Messages in this thread | | | Subject | Re: [PATCH v13 14/14] powerpc/64s/radix: Enable huge vmalloc mappings | From | Christophe Leroy <> | Date | Thu, 15 Apr 2021 12:23:55 +0200 |
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Hi Nick,
Le 17/03/2021 à 07:24, 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. > > Cc: linuxppc-dev@lists.ozlabs.org > Acked-by: Michael Ellerman <mpe@ellerman.id.au> > Signed-off-by: Nicholas Piggin <npiggin@gmail.com> > --- > .../admin-guide/kernel-parameters.txt | 2 ++ > arch/powerpc/Kconfig | 1 + > arch/powerpc/kernel/module.c | 22 +++++++++++++++---- > 3 files changed, 21 insertions(+), 4 deletions(-) > > --- 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> > @@ -87,13 +88,26 @@ int module_finalize(const Elf_Ehdr *hdr, > return 0; > } > > -#ifdef MODULES_VADDR > void *module_alloc(unsigned long size) > { > + unsigned long start = VMALLOC_START; > + unsigned long end = VMALLOC_END; > + > +#ifdef MODULES_VADDR > BUILD_BUG_ON(TASK_SIZE > MODULES_VADDR); > + start = MODULES_VADDR; > + end = MODULES_END; > +#endif > + > + /* > + * 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, MODULES_VADDR, MODULES_END, GFP_KERNEL, > - PAGE_KERNEL_EXEC, VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
I think you should add the following in <asm/pgtable.h>
#ifndef MODULES_VADDR #define MODULES_VADDR VMALLOC_START #define MODULES_END VMALLOC_END #endif
And leave module_alloc() as is (just removing the enclosing #ifdef MODULES_VADDR and adding the VM_NO_HUGE_VMAP flag)
This would minimise the conflits with the changes I did in powerpc/next reported by Stephen R.
> + return __vmalloc_node_range(size, 1, start, end, GFP_KERNEL, > + PAGE_KERNEL_EXEC, > + VM_NO_HUGE_VMAP | VM_FLUSH_RESET_PERMS, > + NUMA_NO_NODE, > __builtin_return_address(0)); > } > -#endif >
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