The io_queue flag informs multiqueue device drivers where to place
hardware queues. Document this new flag in the isolcpus
command-line argument description.
Signed-off-by: Daniel Wagner <w...@kernel.org>
---
Documentation/admin-guide/kernel-parameters.txt | 19 ++++++++++++++++++-
1 file changed, 18 insertions(+), 1 deletion(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt
b/Documentation/admin-guide/kernel-parameters.txt
index
f1f2c0874da9ddfc95058c464fdf5dabaf0de713..7594ac5448575cc895ebf7af0fe051d42dc5e0e9
100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2590,7 +2590,6 @@
"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
@@ -2613,6 +2612,24 @@
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.
+
+ Housekeeping CPUs that serve isolated CPUs
+ cannot be offlined.
+
+ The io_queue configuration takes precedence over
+ managed_irq; thus, when io_queue is used,
+ managed_irq has no effect.
+
+ 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]
--
2.50.0
