linux-kernel - Re: [PATCH v11 01/23] x86/resctrl: Add __init attribute to functions called from resctrl_late

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Message-ID: <68cab18c-9a17-45a2-8374-86deccf2664b@amd.com>
Date: Wed, 19 Feb 2025 10:53:41 -0600
From: "Moger, Babu" <babu.moger@....com>
To: Dave Martin <Dave.Martin@....com>
Cc: corbet@....net, reinette.chatre@...el.com, tglx@...utronix.de,
 mingo@...hat.com, bp@...en8.de, dave.hansen@...ux.intel.com,
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Subject: Re: [PATCH v11 01/23] x86/resctrl: Add __init attribute to functions
 called from resctrl_late_init()

Hi Dave,

On 2/19/25 07:28, Dave Martin wrote:
> Hi,
> 
> On Wed, Jan 22, 2025 at 02:20:09PM -0600, Babu Moger wrote:
>> resctrl_late_init() has the __init attribute, but some of the functions
>> called from it do not have the __init attribute.
>>
>> Add the __init attribute to all the functions in the call sequences to
>> maintain consistency throughout.
> 
> (BTW, did you just find these cases by inspection, or were you getting
> build warnings?
> 
> Even with CONFIG_DEBUG_SECTION_MISMATCH=y, I struggle to get build
> warnings about section mismatches on inlined functions.  Even building
> with -fno-inline doesn't flag them all up (though I don't think this
> suppresses all inlining).
> 
> If you have a way of tracking these cases down automatically, I'd be
> interested to know so that I can apply it elsewhere.)

It is mostly by code inspection at this point.

You can refer to this commit [1].

We used to see section mismatch warnings when non-init functions call
__init functions.

MODPOST Module.symvers
WARNING: modpost: vmlinux: section mismatch in reference:
rdt_get_mon_l3_config+0x2b5 (section: .text) -> rdt_cpu_has (section:
.init.text)
WARNING: modpost: vmlinux: section mismatch in reference:
rdt_get_mon_l3_config+0x408 (section: .text) -> rdt_cpu_has (section:
.init.text)


1.
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v6.14-rc3&id=bd334c86b5d70e5d1c6169991802e62c828d6f38

> 
> Cheers
> ---Dave
> 
> 
>>
>> Fixes: 6a445edce657 ("x86/intel_rdt/cqm: Add RDT monitoring initialization")
>> Fixes: def10853930a ("x86/intel_rdt: Add two new resources for L2 Code and Data Prioritization (CDP)")
>> Fixes: bd334c86b5d7 ("x86/resctrl: Add __init attribute to rdt_get_mon_l3_config()")
>> Suggested-by: Reinette Chatre <reinette.chatre@...el.com>
>> Signed-off-by: Babu Moger <babu.moger@....com>
>> ---
> 
> [...]
> 
>> diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
>> index 3d1735ed8d1f..f0a331287979 100644
>> --- a/arch/x86/kernel/cpu/resctrl/core.c
>> +++ b/arch/x86/kernel/cpu/resctrl/core.c
>> @@ -145,7 +145,7 @@ u32 resctrl_arch_system_num_rmid_idx(void)
>>   * is always 20 on hsw server parts. The minimum cache bitmask length
>>   * allowed for HSW server is always 2 bits. Hardcode all of them.
>>   */
>> -static inline void cache_alloc_hsw_probe(void)
>> +static inline __init void cache_alloc_hsw_probe(void)
>>  {
>>  	struct rdt_hw_resource *hw_res = &rdt_resources_all[RDT_RESOURCE_L3];
>>  	struct rdt_resource *r  = &hw_res->r_resctrl;
>> @@ -277,7 +277,7 @@ static __init bool __rdt_get_mem_config_amd(struct rdt_resource *r)
> 
> [...]
> 

-- 
Thanks
Babu Moger