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authorDr. David Alan Gilbert <dgilbert@redhat.com>2017-07-17 12:09:34 +0100
committerJuan Quintela <quintela@redhat.com>2017-07-18 17:36:17 +0200
commit9c98cfbe72b21d9d84b9ea8d231bde103b9fb7ae (patch)
treed8bd7049b08e2de3267d674e3c27a4fa682cd503 /migration/rdma.c
parent0b3c15f09715acd78063e720444cc86ac357bab4 (diff)
migration/rdma: Allow cancelling while waiting for wrid
When waiting for a WRID, if the other side dies we end up waiting for ever with no way to cancel the migration. Cure this by poll()ing the fd first with a timeout and checking error flags and migration state. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Message-Id: <20170717110936.23314-5-dgilbert@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
Diffstat (limited to 'migration/rdma.c')
-rw-r--r--migration/rdma.c59
1 files changed, 53 insertions, 6 deletions
diff --git a/migration/rdma.c b/migration/rdma.c
index 59810aec2e..0cf55a6d5b 100644
--- a/migration/rdma.c
+++ b/migration/rdma.c
@@ -1466,6 +1466,56 @@ static uint64_t qemu_rdma_poll(RDMAContext *rdma, uint64_t *wr_id_out,
return 0;
}
+/* Wait for activity on the completion channel.
+ * Returns 0 on success, none-0 on error.
+ */
+static int qemu_rdma_wait_comp_channel(RDMAContext *rdma)
+{
+ /*
+ * Coroutine doesn't start until migration_fd_process_incoming()
+ * so don't yield unless we know we're running inside of a coroutine.
+ */
+ if (rdma->migration_started_on_destination) {
+ yield_until_fd_readable(rdma->comp_channel->fd);
+ } else {
+ /* This is the source side, we're in a separate thread
+ * or destination prior to migration_fd_process_incoming()
+ * we can't yield; so we have to poll the fd.
+ * But we need to be able to handle 'cancel' or an error
+ * without hanging forever.
+ */
+ while (!rdma->error_state && !rdma->received_error) {
+ GPollFD pfds[1];
+ pfds[0].fd = rdma->comp_channel->fd;
+ pfds[0].events = G_IO_IN | G_IO_HUP | G_IO_ERR;
+ /* 0.1s timeout, should be fine for a 'cancel' */
+ switch (qemu_poll_ns(pfds, 1, 100 * 1000 * 1000)) {
+ case 1: /* fd active */
+ return 0;
+
+ case 0: /* Timeout, go around again */
+ break;
+
+ default: /* Error of some type -
+ * I don't trust errno from qemu_poll_ns
+ */
+ error_report("%s: poll failed", __func__);
+ return -EPIPE;
+ }
+
+ if (migrate_get_current()->state == MIGRATION_STATUS_CANCELLING) {
+ /* Bail out and let the cancellation happen */
+ return -EPIPE;
+ }
+ }
+ }
+
+ if (rdma->received_error) {
+ return -EPIPE;
+ }
+ return rdma->error_state;
+}
+
/*
* Block until the next work request has completed.
*
@@ -1513,12 +1563,9 @@ static int qemu_rdma_block_for_wrid(RDMAContext *rdma, int wrid_requested,
}
while (1) {
- /*
- * Coroutine doesn't start until migration_fd_process_incoming()
- * so don't yield unless we know we're running inside of a coroutine.
- */
- if (rdma->migration_started_on_destination) {
- yield_until_fd_readable(rdma->comp_channel->fd);
+ ret = qemu_rdma_wait_comp_channel(rdma);
+ if (ret) {
+ goto err_block_for_wrid;
}
ret = ibv_get_cq_event(rdma->comp_channel, &cq, &cq_ctx);