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References: <20221024070105.306280-1-chenhuacai@loongson.cn> <20221024070105.306280-5-chenhuacai@loongson.cn>
In-Reply-To: <20221024070105.306280-5-chenhuacai@loongson.cn>
From:   Guo Ren <guoren@kernel.org>
Date:   Mon, 24 Oct 2022 16:04:06 +0800
Message-ID: <CAJF2gTSN3zzvgAdiM8rYc3EGFxR4JJnHSh12mvsfUOQsqRRvkg@mail.gmail.com>
Subject: Re: [PATCH V13 4/4] LoongArch: Enable ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
To:     Huacai Chen <chenhuacai@loongson.cn>
Cc:     Arnd Bergmann <arnd@arndb.de>, Huacai Chen <chenhuacai@kernel.org>,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Andy Lutomirski <luto@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Dinh Nguyen <dinguyen@kernel.org>, loongarch@lists.linux.dev,
        linux-arch@vger.kernel.org, Xuefeng Li <lixuefeng@loongson.cn>,
        Xuerui Wang <kernel@xen0n.name>,
        Jiaxun Yang <jiaxun.yang@flygoat.com>,
        Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
        linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        Feiyang Chen <chenfeiyang@loongson.cn>,
        =?UTF-8?Q?Philippe_Mathieu=2DDaud=C3=A9?= <philmd@linaro.org>
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On Mon, Oct 24, 2022 at 3:05 PM Huacai Chen <chenhuacai@loongson.cn> wrote:
>
> From: Feiyang Chen <chenfeiyang@loongson.cn>
>
> The feature of minimizing overhead of struct page associated with each
> HugeTLB page is implemented on x86_64. However, the infrastructure of
> this feature is already there, so just select ARCH_WANT_HUGETLB_PAGE_
> OPTIMIZE_VMEMMAP is enough to enable this feature for LoongArch.
>
> To avoid the following build error on LoongArch we should include linux/
> static_key.h in page-flags.h. This is straightforward but the build
> error is implicitly a LoongArch-specific problem, because ARM64 and X86
> have already include static_key.h from their arch-specific core headers.
>
> In file included from ./include/linux/mmzone.h:22,
> from ./include/linux/gfp.h:6,
> from ./include/linux/mm.h:7,
> from arch/loongarch/kernel/asm-offsets.c:9:
> ./include/linux/page-flags.h:208:1: warning: data definition has no
> type or storage class
> 208 | DECLARE_STATIC_KEY_MAYBE(CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAU=
LT_ON,
> | ^~~~~~~~~~~~~~~~~~~~~~~~
> ./include/linux/page-flags.h:208:1: error: type defaults to 'int' in
> declaration of 'DECLARE_STATIC_KEY_MAYBE' [-Werror=3Dimplicit-int]
> ./include/linux/page-flags.h:209:26: warning: parameter names (without
> types) in function declaration
> 209 | hugetlb_optimize_vmemmap_key);
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ./include/linux/page-flags.h: In function 'hugetlb_optimize_vmemmap_enabl=
ed':
> ./include/linux/page-flags.h:213:16: error: implicit declaration of
> function 'static_branch_maybe' [-Werror=3Dimplicit-function-declaration]
> 213 | return static_branch_maybe(CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEF=
AULT_ON,
> | ^~~~~~~~~~~~~~~~~~~
> ./include/linux/page-flags.h:213:36: error:
> 'CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON' undeclared (first
> use in this function); did you mean
> 'CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP'?
> 213 | return static_branch_maybe(CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEF=
AULT_ON,
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> | CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
> ./include/linux/page-flags.h:213:36: note: each undeclared identifier
> is reported only once for each function it appears in
> ./include/linux/page-flags.h:214:37: error:
> 'hugetlb_optimize_vmemmap_key' undeclared (first use in this
> function); did you mean 'hugetlb_optimize_vmemmap_enabled'?
> 214 | &hugetlb_optimize_vmemmap_key);
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
> | hugetlb_optimize_vmemmap_enabled
>
> Reviewed-by: Philippe Mathieu-Daud=C3=A9 <philmd@linaro.org>
> Signed-off-by: Feiyang Chen <chenfeiyang@loongson.cn>
> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
> ---
>  arch/loongarch/Kconfig     | 1 +
>  include/linux/page-flags.h | 1 +
>  2 files changed, 2 insertions(+)
>
> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
> index 6f7fa0c0ca08..0a6ef613124c 100644
> --- a/arch/loongarch/Kconfig
> +++ b/arch/loongarch/Kconfig
> @@ -52,6 +52,7 @@ config LOONGARCH
>         select ARCH_USE_QUEUED_RWLOCKS
>         select ARCH_USE_QUEUED_SPINLOCKS
>         select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
> +       select ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
>         select ARCH_WANT_LD_ORPHAN_WARN
>         select ARCH_WANTS_NO_INSTR
>         select BUILDTIME_TABLE_SORT
> diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
> index 0b0ae5084e60..1aafdc73e399 100644
> --- a/include/linux/page-flags.h
> +++ b/include/linux/page-flags.h
> @@ -9,6 +9,7 @@
>  #include <linux/types.h>
>  #include <linux/bug.h>
>  #include <linux/mmdebug.h>
> +#include <linux/static_key.h>
Em... riscv needn't this.

>  #ifndef __GENERATING_BOUNDS_H
>  #include <linux/mm_types.h>
>  #include <generated/bounds.h>
> --
> 2.31.1
>


--=20
Best Regards
 Guo Ren