diff options
| author | Amitay Isaacs <amitay@gmail.com> | 2015-02-23 12:38:11 +1100 |
|---|---|---|
| committer | Martin Schwenke <martins@samba.org> | 2015-02-24 12:29:30 +0100 |
| commit | 04a061e4d19d5bdbd8179fb0fab8b0875eec243e (patch) | |
| tree | ae6fc393bd3dfff37f43f78d0ee41349900892c8 /ctdb | |
| parent | 84d4270c8e4ec18e9f83722d6df1a07f70acaade (diff) | |
| download | samba-04a061e4d19d5bdbd8179fb0fab8b0875eec243e.tar.gz samba-04a061e4d19d5bdbd8179fb0fab8b0875eec243e.tar.xz samba-04a061e4d19d5bdbd8179fb0fab8b0875eec243e.zip | |
ctdb-io: Do not use sys_write to write to client sockets
When sending messages to clients, ctdb checks for EAGAIN error code and
schedules next write in the subsequent event loop. Using sys_write in
these places causes ctdb to loop hard till a client is able to read from
the socket. With real time scheduling, ctdb daemon spins consuming 100%
of CPU trying to write to the client sockets. This can be quite harmful
when running under VMs or machines with single CPU.
This regression was introduced when all read/write calls were replaced to
use sys_read/sys_write wrappers (c1558adeaa980fb4bd6177d36250ec8262e9b9fe).
The existing code backs off in case of EAGAIN failures and waits for an
event loop to process the write again. This should give ctdb clients
a chance to get scheduled and to process the ctdb socket.
Signed-off-by: Amitay Isaacs <amitay@gmail.com>
Reviewed-by: Martin Schwenke <martin@meltin.net>
Autobuild-User(master): Martin Schwenke <martins@samba.org>
Autobuild-Date(master): Tue Feb 24 12:29:30 CET 2015 on sn-devel-104
Diffstat (limited to 'ctdb')
| -rw-r--r-- | ctdb/common/ctdb_io.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/ctdb/common/ctdb_io.c b/ctdb/common/ctdb_io.c index 467ec9a0fa..53486f43da 100644 --- a/ctdb/common/ctdb_io.c +++ b/ctdb/common/ctdb_io.c @@ -232,9 +232,9 @@ static void queue_io_write(struct ctdb_queue *queue) struct ctdb_queue_pkt *pkt = queue->out_queue; ssize_t n; if (queue->ctdb->flags & CTDB_FLAG_TORTURE) { - n = sys_write(queue->fd, pkt->data, 1); + n = write(queue->fd, pkt->data, 1); } else { - n = sys_write(queue->fd, pkt->data, pkt->length); + n = write(queue->fd, pkt->data, pkt->length); } if (n == -1 && errno != EAGAIN && errno != EWOULDBLOCK) { @@ -310,7 +310,7 @@ int ctdb_queue_send(struct ctdb_queue *queue, uint8_t *data, uint32_t length) queue overhead. This relies on non-blocking sockets */ if (queue->out_queue == NULL && queue->fd != -1 && !(queue->ctdb->flags & CTDB_FLAG_TORTURE)) { - ssize_t n = sys_write(queue->fd, data, length2); + ssize_t n = write(queue->fd, data, length2); if (n == -1 && errno != EAGAIN && errno != EWOULDBLOCK) { talloc_free(queue->fde); queue->fde = NULL; |