• W
    arm64/mpam: resctrl: Remove ctrlmon sysfile · ae4ab499
    Wang ShaoBo 提交于
    hulk inclusion
    category: feature
    bugzilla: 34278
    CVE: NA
    
    -------------------------------------------------
    
    We redesign monitoring process for user, as following illustrates:
    
      e.g. before rewriting:
         mount /sys/fs/resctrl && cd /sys/fs/resctrl
    	 mkdir p1 && cd p1
         echo 1 > ctrlmon  # this allocates a monitor resource for this group
         ...               # associating task/cpu with this group
         grep . mon_data/* # get monitor data from mon_data directory
      e.g. after rewriting:
    	 mount /sys/fs/resctrl && cd /sys/fs/resctrl
     	 mkdir p1 && cd p1 # automically allocating a monitoring resource
         ...               # associate task/cpu with this group
         grep . mon_data/* # directly get monitor data
    
    ctrlmon is used for manually allocating a monitor resource for monitoring
    a specified group (labeled by partid and pmg), we delete ctrlmon because
    this action is redundant.
    
    User should know which group has been allocated a available monitor resource
    and only this monitor resource is released then this monitor resource can
    be reallocated to a new group after, this action is redundant and unnecessary,
    as monitor resource is used only when monitoring process happens, so a
    relax monitor resource can be allocated to multiple groups and take effect
    when monitoring process happened.
    
    But should some restrictions be known, a monitor resource for monitoring
    Cache-occupancy might be kept for a long time until it doesn't need to
    be use anymore, or below a threshold as like intel-RDT limbo list works,
    otherwise you may see that the monitoring result is very small beyond
    exception when you force switch one mon resource from one group to another.
    
    We deliver a simple LRU mon resource allocation mechanism, but so far
    it just assign a monitor according to the order in which groups was created,
    this is incomplete and needs subsequent improvement.
    Signed-off-by: NWang ShaoBo <bobo.shaobowang@huawei.com>
    Reviewed-by: NXiongfeng Wang <wangxiongfeng2@huawei.com>
    Reviewed-by: NCheng Jian <cj.chengjian@huawei.com>
    Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
    Signed-off-by: NCheng Jian <cj.chengjian@huawei.com>
    ae4ab499
mpam_ctrlmon.c 14.1 KB