LinuxLists.cc - [PATCH 1/2] riscv: percpu:Add riscv percpu operations

2022-10-26 10:47:34

Subject: [PATCH 1/2] riscv: percpu:Add riscv percpu operations

This patch use riscv AMO(Atomic Memory Operation) instructions to
optimise some this_cpu_and this_cpu_or this_cpu_add operations.
It reuse cmpxchg_local() to impletment this_cpu_cmpxchg macros.
It reuse xchg_relaxed() to impletment this_cpu_xchg macros.

Signed-off-by: Wen Yao <[email protected]>
---
arch/riscv/include/asm/percpu.h | 101 ++++++++++++++++++++++++++++++++
1 file changed, 101 insertions(+)
create mode 100644 arch/riscv/include/asm/percpu.h

diff --git a/arch/riscv/include/asm/percpu.h b/arch/riscv/include/asm/percpu.h
new file mode 100644
index 000000000000..ae796e328442
--- /dev/null
+++ b/arch/riscv/include/asm/percpu.h
@@ -0,0 +1,101 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Union Tech Software Technology Corporation Limited
+ */
+#ifndef __ASM_PERCPU_H
+#define __ASM_PERCPU_H
+
+#include <asm/cmpxchg.h>
+
+#define PERCPU_OP(op, asm_op, c_op) \
+ static inline unsigned long __percpu_##op(void *ptr, \
+ unsigned long val, int size) \
+ { \
+ unsigned long ret; \
+ switch (size) { \
+ case 4: \
+ __asm__ __volatile__( \
+ "amo" #asm_op ".w" \
+ " %[ret], %[val], %[ptr]\n" \
+ : [ret] "=&r"(ret), [ptr] "+A"(*(u32 *)ptr) \
+ : [val] "r"(val)); \
+ break; \
+ case 8: \
+ __asm__ __volatile__( \
+ "amo" #asm_op ".d" \
+ " %[ret], %[val], %[ptr]\n" \
+ : [ret] "=&r"(ret), [ptr] "+A"(*(u64 *)ptr) \
+ : [val] "r"(val)); \
+ break; \
+ default: \
+ ret = 0; \
+ BUILD_BUG(); \
+ } \
+ \
+ return ret c_op val; \
+ }
+
+PERCPU_OP(add, add, +)
+PERCPU_OP(and, and, &)
+PERCPU_OP(or, or, |)
+#undef PERCPU_OP
+
+/* this_cpu_xchg */
+#define _protect_xchg_local(pcp, val) \
+ ({ \
+ typeof(*raw_cpu_ptr(&(pcp))) __ret; \
+ preempt_disable_notrace(); \
+ __ret = xchg_relaxed(raw_cpu_ptr(&(pcp)), val); \
+ preempt_enable_notrace(); \
+ __ret; \
+ })
+
+/* this_cpu_cmpxchg */
+#define _protect_cmpxchg_local(pcp, o, n) \
+ ({ \
+ typeof(*raw_cpu_ptr(&(pcp))) __ret; \
+ preempt_disable_notrace(); \
+ __ret = cmpxchg_local(raw_cpu_ptr(&(pcp)), o, n); \
+ preempt_enable_notrace(); \
+ __ret; \
+ })
+
+#define _pcp_protect(operation, pcp, val) \
+ ({ \
+ typeof(pcp) __retval; \
+ preempt_disable_notrace(); \
+ __retval = (typeof(pcp))operation(raw_cpu_ptr(&(pcp)), (val), \
+ sizeof(pcp)); \
+ preempt_enable_notrace(); \
+ __retval; \
+ })
+
+#define _percpu_add(pcp, val) _pcp_protect(__percpu_add, pcp, val)
+
+#define _percpu_add_return(pcp, val) _percpu_add(pcp, val)
+
+#define _percpu_and(pcp, val) _pcp_protect(__percpu_and, pcp, val)
+
+#define _percpu_or(pcp, val) _pcp_protect(__percpu_or, pcp, val)
+
+#define this_cpu_add_4(pcp, val) _percpu_add(pcp, val)
+#define this_cpu_add_8(pcp, val) _percpu_add(pcp, val)
+
+#define this_cpu_add_return_4(pcp, val) _percpu_add_return(pcp, val)
+#define this_cpu_add_return_8(pcp, val) _percpu_add_return(pcp, val)
+
+#define this_cpu_and_4(pcp, val) _percpu_and(pcp, val)
+#define this_cpu_and_8(pcp, val) _percpu_and(pcp, val)
+
+#define this_cpu_or_4(pcp, val) _percpu_or(pcp, val)
+#define this_cpu_or_8(pcp, val) _percpu_or(pcp, val)
+
+#define this_cpu_xchg_4(pcp, val) _protect_xchg_local(pcp, val)
+#define this_cpu_xchg_8(pcp, val) _protect_xchg_local(pcp, val)
+
+#define this_cpu_cmpxchg_4(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
+#define this_cpu_cmpxchg_8(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
+
+#include <asm-generic/percpu.h>
+
+#endif /* __ASM_PERCPU_H */
--
2.25.1

2022-10-26 19:37:42

by Conor Dooley

[permalink] [raw]

Subject: Re: [PATCH 1/2] riscv: percpu:Add riscv percpu operations

Hey Wen Yao,
Couple comments for you.

On Wed, Oct 26, 2022 at 06:40:14PM +0800, Wen Yao wrote:
> riscv: percpu:Add riscv percpu operations

Can you please consistently use ": " between parts of the commit
messages? For both this and patch 2/2.

> This patch use riscv AMO(Atomic Memory Operation) instructions to

nit: s/This patch/Use (or better:
"Optimise some ... using RISC-V AMO (Atomic..."

> optimise some this_cpu_and this_cpu_or this_cpu_add operations.
> It reuse cmpxchg_local() to impletment this_cpu_cmpxchg macros.

s/It Reuse/Reuse, and "impletment" is a typo.

> It reuse xchg_relaxed() to impletment this_cpu_xchg macros.
>
> Signed-off-by: Wen Yao <[email protected]>
> ---
> arch/riscv/include/asm/percpu.h | 101 ++++++++++++++++++++++++++++++++
> 1 file changed, 101 insertions(+)
> create mode 100644 arch/riscv/include/asm/percpu.h
>
> diff --git a/arch/riscv/include/asm/percpu.h b/arch/riscv/include/asm/percpu.h
> new file mode 100644
> index 000000000000..ae796e328442
> --- /dev/null
> +++ b/arch/riscv/include/asm/percpu.h
> @@ -0,0 +1,101 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2020-2022 Union Tech Software Technology Corporation Limited
> + */
> +#ifndef __ASM_PERCPU_H
> +#define __ASM_PERCPU_H
> +
> +#include <asm/cmpxchg.h>
> +
> +#define PERCPU_OP(op, asm_op, c_op) \
> + static inline unsigned long __percpu_##op(void *ptr, \

Can you please make sure that these \s are actually aligned & swap the
spaces you've used for tabs? The other files that I checked in this
directory all use tabs for \ alignment in macros.

Thanks,
Conor.

> + unsigned long val, int size) \
> + { \
> + unsigned long ret; \
> + switch (size) { \
> + case 4: \
> + __asm__ __volatile__( \
> + "amo" #asm_op ".w" \
> + " %[ret], %[val], %[ptr]\n" \
> + : [ret] "=&r"(ret), [ptr] "+A"(*(u32 *)ptr) \
> + : [val] "r"(val)); \
> + break; \
> + case 8: \
> + __asm__ __volatile__( \
> + "amo" #asm_op ".d" \
> + " %[ret], %[val], %[ptr]\n" \
> + : [ret] "=&r"(ret), [ptr] "+A"(*(u64 *)ptr) \
> + : [val] "r"(val)); \
> + break; \
> + default: \
> + ret = 0; \
> + BUILD_BUG(); \
> + } \
> + \
> + return ret c_op val; \
> + }
> +
> +PERCPU_OP(add, add, +)
> +PERCPU_OP(and, and, &)
> +PERCPU_OP(or, or, |)
> +#undef PERCPU_OP
> +
> +/* this_cpu_xchg */
> +#define _protect_xchg_local(pcp, val) \
> + ({ \
> + typeof(*raw_cpu_ptr(&(pcp))) __ret; \
> + preempt_disable_notrace(); \
> + __ret = xchg_relaxed(raw_cpu_ptr(&(pcp)), val); \
> + preempt_enable_notrace(); \
> + __ret; \
> + })
> +
> +/* this_cpu_cmpxchg */
> +#define _protect_cmpxchg_local(pcp, o, n) \
> + ({ \
> + typeof(*raw_cpu_ptr(&(pcp))) __ret; \
> + preempt_disable_notrace(); \
> + __ret = cmpxchg_local(raw_cpu_ptr(&(pcp)), o, n); \
> + preempt_enable_notrace(); \
> + __ret; \
> + })
> +
> +#define _pcp_protect(operation, pcp, val) \
> + ({ \
> + typeof(pcp) __retval; \
> + preempt_disable_notrace(); \
> + __retval = (typeof(pcp))operation(raw_cpu_ptr(&(pcp)), (val), \
> + sizeof(pcp)); \
> + preempt_enable_notrace(); \
> + __retval; \
> + })
> +
> +#define _percpu_add(pcp, val) _pcp_protect(__percpu_add, pcp, val)
> +
> +#define _percpu_add_return(pcp, val) _percpu_add(pcp, val)
> +
> +#define _percpu_and(pcp, val) _pcp_protect(__percpu_and, pcp, val)
> +
> +#define _percpu_or(pcp, val) _pcp_protect(__percpu_or, pcp, val)
> +
> +#define this_cpu_add_4(pcp, val) _percpu_add(pcp, val)
> +#define this_cpu_add_8(pcp, val) _percpu_add(pcp, val)
> +
> +#define this_cpu_add_return_4(pcp, val) _percpu_add_return(pcp, val)
> +#define this_cpu_add_return_8(pcp, val) _percpu_add_return(pcp, val)
> +
> +#define this_cpu_and_4(pcp, val) _percpu_and(pcp, val)
> +#define this_cpu_and_8(pcp, val) _percpu_and(pcp, val)
> +
> +#define this_cpu_or_4(pcp, val) _percpu_or(pcp, val)
> +#define this_cpu_or_8(pcp, val) _percpu_or(pcp, val)
> +
> +#define this_cpu_xchg_4(pcp, val) _protect_xchg_local(pcp, val)
> +#define this_cpu_xchg_8(pcp, val) _protect_xchg_local(pcp, val)
> +
> +#define this_cpu_cmpxchg_4(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
> +#define this_cpu_cmpxchg_8(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
> +
> +#include <asm-generic/percpu.h>
> +
> +#endif /* __ASM_PERCPU_H */
> --
> 2.25.1
>

2022-10-27 00:32:03

by kernel test robot

[permalink] [raw]

Subject: Re: [PATCH 1/2] riscv: percpu:Add riscv percpu operations

Hi Wen,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v6.1-rc2 next-20221026]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url: https://github.com/intel-lab-lkp/linux/commits/Wen-Yao/riscv-Rewrite-percpu-operations-and-support-cmpxchg-local-feature/20221026-184310
patch link: https://lore.kernel.org/r/20221026104015.565468-2-haiwenyao%40uniontech.com
patch subject: [PATCH 1/2] riscv: percpu:Add riscv percpu operations
config: riscv-rv32_defconfig
compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project 791a7ae1ba3efd6bca96338e10ffde557ba83920)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install riscv cross compiling tool for clang build
# apt-get install binutils-riscv-linux-gnu
# https://github.com/intel-lab-lkp/linux/commit/bb33e199935b65336d45c367d7581682dff63cdb
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Wen-Yao/riscv-Rewrite-percpu-operations-and-support-cmpxchg-local-feature/20221026-184310
git checkout bb33e199935b65336d45c367d7581682dff63cdb
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <[email protected]>

All errors (new ones prefixed by >>):

In file included from fs/nfs/file.c:20:
In file included from include/linux/module.h:13:
In file included from include/linux/stat.h:19:
In file included from include/linux/time.h:6:
In file included from include/linux/math64.h:6:
In file included from include/linux/math.h:6:
In file included from ./arch/riscv/include/generated/asm/div64.h:1:
In file included from include/asm-generic/div64.h:55:
In file included from include/linux/log2.h:12:
In file included from include/linux/bitops.h:68:
In file included from arch/riscv/include/asm/bitops.h:14:
In file included from include/linux/irqflags.h:17:
>> arch/riscv/include/asm/percpu.h:38:1: error: instruction requires the following: RV64I Base Instruction Set
PERCPU_OP(add, add, +)
^
arch/riscv/include/asm/percpu.h:25:5: note: expanded from macro 'PERCPU_OP'
"amo" #asm_op ".d" \
^
<inline asm>:1:2: note: instantiated into assembly here
amoadd.d a1, s3, 0(a0)
^
In file included from fs/nfs/file.c:20:
In file included from include/linux/module.h:13:
In file included from include/linux/stat.h:19:
In file included from include/linux/time.h:6:
In file included from include/linux/math64.h:6:
In file included from include/linux/math.h:6:
In file included from ./arch/riscv/include/generated/asm/div64.h:1:
In file included from include/asm-generic/div64.h:55:
In file included from include/linux/log2.h:12:
In file included from include/linux/bitops.h:68:
In file included from arch/riscv/include/asm/bitops.h:14:
In file included from include/linux/irqflags.h:17:
>> arch/riscv/include/asm/percpu.h:38:1: error: instruction requires the following: RV64I Base Instruction Set
PERCPU_OP(add, add, +)
^
arch/riscv/include/asm/percpu.h:25:5: note: expanded from macro 'PERCPU_OP'
"amo" #asm_op ".d" \
^
<inline asm>:1:2: note: instantiated into assembly here
amoadd.d a1, s4, 0(a0)
^
2 errors generated.
--
In file included from fs/nfs/direct.c:43:
In file included from include/linux/sched.h:14:
In file included from include/linux/pid.h:5:
In file included from include/linux/rculist.h:11:
In file included from include/linux/rcupdate.h:26:
In file included from include/linux/irqflags.h:17:
>> arch/riscv/include/asm/percpu.h:38:1: error: instruction requires the following: RV64I Base Instruction Set
PERCPU_OP(add, add, +)
^
arch/riscv/include/asm/percpu.h:25:5: note: expanded from macro 'PERCPU_OP'
"amo" #asm_op ".d" \
^
<inline asm>:1:2: note: instantiated into assembly here
amoadd.d a1, s1, 0(a0)
^
In file included from fs/nfs/direct.c:43:
In file included from include/linux/sched.h:14:
In file included from include/linux/pid.h:5:
In file included from include/linux/rculist.h:11:
In file included from include/linux/rcupdate.h:26:
In file included from include/linux/irqflags.h:17:
>> arch/riscv/include/asm/percpu.h:38:1: error: instruction requires the following: RV64I Base Instruction Set
PERCPU_OP(add, add, +)
^
arch/riscv/include/asm/percpu.h:25:5: note: expanded from macro 'PERCPU_OP'
"amo" #asm_op ".d" \
^
<inline asm>:1:2: note: instantiated into assembly here
amoadd.d a1, s4, 0(a0)
^
2 errors generated.
--
In file included from fs/nfs/read.c:11:
In file included from include/linux/time.h:6:
In file included from include/linux/math64.h:6:
In file included from include/linux/math.h:6:
In file included from ./arch/riscv/include/generated/asm/div64.h:1:
In file included from include/asm-generic/div64.h:55:
In file included from include/linux/log2.h:12:
In file included from include/linux/bitops.h:68:
In file included from arch/riscv/include/asm/bitops.h:14:
In file included from include/linux/irqflags.h:17:
>> arch/riscv/include/asm/percpu.h:38:1: error: instruction requires the following: RV64I Base Instruction Set
PERCPU_OP(add, add, +)
^
arch/riscv/include/asm/percpu.h:25:5: note: expanded from macro 'PERCPU_OP'
"amo" #asm_op ".d" \
^
<inline asm>:1:2: note: instantiated into assembly here
amoadd.d a2, a0, 0(a1)
^
In file included from fs/nfs/read.c:11:
In file included from include/linux/time.h:6:
In file included from include/linux/math64.h:6:
In file included from include/linux/math.h:6:
In file included from ./arch/riscv/include/generated/asm/div64.h:1:
In file included from include/asm-generic/div64.h:55:
In file included from include/linux/log2.h:12:
In file included from include/linux/bitops.h:68:
In file included from arch/riscv/include/asm/bitops.h:14:
In file included from include/linux/irqflags.h:17:
>> arch/riscv/include/asm/percpu.h:38:1: error: instruction requires the following: RV64I Base Instruction Set
PERCPU_OP(add, add, +)
^
arch/riscv/include/asm/percpu.h:25:5: note: expanded from macro 'PERCPU_OP'
"amo" #asm_op ".d" \
^
<inline asm>:1:2: note: instantiated into assembly here
amoadd.d a2, a0, 0(a1)
^
In file included from fs/nfs/read.c:11:
In file included from include/linux/time.h:6:
In file included from include/linux/math64.h:6:
In file included from include/linux/math.h:6:
In file included from ./arch/riscv/include/generated/asm/div64.h:1:
In file included from include/asm-generic/div64.h:55:
In file included from include/linux/log2.h:12:
In file included from include/linux/bitops.h:68:
In file included from arch/riscv/include/asm/bitops.h:14:
In file included from include/linux/irqflags.h:17:
>> arch/riscv/include/asm/percpu.h:38:1: error: instruction requires the following: RV64I Base Instruction Set
PERCPU_OP(add, add, +)
^
arch/riscv/include/asm/percpu.h:25:5: note: expanded from macro 'PERCPU_OP'
"amo" #asm_op ".d" \
^
<inline asm>:1:2: note: instantiated into assembly here
amoadd.d a2, a1, 0(a0)
^
3 errors generated.
--
In file included from fs/nfs/write.c:11:
In file included from include/linux/slab.h:15:
In file included from include/linux/gfp.h:7:
In file included from include/linux/mmzone.h:8:
In file included from include/linux/spinlock.h:56:
In file included from include/linux/preempt.h:78:
In file included from ./arch/riscv/include/generated/asm/preempt.h:1:
In file included from include/asm-generic/preempt.h:5:
In file included from include/linux/thread_info.h:14:
In file included from include/linux/restart_block.h:10:
In file included from include/linux/time64.h:5:
In file included from include/linux/math64.h:6:
In file included from include/linux/math.h:6:
In file included from ./arch/riscv/include/generated/asm/div64.h:1:
In file included from include/asm-generic/div64.h:55:
In file included from include/linux/log2.h:12:
In file included from include/linux/bitops.h:68:
In file included from arch/riscv/include/asm/bitops.h:14:
In file included from include/linux/irqflags.h:17:
>> arch/riscv/include/asm/percpu.h:38:1: error: instruction requires the following: RV64I Base Instruction Set
PERCPU_OP(add, add, +)
^
arch/riscv/include/asm/percpu.h:25:5: note: expanded from macro 'PERCPU_OP'
"amo" #asm_op ".d" \
^
<inline asm>:1:2: note: instantiated into assembly here
amoadd.d a2, a1, 0(a0)
^
In file included from fs/nfs/write.c:11:
In file included from include/linux/slab.h:15:
In file included from include/linux/gfp.h:7:
In file included from include/linux/mmzone.h:8:
In file included from include/linux/spinlock.h:56:
In file included from include/linux/preempt.h:78:
In file included from ./arch/riscv/include/generated/asm/preempt.h:1:
In file included from include/asm-generic/preempt.h:5:
In file included from include/linux/thread_info.h:14:
In file included from include/linux/restart_block.h:10:
In file included from include/linux/time64.h:5:
In file included from include/linux/math64.h:6:
In file included from include/linux/math.h:6:
In file included from ./arch/riscv/include/generated/asm/div64.h:1:
In file included from include/asm-generic/div64.h:55:
In file included from include/linux/log2.h:12:
In file included from include/linux/bitops.h:68:
In file included from arch/riscv/include/asm/bitops.h:14:
In file included from include/linux/irqflags.h:17:
>> arch/riscv/include/asm/percpu.h:38:1: error: instruction requires the following: RV64I Base Instruction Set
PERCPU_OP(add, add, +)
^
arch/riscv/include/asm/percpu.h:25:5: note: expanded from macro 'PERCPU_OP'
"amo" #asm_op ".d" \
^
<inline asm>:1:2: note: instantiated into assembly here
amoadd.d a2, a1, 0(a0)
^
2 errors generated.
--
In file included from fs/ext4/mballoc.c:12:
In file included from fs/ext4/ext4_jbd2.h:15:
In file included from include/linux/fs.h:6:
In file included from include/linux/wait_bit.h:8:
In file included from include/linux/wait.h:9:
In file included from include/linux/spinlock.h:56:
In file included from include/linux/preempt.h:78:
In file included from ./arch/riscv/include/generated/asm/preempt.h:1:
In file included from include/asm-generic/preempt.h:5:
In file included from include/linux/thread_info.h:14:
In file included from include/linux/restart_block.h:10:
In file included from include/linux/time64.h:5:
In file included from include/linux/math64.h:6:
In file included from include/linux/math.h:6:
In file included from ./arch/riscv/include/generated/asm/div64.h:1:
In file included from include/asm-generic/div64.h:55:
In file included from include/linux/log2.h:12:
In file included from include/linux/bitops.h:68:
In file included from arch/riscv/include/asm/bitops.h:14:
In file included from include/linux/irqflags.h:17:
>> arch/riscv/include/asm/percpu.h:38:1: error: instruction requires the following: RV64I Base Instruction Set
PERCPU_OP(add, add, +)
^
arch/riscv/include/asm/percpu.h:25:5: note: expanded from macro 'PERCPU_OP'
"amo" #asm_op ".d" \
^
<inline asm>:1:2: note: instantiated into assembly here
amoadd.d a2, a1, 0(a0)
^
In file included from fs/ext4/mballoc.c:12:
In file included from fs/ext4/ext4_jbd2.h:15:
In file included from include/linux/fs.h:6:
In file included from include/linux/wait_bit.h:8:
In file included from include/linux/wait.h:9:
In file included from include/linux/spinlock.h:56:
In file included from include/linux/preempt.h:78:
In file included from ./arch/riscv/include/generated/asm/preempt.h:1:
In file included from include/asm-generic/preempt.h:5:
In file included from include/linux/thread_info.h:14:
In file included from include/linux/restart_block.h:10:
In file included from include/linux/time64.h:5:
In file included from include/linux/math64.h:6:
In file included from include/linux/math.h:6:
In file included from ./arch/riscv/include/generated/asm/div64.h:1:
In file included from include/asm-generic/div64.h:55:
In file included from include/linux/log2.h:12:
In file included from include/linux/bitops.h:68:
In file included from arch/riscv/include/asm/bitops.h:14:
In file included from include/linux/irqflags.h:17:
>> arch/riscv/include/asm/percpu.h:38:1: error: instruction requires the following: RV64I Base Instruction Set
PERCPU_OP(add, add, +)
^
arch/riscv/include/asm/percpu.h:25:5: note: expanded from macro 'PERCPU_OP'
"amo" #asm_op ".d" \
^
<inline asm>:1:2: note: instantiated into assembly here
amoadd.d a4, a3, 0(a2)
^
In file included from fs/ext4/mballoc.c:12:
In file included from fs/ext4/ext4_jbd2.h:15:
In file included from include/linux/fs.h:6:
In file included from include/linux/wait_bit.h:8:
In file included from include/linux/wait.h:9:
In file included from include/linux/spinlock.h:56:
In file included from include/linux/preempt.h:78:
In file included from ./arch/riscv/include/generated/asm/preempt.h:1:
In file included from include/asm-generic/preempt.h:5:
In file included from include/linux/thread_info.h:14:
In file included from include/linux/restart_block.h:10:
In file included from include/linux/time64.h:5:
In file included from include/linux/math64.h:6:
In file included from include/linux/math.h:6:
In file included from ./arch/riscv/include/generated/asm/div64.h:1:
In file included from include/asm-generic/div64.h:55:
In file included from include/linux/log2.h:12:
In file included from include/linux/bitops.h:68:
In file included from arch/riscv/include/asm/bitops.h:14:
In file included from include/linux/irqflags.h:17:
>> arch/riscv/include/asm/percpu.h:38:1: error: instruction requires the following: RV64I Base Instruction Set
PERCPU_OP(add, add, +)
^
arch/riscv/include/asm/percpu.h:25:5: note: expanded from macro 'PERCPU_OP'
"amo" #asm_op ".d" \
^
<inline asm>:1:2: note: instantiated into assembly here
amoadd.d a1, s9, 0(a0)
^
3 errors generated.
--
In file included from net/ipv6/ip6_output.c:26:
In file included from include/linux/kernel.h:22:
In file included from include/linux/bitops.h:68:
In file included from arch/riscv/include/asm/bitops.h:14:
In file included from include/linux/irqflags.h:17:
>> arch/riscv/include/asm/percpu.h:38:1: error: instruction requires the following: RV64I Base Instruction Set
PERCPU_OP(add, add, +)
^
arch/riscv/include/asm/percpu.h:25:5: note: expanded from macro 'PERCPU_OP'
"amo" #asm_op ".d" \
^
<inline asm>:1:2: note: instantiated into assembly here
amoadd.d a4, a3, 0(a2)
^
In file included from net/ipv6/ip6_output.c:26:
In file included from include/linux/kernel.h:22:
In file included from include/linux/bitops.h:68:
In file included from arch/riscv/include/asm/bitops.h:14:
In file included from include/linux/irqflags.h:17:
>> arch/riscv/include/asm/percpu.h:38:1: error: instruction requires the following: RV64I Base Instruction Set
PERCPU_OP(add, add, +)
^
arch/riscv/include/asm/percpu.h:25:5: note: expanded from macro 'PERCPU_OP'
"amo" #asm_op ".d" \
^
<inline asm>:1:2: note: instantiated into assembly here
amoadd.d a2, a3, 0(a1)
^
In file included from net/ipv6/ip6_output.c:26:
In file included from include/linux/kernel.h:22:
In file included from include/linux/bitops.h:68:
In file included from arch/riscv/include/asm/bitops.h:14:
In file included from include/linux/irqflags.h:17:
>> arch/riscv/include/asm/percpu.h:38:1: error: instruction requires the following: RV64I Base Instruction Set
PERCPU_OP(add, add, +)
^
arch/riscv/include/asm/percpu.h:25:5: note: expanded from macro 'PERCPU_OP'
"amo" #asm_op ".d" \
^
<inline asm>:1:2: note: instantiated into assembly here
amoadd.d a4, a3, 0(a2)
^
In file included from net/ipv6/ip6_output.c:26:
In file included from include/linux/kernel.h:22:
In file included from include/linux/bitops.h:68:
In file included from arch/riscv/include/asm/bitops.h:14:
In file included from include/linux/irqflags.h:17:
>> arch/riscv/include/asm/percpu.h:38:1: error: instruction requires the following: RV64I Base Instruction Set
PERCPU_OP(add, add, +)
^
arch/riscv/include/asm/percpu.h:25:5: note: expanded from macro 'PERCPU_OP'
"amo" #asm_op ".d" \
^
<inline asm>:1:2: note: instantiated into assembly here
amoadd.d a1, a2, 0(a0)
^
In file included from net/ipv6/ip6_output.c:26:
In file included from include/linux/kernel.h:22:
In file included from include/linux/bitops.h:68:
In file included from arch/riscv/include/asm/bitops.h:14:
In file included from include/linux/irqflags.h:17:
>> arch/riscv/include/asm/percpu.h:38:1: error: instruction requires the following: RV64I Base Instruction Set
PERCPU_OP(add, add, +)
^
arch/riscv/include/asm/percpu.h:25:5: note: expanded from macro 'PERCPU_OP'
"amo" #asm_op ".d" \
^
<inline asm>:1:2: note: instantiated into assembly here
amoadd.d a4, a3, 0(a2)
^
In file included from net/ipv6/ip6_output.c:26:
In file included from include/linux/kernel.h:22:
In file included from include/linux/bitops.h:68:
In file included from arch/riscv/include/asm/bitops.h:14:
In file included from include/linux/irqflags.h:17:
>> arch/riscv/include/asm/percpu.h:38:1: error: instruction requires the following: RV64I Base Instruction Set
PERCPU_OP(add, add, +)
^
arch/riscv/include/asm/percpu.h:25:5: note: expanded from macro 'PERCPU_OP'
"amo" #asm_op ".d" \
^
<inline asm>:1:2: note: instantiated into assembly here
amoadd.d a2, a3, 0(a1)
^
In file included from net/ipv6/ip6_output.c:26:
In file included from include/linux/kernel.h:22:
In file included from include/linux/bitops.h:68:
In file included from arch/riscv/include/asm/bitops.h:14:
In file included from include/linux/irqflags.h:17:
>> arch/riscv/include/asm/percpu.h:38:1: error: instruction requires the following: RV64I Base Instruction Set
PERCPU_OP(add, add, +)
^
arch/riscv/include/asm/percpu.h:25:5: note: expanded from macro 'PERCPU_OP'
"amo" #asm_op ".d" \
^
<inline asm>:1:2: note: instantiated into assembly here
amoadd.d a4, a3, 0(a2)
^
In file included from net/ipv6/ip6_output.c:26:
In file included from include/linux/kernel.h:22:
In file included from include/linux/bitops.h:68:
In file included from arch/riscv/include/asm/bitops.h:14:
In file included from include/linux/irqflags.h:17:
>> arch/riscv/include/asm/percpu.h:38:1: error: instruction requires the following: RV64I Base Instruction Set
PERCPU_OP(add, add, +)
^
arch/riscv/include/asm/percpu.h:25:5: note: expanded from macro 'PERCPU_OP'
"amo" #asm_op ".d" \
^
<inline asm>:1:2: note: instantiated into assembly here
amoadd.d a2, a3, 0(a1)
^
In file included from net/ipv6/ip6_output.c:26:
In file included from include/linux/kernel.h:22:
In file included from include/linux/bitops.h:68:
In file included from arch/riscv/include/asm/bitops.h:14:
In file included from include/linux/irqflags.h:17:
>> arch/riscv/include/asm/percpu.h:38:1: error: instruction requires the following: RV64I Base Instruction Set
PERCPU_OP(add, add, +)
^
arch/riscv/include/asm/percpu.h:25:5: note: expanded from macro 'PERCPU_OP'
"amo" #asm_op ".d" \
^
<inline asm>:1:2: note: instantiated into assembly here
amoadd.d a4, a3, 0(a1)
^
In file included from net/ipv6/ip6_output.c:26:
In file included from include/linux/kernel.h:22:
In file included from include/linux/bitops.h:68:
In file included from arch/riscv/include/asm/bitops.h:14:
In file included from include/linux/irqflags.h:17:
>> arch/riscv/include/asm/percpu.h:38:1: error: instruction requires the following: RV64I Base Instruction Set
PERCPU_OP(add, add, +)
^
arch/riscv/include/asm/percpu.h:25:5: note: expanded from macro 'PERCPU_OP'
"amo" #asm_op ".d" \
^
<inline asm>:1:2: note: instantiated into assembly here
amoadd.d a1, a2, 0(a0)
^
In file included from net/ipv6/ip6_output.c:26:
In file included from include/linux/kernel.h:22:
In file included from include/linux/bitops.h:68:
In file included from arch/riscv/include/asm/bitops.h:14:
In file included from include/linux/irqflags.h:17:
>> arch/riscv/include/asm/percpu.h:38:1: error: instruction requires the following: RV64I Base Instruction Set
PERCPU_OP(add, add, +)
^
arch/riscv/include/asm/percpu.h:25:5: note: expanded from macro 'PERCPU_OP'
"amo" #asm_op ".d" \
^
<inline asm>:1:2: note: instantiated into assembly here
amoadd.d a4, a3, 0(a1)
^
In file included from net/ipv6/ip6_output.c:26:
In file included from include/linux/kernel.h:22:
In file included from include/linux/bitops.h:68:
In file included from arch/riscv/include/asm/bitops.h:14:
In file included from include/linux/irqflags.h:17:
>> arch/riscv/include/asm/percpu.h:38:1: error: instruction requires the following: RV64I Base Instruction Set
PERCPU_OP(add, add, +)
^
arch/riscv/include/asm/percpu.h:25:5: note: expanded from macro 'PERCPU_OP'
"amo" #asm_op ".d" \
^
<inline asm>:1:2: note: instantiated into assembly here
amoadd.d a1, a2, 0(a0)
^
12 errors generated.
..

vim +38 arch/riscv/include/asm/percpu.h

9
10 #define PERCPU_OP(op, asm_op, c_op) \
11 static inline unsigned long __percpu_##op(void *ptr, \
12 unsigned long val, int size) \
13 { \
14 unsigned long ret; \
15 switch (size) { \
16 case 4: \
17 __asm__ __volatile__( \
18 "amo" #asm_op ".w" \
19 " %[ret], %[val], %[ptr]\n" \
20 : [ret] "=&r"(ret), [ptr] "+A"(*(u32 *)ptr) \
21 : [val] "r"(val)); \
22 break; \
23 case 8: \
24 __asm__ __volatile__( \
25 "amo" #asm_op ".d" \
26 " %[ret], %[val], %[ptr]\n" \
27 : [ret] "=&r"(ret), [ptr] "+A"(*(u64 *)ptr) \
28 : [val] "r"(val)); \
29 break; \
30 default: \
31 ret = 0; \
32 BUILD_BUG(); \
33 } \
34 \
35 return ret c_op val; \
36 }
37
> 38 PERCPU_OP(add, add, +)
39 PERCPU_OP(and, and, &)
40 PERCPU_OP(or, or, |)
41 #undef PERCPU_OP
42

--
0-DAY CI Kernel Test Service
https://01.org/lkp

Attachments:

(No filename) (26.67 kB)
config (115.60 kB)
Download all attachments

2022-10-27 01:20:16

by kernel test robot

[permalink] [raw]

Subject: Re: [PATCH 1/2] riscv: percpu:Add riscv percpu operations

Attachments:

(No filename) (7.12 kB)
config (115.46 kB)
Download all attachments

2022-10-30 13:51:19

by Christoph Lameter

[permalink] [raw]

Subject: Re: [PATCH 1/2] riscv: percpu:Add riscv percpu operations

On Wed, 26 Oct 2022, Wen Yao wrote:

> This patch use riscv AMO(Atomic Memory Operation) instructions to
> optimise some this_cpu_and this_cpu_or this_cpu_add operations.
> It reuse cmpxchg_local() to impletment this_cpu_cmpxchg macros.
> It reuse xchg_relaxed() to impletment this_cpu_xchg macros.

Are you sure that these changes gives you any benefit vs disabling preempt
or irq offs? I dont know too much about atomics on riscv but it looks like
you are using full atomics. The performance penalty for the use of those
is usually drastic. Often irq/preempt off is better.

Could you run some of the synthetic tests to establish the benefit? F.e.
run the synthetic tests for the slub allcator with and without these
patches.

> + __asm__ __volatile__( \
> + "amo" #asm_op ".w" \

amo = atomic operation?