On 7/10/19 8:24 AM, Konstantin Khlebnikov wrote:
On 10.07.2019 17:00, Jens Axboe wrote:
On 7/8/19 9:29 AM, Konstantin Khlebnikov wrote:
After commit 991f61fe7e1d ("Blk-throttle: reduce tail io latency when iops limit is enforced") wait time could be zero even if group is throttled and cannot issue requests right now. As a result throtl_select_dispatch() turns into busy-loop under irq-safe queue spinlock.
Fix is simple: always round up target time to the next throttle slice.
Applied, thanks. In the future, please break lines at 72 chars in commit messages, I fixed it up.
Ok, but Documentation/process/submitting-patches.rst and scripts/checkpatch.pl recommends 75 chars per line.
Huh, oh well. Not a big deal for me, line breaking is easily automated.