From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46482) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fBl6l-00083s-Sq for qemu-devel@nongnu.org; Thu, 26 Apr 2018 13:55:04 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fBl6h-0007bJ-P7 for qemu-devel@nongnu.org; Thu, 26 Apr 2018 13:55:03 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:58102 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fBl6h-0007bF-Ji for qemu-devel@nongnu.org; Thu, 26 Apr 2018 13:54:59 -0400 Date: Thu, 26 Apr 2018 18:54:55 +0100 From: "Dr. David Alan Gilbert" Message-ID: <20180426175454.GO2631@work-vm> References: <1524666934-8064-1-git-send-email-lidongchen@tencent.com> <1524666934-8064-6-git-send-email-lidongchen@tencent.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1524666934-8064-6-git-send-email-lidongchen@tencent.com> Subject: Re: [Qemu-devel] [PATCH v2 5/5] migration: Stop rdma yielding during incoming postcopy List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Lidong Chen Cc: quintela@redhat.com, qemu-devel@nongnu.org, galsha@mellanox.com, aviadye@mellanox.com, licq@mellanox.com, adido@mellanox.com, Lidong Chen * Lidong Chen (jemmy858585@gmail.com) wrote: > During incoming postcopy, the destination qemu will invoke > qemu_rdma_wait_comp_channel in a seprate thread. So does not use rdma > yield, and poll the completion channel fd instead. > > Signed-off-by: Lidong Chen OK, I think so; it's a bit delicate, but I can't currently see a better way. Reviewed-by: Dr. David Alan Gilbert > --- > migration/rdma.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/migration/rdma.c b/migration/rdma.c > index 0652224..4ba9fe2 100644 > --- a/migration/rdma.c > +++ b/migration/rdma.c > @@ -1490,11 +1490,13 @@ 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) { > + if (rdma->migration_started_on_destination && > + migration_incoming_get_current()->state == MIGRATION_STATUS_ACTIVE) { > 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() > + * after postcopy, the destination also in a seprate thread. > * 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. > -- > 1.8.3.1 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK