Re: [PATCH v3 0/3] blk-mq: Don't complete in IRQ, use llist_head

From: Jens Axboe
Date: Wed Feb 10 2021 - 09:44:18 EST


On 1/23/21 1:10 PM, Sebastian Andrzej Siewior wrote:
> Patch 2+3 were applied and then dropped by Jens due to a NOHZ+softirq
> related warning [0]. Turns out a successful wakeup via
> set_nr_if_polling() will not process any softirqs and the CPU may go
> back to idle. This is addressed by patch #1.
>
> smpcfd_dying_cpu() will also invoke SMP-functions calls via
> flush_smp_call_function_queue() but the block layer shouldn't queue
> anything because the CPU isn't online anymore.
> The two caller of flush_smp_call_function_from_idle() look fine with
> opening interrupts from within do_softirq().

Applied, thanks.

--
Jens Axboe