diff options
author | jh <jh@FreeBSD.org> | 2010-11-22 16:47:53 +0000 |
---|---|---|
committer | jh <jh@FreeBSD.org> | 2010-11-22 16:47:53 +0000 |
commit | 9c043d590896a77d5d66b978a963573a41d66ad3 (patch) | |
tree | 8c264d57d00d8346acaa49f76072c5ea06e7e188 | |
parent | 40b50edac393cf5770259c50d9e268b957a76878 (diff) | |
download | FreeBSD-src-9c043d590896a77d5d66b978a963573a41d66ad3.zip FreeBSD-src-9c043d590896a77d5d66b978a963573a41d66ad3.tar.gz |
Use g_eventlock to protect against losing wakeups in the g_event process
and replace tsleep(9) with msleep(9) which doesn't use a timeout. The
previously used timeout caused the event process to wake up ten times
per second on an idle system.
one_event() is now called with the topology lock held and it returns
with both the topology and event locks held when there are no more
events in the queue.
Reported by: mav, Marius NĂ¼nnerich
Reviewed by: freebsd-geom
-rw-r--r-- | sys/geom/geom_event.c | 63 | ||||
-rw-r--r-- | sys/geom/geom_kern.c | 6 |
2 files changed, 37 insertions, 32 deletions
diff --git a/sys/geom/geom_event.c b/sys/geom/geom_event.c index 44890aa..d6e5498 100644 --- a/sys/geom/geom_event.c +++ b/sys/geom/geom_event.c @@ -183,33 +183,27 @@ one_event(void) struct g_event *ep; struct g_provider *pp; - g_topology_lock(); - for (;;) { - mtx_lock(&g_eventlock); - TAILQ_FOREACH(pp, &g_doorstep, orphan) { - if (pp->nstart == pp->nend) - break; - } - if (pp != NULL) { - G_VALID_PROVIDER(pp); - TAILQ_REMOVE(&g_doorstep, pp, orphan); - } - mtx_unlock(&g_eventlock); - if (pp == NULL) + g_topology_assert(); + mtx_lock(&g_eventlock); + TAILQ_FOREACH(pp, &g_doorstep, orphan) { + if (pp->nstart == pp->nend) break; + } + if (pp != NULL) { + G_VALID_PROVIDER(pp); + TAILQ_REMOVE(&g_doorstep, pp, orphan); + mtx_unlock(&g_eventlock); g_orphan_register(pp); + return (1); } - mtx_lock(&g_eventlock); + ep = TAILQ_FIRST(&g_events); if (ep == NULL) { wakeup(&g_pending_events); - mtx_unlock(&g_eventlock); - g_topology_unlock(); return (0); } if (ep->flag & EV_INPROGRESS) { mtx_unlock(&g_eventlock); - g_topology_unlock(); return (1); } ep->flag |= EV_INPROGRESS; @@ -228,7 +222,6 @@ one_event(void) mtx_unlock(&g_eventlock); g_free(ep); } - g_topology_unlock(); return (1); } @@ -237,16 +230,27 @@ g_run_events() { int i; - while (one_event()) - ; - g_topology_lock(); - i = g_wither_work; - while (i) { - i = g_wither_washer(); - g_wither_work = i & 1; - i &= 2; + for (;;) { + g_topology_lock(); + while (one_event()) + ; + mtx_assert(&g_eventlock, MA_OWNED); + i = g_wither_work; + if (i) { + mtx_unlock(&g_eventlock); + while (i) { + i = g_wither_washer(); + g_wither_work = i & 1; + i &= 2; + } + g_topology_unlock(); + } else { + g_topology_unlock(); + msleep(&g_wait_event, &g_eventlock, PRIBIO | PDROP, + "-", 0); + } } - g_topology_unlock(); + /* NOTREACHED */ } void @@ -338,9 +342,12 @@ g_post_event(g_event_t *func, void *arg, int flag, ...) } void -g_do_wither() { +g_do_wither() +{ + mtx_lock(&g_eventlock); g_wither_work = 1; + mtx_unlock(&g_eventlock); wakeup(&g_wait_event); } diff --git a/sys/geom/geom_kern.c b/sys/geom/geom_kern.c index fc4e245..5e7e274 100644 --- a/sys/geom/geom_kern.c +++ b/sys/geom/geom_kern.c @@ -137,10 +137,8 @@ g_event_procbody(void) thread_lock(tp); sched_prio(tp, PRIBIO); thread_unlock(tp); - for(;;) { - g_run_events(); - tsleep(&g_wait_event, PRIBIO, "-", hz/10); - } + g_run_events(); + /* NOTREACHED */ } static struct kproc_desc g_event_kp = { |