mirror of
https://github.com/xemu-project/xemu.git
synced 2024-12-12 14:05:56 +00:00
6579f10779
Signed-off-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
225 lines
7.2 KiB
C
225 lines
7.2 KiB
C
/*
|
|
* Copyright (C) 2016, Emilio G. Cota <cota@braap.org>
|
|
*
|
|
* License: GNU GPL, version 2 or later.
|
|
* See the COPYING file in the top-level directory.
|
|
*/
|
|
#ifndef QEMU_QHT_H
|
|
#define QEMU_QHT_H
|
|
|
|
#include "qemu/seqlock.h"
|
|
#include "qemu/thread.h"
|
|
#include "qemu/qdist.h"
|
|
|
|
typedef bool (*qht_cmp_func_t)(const void *a, const void *b);
|
|
|
|
struct qht {
|
|
struct qht_map *map;
|
|
qht_cmp_func_t cmp;
|
|
QemuMutex lock; /* serializes setters of ht->map */
|
|
unsigned int mode;
|
|
};
|
|
|
|
/**
|
|
* struct qht_stats - Statistics of a QHT
|
|
* @head_buckets: number of head buckets
|
|
* @used_head_buckets: number of non-empty head buckets
|
|
* @entries: total number of entries
|
|
* @chain: frequency distribution representing the number of buckets in each
|
|
* chain, excluding empty chains.
|
|
* @occupancy: frequency distribution representing chain occupancy rate.
|
|
* Valid range: from 0.0 (empty) to 1.0 (full occupancy).
|
|
*
|
|
* An entry is a pointer-hash pair.
|
|
* Each bucket can host several entries.
|
|
* Chains are chains of buckets, whose first link is always a head bucket.
|
|
*/
|
|
struct qht_stats {
|
|
size_t head_buckets;
|
|
size_t used_head_buckets;
|
|
size_t entries;
|
|
struct qdist chain;
|
|
struct qdist occupancy;
|
|
};
|
|
|
|
typedef bool (*qht_lookup_func_t)(const void *obj, const void *userp);
|
|
typedef void (*qht_iter_func_t)(void *p, uint32_t h, void *up);
|
|
typedef bool (*qht_iter_bool_func_t)(void *p, uint32_t h, void *up);
|
|
|
|
#define QHT_MODE_AUTO_RESIZE 0x1 /* auto-resize when heavily loaded */
|
|
#define QHT_MODE_RAW_MUTEXES 0x2 /* bypass the profiler (QSP) */
|
|
|
|
/**
|
|
* qht_init - Initialize a QHT
|
|
* @ht: QHT to be initialized
|
|
* @cmp: default comparison function. Cannot be NULL.
|
|
* @n_elems: number of entries the hash table should be optimized for.
|
|
* @mode: bitmask with OR'ed QHT_MODE_*
|
|
*/
|
|
void qht_init(struct qht *ht, qht_cmp_func_t cmp, size_t n_elems,
|
|
unsigned int mode);
|
|
|
|
/**
|
|
* qht_destroy - destroy a previously initialized QHT
|
|
* @ht: QHT to be destroyed
|
|
*
|
|
* Call only when there are no readers/writers left.
|
|
*/
|
|
void qht_destroy(struct qht *ht);
|
|
|
|
/**
|
|
* qht_insert - Insert a pointer into the hash table
|
|
* @ht: QHT to insert to
|
|
* @p: pointer to be inserted
|
|
* @hash: hash corresponding to @p
|
|
* @existing: address where the pointer to an existing entry can be copied to
|
|
*
|
|
* Attempting to insert a NULL @p is a bug.
|
|
* Inserting the same pointer @p with different @hash values is a bug.
|
|
*
|
|
* In case of successful operation, smp_wmb() is implied before the pointer is
|
|
* inserted into the hash table.
|
|
*
|
|
* Returns true on success.
|
|
* Returns false if there is an existing entry in the table that is equivalent
|
|
* (i.e. ht->cmp matches and the hash is the same) to @p-@h. If @existing
|
|
* is !NULL, a pointer to this existing entry is copied to it.
|
|
*/
|
|
bool qht_insert(struct qht *ht, void *p, uint32_t hash, void **existing);
|
|
|
|
/**
|
|
* qht_lookup_custom - Look up a pointer using a custom comparison function.
|
|
* @ht: QHT to be looked up
|
|
* @userp: pointer to pass to @func
|
|
* @hash: hash of the pointer to be looked up
|
|
* @func: function to compare existing pointers against @userp
|
|
*
|
|
* Needs to be called under an RCU read-critical section.
|
|
*
|
|
* smp_read_barrier_depends() is implied before the call to @func.
|
|
*
|
|
* The user-provided @func compares pointers in QHT against @userp.
|
|
* If the function returns true, a match has been found.
|
|
*
|
|
* Returns the corresponding pointer when a match is found.
|
|
* Returns NULL otherwise.
|
|
*/
|
|
void *qht_lookup_custom(const struct qht *ht, const void *userp, uint32_t hash,
|
|
qht_lookup_func_t func);
|
|
|
|
/**
|
|
* qht_lookup - Look up a pointer in a QHT
|
|
* @ht: QHT to be looked up
|
|
* @userp: pointer to pass to the comparison function
|
|
* @hash: hash of the pointer to be looked up
|
|
*
|
|
* Calls qht_lookup_custom() using @ht's default comparison function.
|
|
*/
|
|
void *qht_lookup(const struct qht *ht, const void *userp, uint32_t hash);
|
|
|
|
/**
|
|
* qht_remove - remove a pointer from the hash table
|
|
* @ht: QHT to remove from
|
|
* @p: pointer to be removed
|
|
* @hash: hash corresponding to @p
|
|
*
|
|
* Attempting to remove a NULL @p is a bug.
|
|
*
|
|
* Just-removed @p pointers cannot be immediately freed; they need to remain
|
|
* valid until the end of the RCU grace period in which qht_remove() is called.
|
|
* This guarantees that concurrent lookups will always compare against valid
|
|
* data.
|
|
*
|
|
* Returns true on success.
|
|
* Returns false if the @p-@hash pair was not found.
|
|
*/
|
|
bool qht_remove(struct qht *ht, const void *p, uint32_t hash);
|
|
|
|
/**
|
|
* qht_reset - reset a QHT
|
|
* @ht: QHT to be reset
|
|
*
|
|
* All entries in the hash table are reset. No resizing is performed.
|
|
*
|
|
* If concurrent readers may exist, the objects pointed to by the hash table
|
|
* must remain valid for the existing RCU grace period -- see qht_remove().
|
|
* See also: qht_reset_size()
|
|
*/
|
|
void qht_reset(struct qht *ht);
|
|
|
|
/**
|
|
* qht_reset_size - reset and resize a QHT
|
|
* @ht: QHT to be reset and resized
|
|
* @n_elems: number of entries the resized hash table should be optimized for.
|
|
*
|
|
* Returns true if the resize was necessary and therefore performed.
|
|
* Returns false otherwise.
|
|
*
|
|
* If concurrent readers may exist, the objects pointed to by the hash table
|
|
* must remain valid for the existing RCU grace period -- see qht_remove().
|
|
* See also: qht_reset(), qht_resize().
|
|
*/
|
|
bool qht_reset_size(struct qht *ht, size_t n_elems);
|
|
|
|
/**
|
|
* qht_resize - resize a QHT
|
|
* @ht: QHT to be resized
|
|
* @n_elems: number of entries the resized hash table should be optimized for
|
|
*
|
|
* Returns true on success.
|
|
* Returns false if the resize was not necessary and therefore not performed.
|
|
* See also: qht_reset_size().
|
|
*/
|
|
bool qht_resize(struct qht *ht, size_t n_elems);
|
|
|
|
/**
|
|
* qht_iter - Iterate over a QHT
|
|
* @ht: QHT to be iterated over
|
|
* @func: function to be called for each entry in QHT
|
|
* @userp: additional pointer to be passed to @func
|
|
*
|
|
* Each time it is called, user-provided @func is passed a pointer-hash pair,
|
|
* plus @userp.
|
|
*
|
|
* Note: @ht cannot be accessed from @func
|
|
* See also: qht_iter_remove()
|
|
*/
|
|
void qht_iter(struct qht *ht, qht_iter_func_t func, void *userp);
|
|
|
|
/**
|
|
* qht_iter_remove - Iterate over a QHT, optionally removing entries
|
|
* @ht: QHT to be iterated over
|
|
* @func: function to be called for each entry in QHT
|
|
* @userp: additional pointer to be passed to @func
|
|
*
|
|
* Each time it is called, user-provided @func is passed a pointer-hash pair,
|
|
* plus @userp. If @func returns true, the pointer-hash pair is removed.
|
|
*
|
|
* Note: @ht cannot be accessed from @func
|
|
* See also: qht_iter()
|
|
*/
|
|
void qht_iter_remove(struct qht *ht, qht_iter_bool_func_t func, void *userp);
|
|
|
|
/**
|
|
* qht_statistics_init - Gather statistics from a QHT
|
|
* @ht: QHT to gather statistics from
|
|
* @stats: pointer to a &struct qht_stats to be filled in
|
|
*
|
|
* Does NOT need to be called under an RCU read-critical section,
|
|
* since it does not dereference any pointers stored in the hash table.
|
|
*
|
|
* When done with @stats, pass the struct to qht_statistics_destroy().
|
|
* Failing to do this will leak memory.
|
|
*/
|
|
void qht_statistics_init(const struct qht *ht, struct qht_stats *stats);
|
|
|
|
/**
|
|
* qht_statistics_destroy - Destroy a &struct qht_stats
|
|
* @stats: &struct qht_stats to be destroyed
|
|
*
|
|
* See also: qht_statistics_init().
|
|
*/
|
|
void qht_statistics_destroy(struct qht_stats *stats);
|
|
|
|
#endif /* QEMU_QHT_H */
|