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SubjectRe: [PATCH 4/4] blk-throttle: cleanup throtl_dequeue_tg()
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Hi, Tejun

在 2022/08/24 2:34, Tejun Heo 写道:
> On Tue, Aug 23, 2022 at 09:38:10AM +0800, Yu Kuai wrote:
>> From: Yu Kuai <yukuai3@huawei.com>
>>
>> Now that throtl_dequeue_tg() is called when the last bio is dispatched,
>> there is no need to check the flag THROTL_TG_PENDING, since it's ensured
>> to be set when bio is throttled.
>>
>> There are no functional changes.
>>
>> Signed-off-by: Yu Kuai <yukuai3@huawei.com>
>> ---
>> block/blk-throttle.c | 11 ++++-------
>> 1 file changed, 4 insertions(+), 7 deletions(-)
>>
>> diff --git a/block/blk-throttle.c b/block/blk-throttle.c
>> index 47142a1dd102..e47506a8ef47 100644
>> --- a/block/blk-throttle.c
>> +++ b/block/blk-throttle.c
>> @@ -570,14 +570,11 @@ static void throtl_enqueue_tg(struct throtl_grp *tg)
>>
>> static void throtl_dequeue_tg(struct throtl_grp *tg)
>> {
>> - if (tg->flags & THROTL_TG_PENDING) {
>> - struct throtl_service_queue *parent_sq =
>> - tg->service_queue.parent_sq;
>> + struct throtl_service_queue *parent_sq = tg->service_queue.parent_sq;
>>
>> - throtl_rb_erase(&tg->rb_node, parent_sq);
>> - --parent_sq->nr_pending;
>> - tg->flags &= ~THROTL_TG_PENDING;
>> - }
>> + throtl_rb_erase(&tg->rb_node, parent_sq);
>> + --parent_sq->nr_pending;
>> + tg->flags &= ~THROTL_TG_PENDING;
>
> Yeah, I don't know about this one. This breaks the symmetry with
> throtl_enqueue_tg() and it's a bit odd that we aren't at least
> WARN_ON_ONCE() on the flag given what the flag tracks. If you want to do
> this, I think the prev approach of just removing the flag is better as that
> was symmetric at least.

Yes, you are right, thanks for the advice. Since now it's a bit
ambivalent, we might as well just remove this patch?

Thanks,
Kuai
>
> Thanks.
>

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