diff options
Diffstat (limited to 'Documentation/cgroups')
| -rw-r--r-- | Documentation/cgroups/cpusets.txt | 10 | ||||
| -rw-r--r-- | Documentation/cgroups/memory.txt | 8 |
2 files changed, 11 insertions, 7 deletions
diff --git a/Documentation/cgroups/cpusets.txt b/Documentation/cgroups/cpusets.txt index f2235a162529..fdf7dff3f607 100644 --- a/Documentation/cgroups/cpusets.txt +++ b/Documentation/cgroups/cpusets.txt @@ -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. ------------------------------------------------ diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt index a22df3ad35ff..f456b4315e86 100644 --- a/Documentation/cgroups/memory.txt +++ b/Documentation/cgroups/memory.txt @@ -275,11 +275,6 @@ When oom event notifier is registered, event will be delivered. 2.7 Kernel Memory Extension (CONFIG_MEMCG_KMEM) -WARNING: Current implementation lacks reclaim support. That means allocation - attempts will fail when close to the limit even if there are plenty of - kmem available for reclaim. That makes this option unusable in real - life so DO NOT SELECT IT unless for development purposes. - With the Kernel memory extension, the Memory Controller is able to limit the amount of kernel memory used by the system. Kernel memory is fundamentally different than user memory, since it can't be swapped out, which makes it @@ -345,6 +340,9 @@ set: In this case, the admin could set up K so that the sum of all groups is never greater than the total memory, and freely set U at the cost of his QoS. + WARNING: In the current implementation, memory reclaim will NOT be + triggered for a cgroup when it hits K while staying below U, which makes + this setup impractical. U != 0, K >= U: Since kmem charges will also be fed to the user counter and reclaim will be |