lib: introduce arch optimized hash library (71ae8aac) · Commits · 戴 / test

arch/x86/include/asm/hash.h

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+7 −0

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		#ifndef _ASM_X86_HASH_H
		#define _ASM_X86_HASH_H

		struct fast_hash_ops;
		extern void setup_arch_fast_hash(struct fast_hash_ops *ops);

		#endif /* _ASM_X86_HASH_H */

arch/x86/lib/Makefile

+1 −1

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		@@ -24,7 +24,7 @@ lib-$(CONFIG_SMP) += rwlock.o
		lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
		lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o

		obj-y += msr.o msr-reg.o msr-reg-export.o
		obj-y += msr.o msr-reg.o msr-reg-export.o hash.o

		ifeq ($(CONFIG_X86_32),y)
		obj-y += atomic64_32.o

arch/x86/lib/hash.c

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+88 −0

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		/*
		* Some portions derived from code covered by the following notice:
		*
		* Copyright (c) 2010-2013 Intel Corporation. All rights reserved.
		* All rights reserved.
		*
		* Redistribution and use in source and binary forms, with or without
		* modification, are permitted provided that the following conditions
		* are met:
		*
		* * Redistributions of source code must retain the above copyright
		* notice, this list of conditions and the following disclaimer.
		* * Redistributions in binary form must reproduce the above copyright
		* notice, this list of conditions and the following disclaimer in
		* the documentation and/or other materials provided with the
		* distribution.
		* * Neither the name of Intel Corporation nor the names of its
		* contributors may be used to endorse or promote products derived
		* from this software without specific prior written permission.
		*
		* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
		* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
		* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
		* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
		* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
		* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
		* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
		* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
		* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
		* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
		* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
		*/

		#include <linux/hash.h>

		#include <asm/processor.h>
		#include <asm/cpufeature.h>
		#include <asm/hash.h>

		static inline u32 crc32_u32(u32 crc, u32 val)
		{
		asm ("crc32l %1,%0\n" : "+r" (crc) : "rm" (val));
		return crc;
		}

		static u32 intel_crc4_2_hash(const void *data, u32 len, u32 seed)
		{
		const u32 p32 = (const u32 ) data;
		u32 i, tmp = 0;

		for (i = 0; i < len / 4; i++)
		seed = crc32_u32(*p32++, seed);

		switch (3 - (len & 0x03)) {
		case 0:
		tmp \|= ((const u8 ) p32 + 2) << 16;
		/* fallthrough */
		case 1:
		tmp \|= ((const u8 ) p32 + 1) << 8;
		/* fallthrough */
		case 2:
		tmp \|= ((const u8 ) p32);
		seed = crc32_u32(tmp, seed);
		default:
		break;
		}

		return seed;
		}

		static u32 intel_crc4_2_hash2(const u32 *data, u32 len, u32 seed)
		{
		const u32 p32 = (const u32 ) data;
		u32 i;

		for (i = 0; i < len; i++)
		seed = crc32_u32(*p32++, seed);

		return seed;
		}

		void setup_arch_fast_hash(struct fast_hash_ops *ops)
		{
		if (cpu_has_xmm4_2) {
		ops->hash = intel_crc4_2_hash;
		ops->hash2 = intel_crc4_2_hash2;
		}
		}

include/asm-generic/hash.h

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Original line number	Diff line number	Diff line
		#ifndef __ASM_GENERIC_HASH_H
		#define __ASM_GENERIC_HASH_H

		struct arch_hash_ops;
		static inline void setup_arch_fast_hash(struct arch_hash_ops *ops)
		{
		}

		#endif /* __ASM_GENERIC_HASH_H */

include/linux/hash.h

+36 −0

Original line number	Diff line number	Diff line
		@@ -15,6 +15,7 @@
		*/

		#include <asm/types.h>
		#include <asm/hash.h>
		#include <linux/compiler.h>

		/* 2^31 + 2^29 - 2^25 + 2^22 - 2^19 - 2^16 + 1 */
		@@ -78,4 +79,39 @@ static inline u32 hash32_ptr(const void *ptr)
		#endif
		return (u32)val;
		}

		struct fast_hash_ops {
		u32 (hash)(const void data, u32 len, u32 seed);
		u32 (hash2)(const u32 data, u32 len, u32 seed);
		};

		/**
		* arch_fast_hash - Caclulates a hash over a given buffer that can have
		* arbitrary size. This function will eventually use an
		* architecture-optimized hashing implementation if
		* available, and trades off distribution for speed.
		*
		* @data: buffer to hash
		* @len: length of buffer in bytes
		* @seed: start seed
		*
		* Returns 32bit hash.
		*/
		extern u32 arch_fast_hash(const void *data, u32 len, u32 seed);

		/**
		* arch_fast_hash2 - Caclulates a hash over a given buffer that has a
		* size that is of a multiple of 32bit words. This
		* function will eventually use an architecture-
		* optimized hashing implementation if available,
		* and trades off distribution for speed.
		*
		* @data: buffer to hash (must be 32bit padded)
		* @len: number of 32bit words
		* @seed: start seed
		*
		* Returns 32bit hash.
		*/
		extern u32 arch_fast_hash2(const u32 *data, u32 len, u32 seed);

		#endif /* _LINUX_HASH_H */

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