Re: [PATCH] blk-wbt: Avoid lock contention and thundering herd issue in wbt_wait

2018-08-22 Thread Holger Hoffstätte
On 08/22/18 21:46, Jens Axboe wrote: On 8/22/18 1:37 PM, Holger Hoffstätte wrote: On 08/22/18 21:17, Jens Axboe wrote: So the obvious suspect is the new return of UINT_MAX from get_limit() to __wbt_wait(). I first suspected that I mispatched something, but it's all like in mainline or your tree

Re: [PATCH] blk-wbt: Avoid lock contention and thundering herd issue in wbt_wait

2018-08-22 Thread Jens Axboe
On 8/22/18 1:37 PM, Holger Hoffstätte wrote: > On 08/22/18 21:17, Jens Axboe wrote: >>> So the obvious suspect is the new return of UINT_MAX from get_limit() to >>> __wbt_wait(). I first suspected that I mispatched something, but it's all >>> like in mainline or your tree. Even the recently moved-a

Re: [PATCH] blk-wbt: Avoid lock contention and thundering herd issue in wbt_wait

2018-08-22 Thread Holger Hoffstätte
On 08/22/18 21:17, Jens Axboe wrote: So the obvious suspect is the new return of UINT_MAX from get_limit() to __wbt_wait(). I first suspected that I mispatched something, but it's all like in mainline or your tree. Even the recently moved-around atomic loop inside rq_wait_inc_below() is 1:1 the s

Re: [PATCH] blk-wbt: Avoid lock contention and thundering herd issue in wbt_wait

2018-08-22 Thread Jens Axboe
On 8/22/18 1:12 PM, Holger Hoffstätte wrote: > On 08/22/18 19:28, Jens Axboe wrote: >> On 8/22/18 8:27 AM, Jens Axboe wrote: >>> On 8/22/18 6:54 AM, Holger Hoffstätte wrote: On 08/22/18 06:10, Jens Axboe wrote: > [...] > If you have time, please look at the 3 patches I posted earlier t

Re: [PATCH] blk-wbt: Avoid lock contention and thundering herd issue in wbt_wait

2018-08-22 Thread Holger Hoffstätte
On 08/22/18 19:28, Jens Axboe wrote: On 8/22/18 8:27 AM, Jens Axboe wrote: On 8/22/18 6:54 AM, Holger Hoffstätte wrote: On 08/22/18 06:10, Jens Axboe wrote: [...] If you have time, please look at the 3 patches I posted earlier today. Those are for mainline, so should be OK :-) I'm just playi