From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53719) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dX3uV-0002zT-2a for qemu-devel@nongnu.org; Mon, 17 Jul 2017 07:09:56 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dX3uQ-0002sn-Sn for qemu-devel@nongnu.org; Mon, 17 Jul 2017 07:09:55 -0400 Received: from mx1.redhat.com ([209.132.183.28]:35610) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dX3uQ-0002sM-JX for qemu-devel@nongnu.org; Mon, 17 Jul 2017 07:09:50 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id AB20F4E03F for ; Mon, 17 Jul 2017 11:09:49 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" Date: Mon, 17 Jul 2017 12:09:34 +0100 Message-Id: <20170717110936.23314-5-dgilbert@redhat.com> In-Reply-To: <20170717110936.23314-1-dgilbert@redhat.com> References: <20170717110936.23314-1-dgilbert@redhat.com> Subject: [Qemu-devel] [PATCH v4 4/6] migration/rdma: Allow cancelling while waiting for wrid List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: quintela@redhat.com, lvivier@redhat.com, peterx@redhat.com 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 --- migration/rdma.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++------ 1 file 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); -- 2.13.0