From b6f11743278aeb3889ff42c98176b3e265654587 Mon Sep 17 00:00:00 2001 From: "Dr. David Alan Gilbert" Date: Thu, 27 Jul 2017 12:06:57 +0200 Subject: [PATCH 09/17] migration/rdma: Allow cancelling while waiting for wrid RH-Author: Dr. David Alan Gilbert Message-id: <20170727120659.8640-4-dgilbert@redhat.com> Patchwork-id: 75857 O-Subject: [Pegas-1.0 qemu-kvm PATCH 3/5] migration/rdma: Allow cancelling while waiting for wrid Bugzilla: 1475751 RH-Acked-by: Peter Xu RH-Acked-by: Laurent Vivier RH-Acked-by: Miroslav Rezanina From: "Dr. David Alan Gilbert" 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 Reviewed-by: Peter Xu Message-Id: <20170717110936.23314-5-dgilbert@redhat.com> Signed-off-by: Juan Quintela (cherry picked from commit 9c98cfbe72b21d9d84b9ea8d231bde103b9fb7ae) Signed-off-by: Miroslav Rezanina --- migration/rdma.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 53 insertions(+), 6 deletions(-) diff --git a/migration/rdma.c b/migration/rdma.c index 44a174f..666c84f 100644 --- a/migration/rdma.c +++ b/migration/rdma.c @@ -1464,6 +1464,56 @@ 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. * @@ -1511,12 +1561,9 @@ 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); -- 1.8.3.1