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Re: [Qemu-devel] [PATCH 07/26] block: add the support to drain throttled
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH 07/26] block: add the support to drain throttled requests |
Date: |
Fri, 13 Apr 2012 09:18:39 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:11.0) Gecko/20120329 Thunderbird/11.0.1 |
Il 13/04/2012 03:55, Zhi Yong Wu ha scritto:
> On Thu, Apr 12, 2012 at 8:00 PM, 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 file changed, 20 insertions(+), 1 deletion(-)
>>
>> diff --git a/block.c b/block.c
>> index 4b96654..33efa95 100644
>> --- a/block.c
>> +++ b/block.c
>> @@ -863,12 +863,31 @@ 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 can come until the
>> + * coroutine is complete. Because of this, it is not possible to have a
>> + * function 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();
> When bdrv_drain_all is invoked, if bs->tracked_requests has some
> pending I/O requests, only qemu_aio_wait is called here, not
> qemu_aio_flush() to restart them in bs->tracked_requests. It will
> cause assert about bs->tracked_requests.
qemu_aio_flush does not do that. Instead, the code just below does it:
>> +
>> + /* 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) {
>> --
>> 1.7.9.3
>>
>>
>>
>
>
>
- [Qemu-devel] [PATCH 00/26] My block patches queue for 1.1, Paolo Bonzini, 2012/04/12
- [Qemu-devel] [PATCH 01/26] qemu-io: use main_loop_wait, Paolo Bonzini, 2012/04/12
- [Qemu-devel] [PATCH 02/26] qemu-tool: map vm_clock to rt_clock, Paolo Bonzini, 2012/04/12
- [Qemu-devel] [PATCH 03/26] posix-aio: merge posix_aio_process_queue and posix_aio_read, Paolo Bonzini, 2012/04/12
- [Qemu-devel] [PATCH 05/26] aio: return "AIO in progress" state from qemu_aio_wait, Paolo Bonzini, 2012/04/12
- [Qemu-devel] [PATCH 04/26] aio: remove process_queue callback and qemu_aio_process_queue, Paolo Bonzini, 2012/04/12
- [Qemu-devel] [PATCH 07/26] block: add the support to drain throttled requests, Paolo Bonzini, 2012/04/12
- Re: [Qemu-devel] [PATCH 07/26] block: add the support to drain throttled requests, Zhi Yong Wu, 2012/04/12
- Re: [Qemu-devel] [PATCH 07/26] block: add the support to drain throttled requests,
Paolo Bonzini <=
- Re: [Qemu-devel] [PATCH 07/26] block: add the support to drain throttled requests, Zhi Yong Wu, 2012/04/13
- Re: [Qemu-devel] [PATCH 07/26] block: add the support to drain throttled requests, Paolo Bonzini, 2012/04/13
- Re: [Qemu-devel] [PATCH 07/26] block: add the support to drain throttled requests, Zhi Yong Wu, 2012/04/13
- Re: [Qemu-devel] [PATCH 07/26] block: add the support to drain throttled requests, Paolo Bonzini, 2012/04/13
- Re: [Qemu-devel] [PATCH 07/26] block: add the support to drain throttled requests, Zhi Yong Wu, 2012/04/13
- Re: [Qemu-devel] [PATCH 07/26] block: add the support to drain throttled requests, Zhi Yong Wu, 2012/04/13
[Qemu-devel] [PATCH 08/26] block: add mode argument to blockdev-snapshot-sync, Paolo Bonzini, 2012/04/12
[Qemu-devel] [PATCH 06/26] aio: simplify qemu_aio_wait, Paolo Bonzini, 2012/04/12
[Qemu-devel] [PATCH 09/26] block: fail live snapshot if disk has no medium, Paolo Bonzini, 2012/04/12
[Qemu-devel] [PATCH 10/26] block: fix snapshot on QED, Paolo Bonzini, 2012/04/12