From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49583) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XsrsL-0002uI-LG for qemu-devel@nongnu.org; Mon, 24 Nov 2014 06:32:19 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XsrsF-00049f-G0 for qemu-devel@nongnu.org; Mon, 24 Nov 2014 06:32:13 -0500 Received: from mail-pd0-f169.google.com ([209.85.192.169]:61421) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XsrsF-00049K-BQ for qemu-devel@nongnu.org; Mon, 24 Nov 2014 06:32:07 -0500 Received: by mail-pd0-f169.google.com with SMTP id fp1so9557039pdb.0 for ; Mon, 24 Nov 2014 03:32:06 -0800 (PST) From: Ming Lei Date: Mon, 24 Nov 2014 19:31:32 +0800 Message-Id: <1416828693-30767-3-git-send-email-ming.lei@canonical.com> In-Reply-To: <1416828693-30767-1-git-send-email-ming.lei@canonical.com> References: <1416828693-30767-1-git-send-email-ming.lei@canonical.com> Subject: [Qemu-devel] [PATCH v4 2/3] linux-aio: handling -EAGAIN for !s->io_q.plugged case List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, Paolo Bonzini , Stefan Hajnoczi , Kevin Wolf Cc: Ming Lei Previously -EAGAIN is simply ignored for !s->io_q.plugged case, and sometimes it is easy to cause -EIO to VM, such as NVME device. This patch handles -EAGAIN by io queue for !s->io_q.plugged case, and it will be retried in following aio completion cb. Suggested-by: Paolo Bonzini Signed-off-by: Ming Lei --- block/linux-aio.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) diff --git a/block/linux-aio.c b/block/linux-aio.c index 11fcedb..974e4f9 100644 --- a/block/linux-aio.c +++ b/block/linux-aio.c @@ -259,6 +259,11 @@ static int ioq_enqueue(struct qemu_laio_state *s, struct iocb *iocb) s->io_q.iocbs[idx++] = iocb; s->io_q.idx = idx; + /* don't submit until next completion for -EAGAIN of non plug case */ + if (unlikely(!s->io_q.plugged)) { + return 0; + } + /* submit immediately if queue depth is above 2/3 */ if (idx > s->io_q.size * 2 / 3) { return ioq_submit(s); @@ -325,15 +330,18 @@ BlockAIOCB *laio_submit(BlockDriverState *bs, void *aio_ctx, int fd, } io_set_eventfd(&laiocb->iocb, event_notifier_get_fd(&s->e)); - if (!s->io_q.plugged) { - if (io_submit(s->ctx, 1, &iocbs) < 0) { - goto out_free_aiocb; - } - } else { - if (ioq_enqueue(s, iocbs) < 0) { + /* Switch to queue mode until -EAGAIN is handled */ + if (!s->io_q.plugged && !s->io_q.idx) { + int ret = io_submit(s->ctx, 1, &iocbs); + if (ret >= 0) { + return &laiocb->common; + } else if (ret != -EAGAIN) { goto out_free_aiocb; } } + if (ioq_enqueue(s, iocbs) < 0) { + goto out_free_aiocb; + } return &laiocb->common; out_free_aiocb: -- 1.7.9.5