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Re: [Qemu-devel] [PATCH v10 2/3] block: add I/O throttling algorithm
From: |
Zhi Yong Wu |
Subject: |
Re: [Qemu-devel] [PATCH v10 2/3] block: add I/O throttling algorithm |
Date: |
Tue, 1 Nov 2011 19:40:32 +0800 |
On Tue, Nov 1, 2011 at 7:33 PM, Stefan Hajnoczi <address@hidden> wrote:
> On Tue, Nov 1, 2011 at 7:40 AM, Zhi Yong Wu <address@hidden> wrote:
>> +static void bdrv_io_limits_intercept(BlockDriverState *bs,
>> + int nb_sectors)
>> +{
>> + int64_t wait_time = -1;
>> +
>> + if (!qemu_co_queue_empty(&bs->throttled_reqs)) {
>> + qemu_co_queue_wait(&bs->throttled_reqs);
>> + goto resume;
>> + } else if (bdrv_exceed_io_limits(bs, nb_sectors, false, &wait_time)) {
>> + if (wait_time != -1) {
>> + qemu_mod_timer(bs->block_timer,
>> + wait_time + qemu_get_clock_ns(vm_clock));
>> + }
>> +
>> + qemu_co_queue_wait(&bs->throttled_reqs);
>> +
>> +resume:
>> + while (bdrv_exceed_io_limits(bs, nb_sectors, false, &wait_time)) {
>
> is_write needs to be passed in to bdrv_exceed_io_limits(). Currently
> this accounts every I/O as a read.
Sorry, It is one stupid error.
>
>> + qemu_mod_timer(bs->block_timer,
>> + wait_time + qemu_get_clock_ns(vm_clock));
>
> Do you need if (wait_time != -1) here?
Actually i think that we can drop the condition in our code.
>
> Stefan
>
--
Regards,
Zhi Yong Wu