Re: [PATCH RFC v3 02/15] block: add QUEUE_FLAG_BIO_ISSUE

[Yu Kuai <yukuai1@huaweicloud.com>]

Hi,

在 2025/09/03 1:05, Bart Van Assche 写道:
> On 8/31/25 8:32 PM, Yu Kuai wrote:
>> @@ -372,7 +372,10 @@ static inline void blkg_put(struct blkcg_gq *blkg)
>>   static inline void blkcg_bio_issue_init(struct bio *bio)
>>   {
>> -    bio->issue_time_ns = blk_time_get_ns();
>> +    struct request_queue *q = bdev_get_queue(bio->bi_bdev);
>> +
>> +    if (test_bit(QUEUE_FLAG_BIO_ISSUE, &q->queue_flags))
>> +        bio->issue_time_ns = blk_time_get_ns();
>>   }
>>   static inline void blkcg_use_delay(struct blkcg_gq *blkg)
>> diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
>> index 554b191a6892..c9b3bd12c87c 100644
>> --- a/block/blk-iolatency.c
>> +++ b/block/blk-iolatency.c
>> @@ -767,6 +767,7 @@ static int blk_iolatency_init(struct gendisk *disk)
>>       if (ret)
>>           goto err_qos_del;
>> +    blk_queue_flag_set(QUEUE_FLAG_BIO_ISSUE, disk->queue);
>>       timer_setup(&blkiolat->timer, blkiolatency_timer_fn, 0);
>>       INIT_WORK(&blkiolat->enable_work, blkiolatency_enable_work_fn);
> 
> Shouldn't QUEUE_FLAG_BIO_ISSUE be cleared when initializing
> bio->issue_time_ns is no longer necessary?
> 

iolatency can never be freed after it's initialized, however, I can add
and clear this flag in blkiolatency_enable_work_fn() instead, when
iolatency is really enabled or discabled.

Thanks,
Kuai

> Thanks,
> 
> Bart.
> 
> .
>