On 5/5/21 3:07 PM, Hao Xu wrote:
> 在 2021/4/29 下午5:11, Pavel Begunkov 写道:
>> On 4/29/21 4:41 AM, Hao Xu wrote:
>>> 在 2021/4/28 下午10:16, Jens Axboe 写道:
>>>> On 4/28/21 8:07 AM, Pavel Begunkov wrote:
>>>>>> diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
>>>>>> index e1ae46683301..311532ff6ce3 100644
>>>>>> --- a/include/uapi/linux/io_uring.h
>>>>>> +++ b/include/uapi/linux/io_uring.h
>>>>>> @@ -98,6 +98,7 @@ enum {
>>>>>> #define IORING_SETUP_CLAMP (1U << 4) /* clamp SQ/CQ ring sizes */
>>>>>> #define IORING_SETUP_ATTACH_WQ (1U << 5) /* attach to existing wq */
>>>>>> #define IORING_SETUP_R_DISABLED (1U << 6) /* start with ring disabled */
>>>>>> +#define IORING_SETUP_IDLE_NS (1U << 7) /* unit of thread_idle is nano second */
>>>>>> enum {
>>>>>> IORING_OP_NOP,
>>>>>> @@ -259,7 +260,7 @@ struct io_uring_params {
>>>>>> __u32 cq_entries;
>>>>>> __u32 flags;
>>>>>> __u32 sq_thread_cpu;
>>>>>> - __u32 sq_thread_idle;
>>>>>> + __u64 sq_thread_idle;
>>>>>
>>>>> breaks userspace API
>>>>
>>>> And I don't think we need to. If you're using IDLE_NS, then the value
>>>> should by definition be small enough that it'd fit in 32-bits. If you
>>> I make it u64 since I thought users may want a full flexibility to set
>>> idle in nanosecond granularity(eg. (1e6 + 10) ns cannot be set by
>>
>> It's a really weird user requiring such a precision. u32 allows up to
>> ~1s, and if more is needed users can switch to ms mode, so in the worst
>> case the precision is 1/1000 of the desired value, more than enough.
>>
>>> millisecond granularity). But I'm not sure if this deserve changing the
>>> userspace API.
>> That's not about deserve or not, we can't break ABI. Can be worked around,
> Is it for compatibility reason?
Right, all binaries should work without recompilation, including
those not using liburing.
>> e.g. by taking resv fields, but don't see a reason
>>
>>>> need higher timeouts, don't set it and it's in usec instead.
>>>>
>>>> So I'd just leave this one alone.
>>>>
>>>
>>
>
--
Pavel Begunkov
