Re: [PATCH RFC v3 15/21] x86: mm: skip collapse_pud_page() when CONFIG_X86_DIRECT_GBPAGES disabled

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Incorrect Kconfig macro name `CONFIG_X86_FEATURE_GBPAGES` unconditionally disables PUD page collapsing on x86.
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commit e72cd2f328b1fab1c51fad6dcdfc5273b0764f4b
Author: Yeoreum Yun <yeoreum.yun@arm.com>

x86: mm: skip collapse_pud_page() when CONFIG_X86_DIRECT_GBPAGES disabled

This commit skips collapse_pud_page() when gbpages are disabled to prepare 
for compile-time folded page table changes.

> diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
> index a1a061d995b31..07a873775279f 100644
> --- a/arch/x86/mm/pat/set_memory.c
> +++ b/arch/x86/mm/pat/set_memory.c
> @@ -1315,7 +1315,7 @@ static int collapse_pud_page(pud_t *pud, unsigned long addr,
>  	pmd_t *pmd, first;
>  	int i;
>  
> -	if (!direct_gbpages)
> +	if (!IS_ENABLED(CONFIG_X86_FEATURE_GBPAGES) || !direct_gbpages)

[Severity: High]
Does CONFIG_X86_FEATURE_GBPAGES exist as a Kconfig option? The commit
message mentions CONFIG_X86_DIRECT_GBPAGES, so it looks like the Kconfig
macro might have been mixed up with the CPU feature flag X86_FEATURE_GBPAGES.

Because this Kconfig option does not exist, IS_ENABLED() will resolve to 0,
making the condition unconditionally true. Will this completely disable PUD
page collapsing on x86, preventing 1GB huge pages from being collapsed in
the kernel direct map?

>  		return 0;
>  
>  	addr &= PUD_MASK;

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Sashiko AI review · https://sashiko.dev/#/patchset/20260902-dummy_ptxp3-v3-0-5d8f5b17c25c@arm.com?part=15