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Re: [Qemu-devel] [PATCH 7/7] block: add the support to drain throttled r
From: |
Zhi Yong Wu |
Subject: |
Re: [Qemu-devel] [PATCH 7/7] block: add the support to drain throttled requests |
Date: |
Tue, 13 Mar 2012 09:38:39 +0800 |
On Tue, Mar 13, 2012 at 2:22 AM, Paolo Bonzini <address@hidden> wrote:
> From: Zhi Yong Wu <address@hidden>
>
> Signed-off-by: Zhi Yong Wu <address@hidden>
> [ Iterate until all block devices have processed all requests,
> add comments. - Paolo ]
> Signed-off-by: Paolo Bonzini <address@hidden>
> ---
> block.c | 21 ++++++++++++++++++++-
> 1 files changed, 20 insertions(+), 1 deletions(-)
>
> diff --git a/block.c b/block.c
> index dac62a1..0d769a6 100644
> --- a/block.c
> +++ b/block.c
> @@ -858,12 +858,31 @@ void bdrv_close_all(void)
> *
> * This function does not flush data to disk, use bdrv_flush_all() for that
> * after calling this function.
> + *
> + * Note that completion of an asynchronous I/O operation can trigger any
> + * number of other I/O operations on other devices---for example a coroutine
> + * can be arbitrarily complex and a constant flow of I/O to multiple devices
> + * can come until the coroutine is complete. Because of this, it is not
> + * possible to drain a single device's I/O queue.
> */
> void bdrv_drain_all(void)
> {
> BlockDriverState *bs;
> + bool busy;
>
> - qemu_aio_flush();
> + do {
> + busy = qemu_aio_wait();
busy is bool type, while qemu_aio_wait return void.
> +
> + /* FIXME: We do not have timer support here, so this is effectively
> + * a busy wait.
> + */
> + QTAILQ_FOREACH(bs, &bdrv_states, list) {
> + if (!qemu_co_queue_empty(&bs->throttled_reqs)) {
> + qemu_co_queue_restart_all(&bs->throttled_reqs);
> + busy = true;
> + }
> + }
> + } while (busy);
>
> /* If requests are still pending there is a bug somewhere */
> QTAILQ_FOREACH(bs, &bdrv_states, list) {
> --
> 1.7.7.6
>
>
--
Regards,
Zhi Yong Wu
- [Qemu-devel] [PATCH 0/7] AIO nested loop and bdrv_drain_all changes, Paolo Bonzini, 2012/03/12
- [Qemu-devel] [PATCH 1/7] qemu-io: use main_loop_wait, Paolo Bonzini, 2012/03/12
- [Qemu-devel] [PATCH 3/7] posix-aio: merge posix_aio_process_queue and posix_aio_read, Paolo Bonzini, 2012/03/12
- [Qemu-devel] [PATCH 7/7] block: add the support to drain throttled requests, Paolo Bonzini, 2012/03/12
- [Qemu-devel] [PATCH 4/7] aio: remove process_queue callback and qemu_aio_process_queue, Paolo Bonzini, 2012/03/12
- [Qemu-devel] [PATCH 5/7] aio: return "AIO in progress" state from qemu_aio_wait, Paolo Bonzini, 2012/03/12
- [Qemu-devel] [PATCH 2/7] qemu-tool: map vm_clock to rt_clock, Paolo Bonzini, 2012/03/12
- [Qemu-devel] [PATCH 6/7] aio: simplify qemu_aio_wait, Paolo Bonzini, 2012/03/12