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tcp/lro: Allow drivers to set the TCP ACK/data segment aggregation limit

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ACK aggregation limit is append count based, while the TCP data segment
aggregation limit is length based.  Unless the network driver sets these
two limits, it's an NO-OP.

Reviewed by:	adrian, gallatin (previous version), hselasky (previous version)
Approved by:	adrian (mentor)
MFC after:	1 week
Sponsored by:	Microsoft OSTC
Differential Revision:	https://reviews.freebsd.org/D5185
This commit is contained in:
Sepherosa Ziehau 2016-02-18 04:58:34 +00:00
parent 4a1ff07b39
commit 7ae3d4bf54
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=295739
3 changed files with 19 additions and 3 deletions
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15
sys/netinet/tcp_lro.c
View File

@ -88,6 +88,8 @@ tcp_lro_init_args(struct lro_ctrl *lc, struct ifnet *ifp,
lc->lro_mbuf_count = 0;
lc->lro_mbuf_max = lro_mbufs;
lc->lro_cnt = lro_entries;
lc->lro_ackcnt_lim = TCP_LRO_ACKCNT_MAX;
lc->lro_length_lim = TCP_LRO_LENGTH_MAX;
lc->ifp = ifp;
SLIST_INIT(&lc->lro_free);
SLIST_INIT(&lc->lro_active);
@ -610,7 +612,7 @@ tcp_lro_rx(struct lro_ctrl *lc, struct mbuf *m, uint32_t csum)
}
/* Flush now if appending will result in overflow. */
if (le->p_len > (65535 - tcp_data_len)) {
if (le->p_len > (lc->lro_length_lim - tcp_data_len)) {
SLIST_REMOVE(&lc->lro_active, le, lro_entry, next);
tcp_lro_flush(lc, le);
break;
@ -648,6 +650,15 @@ tcp_lro_rx(struct lro_ctrl *lc, struct mbuf *m, uint32_t csum)
if (tcp_data_len == 0) {
m_freem(m);
/*
* Flush this LRO entry, if this ACK should not
* be further delayed.
*/
if (le->append_cnt >= lc->lro_ackcnt_lim) {
SLIST_REMOVE(&lc->lro_active, le, lro_entry,
next);
tcp_lro_flush(lc, le);
}
return (0);
}
@ -668,7 +679,7 @@ tcp_lro_rx(struct lro_ctrl *lc, struct mbuf *m, uint32_t csum)
* If a possible next full length packet would cause an
* overflow, pro-actively flush now.
*/
if (le->p_len > (65535 - lc->ifp->if_mtu)) {
if (le->p_len > (lc->lro_length_lim - lc->ifp->if_mtu)) {
SLIST_REMOVE(&lc->lro_active, le, lro_entry, next);
tcp_lro_flush(lc, le);
} else

5
sys/netinet/tcp_lro.h
View File

@ -91,11 +91,16 @@ struct lro_ctrl {
unsigned lro_cnt;
unsigned lro_mbuf_count;
unsigned lro_mbuf_max;
unsigned short lro_ackcnt_lim; /* max # of aggregated ACKs */
unsigned lro_length_lim; /* max len of aggregated data */
struct lro_head lro_active;
struct lro_head lro_free;
};
#define TCP_LRO_LENGTH_MAX 65535
#define TCP_LRO_ACKCNT_MAX 65535 /* unlimited */
int tcp_lro_init(struct lro_ctrl *);
int tcp_lro_init_args(struct lro_ctrl *, struct ifnet *, unsigned, unsigned);
void tcp_lro_free(struct lro_ctrl *);

2
sys/sys/param.h
View File

@ -58,7 +58,7 @@
* in the range 5 to 9.
*/
#undef __FreeBSD_version
#define __FreeBSD_version 1100098 /* Master, propagated to newvers */
#define __FreeBSD_version 1100099 /* Master, propagated to newvers */
/*
* __FreeBSD_kernel__ indicates that this system uses the kernel of FreeBSD,