Am 02.07.2014 um 14:18 hat Ming Lei geschrieben:
> This patch implements .bdrv_io_plug, .bdrv_io_unplug and
> .bdrv_flush_io_queue callbacks for linux-aio Block Drivers,
> so that submitting I/O as a batch can be supported on linux-aio.
>
> Signed-off-by: Ming Lei <ming....@canonical.com>
Just a couple of minor comments, see inline.
> block/linux-aio.c | 88
> +++++++++++++++++++++++++++++++++++++++++++++++++++--
> block/raw-aio.h | 2 ++
> block/raw-posix.c | 45 +++++++++++++++++++++++++++
> 3 files changed, 133 insertions(+), 2 deletions(-)
>
> diff --git a/block/linux-aio.c b/block/linux-aio.c
> index f0a2c08..1cb4845 100644
> --- a/block/linux-aio.c
> +++ b/block/linux-aio.c
> @@ -25,6 +25,8 @@
> */
> #define MAX_EVENTS 128
>
> +#define MAX_QUEUED_IO 128
> +
> struct qemu_laiocb {
> BlockDriverAIOCB common;
> struct qemu_laio_state *ctx;
> @@ -36,9 +38,19 @@ struct qemu_laiocb {
> QLIST_ENTRY(qemu_laiocb) node;
> };
>
> +struct laio_queue {
> + struct iocb *iocbs[MAX_QUEUED_IO];
> + int plugged;
Why signed?
> + unsigned int size;
> + unsigned int idx;
> +};
> +
> struct qemu_laio_state {
> io_context_t ctx;
> EventNotifier e;
> +
> + /* io queue for submit at batch */
> + struct laio_queue io_q;
> };
>
> static inline ssize_t io_event_ret(struct io_event *ev)
> @@ -135,6 +147,72 @@ static const AIOCBInfo laio_aiocb_info = {
> .cancel = laio_cancel,
> };
>
> +static void ioq_init(struct laio_queue *io_q)
> +{
> + io_q->size = MAX_QUEUED_IO;
> + io_q->idx = 0;
> + io_q->plugged = 0;
> +}
> +
> +static int ioq_submit(struct qemu_laio_state *s)
> +{
> + int ret, i = 0;
> + int len = s->io_q.idx;
> +
> + do {
> + ret = io_submit(s->ctx, len, s->io_q.iocbs);
> + } while (i++ < 3 && ret == -EAGAIN);
> +
> + /* empty io queue */
> + s->io_q.idx = 0;
> +
> + if (ret >= 0)
> + return 0;
Indentation is off and braces are missing.
> +
> + for (i = 0; i < len; i++) {
> + struct qemu_laiocb *laiocb =
> + container_of(s->io_q.iocbs[i], struct qemu_laiocb, iocb);
> +
> + laiocb->ret = ret;
> + qemu_laio_process_completion(s, laiocb);
> + }
> + return ret;
> +}
> +
> +static void ioq_enqueue(struct qemu_laio_state *s, struct iocb *iocb)
> +{
> + unsigned int idx = s->io_q.idx;
> +
> + s->io_q.iocbs[idx++] = iocb;
> + s->io_q.idx = idx;
> +
> + /* submit immediately if queue is full */
> + if (idx == s->io_q.size)
> + ioq_submit(s);
Missing braces.
> +}
> +
> +void laio_io_plug(BlockDriverState *bs, void *aio_ctx)
> +{
> + struct qemu_laio_state *s = aio_ctx;
> +
> + s->io_q.plugged++;
> +}
> +
> +int laio_io_unplug(BlockDriverState *bs, void *aio_ctx, bool unplug)
> +{
> + struct qemu_laio_state *s = aio_ctx;
> + int ret = 0;
> +
How about an assert(s->io_q.plugged > 0); here?
> + if (unplug && --s->io_q.plugged > 0)
> + return 0;
Missing braces.
> +
> + if (s->io_q.idx > 0) {
> + ret = ioq_submit(s);
> + }
> +
> + return ret;
> +}
> +
> BlockDriverAIOCB *laio_submit(BlockDriverState *bs, void *aio_ctx, int fd,
> int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
> BlockDriverCompletionFunc *cb, void *opaque, int type)
