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[ar531x] [if_are] Fix if_are behaviour under high load traffic

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* use ifqmaxlen
* handle (inefficiently for now) meeting padding and alignment requirements for
  transmit mbufs.
* change how TX ring handling is done

Submitted by:	Hiroki Mori <yamori813@yahoo.co.jp>
Differential Revision:	https://reviews.freebsd.org/D10557
This commit is contained in:
Adrian Chadd 2017-05-06 06:06:11 +00:00
parent 52d3eee999
commit a10430e0a3
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=317868
2 changed files with 98 additions and 15 deletions
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111
sys/mips/atheros/ar531x/if_are.c
View File

@ -302,9 +302,9 @@ are_attach(device_t dev)
ifp->if_init = are_init;
sc->are_if_flags = ifp->if_flags;
/* XXX: add real size */
IFQ_SET_MAXLEN(&ifp->if_snd, 9);
ifp->if_snd.ifq_maxlen = 9;
/* ifqmaxlen is sysctl value in net/if.c */
IFQ_SET_MAXLEN(&ifp->if_snd, ifqmaxlen);
ifp->if_snd.ifq_maxlen = ifqmaxlen;
IFQ_SET_READY(&ifp->if_snd);
/* Tell the upper layer(s) we support long frames. */
@ -686,19 +686,92 @@ are_encap(struct are_softc *sc, struct mbuf **m_head)
{
struct are_txdesc *txd;
struct are_desc *desc, *prev_desc;
struct mbuf *m;
bus_dma_segment_t txsegs[ARE_MAXFRAGS];
uint32_t link_addr;
int error, i, nsegs, prod, si, prev_prod;
int txstat;
int startcount;
int padlen;
startcount = sc->are_cdata.are_tx_cnt;
ARE_LOCK_ASSERT(sc);
/*
* Some VIA Rhine wants packet buffers to be longword
* aligned, but very often our mbufs aren't. Rather than
* waste time trying to decide when to copy and when not
* to copy, just do it all the time.
*/
m = m_defrag(*m_head, M_NOWAIT);
if (m == NULL) {
device_printf(sc->are_dev, "are_encap m_defrag error\n");
m_freem(*m_head);
*m_head = NULL;
return (ENOBUFS);
}
*m_head = m;
/*
* The Rhine chip doesn't auto-pad, so we have to make
* sure to pad short frames out to the minimum frame length
* ourselves.
*/
if ((*m_head)->m_pkthdr.len < ARE_MIN_FRAMELEN) {
m = *m_head;
padlen = ARE_MIN_FRAMELEN - m->m_pkthdr.len;
if (M_WRITABLE(m) == 0) {
/* Get a writable copy. */
m = m_dup(*m_head, M_NOWAIT);
m_freem(*m_head);
if (m == NULL) {
device_printf(sc->are_dev, "are_encap m_dup error\n");
*m_head = NULL;
return (ENOBUFS);
}
*m_head = m;
}
if (m->m_next != NULL || M_TRAILINGSPACE(m) < padlen) {
m = m_defrag(m, M_NOWAIT);
if (m == NULL) {
device_printf(sc->are_dev, "are_encap m_defrag error\n");
m_freem(*m_head);
*m_head = NULL;
return (ENOBUFS);
}
}
/*
* Manually pad short frames, and zero the pad space
* to avoid leaking data.
*/
bzero(mtod(m, char *) + m->m_pkthdr.len, padlen);
m->m_pkthdr.len += padlen;
m->m_len = m->m_pkthdr.len;
*m_head = m;
}
prod = sc->are_cdata.are_tx_prod;
txd = &sc->are_cdata.are_txdesc[prod];
error = bus_dmamap_load_mbuf_sg(sc->are_cdata.are_tx_tag, txd->tx_dmamap,
*m_head, txsegs, &nsegs, BUS_DMA_NOWAIT);
error = bus_dmamap_load_mbuf_sg(sc->are_cdata.are_tx_tag,
txd->tx_dmamap, *m_head, txsegs, &nsegs, BUS_DMA_NOWAIT);
if (error == EFBIG) {
panic("EFBIG");
device_printf(sc->are_dev, "are_encap EFBIG error\n");
m = m_defrag(*m_head, M_NOWAIT);
if (m == NULL) {
m_freem(*m_head);
*m_head = NULL;
return (ENOBUFS);
}
*m_head = m;
error = bus_dmamap_load_mbuf_sg(sc->are_cdata.are_tx_tag,
txd->tx_dmamap, *m_head, txsegs, &nsegs, BUS_DMA_NOWAIT);
if (error != 0) {
m_freem(*m_head);
*m_head = NULL;
return (error);
}
} else if (error != 0)
return (error);
if (nsegs == 0) {
@ -729,13 +802,12 @@ are_encap(struct are_softc *sc, struct mbuf **m_head)
for (i = 0; i < nsegs; i++) {
desc = &sc->are_rdata.are_tx_ring[prod];
desc->are_stat = ADSTAT_OWN;
desc->are_devcs = ARE_DMASIZE(txsegs[i].ds_len) | ADCTL_CH;
if (i == 0)
desc->are_devcs |= ADCTL_Tx_FS;
desc->are_devcs = ARE_DMASIZE(txsegs[i].ds_len);
desc->are_addr = txsegs[i].ds_addr;
/* link with previous descriptor */
if (prev_desc)
prev_desc->are_link = ARE_TX_RING_ADDR(sc, prod);
/* end of descriptor */
if (prod == ARE_TX_RING_CNT - 1)
desc->are_devcs |= ADCTL_ER;
sc->are_cdata.are_tx_cnt++;
prev_desc = desc;
@ -761,16 +833,16 @@ are_encap(struct are_softc *sc, struct mbuf **m_head)
/* Start transmitting */
/* Check if new list is queued in NDPTR */
txstat = (CSR_READ_4(sc, CSR_STATUS) >> 20) & 7;
if (txstat == 0 || txstat == 6) {
/* Transmit Process Stat is stop or suspended */
CSR_WRITE_4(sc, CSR_TXPOLL, TXPOLL_TPD);
if (startcount == 0 && (txstat == 0 || txstat == 6)) {
desc = &sc->are_rdata.are_tx_ring[si];
desc->are_devcs |= ADCTL_Tx_FS;
}
else {
link_addr = ARE_TX_RING_ADDR(sc, si);
/* Get previous descriptor */
si = (si + ARE_TX_RING_CNT - 1) % ARE_TX_RING_CNT;
desc = &sc->are_rdata.are_tx_ring[si];
desc->are_link = link_addr;
desc->are_devcs &= ~(ADCTL_Tx_IC | ADCTL_Tx_LS);
}
return (0);
@ -782,6 +854,7 @@ are_start_locked(struct ifnet *ifp)
struct are_softc *sc;
struct mbuf *m_head;
int enq;
int txstat;
sc = ifp->if_softc;
@ -816,6 +889,14 @@ are_start_locked(struct ifnet *ifp)
*/
ETHER_BPF_MTAP(ifp, m_head);
}
if (enq > 0) {
txstat = (CSR_READ_4(sc, CSR_STATUS) >> 20) & 7;
if (txstat == 0 || txstat == 6) {
/* Transmit Process Stat is stop or suspended */
CSR_WRITE_4(sc, CSR_TXPOLL, TXPOLL_TPD);
}
}
}
static void

2
sys/mips/atheros/ar531x/if_arereg.h
View File

@ -44,6 +44,8 @@ struct are_desc {
#define ARE_TX_RING_CNT 128
#define ARE_TX_RING_SIZE sizeof(struct are_desc) * ARE_TX_RING_CNT
#define ARE_RX_RING_SIZE sizeof(struct are_desc) * ARE_RX_RING_CNT
#define ARE_MIN_FRAMELEN 60
#define ARE_RING_ALIGN sizeof(struct are_desc)
#define ARE_RX_ALIGN sizeof(uint32_t)
#define ARE_MAXFRAGS 8