On Fri, Dec 03, 2021 at 09:39:47AM +0800, huang...@chinatelecom.cn wrote:
> From: Hyman Huang(黄勇) <huang...@chinatelecom.cn>
>
> Implement dirtyrate calculation periodically basing on
> dirty-ring and throttle vCPU until it reachs the quota
> dirty page rate given by user.
>
> Introduce qmp commands "vcpu-dirty-limit", "query-vcpu-dirty-limit"
> to enable, disable, query dirty page limit for virtual CPU.
>
> Meanwhile, introduce corresponding hmp commands "vcpu_dirty_limit",
> "info vcpu_dirty_limit" so developers can play with them easier.
Thanks. Even if I start to use qmp-shell more recently but still in some case
where only hmp is specified this could still be handy.
> +void qmp_vcpu_dirty_limit(int64_t cpu_index,
> + bool enable,
> + uint64_t dirty_rate,
> + Error **errp)
> +{
> + if (!kvm_enabled() || !kvm_dirty_ring_enabled()) {
> + error_setg(errp, "dirty page limit feature requires KVM with"
> + " accelerator property 'dirty-ring-size' set'");
> + return;
> + }
> +
> + if (!dirtylimit_is_vcpu_index_valid(cpu_index)) {
> + error_setg(errp, "cpu index out of range");
> + return;
> + }
> +
> + if (enable) {
> + dirtylimit_calc();
> + dirtylimit_vcpu(cpu_index, dirty_rate);
> + } else {
> + if (!dirtylimit_enabled(cpu_index)) {
> + error_setg(errp, "dirty page limit for CPU %ld not set",
> + cpu_index);
> + return;
> + }
We don't need to fail the user for enable=off even if vcpu is not throttled,
imho.
> +
> + if (!dirtylimit_cancel_vcpu(cpu_index)) {
> + dirtylimit_calc_quit();
> + }
> + }
> +}
[...]
> +struct DirtyLimitInfoList *qmp_query_vcpu_dirty_limit(bool has_cpu_index,
> + int64_t cpu_index,
> + Error **errp)
> +{
> + DirtyLimitInfo *info = NULL;
> + DirtyLimitInfoList *head = NULL, **tail = &head;
> +
> + if (has_cpu_index &&
> + (!dirtylimit_is_vcpu_index_valid(cpu_index))) {
> + error_setg(errp, "cpu index out of range");
> + return NULL;
> + }
> +
> + if (has_cpu_index) {
> + info = dirtylimit_query_vcpu(cpu_index);
> + QAPI_LIST_APPEND(tail, info);
> + } else {
> + CPUState *cpu;
> + CPU_FOREACH(cpu) {
> + if (!cpu->unplug) {
> + info = dirtylimit_query_vcpu(cpu->cpu_index);
> + QAPI_LIST_APPEND(tail, info);
> + }
There're special handling for unplug in a few places. Could you explain why?
E.g. if the vcpu is unplugged then dirty rate is zero, then it seems fine to
even keep it there?
> + }
> + }
> +
> + return head;
> +}
--
Peter Xu
