Re: [PATCH v2 2/3] arm64: Support huge vmalloc mappings

From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Kefeng Wang <wangkefeng.wang@huawei.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Andrew Morton <akpm@linux-foundation.org>,
	"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
	"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"x86@kernel.org" <x86@kernel.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>
Cc: Nicholas Piggin <npiggin@gmail.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Matthew Wilcox <willy@infradead.org>
Subject: Re: [PATCH v2 2/3] arm64: Support huge vmalloc mappings
Date: Sat, 15 Jan 2022 10:05:55 +0000	[thread overview]
Message-ID: <41f715ce-5597-b66a-e708-26d102668cf5@csgroup.eu> (raw)
In-Reply-To: <20211227145903.187152-3-wangkefeng.wang@huawei.com>


Le 27/12/2021 à 15:59, Kefeng Wang a écrit :
> This patch select HAVE_ARCH_HUGE_VMALLOC to let arm64 support huge
> vmalloc mappings.
> 
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will@kernel.org>
> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
> ---
>   Documentation/admin-guide/kernel-parameters.txt | 4 ++--
>   arch/arm64/Kconfig                              | 1 +
>   arch/arm64/kernel/module.c                      | 5 +++--
>   3 files changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 7b2f900fd243..e3f9fd7ec106 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -1639,7 +1639,7 @@
>   			precedence over memory_hotplug.memmap_on_memory.
>   
>   
> -	hugevmalloc=	[PPC] Reguires CONFIG_HAVE_ARCH_HUGE_VMALLOC
> +	hugevmalloc=	[KNL,PPC,ARM64] Reguires CONFIG_HAVE_ARCH_HUGE_VMALLOC
>   			Format: { on | off }
>   			Default set by CONFIG_HUGE_VMALLOC_DEFAULT_ENABLED.
>   
> @@ -3424,7 +3424,7 @@
>   
>   	nohugeiomap	[KNL,X86,PPC,ARM64] Disable kernel huge I/O mappings.
>   
> -	nohugevmalloc	[PPC] Disable kernel huge vmalloc mappings.
> +	nohugevmalloc	[KNL,PPC,ARM64] Disable kernel huge vmalloc mappings.
>   
>   	nosmt		[KNL,S390] Disable symmetric multithreading (SMT).
>   			Equivalent to smt=1.
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 3bb0b67292b5..c34bbb4482b0 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -142,6 +142,7 @@ config ARM64
>   	select HAVE_ARCH_AUDITSYSCALL
>   	select HAVE_ARCH_BITREVERSE
>   	select HAVE_ARCH_COMPILER_H
> +	select HAVE_ARCH_HUGE_VMALLOC
>   	select HAVE_ARCH_HUGE_VMAP
>   	select HAVE_ARCH_JUMP_LABEL
>   	select HAVE_ARCH_JUMP_LABEL_RELATIVE
> diff --git a/arch/arm64/kernel/module.c b/arch/arm64/kernel/module.c
> index 309a27553c87..af7b4cbace2b 100644
> --- a/arch/arm64/kernel/module.c
> +++ b/arch/arm64/kernel/module.c
> @@ -36,7 +36,8 @@ void *module_alloc(unsigned long size)
>   		module_alloc_end = MODULES_END;
>   
>   	p = __vmalloc_node_range(size, MODULE_ALIGN, module_alloc_base,
> -				module_alloc_end, gfp_mask, PAGE_KERNEL, VM_DEFER_KMEMLEAK,
> +				module_alloc_end, gfp_mask, PAGE_KERNEL,
> +				VM_DEFER_KMEMLEAK | VM_NO_HUGE_VMAP,

you should add a comment like powerpc (commit 8abddd968a30 
("powerpc/64s/radix: Enable huge vmalloc mappings")) to explain why this 
requires VM_NO_HUGE_VMAP

>   				NUMA_NO_NODE, __builtin_return_address(0));
>   
>   	if (!p && IS_ENABLED(CONFIG_ARM64_MODULE_PLTS) &&
> @@ -55,7 +56,7 @@ void *module_alloc(unsigned long size)
>   		 */
>   		p = __vmalloc_node_range(size, MODULE_ALIGN, module_alloc_base,
>   				module_alloc_base + SZ_2G, GFP_KERNEL,
> -				PAGE_KERNEL, 0, NUMA_NO_NODE,
> +				PAGE_KERNEL, VM_NO_HUGE_VMAP, NUMA_NO_NODE,

Same

>   				__builtin_return_address(0));
>   
>   	if (p && (kasan_module_alloc(p, size, gfp_mask) < 0)) {