Re: [PATCH 0/2] block: invalidate cached plug timestamp on context switch

[Jens Axboe]

On 6/16/26 10:54 AM, Peter Zijlstra wrote:
> On Tue, Jun 16, 2026 at 10:10:31AM -0600, Jens Axboe wrote:
>> On 6/16/26 10:08 AM, Jens Axboe wrote:
>>>
>>> On Tue, 16 Jun 2026 07:15:16 -0700, Usama Arif wrote:
>>>> The details for this are in patch 2. The main reason for this series
>>>> is to invalidate the cached timestamp on context switch. This was
>>>> done in sched_update_worker() only before which was resulting in
>>>> blk-iocost reading stale timestamps and throttling based on wrong
>>>> information.
>>>>
>>>> Patch 1 is a prerequisite to create the invariant that
>>>> PF_BLOCK_TS set implies current->plug != NULL.
>>>>
>>>> [...]
>>>
>>> Applied, thanks!
>>>
>>> [1/2] kernel/fork: clear PF_BLOCK_TS in copy_process()
>>>       commit: fd38b75c4b43295b10d69772a46d1c74dbd6fc81
>>> [2/2] block: invalidate cached plug timestamp after task switch
>>>       commit: fad156c2af227f42ca796cbb20ddc354a6dd9932
>>
>> Note: I tentatively queued this on up as a) it looks good to me (and
>> thanks Usama for fixing this!), and b) about to head OOO for a week
>> or so. If Peter or any of the sched people disagree, let me know and
>> we can deal with it. If not, then I plan on sending this in with the
>> usual follow-up merge window fixes next week.
> 
> FWIW, looks good to me.

Great, thanks Peter!

-- 
Jens Axboe