From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Nicholas Piggin <npiggin@gmail.com>, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v3] powerpc/64s/radix: Enable huge vmalloc mappings
Date: Mon, 3 May 2021 11:22:04 +0200 [thread overview]
Message-ID: <6307baa4-a817-196c-9f12-65bede20b2a5@csgroup.eu> (raw)
In-Reply-To: <20210503091755.613393-1-npiggin@gmail.com>
Le 03/05/2021 à 11:17, Nicholas Piggin a écrit :
> This reduces TLB misses by nearly 30x on a `git diff` workload on a
> 2-node POWER9 (59,800 -> 2,100) and reduces CPU cycles by 0.54%, due
> to vfs hashes being allocated with 2MB pages.
>
> Acked-by: Michael Ellerman <mpe@ellerman.id.au>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
> ---
> Since v2:
> - Fix ppc32 compile bug.
>
> Since v1:
> - Don't define MODULES_VADDR which has some other side effect (e.g.,
> ptdump).
> - Fixed (hopefully) kbuild warning.
> - Keep __vmalloc_node_range call on 3 lines.
>
> .../admin-guide/kernel-parameters.txt | 2 ++
> arch/powerpc/Kconfig | 1 +
> arch/powerpc/kernel/module.c | 18 +++++++++++++-----
> 3 files changed, 16 insertions(+), 5 deletions(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 1c0a3cf6fcc9..1be38b25c485 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -3250,6 +3250,8 @@
>
> nohugeiomap [KNL,X86,PPC,ARM64] Disable kernel huge I/O mappings.
>
> + nohugevmalloc [PPC] Disable kernel huge vmalloc mappings.
> +
> nosmt [KNL,S390] Disable symmetric multithreading (SMT).
> Equivalent to smt=1.
>
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index 1e6230bea09d..c547a9d6a2dd 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -185,6 +185,7 @@ config PPC
> select GENERIC_VDSO_TIME_NS
> select HAVE_ARCH_AUDITSYSCALL
> select HAVE_ARCH_HUGE_VMAP if PPC_BOOK3S_64 && PPC_RADIX_MMU
> + select HAVE_ARCH_HUGE_VMALLOC if HAVE_ARCH_HUGE_VMAP
> select HAVE_ARCH_JUMP_LABEL
> select HAVE_ARCH_JUMP_LABEL_RELATIVE
> select HAVE_ARCH_KASAN if PPC32 && PPC_PAGE_SHIFT <= 14
> diff --git a/arch/powerpc/kernel/module.c b/arch/powerpc/kernel/module.c
> index fab84024650c..3f35c8d20be7 100644
> --- a/arch/powerpc/kernel/module.c
> +++ b/arch/powerpc/kernel/module.c
> @@ -8,6 +8,7 @@
> #include <linux/moduleloader.h>
> #include <linux/err.h>
> #include <linux/vmalloc.h>
> +#include <linux/mm.h>
> #include <linux/bug.h>
> #include <asm/module.h>
> #include <linux/uaccess.h>
> @@ -88,17 +89,22 @@ int module_finalize(const Elf_Ehdr *hdr,
> return 0;
> }
>
> -#ifdef MODULES_VADDR
> static __always_inline void *
> __module_alloc(unsigned long size, unsigned long start, unsigned long end)
> {
> - return __vmalloc_node_range(size, 1, start, end, GFP_KERNEL,
> - PAGE_KERNEL_EXEC, VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
> - __builtin_return_address(0));
> + /*
> + * Don't do huge page allocations for modules yet until more testing
> + * is done. STRICT_MODULE_RWX may require extra work to support this
> + * too.
> + */
> + return __vmalloc_node_range(size, 1, start, end, GFP_KERNEL, PAGE_KERNEL_EXEC,
> + VM_FLUSH_RESET_PERMS | VM_NO_HUGE_VMAP,
> + NUMA_NO_NODE, __builtin_return_address(0));
> }
>
> void *module_alloc(unsigned long size)
> {
> +#ifdef MODULES_VADDR
> unsigned long limit = (unsigned long)_etext - SZ_32M;
> void *ptr = NULL;
>
> @@ -112,5 +118,7 @@ void *module_alloc(unsigned long size)
> ptr = __module_alloc(size, MODULES_VADDR, MODULES_END);
>
> return ptr;
> -}
> +#else
> + return __module_alloc(size, VMALLOC_START, VMALLOC_END);
> #endif
> +}
>
prev parent reply other threads:[~2021-05-03 9:22 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-03 9:17 [PATCH v3] powerpc/64s/radix: Enable huge vmalloc mappings Nicholas Piggin
2021-05-03 9:22 ` Christophe Leroy [this message]
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