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-rw-r--r--Documentation/admin-guide/kernel-parameters.txt39
1 files changed, 26 insertions, 13 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 6b99c8b77c59..17eb0234d5be 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1727,20 +1727,33 @@
isapnp= [ISAPNP]
Format: <RDP>,<reset>,<pci_scan>,<verbosity>
- isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
- The argument is a cpu list, as described above.
+ isolcpus= [KNL,SMP] Isolate a given set of CPUs from disturbance.
+ [Deprecated - use cpusets instead]
+ Format: [flag-list,]<cpu-list>
+
+ Specify one or more CPUs to isolate from disturbances
+ specified in the flag list (default: domain):
+
+ nohz
+ Disable the tick when a single task runs.
+ domain
+ Isolate from the general SMP balancing and scheduling
+ algorithms. Note that performing domain isolation this way
+ is irreversible: it's not possible to bring back a CPU to
+ the domains once isolated through isolcpus. It's strongly
+ advised to use cpusets instead to disable scheduler load
+ balancing through the "cpuset.sched_load_balance" file.
+ It offers a much more flexible interface where CPUs can
+ move in and out of an isolated set anytime.
+
+ You can move a process onto or off an "isolated" CPU via
+ the CPU affinity syscalls or cpuset.
+ <cpu number> begins at 0 and the maximum value is
+ "number of CPUs in system - 1".
+
+ The format of <cpu-list> is described above.
+
- This option can be used to specify one or more CPUs
- to isolate from the general SMP balancing and scheduling
- algorithms. You can move a process onto or off an
- "isolated" CPU via the CPU affinity syscalls or cpuset.
- <cpu number> begins at 0 and the maximum value is
- "number of CPUs in system - 1".
-
- This option is the preferred way to isolate CPUs. The
- alternative -- manually setting the CPU mask of all
- tasks in the system -- can cause problems and
- suboptimal load balancer performance.
iucv= [HW,NET]