On Sun, Apr 26, 2020 at 10:06:21AM +0800, Ming Lei wrote: > On Sat, Apr 25, 2020 at 05:48:32PM +0200, Christoph Hellwig wrote: > > FYI, here is what I think we should be doing (but the memory model > > experts please correct me): > > > > - just drop the direct_issue flag and check for the CPU, which is > > cheap enough > > That isn't correct because the CPU for running async queue may not be > same with rq->mq_ctx->cpu since hctx->cpumask may include several CPUs > and we run queue in RR style and it is really a normal case. But in that case the memory barrier really doesn't matter anywaẏ.
