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Message-ID: <1ca11693-17c2-7260-b642-70b033c64b30@linaro.org>
Date:   Fri, 21 Oct 2022 12:16:50 +0200
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Subject: Re: [PATCH V12 4/4] LoongArch: Enable
 ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
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To:     Huacai Chen <chenhuacai@loongson.cn>,
        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>
Cc:     loongarch@lists.linux.dev, linux-arch@vger.kernel.org,
        Xuefeng Li <lixuefeng@loongson.cn>,
        Guo Ren <guoren@kernel.org>, 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>
References: <20221020072317.492906-1-chenhuacai@loongson.cn>
 <20221020072317.492906-5-chenhuacai@loongson.cn>
From:   =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= <philmd@linaro.org>
In-Reply-To: <20221020072317.492906-5-chenhuacai@loongson.cn>
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On 20/10/22 09:23, Huacai Chen 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/

s/should/have to/

> static_key.h in page-flags.h.

This looks like 2 different changes in a single patch.. The first is a
generic "fix missing include" and the second is LoongArch specific.

Splitting in 2 would ease backport cherry-picks.

> 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_DEFAULT_ON,
> | ^~~~~~~~~~~~~~~~~~~~~~~~
> ./include/linux/page-flags.h:208:1: error: type defaults to 'int' in
> declaration of 'DECLARE_STATIC_KEY_MAYBE' [-Werror=implicit-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_enabled':
> ./include/linux/page-flags.h:213:16: error: implicit declaration of
> function 'static_branch_maybe' [-Werror=implicit-function-declaration]
> 213 | return static_branch_maybe(CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_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_DEFAULT_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
> 
> 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>
>   #ifndef __GENERATING_BOUNDS_H
>   #include <linux/mm_types.h>
>   #include <generated/bounds.h>

Preferably splitting in 2 distinct patches (for each):

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>