On Tue, Dec 14, 2021 at 01:49:34PM -0700, Jens Axboe wrote: > Dexuan reports that he's seeing spikes of very heavy CPU utilization when > running 24 disks and using the 'none' scheduler. This happens off the > sched restart path, because SCSI requires the queue to be restarted async, > and hence we're hammering on mod_delayed_work_on() to ensure that the work > item gets run appropriately. > > Avoid hammering on the timer and just use queue_work_on() if no delay > has been specified. > > Reported-and-tested-by: Dexuan Cui <decui@xxxxxxxxxxxxx> > Link: https://lore.kernel.org/linux-block/BYAPR21MB1270C598ED214C0490F47400BF719@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ > Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> > > --- > > diff --git a/block/blk-core.c b/block/blk-core.c > index 1378d084c770..c1833f95cb97 100644 > --- a/block/blk-core.c > +++ b/block/blk-core.c > @@ -1484,6 +1484,8 @@ EXPORT_SYMBOL(kblockd_schedule_work); > int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork, > unsigned long delay) > { > + if (!delay) > + return queue_work_on(cpu, kblockd_workqueue, &dwork->work); > return mod_delayed_work_on(cpu, kblockd_workqueue, dwork, delay); Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx> Thanks, Ming
