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On x86 it used to read a single architecture-provided > > flag. Calls on paths that run repeatedly now pay for the scan. > > > > Two such callers already know that monitoring is supported: > > > > 1) mbm_handle_overflow() > > The MBM overflow handler runs once per second on each L3 monitoring > > domain. It is only set up when MBM events are enabled, which requires > > L3 monitoring support. > > > > There is also a resctrl_mon_capable() check in mbm_setup_overflow_handler(), > do we need to remove it too? But it is only called once in mbm_setup_overflow_handler(), > leave it as it is should be OK. Yes. I was only worried about calls in hot code paths. This call can happen more than once if CPU hotplug removes and adds a domain. But that's still not a hot code path. > > > 2) is_rmid_match() > > Called for every task in the system when walking the task list to read > > a tasks file, remove a group, or unmount. It only matches MON groups, > > which can only be created on a system that supports monitoring. > > > > Remove the call to resctrl_mon_capable() from both functions. > > > > No functional change intended. > > > > Signed-off-by: Tony Luck > > > > Reviewed-by: Chen Yu Thanks for the review. > > thanks, > Chenyu -Tony