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Garbage collect mtxpool_lockbuilder, the mutex pool historically used

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for lockmgr and sx interlocks, but unused since optimised versions of
those sleep locks were introduced.  This will save a (quite) small
amount of memory in all kernel configurations.  The sleep mutex pool is
retained as it is used for 'struct bio' and several other consumers.

Discussed with:	jhb
MFC after:	3 days
This commit is contained in:
Robert Watson 2014-05-02 07:57:40 +00:00
parent 804e017089
commit a2496f6e01
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=265216
3 changed files with 0 additions and 35 deletions
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30
sys/kern/kern_mtxpool.c
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@ -59,9 +59,6 @@ __FBSDID("$FreeBSD$");
static 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
@ -78,18 +75,12 @@ struct mtx_pool {
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
@ -165,15 +156,6 @@ mtx_pool_destroy(struct mtx_pool **poolp)
*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)
{
@ -202,17 +184,5 @@ mtx_pool_alloc(struct mtx_pool *pool)
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);

1
sys/sys/kernel.h
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@ -92,7 +92,6 @@ enum sysinit_sub_id {
SI_SUB_COPYRIGHT = 0x0800001, /* first use of console*/
SI_SUB_SETTINGS = 0x0880000, /* check and recheck settings */
SI_SUB_MTX_POOL_STATIC = 0x0900000, /* static mutex pool */
SI_SUB_LOCKMGR = 0x0980000, /* lockmgr locks */
SI_SUB_VM = 0x1000000, /* virtual memory system init*/
SI_SUB_KMEM = 0x1800000, /* kernel memory*/
SI_SUB_KVM_RSRC = 0x1A00000, /* kvm operational limits*/

4
sys/sys/mutex.h
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@ -323,12 +323,8 @@ struct mtx *mtx_pool_alloc(struct mtx_pool *pool);
mtx_unlock_spin(mtx_pool_find((pool), (ptr)))
/*
* mtxpool_lockbuilder is a pool of sleep locks that is not witness
* checked and should only be used for building higher level locks.
*
* mtxpool_sleep is a general purpose pool of sleep mutexes.
*/
extern struct mtx_pool *mtxpool_lockbuilder;
extern struct mtx_pool *mtxpool_sleep;
#ifndef LOCK_DEBUG