Re: [PATCH v2] block: do not merge requests without consulting with io scheduler

2016-07-20 Thread Jens Axboe
On 07/07/2016 12:48 PM, Tahsin Erdogan wrote: Before merging a bio into an existing request, io scheduler is called to get its approval first. However, the requests that come from a plug flush may get merged by block layer without consulting with io scheduler. In case of CFQ, this can cause fair

[PATCH v2] block: do not merge requests without consulting with io scheduler

2016-07-07 Thread Tahsin Erdogan
Before merging a bio into an existing request, io scheduler is called to get its approval first. However, the requests that come from a plug flush may get merged by block layer without consulting with io scheduler. In case of CFQ, this can cause fairness problems. For instance, if a request gets m