219 lines
6.8 KiB
C
219 lines
6.8 KiB
C
/*-
|
|
* Copyright (c) 2001 Matthew Dillon. All Rights Reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. 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.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY AUTHOR 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 AUTHOR 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.
|
|
*/
|
|
|
|
/* Mutex pool routines. These routines are designed to be used as short
|
|
* term leaf mutexes (e.g. the last mutex you might aquire other then
|
|
* calling msleep()). They operate using a shared pool. A mutex is chosen
|
|
* from the pool based on the supplied pointer (which may or may not be
|
|
* valid).
|
|
*
|
|
* Advantages:
|
|
* - no structural overhead. Mutexes can be associated with structures
|
|
* without adding bloat to the structures.
|
|
* - mutexes can be obtained for invalid pointers, useful when uses
|
|
* mutexes to interlock destructor ops.
|
|
* - no initialization/destructor overhead.
|
|
* - can be used with msleep.
|
|
*
|
|
* Disadvantages:
|
|
* - should generally only be used as leaf mutexes.
|
|
* - pool/pool dependancy ordering cannot be depended on.
|
|
* - possible L1 cache mastersip contention between cpus.
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
__FBSDID("$FreeBSD$");
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/proc.h>
|
|
#include <sys/kernel.h>
|
|
#include <sys/ktr.h>
|
|
#include <sys/lock.h>
|
|
#include <sys/malloc.h>
|
|
#include <sys/mutex.h>
|
|
#include <sys/systm.h>
|
|
|
|
|
|
MALLOC_DEFINE(M_MTXPOOL, "mtx_pool", "mutex pool");
|
|
|
|
/* Pool sizes must be a power of two */
|
|
#ifndef MTX_POOL_LOCKBUILDER_SIZE
|
|
#define MTX_POOL_LOCKBUILDER_SIZE 128
|
|
#endif
|
|
#ifndef MTX_POOL_SLEEP_SIZE
|
|
#define MTX_POOL_SLEEP_SIZE 128
|
|
#endif
|
|
|
|
struct mtxpool_header {
|
|
int mtxpool_size;
|
|
int mtxpool_mask;
|
|
int mtxpool_shift;
|
|
int mtxpool_next;
|
|
};
|
|
|
|
struct mtx_pool {
|
|
struct mtxpool_header mtx_pool_header;
|
|
struct mtx mtx_pool_ary[1];
|
|
};
|
|
|
|
static struct mtx_pool_lockbuilder {
|
|
struct mtxpool_header mtx_pool_header;
|
|
struct mtx mtx_pool_ary[MTX_POOL_LOCKBUILDER_SIZE];
|
|
} lockbuilder_pool;
|
|
|
|
#define mtx_pool_size mtx_pool_header.mtxpool_size
|
|
#define mtx_pool_mask mtx_pool_header.mtxpool_mask
|
|
#define mtx_pool_shift mtx_pool_header.mtxpool_shift
|
|
#define mtx_pool_next mtx_pool_header.mtxpool_next
|
|
|
|
struct mtx_pool *mtxpool_sleep;
|
|
struct mtx_pool *mtxpool_lockbuilder;
|
|
|
|
#if UINTPTR_MAX == UINT64_MAX /* 64 bits */
|
|
# define POINTER_BITS 64
|
|
# define HASH_MULTIPLIER 11400714819323198485u /* (2^64)*(sqrt(5)-1)/2 */
|
|
#else /* assume 32 bits */
|
|
# define POINTER_BITS 32
|
|
# define HASH_MULTIPLIER 2654435769u /* (2^32)*(sqrt(5)-1)/2 */
|
|
#endif
|
|
|
|
/*
|
|
* Return the (shared) pool mutex associated with the specified address.
|
|
* The returned mutex is a leaf level mutex, meaning that if you obtain it
|
|
* you cannot obtain any other mutexes until you release it. You can
|
|
* legally msleep() on the mutex.
|
|
*/
|
|
struct mtx *
|
|
mtx_pool_find(struct mtx_pool *pool, void *ptr)
|
|
{
|
|
int p;
|
|
|
|
KASSERT(pool != NULL, ("_mtx_pool_find(): null pool"));
|
|
/*
|
|
* Fibonacci hash, see Knuth's
|
|
* _Art of Computer Programming, Volume 3 / Sorting and Searching_
|
|
*/
|
|
p = ((HASH_MULTIPLIER * (uintptr_t)ptr) >> pool->mtx_pool_shift) &
|
|
pool->mtx_pool_mask;
|
|
return (&pool->mtx_pool_ary[p]);
|
|
}
|
|
|
|
static void
|
|
mtx_pool_initialize(struct mtx_pool *pool, const char *mtx_name, int pool_size,
|
|
int opts)
|
|
{
|
|
int i, maskbits;
|
|
|
|
pool->mtx_pool_size = pool_size;
|
|
pool->mtx_pool_mask = pool_size - 1;
|
|
for (i = 1, maskbits = 0; (i & pool_size) == 0; i = i << 1)
|
|
maskbits++;
|
|
pool->mtx_pool_shift = POINTER_BITS - maskbits;
|
|
pool->mtx_pool_next = 0;
|
|
for (i = 0; i < pool_size; ++i)
|
|
mtx_init(&pool->mtx_pool_ary[i], mtx_name, NULL, opts);
|
|
}
|
|
|
|
struct mtx_pool *
|
|
mtx_pool_create(const char *mtx_name, int pool_size, int opts)
|
|
{
|
|
struct mtx_pool *pool;
|
|
|
|
if (pool_size <= 0 || !powerof2(pool_size)) {
|
|
printf("WARNING: %s pool size is not a power of 2.\n",
|
|
mtx_name);
|
|
pool_size = 128;
|
|
}
|
|
MALLOC(pool, struct mtx_pool *,
|
|
sizeof (struct mtx_pool) + ((pool_size - 1) * sizeof (struct mtx)),
|
|
M_MTXPOOL, M_WAITOK | M_ZERO);
|
|
mtx_pool_initialize(pool, mtx_name, pool_size, opts);
|
|
return pool;
|
|
}
|
|
|
|
void
|
|
mtx_pool_destroy(struct mtx_pool **poolp)
|
|
{
|
|
int i;
|
|
struct mtx_pool *pool = *poolp;
|
|
|
|
for (i = pool->mtx_pool_size - 1; i >= 0; --i)
|
|
mtx_destroy(&pool->mtx_pool_ary[i]);
|
|
FREE(pool, M_MTXPOOL);
|
|
*poolp = NULL;
|
|
}
|
|
|
|
static void
|
|
mtx_pool_setup_static(void *dummy __unused)
|
|
{
|
|
mtx_pool_initialize((struct mtx_pool *)&lockbuilder_pool,
|
|
"lockbuilder mtxpool", MTX_POOL_LOCKBUILDER_SIZE,
|
|
MTX_DEF | MTX_NOWITNESS | MTX_QUIET);
|
|
mtxpool_lockbuilder = (struct mtx_pool *)&lockbuilder_pool;
|
|
}
|
|
|
|
static void
|
|
mtx_pool_setup_dynamic(void *dummy __unused)
|
|
{
|
|
mtxpool_sleep = mtx_pool_create("sleep mtxpool",
|
|
MTX_POOL_SLEEP_SIZE, MTX_DEF);
|
|
}
|
|
|
|
/*
|
|
* Obtain a (shared) mutex from the pool. The returned mutex is a leaf
|
|
* level mutex, meaning that if you obtain it you cannot obtain any other
|
|
* mutexes until you release it. You can legally msleep() on the mutex.
|
|
*/
|
|
struct mtx *
|
|
mtx_pool_alloc(struct mtx_pool *pool)
|
|
{
|
|
int i;
|
|
|
|
KASSERT(pool != NULL, ("mtx_pool_alloc(): null pool"));
|
|
/*
|
|
* mtx_pool_next is unprotected against multiple accesses,
|
|
* but simultaneous access by two CPUs should not be very
|
|
* harmful.
|
|
*/
|
|
i = pool->mtx_pool_next;
|
|
pool->mtx_pool_next = (i + 1) & pool->mtx_pool_mask;
|
|
return (&pool->mtx_pool_ary[i]);
|
|
}
|
|
|
|
/*
|
|
* The lockbuilder pool must be initialized early because the lockmgr
|
|
* and sx locks depend on it. The sx locks are used in the kernel
|
|
* memory allocator. The lockmgr subsystem is initialized by
|
|
* SYSINIT(..., SI_SUB_LOCKMGR, ...).
|
|
*
|
|
* We can't call MALLOC() to dynamically allocate the sleep pool
|
|
* until after kmeminit() has been called, which is done by
|
|
* SYSINIT(..., SI_SUB_KMEM, ...).
|
|
*/
|
|
SYSINIT(mtxpooli1, SI_SUB_MTX_POOL_STATIC, SI_ORDER_FIRST,
|
|
mtx_pool_setup_static, NULL);
|
|
SYSINIT(mtxpooli2, SI_SUB_MTX_POOL_DYNAMIC, SI_ORDER_FIRST,
|
|
mtx_pool_setup_dynamic, NULL);
|