On Mon, Jul 07, 2025 at 03:44:30PM +0800, Ming Lei wrote:

On Wed, Jul 02, 2025 at 06:33:59PM +0200, Daniel Wagner wrote:

quoted

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

+1

-- 
Aaron Tomlin