From: Yeoreum Yun <yeoreum.yun@arm.com>
To: sashiko-reviews@lists.linux.dev
Cc: Yeoreum Yun <yeoreum.yun@arm.com>, kvm@vger.kernel.org
Subject: Re: [PATCH RFC v3 15/21] x86: mm: skip collapse_pud_page() when CONFIG_X86_DIRECT_GBPAGES disabled
Date: Wed, 2 Sep 2026 13:29:09 +0100 [thread overview]
Message-ID: <apgWlRtcGwZhKMFO@e129823.arm.com> (raw)
In-Reply-To: <20260902121721.9A2FD1F000E9@smtp.kernel.org>
On Wed, Sep 02, 2026 at 12:17:21PM +0000, sashiko-bot@kernel.org wrote:
> 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.
> --
>
> 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?
Sorry for typo. I'll change into CONFIG_X86_DIRECT_GBPAGES in next
round.
--
Sincerely,
Yeoreum Yun
next prev parent reply other threads:[~2026-09-02 12:29 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-02 11:56 [PATCH RFC v3 00/21] mm: change behavior of pXdp_get()/pXd_page() in compile-time folded pgtable Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 01/21] ARM: mm: make nommu pgd_t a scalar Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 02/21] ARM: mm: make 2-level " Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 03/21] ARM: mm: remove custom pgdp_get() Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 04/21] LoongArch: mm: define pud_leaf() only when PUD exists Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 05/21] MIPS: " Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 06/21] mm/pgtable: define (pgd|p4d|pud)_leaf() for folded page tables Yeoreum Yun
2026-09-02 12:15 ` sashiko-bot
2026-09-02 11:56 ` [PATCH RFC v3 07/21] mm/pgtable: define (pgd|p4d|pud)_offset_lockless() " Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 08/21] mm: vmscan: remove stack copy address of pud/pmd pass in walk_pud/pmd_range() Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 09/21] loongarch: kvm: remove stack copy address of pXd in pXd_offset() Yeoreum Yun
2026-09-02 12:19 ` sashiko-bot
2026-09-02 12:38 ` Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 10/21] riscv: " Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 11/21] riscv: mm: use proper set_pXd() for generic compile-time folded patable in vmalloc_fault() Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 12/21] mm/pgtable: redefine PGTABLE_LEVEL enum with ascend order from PGD Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 13/21] x86: mm: use pgtable_level enum in effective_prot_pXd() Yeoreum Yun
2026-09-02 20:48 ` Dave Hansen
2026-09-02 11:56 ` [PATCH RFC v3 14/21] x86: mm: carve out the generic compile-time folded pgtable case in effective_prot() Yeoreum Yun
2026-09-02 20:46 ` Dave Hansen
2026-09-02 11:56 ` [PATCH RFC v3 15/21] x86: mm: skip collapse_pud_page() when CONFIG_X86_DIRECT_GBPAGES disabled Yeoreum Yun
2026-09-02 12:17 ` sashiko-bot
2026-09-02 12:29 ` Yeoreum Yun [this message]
2026-09-02 15:38 ` Dave Hansen
2026-09-02 16:48 ` Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 16/21] openrisc/pgtable: drop __pmd_offset() Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 17/21] mm/pgtable: optimize pmdp_get() and friends for folded pagetable levels Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 18/21] mm/pgtable: catch abuse of folded dummy pgd_t/p4d_t/pud_t Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 19/21] mm/pgtable: disallow calling (pgd|p4d|pud)_page, pgd_page_vaddr() and (p4d|pud)_pgtable with dummy Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 20/21] mm/pgtable: disallow calling folded set_pgd/set_p4d/set_pud " Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 21/21] Documentation: mm: clarify behaviour of compile-time folded page tables Yeoreum Yun
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