lib: Resizable, Scalable, Concurrent Hash Table (7e1e7763) · Commits · 戴 / test

include/linux/rhashtable.h

0 → 100644

+213 −0

Original line number	Diff line number	Diff line
		/*
		* Resizable, Scalable, Concurrent Hash Table
		*
		* Copyright (c) 2014 Thomas Graf <tgraf@suug.ch>
		* Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net>
		*
		* Based on the following paper by Josh Triplett, Paul E. McKenney
		* and Jonathan Walpole:
		* https://www.usenix.org/legacy/event/atc11/tech/final_files/Triplett.pdf
		*
		* Code partially derived from nft_hash
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License version 2 as
		* published by the Free Software Foundation.
		*/

		#ifndef _LINUX_RHASHTABLE_H
		#define _LINUX_RHASHTABLE_H

		#include <linux/rculist.h>

		struct rhash_head {
		struct rhash_head *next;
		};

		#define INIT_HASH_HEAD(ptr) ((ptr)->next = NULL)

		struct bucket_table {
		size_t size;
		struct rhash_head __rcu *buckets[];
		};

		typedef u32 (rht_hashfn_t)(const void data, u32 len, u32 seed);
		typedef u32 (rht_obj_hashfn_t)(const void data, u32 seed);

		struct rhashtable;

		/**
		* struct rhashtable_params - Hash table construction parameters
		* @nelem_hint: Hint on number of elements, should be 75% of desired size
		* @key_len: Length of key
		* @key_offset: Offset of key in struct to be hashed
		* @head_offset: Offset of rhash_head in struct to be hashed
		* @hash_rnd: Seed to use while hashing
		* @max_shift: Maximum number of shifts while expanding
		* @hashfn: Function to hash key
		* @obj_hashfn: Function to hash object
		* @grow_decision: If defined, may return true if table should expand
		* @shrink_decision: If defined, may return true if table should shrink
		* @mutex_is_held: Must return true if protecting mutex is held
		*/
		struct rhashtable_params {
		size_t nelem_hint;
		size_t key_len;
		size_t key_offset;
		size_t head_offset;
		u32 hash_rnd;
		size_t max_shift;
		rht_hashfn_t hashfn;
		rht_obj_hashfn_t obj_hashfn;
		bool (grow_decision)(const struct rhashtable ht,
		size_t new_size);
		bool (shrink_decision)(const struct rhashtable ht,
		size_t new_size);
		int (*mutex_is_held)(void);
		};

		/**
		* struct rhashtable - Hash table handle
		* @tbl: Bucket table
		* @nelems: Number of elements in table
		* @shift: Current size (1 << shift)
		* @p: Configuration parameters
		*/
		struct rhashtable {
		struct bucket_table __rcu *tbl;
		size_t nelems;
		size_t shift;
		struct rhashtable_params p;
		};

		#ifdef CONFIG_PROVE_LOCKING
		int lockdep_rht_mutex_is_held(const struct rhashtable *ht);
		#else
		static inline int lockdep_rht_mutex_is_held(const struct rhashtable *ht)
		{
		return 1;
		}
		#endif /* CONFIG_PROVE_LOCKING */

		int rhashtable_init(struct rhashtable ht, struct rhashtable_params params);

		u32 rhashtable_hashfn(const struct rhashtable ht, const void key, u32 len);
		u32 rhashtable_obj_hashfn(const struct rhashtable ht, void ptr);

		void rhashtable_insert(struct rhashtable ht, struct rhash_head node, gfp_t);
		bool rhashtable_remove(struct rhashtable ht, struct rhash_head node, gfp_t);
		void rhashtable_remove_pprev(struct rhashtable ht, struct rhash_head obj,
		struct rhash_head **pprev, gfp_t flags);

		bool rht_grow_above_75(const struct rhashtable *ht, size_t new_size);
		bool rht_shrink_below_30(const struct rhashtable *ht, size_t new_size);

		int rhashtable_expand(struct rhashtable *ht, gfp_t flags);
		int rhashtable_shrink(struct rhashtable *ht, gfp_t flags);

		void rhashtable_lookup(const struct rhashtable ht, const void *key);
		void rhashtable_lookup_compare(const struct rhashtable ht, u32 hash,
		bool (compare)(void , void ), void arg);

		void rhashtable_destroy(const struct rhashtable *ht);

		#define rht_dereference(p, ht) \
		rcu_dereference_protected(p, lockdep_rht_mutex_is_held(ht))

		#define rht_dereference_rcu(p, ht) \
		rcu_dereference_check(p, lockdep_rht_mutex_is_held(ht))

		/* Internal, use rht_obj() instead */
		#define rht_entry(ptr, type, member) container_of(ptr, type, member)
		#define rht_entry_safe(ptr, type, member) \
		({ \
		typeof(ptr) __ptr = (ptr); \
		__ptr ? rht_entry(__ptr, type, member) : NULL; \
		})
		#define rht_entry_safe_rcu(ptr, type, member) \
		({ \
		typeof(ptr) __rcu __ptr = (typeof(ptr) __rcu __force )ptr; \
		__ptr ? container_of((typeof(ptr))rcu_dereference_raw(__ptr), type, member) : NULL; \
		})

		#define rht_next_entry_safe(pos, ht, member) \
		({ \
		pos ? rht_entry_safe(rht_dereference((pos)->member.next, ht), \
		typeof(*(pos)), member) : NULL; \
		})

		/**
		* rht_for_each - iterate over hash chain
		* @pos: &struct rhash_head to use as a loop cursor.
		* @head: head of the hash chain (struct rhash_head *)
		* @ht: pointer to your struct rhashtable
		*/
		#define rht_for_each(pos, head, ht) \
		for (pos = rht_dereference(head, ht); \
		pos; \
		pos = rht_dereference((pos)->next, ht))

		/**
		* rht_for_each_entry - iterate over hash chain of given type
		* @pos: type * to use as a loop cursor.
		* @head: head of the hash chain (struct rhash_head *)
		* @ht: pointer to your struct rhashtable
		* @member: name of the rhash_head within the hashable struct.
		*/
		#define rht_for_each_entry(pos, head, ht, member) \
		for (pos = rht_entry_safe(rht_dereference(head, ht), \
		typeof(*(pos)), member); \
		pos; \
		pos = rht_next_entry_safe(pos, ht, member))

		/**
		* rht_for_each_entry_safe - safely iterate over hash chain of given type
		* @pos: type * to use as a loop cursor.
		* @n: type * to use for temporary next object storage
		* @head: head of the hash chain (struct rhash_head *)
		* @ht: pointer to your struct rhashtable
		* @member: name of the rhash_head within the hashable struct.
		*
		* This hash chain list-traversal primitive allows for the looped code to
		* remove the loop cursor from the list.
		*/
		#define rht_for_each_entry_safe(pos, n, head, ht, member) \
		for (pos = rht_entry_safe(rht_dereference(head, ht), \
		typeof(*(pos)), member), \
		n = rht_next_entry_safe(pos, ht, member); \
		pos; \
		pos = n, \
		n = rht_next_entry_safe(pos, ht, member))

		/**
		* rht_for_each_rcu - iterate over rcu hash chain
		* @pos: &struct rhash_head to use as a loop cursor.
		* @head: head of the hash chain (struct rhash_head *)
		* @ht: pointer to your struct rhashtable
		*
		* This hash chain list-traversal primitive may safely run concurrently with
		* the _rcu fkht mutation primitives such as rht_insert() as long as the
		* traversal is guarded by rcu_read_lock().
		*/
		#define rht_for_each_rcu(pos, head, ht) \
		for (pos = rht_dereference_rcu(head, ht); \
		pos; \
		pos = rht_dereference_rcu((pos)->next, ht))

		/**
		* rht_for_each_entry_rcu - iterate over rcu hash chain of given type
		* @pos: type * to use as a loop cursor.
		* @head: head of the hash chain (struct rhash_head *)
		* @member: name of the rhash_head within the hashable struct.
		*
		* This hash chain list-traversal primitive may safely run concurrently with
		* the _rcu fkht mutation primitives such as rht_insert() as long as the
		* traversal is guarded by rcu_read_lock().
		*/
		#define rht_for_each_entry_rcu(pos, head, member) \
		for (pos = rht_entry_safe_rcu(head, typeof(*(pos)), member); \
		pos; \
		pos = rht_entry_safe_rcu((pos)->member.next, \
		typeof(*(pos)), member))

		#endif /* _LINUX_RHASHTABLE_H */

lib/Kconfig.debug

+8 −0

Original line number	Diff line number	Diff line
		@@ -1550,6 +1550,14 @@ config TEST_STRING_HELPERS
		config TEST_KSTRTOX
		tristate "Test kstrto*() family of functions at runtime"

		config TEST_RHASHTABLE
		bool "Perform selftest on resizable hash table"
		default n
		help
		Enable this option to test the rhashtable functions at boot.

		If unsure, say N.

		endmenu # runtime tests

		config PROVIDE_OHCI1394_DMA_INIT

lib/Makefile

+1 −1

Original line number	Diff line number	Diff line
		@@ -26,7 +26,7 @@ obj-y += bcd.o div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \
		bust_spinlocks.o hexdump.o kasprintf.o bitmap.o scatterlist.o \
		gcd.o lcm.o list_sort.o uuid.o flex_array.o iovec.o clz_ctz.o \
		bsearch.o find_last_bit.o find_next_bit.o llist.o memweight.o kfifo.o \
		percpu-refcount.o percpu_ida.o hash.o
		percpu-refcount.o percpu_ida.o hash.o rhashtable.o
		obj-y += string_helpers.o
		obj-$(CONFIG_TEST_STRING_HELPERS) += test-string_helpers.o
		obj-y += kstrtox.o

lib/rhashtable.c

0 → 100644

+797 −0

File added.

Preview size limit exceeded, changes collapsed.

Admin message