On Wed, Jul 02, 2025 at 06:33:59PM +0200, Daniel Wagner wrote: > When isolcpus=io_queue is enabled, and the last housekeeping CPU for a > given hctx goes offline, there would be no CPU left to handle I/O. To > prevent I/O stalls, prevent offlining housekeeping CPUs that are still > serving isolated CPUs. > > When isolcpus=io_queue is enabled and the last housekeeping CPU > for a given hctx goes offline, no CPU would be left to handle I/O. > To prevent I/O stalls, disallow offlining housekeeping CPUs that are > still serving isolated CPUs. If you do so, cpu offline is failed, and this change is user visible, please document the cpu offline failure limit on Documentation/admin-guide/kernel-parameters.txt. in the next patch. Thanks, Ming
