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>>>>>> +    struct rdt_mon_domain *d; >>>>>> +    enum resctrl_event_id evtid; >>>>>> +    u32 rmid; >>>>>> +    u32 closid; >>>>>> +    u32 cntr_id; >>>>>> +    u32 val; >>>>>> +    bool assign; >>>>>> +}; >>>>> >>>>> I think I am missing something because it is not clear to me why this >>>>> new struct is needed. Why not just use union l3_qos_abmc_cfg? >>>> >>>> New struct is needed because we need to call resctrl_arch_reset_rmid() inside IPI. It requires all these parameters. >>> >>> Could you please answer my question? >> >> May be I did not understand your question here. >> >> We need to do couple of things here in the IPI. >> >> 1. Configure the counter. This requires the cntr_id, rmid, event config value and assign(or unassign). This is to populate  l3_qos_abmc_cfg and write the MSR. >> >> 2. Reset RMID. This requires rdt_resource, rdt_mon_domain, RMID, CLOSID and event. >> >> So, I packed all these in a new structure and sent to IPI handler so that both these actions can be done in IPI. >> >> Can this be simplified? > > This is all architecture specific code so I think l3_qos_abmc_cfg can be > initialized once and then passed around. Bouncing the individual members of > l3_qos_abmc_cfg through struct cntr_config seems unnecessary to me. More specifically, > would it not make things simpler to make l3_qos_abmc_cfg a member of cntr_config? Yes. It can be done. > >>>>>> @@ -1869,6 +1897,36 @@ static ssize_t mbm_local_bytes_config_write(struct kernfs_open_file *of, >>>>>>        return ret ?: nbytes; >>>>>>    } >>>>>>    +/* >>>>>> + * Send an IPI to the domain to assign the counter to RMID, event pair. >>>>>> + */ >>>>>> +int resctrl_arch_config_cntr(struct rdt_resource *r, struct rdt_mon_domain *d, >>>>>> +                 enum resctrl_event_id evtid, u32 rmid, u32 closid, >>>>>> +                 u32 cntr_id, bool assign) >>>>>> +{ >>>>>> +    struct rdt_hw_mon_domain *hw_dom = resctrl_to_arch_mon_dom(d); >>>>>> +    struct cntr_config config = { 0 }; >>>>> >>>>> Please see 29eaa7958367 ("x86/resctrl: Slightly clean-up mbm_config_show()") >>>> >>>> This may not apply here. >>>> >>>> x86/resctrl: Slightly clean-up mbm_config_show() >>>> >>>> "mon_info' is already zeroed in the list_for_each_entry() loop below. There  is no need to explicitly initialize it here. It just wastes some space and cycles. >>>> >>>> In our case we are not doing memset again. >>> >>> No, but every member is explicitly initialized instead. It may be needed if >>> union l3_qos_abmc_cfg is used as I asked about earlier where it will be important >>> to ensure reserve bits are initialized. >> >> I missed your comment on reserve bits(Searched in this series). General rule is reserve bits should be written as zeros. > > > I do not think I am being clear. > > Back to original comment: resctrl_arch_config_cntr() zeroes the entire struct and then > initializes every member. I do not think it is necessary to zero the struct if > every member is initialized. If you want to be explicit about the zero initialization > you can do so while initializing the struct only once where it is defined. > See for example, rdtgroup_kn_set_ugid() Yes. I got it. It was not required as we are initializing all the members of config here. With adding l3_qos_abmc_cfg inside cntr_config, we may still have to keep it. Thanks Babu