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- Introduce and use a mutex synchronizing access to the swblock hash table.

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This commit is contained in:
Alan Cox 2003-10-26 19:55:35 +00:00
parent 32801db0f2
commit 7827d9b0fe
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=121583
1 changed files with 20 additions and 4 deletions
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24
sys/vm/swap_pager.c
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@ -197,6 +197,8 @@ static int nsw_cluster_max; /* maximum VOP I/O allowed */
static struct swblock **swhash;
static int swhash_mask;
static struct mtx swhash_mtx;
static int swap_async_max = 4; /* maximum in-progress async I/O's */
static struct sx sw_alloc_sx;
@ -419,7 +421,7 @@ swap_pager_swap_init(void)
n = maxswzone / sizeof(struct swblock);
n2 = n;
swap_zone = uma_zcreate("SWAPMETA", sizeof(struct swblock), NULL, NULL,
NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE | UMA_ZONE_VM);
do {
if (uma_zone_set_obj(swap_zone, NULL, n))
break;
@ -447,6 +449,7 @@ swap_pager_swap_init(void)
;
swhash = malloc(sizeof(struct swblock *) * n, M_VMPGDATA, M_WAITOK | M_ZERO);
swhash_mask = n - 1;
mtx_init(&swhash_mtx, "swap_pager swhash", NULL, MTX_DEF);
}
/*
@ -1625,16 +1628,19 @@ swap_pager_isswapped(vm_object_t object, struct swdevt *sp)
for (bcount = 0; bcount < object->un_pager.swp.swp_bcount; bcount++) {
struct swblock *swap;
mtx_lock(&swhash_mtx);
if ((swap = *swp_pager_hash(object, index)) != NULL) {
for (i = 0; i < SWAP_META_PAGES; ++i) {
daddr_t v = swap->swb_pages[i];
if (v == SWAPBLK_NONE)
continue;
if (swp_pager_find_dev(v) == sp)
if (swp_pager_find_dev(v) == sp) {
mtx_unlock(&swhash_mtx);
return 1;
}
}
}
mtx_unlock(&swhash_mtx);
index += SWAP_META_PAGES;
if (index > 0x20000000)
panic("swap_pager_isswapped: failed to locate all swap meta blocks");
@ -1823,16 +1829,18 @@ swp_pager_meta_build(vm_object_t object, vm_pindex_t pindex, daddr_t swapblk)
* and, since the hash table may have changed, retry.
*/
retry:
mtx_lock(&swhash_mtx);
pswap = swp_pager_hash(object, pindex);
if ((swap = *pswap) == NULL) {
int i;
if (swapblk == SWAPBLK_NONE)
return;
goto done;
swap = *pswap = uma_zalloc(swap_zone, M_NOWAIT);
if (swap == NULL) {
mtx_unlock(&swhash_mtx);
VM_OBJECT_UNLOCK(object);
VM_WAIT;
VM_OBJECT_LOCK(object);
@ -1866,6 +1874,8 @@ swp_pager_meta_build(vm_object_t object, vm_pindex_t pindex, daddr_t swapblk)
swap->swb_pages[idx] = swapblk;
if (swapblk != SWAPBLK_NONE)
++swap->swb_count;
done:
mtx_unlock(&swhash_mtx);
}
/*
@ -1892,6 +1902,7 @@ swp_pager_meta_free(vm_object_t object, vm_pindex_t index, daddr_t count)
struct swblock **pswap;
struct swblock *swap;
mtx_lock(&swhash_mtx);
pswap = swp_pager_hash(object, index);
if ((swap = *pswap) != NULL) {
@ -1914,6 +1925,7 @@ swp_pager_meta_free(vm_object_t object, vm_pindex_t index, daddr_t count)
count -= n;
index += n;
}
mtx_unlock(&swhash_mtx);
}
}
@ -1939,6 +1951,7 @@ swp_pager_meta_free_all(vm_object_t object)
struct swblock **pswap;
struct swblock *swap;
mtx_lock(&swhash_mtx);
pswap = swp_pager_hash(object, index);
if ((swap = *pswap) != NULL) {
int i;
@ -1956,6 +1969,7 @@ swp_pager_meta_free_all(vm_object_t object)
uma_zfree(swap_zone, swap);
--object->un_pager.swp.swp_bcount;
}
mtx_unlock(&swhash_mtx);
index += SWAP_META_PAGES;
if (index > 0x20000000)
panic("swp_pager_meta_free_all: failed to locate all swap meta blocks");
@ -2001,6 +2015,7 @@ swp_pager_meta_ctl(vm_object_t object, vm_pindex_t pindex, int flags)
return (SWAPBLK_NONE);
r1 = SWAPBLK_NONE;
mtx_lock(&swhash_mtx);
pswap = swp_pager_hash(object, pindex);
if ((swap = *pswap) != NULL) {
@ -2022,6 +2037,7 @@ swp_pager_meta_ctl(vm_object_t object, vm_pindex_t pindex, int flags)
}
}
}
mtx_unlock(&swhash_mtx);
return (r1);
}