Messages in this thread | | | Date | Wed, 20 May 2020 11:04:24 +0800 | From | Ming Lei <> | Subject | Re: [PATCH 5/9] blk-mq: don't set data->ctx and data->hctx in blk_mq_alloc_request_hctx |
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On Wed, May 20, 2020 at 09:18:23AM +0800, Ming Lei wrote: > On Tue, May 19, 2020 at 05:30:00PM +0200, Christoph Hellwig wrote: > > On Tue, May 19, 2020 at 09:54:20AM +0800, Ming Lei wrote: > > > As Thomas clarified, workqueue hasn't such issue any more, and only other > > > per CPU kthreads can run until the CPU clears the online bit. > > > > > > So the question is if IO can be submitted from such kernel context? > > > > What other per-CPU kthreads even exist? > > I don't know, so expose to wider audiences.
One user is io uring with IORING_SETUP_SQPOLL & IORING_SETUP_SQ_AFF, see io_sq_offload_start(), and it is a IO submission kthread.
Thanks, Ming
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