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add support for private knote lock (reduces lock contention),

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adapting OS_selrecord accordingly.
Problem and fix suggested by adrian and jmg
This commit is contained in:
Luigi Rizzo 2014-11-13 00:40:34 +00:00
parent efda9da6e6
commit 0e73f29ae2
3 changed files with 49 additions and 18 deletions
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41
sys/dev/netmap/netmap.c
View File

@ -375,9 +375,14 @@ ports attached to the switch)
/* reduce conditional code */
// linux API, use for the knlist in FreeBSD
#define init_waitqueue_head(x) knlist_init_mtx(&(x)->si_note, NULL)
/* use a private mutex for the knlist */
#define init_waitqueue_head(x) do { \
struct mtx *m = &(x)->m; \
mtx_init(m, "nm_kn_lock", NULL, MTX_DEF); \
knlist_init_mtx(&(x)->si.si_note, m); \
} while (0)
void freebsd_selwakeup(struct selinfo *si, int pri);
#define OS_selrecord(a, b) selrecord(a, &((b)->si))
#define OS_selwakeup(a, b) freebsd_selwakeup(a, b)
#elif defined(linux)
@ -806,6 +811,19 @@ netmap_krings_create(struct netmap_adapter *na, u_int tailroom)
}
#ifdef __FreeBSD__
static void
netmap_knlist_destroy(NM_SELINFO_T *si)
{
/* XXX kqueue(9) needed; these will mirror knlist_init. */
knlist_delete(&si->si.si_note, curthread, 0 /* not locked */ );
knlist_destroy(&si->si.si_note);
/* now we don't need the mutex anymore */
mtx_destroy(&si->m);
}
#endif /* __FreeBSD__ */
/* undo the actions performed by netmap_krings_create */
/* call with NMG_LOCK held */
void
@ -816,6 +834,7 @@ netmap_krings_delete(struct netmap_adapter *na)
/* we rely on the krings layout described above */
for ( ; kring != na->tailroom; kring++) {
mtx_destroy(&kring->q_lock);
netmap_knlist_destroy(&kring->si);
}
free(na->tx_rings, M_DEVBUF);
na->tx_rings = na->rx_rings = na->tailroom = NULL;
@ -996,9 +1015,8 @@ netmap_do_unregif(struct netmap_priv_d *priv, struct netmap_if *nifp)
* XXX The wake up now must happen during *_down(), when
* we order all activities to stop. -gl
*/
/* XXX kqueue(9) needed; these will mirror knlist_init. */
/* knlist_destroy(&na->tx_si.si_note); */
/* knlist_destroy(&na->rx_si.si_note); */
netmap_knlist_destroy(&na->tx_si);
netmap_knlist_destroy(&na->rx_si);
/* delete rings and buffers */
netmap_mem_rings_delete(na);
@ -1310,7 +1328,7 @@ netmap_rxsync_from_host(struct netmap_adapter *na, struct thread *td, void *pwai
/* access copies of cur,tail in the kring */
if (kring->rcur == kring->rtail && td) /* no bufs available */
selrecord(td, &kring->si);
OS_selrecord(td, &kring->si);
mbq_unlock(q);
return ret;
@ -2410,7 +2428,7 @@ netmap_poll(struct cdev *dev, int events, struct thread *td)
}
}
if (want_tx && retry_tx && !is_kevent) {
selrecord(td, check_all_tx ?
OS_selrecord(td, check_all_tx ?
&na->tx_si : &na->tx_rings[priv->np_txqfirst].si);
retry_tx = 0;
goto flush_tx;
@ -2479,7 +2497,7 @@ netmap_poll(struct cdev *dev, int events, struct thread *td)
}
if (retry_rx && !is_kevent)
selrecord(td, check_all_rx ?
OS_selrecord(td, check_all_rx ?
&na->rx_si : &na->rx_rings[priv->np_rxqfirst].si);
if (send_down > 0 || retry_rx) {
retry_rx = 0;
@ -3054,8 +3072,15 @@ netmap_init(void)
if (error != 0)
goto fail;
/* XXX could use make_dev_credv() to get error number */
#ifdef __FreeBSD__
/* support for the 'eternal' flag */
netmap_dev = make_dev_credf(MAKEDEV_ETERNAL_KLD,
&netmap_cdevsw, 0, NULL, UID_ROOT, GID_WHEEL, 0660,
"netmap");
#else
netmap_dev = make_dev(&netmap_cdevsw, 0, UID_ROOT, GID_WHEEL, 0660,
"netmap");
#endif
if (!netmap_dev)
goto fail;

17
sys/dev/netmap/netmap_freebsd.c
View File

@ -656,25 +656,24 @@ netmap_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
* and do not need the selrecord().
*/
void freebsd_selwakeup(struct selinfo *si, int pri);
void
freebsd_selwakeup(struct selinfo *si, int pri)
freebsd_selwakeup(struct nm_selinfo *si, int pri)
{
if (netmap_verbose)
D("on knote %p", &si->si_note);
selwakeuppri(si, pri);
D("on knote %p", &si->si.si_note);
selwakeuppri(&si->si, pri);
/* use a non-zero hint to tell the notification from the
* call done in kqueue_scan() which uses 0
*/
KNOTE_UNLOCKED(&si->si_note, 0x100 /* notification */);
KNOTE_UNLOCKED(&si->si.si_note, 0x100 /* notification */);
}
static void
netmap_knrdetach(struct knote *kn)
{
struct netmap_priv_d *priv = (struct netmap_priv_d *)kn->kn_hook;
struct selinfo *si = priv->np_rxsi;
struct selinfo *si = &priv->np_rxsi->si;
D("remove selinfo %p", si);
knlist_remove(&si->si_note, kn, 0);
@ -684,7 +683,7 @@ static void
netmap_knwdetach(struct knote *kn)
{
struct netmap_priv_d *priv = (struct netmap_priv_d *)kn->kn_hook;
struct selinfo *si = priv->np_txsi;
struct selinfo *si = &priv->np_txsi->si;
D("remove selinfo %p", si);
knlist_remove(&si->si_note, kn, 0);
@ -756,7 +755,7 @@ netmap_kqfilter(struct cdev *dev, struct knote *kn)
struct netmap_priv_d *priv;
int error;
struct netmap_adapter *na;
struct selinfo *si;
struct nm_selinfo *si;
int ev = kn->kn_filter;
if (ev != EVFILT_READ && ev != EVFILT_WRITE) {
@ -779,7 +778,7 @@ netmap_kqfilter(struct cdev *dev, struct knote *kn)
kn->kn_fop = (ev == EVFILT_WRITE) ?
&netmap_wfiltops : &netmap_rfiltops;
kn->kn_hook = priv;
knlist_add(&si->si_note, kn, 1);
knlist_add(&si->si.si_note, kn, 1);
// XXX unlock(priv)
ND("register %p %s td %p priv %p kn %p np_nifp %p kn_fp/fpop %s",
na, na->ifp->if_xname, curthread, priv, kn,

9
sys/dev/netmap/netmap_kern.h
View File

@ -55,7 +55,7 @@
#define NMG_UNLOCK() sx_xunlock(&netmap_global_lock)
#define NMG_LOCK_ASSERT() sx_assert(&netmap_global_lock, SA_XLOCKED)
#define NM_SELINFO_T struct selinfo
#define NM_SELINFO_T struct nm_selinfo
#define MBUF_LEN(m) ((m)->m_pkthdr.len)
#define MBUF_IFP(m) ((m)->m_pkthdr.rcvif)
#define NM_SEND_UP(ifp, m) ((NA(ifp))->if_input)(ifp, m)
@ -88,6 +88,13 @@ struct netmap_adapter *netmap_getna(if_t ifp);
MALLOC_DECLARE(M_NETMAP);
struct nm_selinfo {
struct selinfo si;
struct mtx m;
};
void freebsd_selwakeup(struct nm_selinfo *si, int pri);
// XXX linux struct, not used in FreeBSD
struct net_device_ops {
};