Unverified Commit 3f910b7a authored by Jisheng Zhang's avatar Jisheng Zhang Committed by Palmer Dabbelt
Browse files

riscv: enable HAVE_FAST_GUP if MMU 



Activate the fast gup for riscv mmu platforms. Here are some
GUP_FAST_BENCHMARK performance numbers:

Before the patch:
GUP_FAST_BENCHMARK: Time: get:53203 put:5085 us

After the patch:
GUP_FAST_BENCHMARK: Time: get:17711 put:5060 us

The get time is reduced by 66.7%! IOW, 3x get speed!

Signed-off-by: default avatarJisheng Zhang <jszhang@kernel.org>
Reviewed-by: default avatarAlexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20231219175046.2496-5-jszhang@kernel.org


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent 69be3fb1

arch/riscv/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -119,6 +119,7 @@ config RISCV 
	select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER

	select HAVE_FUNCTION_TRACER if !XIP_KERNEL && !PREEMPTION

	select HAVE_EBPF_JIT if MMU

	select HAVE_FAST_GUP if MMU

	select HAVE_FUNCTION_ARG_ACCESS_API

	select HAVE_FUNCTION_ERROR_INJECTION

	select HAVE_GCC_PLUGINS

arch/riscv/include/asm/pgtable.h

+6 −0
Original line number Diff line number Diff line
@@ -673,6 +673,12 @@ static inline int pmd_write(pmd_t pmd) 
	return pte_write(pmd_pte(pmd));

}



#define pud_write pud_write

static inline int pud_write(pud_t pud)

{

	return pte_write(pud_pte(pud));

}



static inline int pmd_dirty(pmd_t pmd)

{

	return pte_dirty(pmd_pte(pmd));