Commit 34ebe933 authored by Rik van Riel's avatar Rik van Riel Committed by Tejun Heo

cpuset, isolcpus: document relationship between cpusets & isolcpus

Document the subtly changed relationship between cpusets and isolcpus.
Turns out the old documentation did not match the code...
Signed-off-by: default avatarRik van Riel <riel@redhat.com>
Suggested-by: default avatarPeter Zijlstra <peterz@infradead.org>
Acked-by: default avatarZefan Li <lizefan@huawei.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 47b8ea71
......@@ -392,8 +392,10 @@ Put simply, it costs less to balance between two smaller sched domains
than one big one, but doing so means that overloads in one of the
two domains won't be load balanced to the other one.
By default, there is one sched domain covering all CPUs, except those
marked isolated using the kernel boot time "isolcpus=" argument.
By default, there is one sched domain covering all CPUs, including those
marked isolated using the kernel boot time "isolcpus=" argument. However,
the isolated CPUs will not participate in load balancing, and will not
have tasks running on them unless explicitly assigned.
This default load balancing across all CPUs is not well suited for
the following two situations:
......@@ -465,6 +467,10 @@ such partially load balanced cpusets, as they may be artificially
constrained to some subset of the CPUs allowed to them, for lack of
load balancing to the other CPUs.
CPUs in "cpuset.isolcpus" were excluded from load balancing by the
isolcpus= kernel boot option, and will never be load balanced regardless
of the value of "cpuset.sched_load_balance" in any cpuset.
1.7.1 sched_load_balance implementation details.
------------------------------------------------
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment