arm64/mpam: Add wait queue for monitor alloc and free
hulk inclusion category: feature feature: ARM MPAM support bugzilla: 48265 CVE: NA -------------------------------- For MPAM, a rmid can do monitoring work only with a monitor resource allocated, we adopt a mechanism for monitor resource dynamic allocation and recycling, it is different from Intel-RDT operation who creates a kworker thread for dynamically monitoring Cache usage and checks if it is below a threshold adjustable for rmid free, for we have detected that this method will affect the cpu utilization in many cases, sometimes this influence cannot be accepted. Our method is simple, as different resource's monitor number varies, we deliever two list, one for storing rmids which has exclusive monitor resource and another for storing this rmids which have monitor resource shared, this shared monitor id always be 0. it works like this, if a new rmid apply for a resource monitor which is in used, then we put this rmid to the tail of latter list and temporarily give a default monitor id 0 util someone releases available monitor resource, if this new rmid has all resources' monitor resource needed, then it will be put into exclusive list. This implements the LRU allocation of monitor resources and give users part control rights of allocation and release, if resctrl group's quantity can be guaranteed or user don't need monitoring too many groups synchronously, this is a more appropriate way for user deployment, not only that, also can it avoid the risk of inaccuracy in monitoring when monitoring operation happen to too many groups at the same time. Signed-off-by:Wang ShaoBo <bobo.shaobowang@huawei.com> Reviewed-by:
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