Re: [PATCH v5 33/40] x86/resctrl: Drop __init/__exit on assorted symbols

[Reinette Chatre]

Hi James,

On 10/4/24 11:03 AM, James Morse wrote:
> Because ARM's MPAM controls are probed using MMIO, resctrl can't be
> initialised until enough CPUs are online to have determined the
> system-wide supported num_closid. Arm64 also supports 'late onlined
> secondaries', where only a subset of CPUs are online during boot.
> 
> These two combine to mean the MPAM driver may not be able to initialise
> resctrl until user-space has brought 'enough' CPUs online.
> 
> To allow MPAM to initialise resctrl after __init text has been free'd,
> remove all the __init markings from resctrl.
> 
> The existing __exit markings cause these functions to be removed by the
> linker as it has never been possible to build resctrl as a module. MPAM
> has an error interrupt which causes the driver to reset and disable
> itself. Remove the __exit markings to allow the MPAM driver to tear down
> resctrl when an error occurs.
> 
> Signed-off-by: James Morse <james.morse@xxxxxxx>
> Tested-by: Carl Worth <carl@xxxxxxxxxxxxxxxxxxxxxx> # arm64
> Tested-by: Shaopeng Tan <tan.shaopeng@xxxxxxxxxxxxxx>
> Reviewed-by: Shaopeng Tan <tan.shaopeng@xxxxxxxxxxxxxx>
> ---
> Changes since v4:
>  * Earlier __init marker removal migrated here.
> ---
>  arch/x86/kernel/cpu/resctrl/core.c     |  6 +++---
>  arch/x86/kernel/cpu/resctrl/internal.h |  6 +++---
>  arch/x86/kernel/cpu/resctrl/monitor.c  |  2 +-
>  arch/x86/kernel/cpu/resctrl/rdtgroup.c | 10 +++++-----
>  include/linux/resctrl.h                |  6 +++---
>  5 files changed, 15 insertions(+), 15 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
> index f484726a2588..f713ac628444 100644
> --- a/arch/x86/kernel/cpu/resctrl/core.c
> +++ b/arch/x86/kernel/cpu/resctrl/core.c
> @@ -775,7 +775,7 @@ struct rdt_options {
>  	bool	force_off, force_on;
>  };
>  
> -static struct rdt_options rdt_options[]  __initdata = {
> +static struct rdt_options rdt_options[]  __ro_after_init = {
>  	RDT_OPT(RDT_FLAG_CMT,	    "cmt",	X86_FEATURE_CQM_OCCUP_LLC),
>  	RDT_OPT(RDT_FLAG_MBM_TOTAL, "mbmtotal", X86_FEATURE_CQM_MBM_TOTAL),
>  	RDT_OPT(RDT_FLAG_MBM_LOCAL, "mbmlocal", X86_FEATURE_CQM_MBM_LOCAL),
> @@ -815,7 +815,7 @@ static int __init set_rdt_options(char *str)
>  }
>  __setup("rdt", set_rdt_options);
>  
> -bool __init rdt_cpu_has(int flag)
> +bool rdt_cpu_has(int flag)

I assume this can be dropped when resctrl_arch_is_evt_configurable() uses
a helper instead?


Reinette