de 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1333,6 +1333,88 @@ static int tcp_sacktag_one(struct sk_buff *skb, struct tcp_sock *tp,
return flag;
}
+static struct sk_buff *tcp_sacktag_walk(struct sk_buff *skb, struct sock *sk,
+ struct tcp_sack_block *next_dup,
+ u32 start_seq, u32 end_seq,
+ int dup_sack_in, int *fack_count,
+ int *reord, int *flag)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+
+ tcp_for_write_queue_from(skb, sk) {
+ int in_sack = 0;
+ int dup_sack = dup_sack_in;
+
+ if (skb == tcp_send_head(sk))
+ break;
+
+ /* queue is in-order => we can short-circuit the walk early */
+ if (!before(TCP_SKB_CB(skb)->seq, end_seq))
+ break;
+
+ if ((next_dup != NULL) &&
+ before(TCP_SKB_CB(skb)->seq, next_dup->end_seq)) {
+ in_sack = tcp_match_skb_to_sack(sk, skb,
+ next_dup->start_seq,
+ next_dup->end_seq);
+ if (in_sack > 0)
+ dup_sack = 1;
+ }
+
+ if (in_sack <= 0)
+ in_sack = tcp_match_skb_to_sack(sk, skb, start_seq, end_seq);
+ if (unlikely(in_sack < 0))
+ break;
+
+ if (in_sack)
+ *flag |= tcp_sacktag_one(skb, tp, reord, dup_sack, *fack_count);
+
+ *fack_count += tcp_skb_pcount(skb);
+ }
+ return skb;
+}
+
+/* Avoid all extra work that is being done by sacktag while walking in
+ * a normal way
+ */
+static struct sk_buff *tcp_sacktag_skip(struct sk_buff *skb, struct sock *sk,
+ u32 skip_to_seq)
+{
+ tcp_for_write_queue_from(skb, sk) {
+ if (skb == tcp_send_head(sk))
+ break;
+
+ if (before(TCP_SKB_CB(skb)->end_seq, skip_to_seq))
+ break;
+ }
+ return skb;
+}
+
+static struct sk_buff *tcp_maybe_skipping_dsack(struct sk_buff *skb,
+ struct sock *sk,
+ struct tcp_sack_block *next_dup,
+ u32 skip_to_seq,
+ int *fack_count, int *reord,
+ int *flag)
+{
+ if (next_dup == NULL)
+ return skb;
+
+ if (before(next_dup->start_seq, skip_to_seq)) {
+ skb = tcp_sacktag_skip(skb, sk, next_dup->start_seq);
+ tcp_sacktag_walk(skb, sk, NULL,
+ next_dup->start_seq, next_dup->end_seq,
+ 1, fack_count, reord, flag);
+ }
+
+ return skb;
+}
+
+static int tcp_sack_cache_ok(struct tcp_sock *tp, struct tcp_sack_block *cache)
+{
+ return cache < tp->recv_sack_cache + ARRAY_SIZE(tp->recv_sack_cache);
+}
+
static int
tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_una)
{
@@ -1342,16 +1424,16 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
TCP_SKB_CB(ack_skb)->sacked);
struct tcp_sack_block_wire *sp_wire = (struct tcp_sack_block_wire *)(ptr+2);
struct tcp_sack_block sp[4];
- struct sk_buff *cached_skb;
+ struct tcp_sack_block *cache;
+ struct sk_buff *skb;
int num_sacks = (ptr[1] - TCPOLEN_SACK_BASE)>>3;
int used_sacks;
int reord = tp->packets_out;
int flag = 0;
int found_dup_sack = 0;
- int cached_fack_count;
- int i;
+ int fack_count;
+ int i, j;
int first_sack_index;
- int force_one_sack;
if (!tp->sacked_out) {
if (WARN_ON(tp->fackets_out))
@@ -1409,132 +1491,123 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
used_sacks++;
}
- /* SACK fastpath:
- * if the only SACK change is the increase of the end_seq of
- * the first block then only apply that SACK block
- * and use retrans queue hinting otherwise slowpath */
- force_one_sack = 1;
- for (i = 0; i < used_sacks; i++) {
- u32 start_seq = sp[i].start_seq;
- u32 end_seq = sp[i].end_seq;
-
- if (i == 0) {
- if (tp->recv_sack_cache[i].start_seq != start_seq)
- force_one_sack = 0;
- } else {
- if ((tp->recv_sack_cache[i].start_seq != start_seq) ||
- (tp->recv_sack_cache[i].end_seq != end_seq))
- force_one_sack = 0;
- }
- tp->recv_sack_cache[i].start_seq = start_seq;
- tp->recv_sack_cache[i].end_seq = end_seq;
- }
- /* Clear the rest of the cache sack blocks so they won't match mistakenly. */
- for (; i < ARRAY_SIZE(tp->recv_sack_cache); i++) {
- tp->recv_sack_cache[i].start_seq = 0;
- tp->recv_sack_cache[i].end_seq = 0;
- }
+ /* order SACK blocks to allow in order walk of the retrans queue */
+ for (i = used_sacks - 1; i > 0; i--) {
+ for (j = 0; j < i; j++){
+ if (after(sp[j].start_seq, sp[j+1].start_seq)) {
+ struct tcp_sack_block tmp;
- if (force_one_sack)
- used_sacks = 1;
- else {
- int j;
- tp->fastpath_skb_hint = NULL;
-
- /* order SACK blocks to allow in order walk of the retrans queue */
- for (i = used_sacks - 1; i > 0; i--) {
- for (j = 0; j < i; j++){
- if (after(sp[j].start_seq, sp[j+1].start_seq)) {
- struct tcp_sack_block tmp;
-
- tmp = sp[j];
- sp[j] = sp[j+1];
- sp[j+1] = tmp;
-
- /* Track where the first SACK block goes to */
- if (j == first_sack_index)
- first_sack_index = j+1;
- }
+ tmp = sp[j];
+ sp[j] = sp[j+1];
+ sp[j+1] = tmp;
+ /* Track where the first SACK block goes to */
+ if (j == first_sack_index)
+ first_sack_index = j+1;
}
}
}
- /* Use SACK fastpath hint if valid */
- cached_skb = tp->fastpath_skb_hint;
- cached_fack_count = tp->fastpath_cnt_hint;
- if (!cached_skb) {
- cached_skb = tcp_write_queue_head(sk);
- cached_fack_count = 0;
+ skb = tcp_write_queue_head(sk);
+ fack_count = 0;
+ i = 0;
+
+ if (!tp->sacked_out) {
+ /* It's already past, so skip checking against it */
+ cache = tp->recv_sack_cache + ARRAY_SIZE(tp->recv_sack_cache);
+ } else {
+ cache = tp->recv_sack_cache;
+ /* Skip empty blocks in at head of the cache */
+ while (tcp_sack_cache_ok(tp, cache) && !cache->start_seq &&
+ !cache->end_seq)
+ cache++;
}
- for (i = 0; i < used_sacks; i++) {
- struct sk_buff *skb;
+ while (i < used_sacks) {
u32 start_seq = sp[i].start_seq;
u32 end_seq = sp[i].end_seq;
- int fack_count;
int dup_sack = (found_dup_sack && (i == first_sack_index));
- int next_dup = (found_dup_sack && (i+1 == first_sack_index));
+ struct tcp_sack_block *next_dup = NULL;
- skb = cached_skb;
- fack_count = cached_fack_count;
+ if (found_dup_sack && ((i + 1) == first_sack_index))
+ next_dup = &sp[i + 1];
/* Event "B" in the comment above. */
if (after(end_seq, tp->high_seq))
flag |= FLAG_DATA_LOST;
- tcp_for_write_queue_from(skb, sk) {
- int in_sack = 0;
-
- if (skb == tcp_send_head(sk))
- break;
-
- cached_skb = skb;
- cached_fack_count = fack_count;
- if (i == first_sack_index) {
- tp->fastpath_skb_hint = skb;
- tp->fastpath_cnt_hint = fack_count;
+ /* Skip too early cached blocks */
+ while (tcp_sack_cache_ok(tp, cache) &&
+ !before(start_seq, cache->end_seq))
+ cache++;
+
+ /* Can skip some work by looking recv_sack_cache? */
+ if (tcp_sack_cache_ok(tp, cache) && !dup_sack &&
+ after(end_seq, cache->start_seq)) {
+
+ /* Head todo? */
+ if (before(start_seq, cache->start_seq)) {
+ skb = tcp_sacktag_skip(skb, sk, start_seq);
+ skb = tcp_sacktag_walk(skb, sk, next_dup, start_seq,
+ cache->start_seq, dup_sack,
+ &fack_count, &reord, &flag);
}
- /* The retransmission queue is always in order, so
- * we can short-circuit the walk early.
- */
- if (!before(TCP_SKB_CB(skb)->seq, end_seq))
- break;
-
- dup_sack = (found_dup_sack && (i == first_sack_index));
+ /* Rest of the block already fully processed? */
+ if (!after(end_seq, cache->end_seq)) {
+ skb = tcp_maybe_skipping_dsack(skb, sk, next_dup, cache->end_seq,
+ &fack_count, &reord, &flag);
+ goto advance_sp;
+ }
- /* Due to sorting DSACK may reside within this SACK block! */
- if (next_dup) {
- u32 dup_start = sp[i+1].start_seq;
- u32 dup_end = sp[i+1].end_seq;
+ /* ...tail remains todo... */
+ if (TCP_SKB_CB(tp->highest_sack)->end_seq == cache->end_seq) {
+ /* ...but better entrypoint exists! Check that DSACKs are
+ * properly accounted while skipping here
+ */
+ tcp_maybe_skipping_dsack(skb, sk, next_dup, cache->end_seq,
+ &fack_count, &reord, &flag);
- if (before(TCP_SKB_CB(skb)->seq, dup_end)) {
- in_sack = tcp_match_skb_to_sack(sk, skb, dup_start, dup_end);
- if (in_sack > 0)
- dup_sack = 1;
- }
+ skb = tcp_write_queue_next(sk, tp->highest_sack);
+ fack_count = tp->fackets_out;
+ cache++;
+ goto walk;
}
- /* DSACK info lost if out-of-mem, try SACK still */
- if (in_sack <= 0)
- in_sack = tcp_match_skb_to_sack(sk, skb, start_seq, end_seq);
- if (unlikely(in_sack < 0))
- break;
-
- if (in_sack)
- flag |= tcp_sacktag_one(skb, tp, &reord, dup_sack, fack_count);
+ skb = tcp_sacktag_skip(skb, sk, cache->end_seq);
+ /* Check overlap against next cached too (past this one already) */
+ cache++;
+ continue;
+ }
- fack_count += tcp_skb_pcount(skb);
+ if (!before(start_seq, tcp_highest_sack_seq(tp))) {
+ skb = tcp_write_queue_next(sk, tp->highest_sack);
+ fack_count = tp->fackets_out;
}
+ skb = tcp_sacktag_skip(skb, sk, start_seq);
+
+walk:
+ skb = tcp_sacktag_walk(skb, sk, next_dup, start_seq, end_seq,
+ dup_sack, &fack_count, &reord, &flag);
+advance_sp:
/* SACK enhanced FRTO (RFC4138, Appendix B): Clearing correct
* due to in-order walk
*/
if (after(end_seq, tp->frto_highmark))
flag &= ~FLAG_ONLY_ORIG_SACKED;
+
+ i++;
}
+ /* Clear the head of the cache sack blocks so we can skip it next time */
+ for (i = 0; i < ARRAY_SIZE(tp->recv_sack_cache) - used_sacks; i++) {
+ tp->recv_sack_cache[i].start_seq = 0;
+ tp->recv_sack_cache[i].end_seq = 0;
+ }
+ for (j = 0; j < used_sacks; j++)
+ tp->recv_sack_cache[i++] = sp[j];
+
flag |= tcp_mark_lost_retrans(sk);
tcp_verify_left_out(tp);
@@ -2821,9 +2894,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, s32 *seq_rtt_p,
}
tp->fackets_out -= min(pkts_acked, tp->fackets_out);
- /* hint's skb might be NULL but we don't need to care */
- tp->fastpath_cnt_hint -= min_t(u32, pkts_acked,
- tp->fastpath_cnt_hint);
+
if (ca_ops->pkts_acked) {
s32 rtt_us = -1;
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index ce506af5ce072b505dc4b71faaba80742fefbfb4..030fc69ea217b9495b87b706ba4e35e28ce412d4 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -653,9 +653,7 @@ static void tcp_set_skb_tso_segs(struct sock *sk, struct sk_buff *skb, unsigned
}
/* When a modification to fackets out becomes necessary, we need to check
- * skb is counted to fackets_out or not. Another important thing is to
- * tweak SACK fastpath hint too as it would overwrite all changes unless
- * hint is also changed.
+ * skb is counted to fackets_out or not.
*/
static void tcp_adjust_fackets_out(struct sock *sk, struct sk_buff *skb,
int decr)
@@ -667,11 +665,6 @@ static void tcp_adjust_fackets_out(struct sock *sk, struct sk_buff *skb,
if (!before(tcp_highest_sack_seq(tp), TCP_SKB_CB(skb)->seq))
tp->fackets_out -= decr;
-
- /* cnt_hint is "off-by-one" compared with fackets_out (see sacktag) */
- if (tp->fastpath_skb_hint != NULL &&
- after(TCP_SKB_CB(tp->fastpath_skb_hint)->seq, TCP_SKB_CB(skb)->seq))
- tp->fastpath_cnt_hint -= decr;
}
/* Function to create two new TCP segments. Shrinks the given segment
@@ -1753,11 +1746,6 @@ static void tcp_retrans_try_collapse(struct sock *sk, struct sk_buff *skb, int m
/* changed transmit queue under us so clear hints */
tcp_clear_retrans_hints_partial(tp);
- /* manually tune sacktag skb hint */
- if (tp->fastpath_skb_hint == next_skb) {
- tp->fastpath_skb_hint = skb;
- tp->fastpath_cnt_hint -= tcp_skb_pcount(skb);
- }
sk_stream_free_skb(sk, next_skb);
}