diff options
Diffstat (limited to 'sys/kern/kern_mtxpool.c')
-rw-r--r-- | sys/kern/kern_mtxpool.c | 187 |
1 files changed, 133 insertions, 54 deletions
diff --git a/sys/kern/kern_mtxpool.c b/sys/kern/kern_mtxpool.c index b93fcfa..93ce655 100644 --- a/sys/kern/kern_mtxpool.c +++ b/sys/kern/kern_mtxpool.c @@ -35,85 +35,164 @@ __FBSDID("$FreeBSD$"); #include <sys/mutex.h> #include <sys/systm.h> -#ifndef MTX_POOL_SIZE -#define MTX_POOL_SIZE 128 -#endif -#define MTX_POOL_MASK (MTX_POOL_SIZE - 1) -static struct mtx mtx_pool_ary[MTX_POOL_SIZE]; +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 -int mtx_pool_valid = 0; +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 /* - * Inline version of mtx_pool_find(), used to streamline our main API - * function calls. + * 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. */ -static __inline struct mtx * -_mtx_pool_find(void *ptr) +struct mtx * +mtx_pool_find(struct mtx_pool *pool, void *ptr) { - int p; - - p = (int)(uintptr_t)ptr; - return (&mtx_pool_ary[(p ^ (p >> 6)) & MTX_POOL_MASK]); + 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_setup(void *dummy __unused) +mtx_pool_initialize(struct mtx_pool *pool, const char *mtx_name, int pool_size, + int opts) { - int i; - - for (i = 0; i < MTX_POOL_SIZE; ++i) - mtx_init(&mtx_pool_ary[i], "pool mutex", NULL, - MTX_DEF | MTX_NOWITNESS | MTX_QUIET); - mtx_pool_valid = 1; + 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); } -/* - * 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(void) +struct mtx_pool * +mtx_pool_create(const char *mtx_name, int pool_size, int opts) { - static int si; - - return (&mtx_pool_ary[si++ & MTX_POOL_MASK]); + 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; } -/* - * 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(void *ptr) +void +mtx_pool_destroy(struct mtx_pool **poolp) { + int i; + struct mtx_pool *pool = *poolp; - return (_mtx_pool_find(ptr)); + for (i = pool->mtx_pool_size - 1; i >= 0; --i) + mtx_destroy(&pool->mtx_pool_ary[i]); + FREE(pool, M_MTXPOOL); + *poolp = NULL; } -/* - * Combined find/lock operation. Lock the pool mutex associated with - * the specified address. - */ -void -mtx_pool_lock(void *ptr) +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; +} - mtx_lock(_mtx_pool_find(ptr)); +static void +mtx_pool_setup_dynamic(void *dummy __unused) +{ + mtxpool_sleep = mtx_pool_create("sleep mtxpool", + MTX_POOL_SLEEP_SIZE, MTX_DEF); } /* - * Combined find/unlock operation. Unlock the pool mutex associated with - * the specified address. + * 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. */ -void -mtx_pool_unlock(void *ptr) +struct mtx * +mtx_pool_alloc(struct mtx_pool *pool) { - - mtx_unlock(_mtx_pool_find(ptr)); + 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]); } -SYSINIT(mtxpooli, SI_SUB_MTX_POOL, SI_ORDER_FIRST, mtx_pool_setup, NULL); +/* + * 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_LOCK, ...). + * + * 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); |