From: Daniel Wagner <[email protected]> The io_queue flag informs multiqueue device drivers where to place hardware queues. Document this new flag in the isolcpus command-line argument description.
Reviewed-by: Aaron Tomlin <[email protected]> Reviewed-by: Hannes Reinecke <[email protected]> Signed-off-by: Daniel Wagner <[email protected]> --- .../admin-guide/kernel-parameters.txt | 22 ++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 03a550630644..9ed7c3ecd158 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2816,7 +2816,6 @@ Kernel parameters "number of CPUs in system - 1". managed_irq - Isolate from being targeted by managed interrupts which have an interrupt mask containing isolated CPUs. The affinity of managed interrupts is @@ -2839,6 +2838,27 @@ Kernel parameters housekeeping CPUs has no influence on those queues. + io_queue + Isolate from I/O queue work caused by multiqueue + device drivers. Restrict the placement of + queues to housekeeping CPUs only, ensuring that + all I/O work is processed by a housekeeping CPU. + + The io_queue configuration takes precedence + over managed_irq. When io_queue is used, + managed_irq placement constrains have no + effect. + + Note: Offlining housekeeping CPUS which serve + isolated CPUs will be rejected. Isolated CPUs + need to be offlined before offlining the + housekeeping CPUs. + + Note: When an isolated CPU issues an I/O request, + it is forwarded to a housekeeping CPU. This will + trigger a software interrupt on the completion + path. + The format of <cpu-list> is described above. iucv= [HW,NET] -- 2.51.0
