| Message ID | 50749821.9090907@inktank.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Reviewed-by: Sage Weil <sage@inktank.com> On Tue, 9 Oct 2012, Alex Elder wrote: > This patch defines a single function, queue_con_delay() to call > queue_delayed_work() for a connection. It basically generalizes > what was previously queue_con() by adding the delay argument. > queue_con() is now a simple helper that passes 0 for its delay. > queue_con_delay() returns 0 if it queued work or an errno if it > did not for some reason. > > If con_work() finds the BACKOFF flag set for a connection, it now > calls queue_con_delay() to handle arranging to start again after a > delay. > > > Note about connection reference counts: con_work() only ever gets > called as a work item function. At the time that work is scheduled, > a reference to the connection is acquired, and the corresponding > con_work() call is then responsible for dropping that reference > before it returns. > > Previously, the backoff handling inside con_work() silently handed > off its reference to delayed work it scheduled. Now that > queue_con_delay() is used, a new reference is acquired for the > newly-scheduled work, and the original reference is dropped by the > con->ops->put() call at the end of the function. > > Signed-off-by: Alex Elder <elder@inktank.com> > --- > net/ceph/messenger.c | 38 +++++++++++++++++++++++--------------- > 1 file changed, 23 insertions(+), 15 deletions(-) > > diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c > index 9170c20..77cc8b1 100644 > --- a/net/ceph/messenger.c > +++ b/net/ceph/messenger.c > @@ -2244,22 +2244,33 @@ bad_tag: > > > /* > - * Atomically queue work on a connection. Bump @con reference to > - * avoid races with connection teardown. > + * Atomically queue work on a connection after the specified delay. > + * Bump @con reference to avoid races with connection teardown. > + * Returns 0 if work was queued, or an error code otherwise. > */ > -static void queue_con(struct ceph_connection *con) > +static int queue_con_delay(struct ceph_connection *con, unsigned long delay) > { > if (!con->ops->get(con)) { > - dout("queue_con %p ref count 0\n", con); > - return; > + dout("%s %p ref count 0\n", __func__, con); > + > + return -ENOENT; > } > > - if (!queue_delayed_work(ceph_msgr_wq, &con->work, 0)) { > - dout("queue_con %p - already queued\n", con); > + if (!queue_delayed_work(ceph_msgr_wq, &con->work, delay)) { > + dout("%s %p - already queued\n", __func__, con); > con->ops->put(con); > - } else { > - dout("queue_con %p\n", con); > + > + return -EBUSY; > } > + > + dout("%s %p %lu\n", __func__, con, delay); > + > + return 0; > +} > + > +static void queue_con(struct ceph_connection *con) > +{ > + (void) queue_con_delay(con, 0); > } > > /* > @@ -2294,14 +2305,11 @@ restart: > > if (test_and_clear_bit(CON_FLAG_BACKOFF, &con->flags)) { > dout("con_work %p backing off\n", con); > - if (queue_delayed_work(ceph_msgr_wq, &con->work, > - round_jiffies_relative(con->delay))) { > - dout("con_work %p backoff %lu\n", con, con->delay); > - mutex_unlock(&con->mutex); > - return; > - } else { > + ret = queue_con_delay(con, > round_jiffies_relative(con->delay)); > + if (ret) { > dout("con_work %p FAILED to back off %lu\n", con, > con->delay); > + BUG_ON(ret == -ENOENT); > set_bit(CON_FLAG_BACKOFF, &con->flags); > } > goto done; > -- > 1.7.9.5 > > -- > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c index 9170c20..77cc8b1 100644 --- a/net/ceph/messenger.c +++ b/net/ceph/messenger.c @@ -2244,22 +2244,33 @@ bad_tag: /* - * Atomically queue work on a connection. Bump @con reference to - * avoid races with connection teardown. + * Atomically queue work on a connection after the specified delay. + * Bump @con reference to avoid races with connection teardown. + * Returns 0 if work was queued, or an error code otherwise. */ -static void queue_con(struct ceph_connection *con) +static int queue_con_delay(struct ceph_connection *con, unsigned long delay) { if (!con->ops->get(con)) { - dout("queue_con %p ref count 0\n", con); - return; + dout("%s %p ref count 0\n", __func__, con); + + return -ENOENT; } - if (!queue_delayed_work(ceph_msgr_wq, &con->work, 0)) { - dout("queue_con %p - already queued\n", con); + if (!queue_delayed_work(ceph_msgr_wq, &con->work, delay)) { + dout("%s %p - already queued\n", __func__, con); con->ops->put(con); - } else { - dout("queue_con %p\n", con); + + return -EBUSY; } + + dout("%s %p %lu\n", __func__, con, delay); + + return 0; +} + +static void queue_con(struct ceph_connection *con) +{ + (void) queue_con_delay(con, 0); }
This patch defines a single function, queue_con_delay() to call queue_delayed_work() for a connection. It basically generalizes what was previously queue_con() by adding the delay argument. queue_con() is now a simple helper that passes 0 for its delay. queue_con_delay() returns 0 if it queued work or an errno if it did not for some reason. If con_work() finds the BACKOFF flag set for a connection, it now calls queue_con_delay() to handle arranging to start again after a delay. Note about connection reference counts: con_work() only ever gets called as a work item function. At the time that work is scheduled, a reference to the connection is acquired, and the corresponding con_work() call is then responsible for dropping that reference before it returns. Previously, the backoff handling inside con_work() silently handed off its reference to delayed work it scheduled. Now that queue_con_delay() is used, a new reference is acquired for the newly-scheduled work, and the original reference is dropped by the con->ops->put() call at the end of the function. Signed-off-by: Alex Elder <elder@inktank.com> --- net/ceph/messenger.c | 38 +++++++++++++++++++++++--------------- 1 file changed, 23 insertions(+), 15 deletions(-) /* @@ -2294,14 +2305,11 @@ restart: if (test_and_clear_bit(CON_FLAG_BACKOFF, &con->flags)) { dout("con_work %p backing off\n", con); - if (queue_delayed_work(ceph_msgr_wq, &con->work, - round_jiffies_relative(con->delay))) { - dout("con_work %p backoff %lu\n", con, con->delay); - mutex_unlock(&con->mutex); - return; - } else { + ret = queue_con_delay(con, round_jiffies_relative(con->delay)); + if (ret) { dout("con_work %p FAILED to back off %lu\n", con, con->delay); + BUG_ON(ret == -ENOENT); set_bit(CON_FLAG_BACKOFF, &con->flags); } goto done;