On Tue, Aug 06, 2024 at 02:06:47PM +0200, Daniel Wagner wrote: > When isolcpus=io_queue is enabled all hardware queues should run on the > housekeeping CPUs only. Thus ignore the affinity mask provided by the > driver. Also we can't use blk_mq_map_queues because it will map all CPUs > to first hctx unless, the CPU is the same as the hctx has the affinity > set to, e.g. 8 CPUs with isolcpus=io_queue,2-3,6-7 config What is the expected behavior if someone still tries to submit IO on isolated CPUs? BTW, I don't see any change in blk_mq_get_ctx()/blk_mq_map_queue() in this patchset, that means one random hctx(or even NULL) may be used for submitting IO from isolated CPUs, then there can be io hang risk during cpu hotplug, or kernel panic when submitting bio. Thanks, Ming
