diff options
| -rw-r--r-- | sys/kern/subr_vmem.c | 63 |
1 files changed, 50 insertions, 13 deletions
diff --git a/sys/kern/subr_vmem.c b/sys/kern/subr_vmem.c index 2c8da6634d7a..b99b895233a4 100644 --- a/sys/kern/subr_vmem.c +++ b/sys/kern/subr_vmem.c @@ -249,6 +249,18 @@ static struct vmem memguard_arena_storage; vmem_t *memguard_arena = &memguard_arena_storage; #endif +static bool +bt_isbusy(bt_t *bt) +{ + return (bt->bt_type == BT_TYPE_BUSY); +} + +static bool +bt_isfree(bt_t *bt) +{ + return (bt->bt_type == BT_TYPE_FREE); +} + /* * Fill the vmem's boundary tag cache. We guarantee that boundary tag * allocation will not fail once bt_fill() passes. To do so we cache @@ -795,24 +807,48 @@ SYSINIT(vfs, SI_SUB_CONFIGURE, SI_ORDER_ANY, vmem_start_callout, NULL); static void vmem_add1(vmem_t *vm, vmem_addr_t addr, vmem_size_t size, int type) { - bt_t *btspan; - bt_t *btfree; + bt_t *btfree, *btprev, *btspan; + VMEM_ASSERT_LOCKED(vm); MPASS(type == BT_TYPE_SPAN || type == BT_TYPE_SPAN_STATIC); MPASS((size & vm->vm_quantum_mask) == 0); - btspan = bt_alloc(vm); - btspan->bt_type = type; - btspan->bt_start = addr; - btspan->bt_size = size; - bt_insseg_tail(vm, btspan); + if (vm->vm_releasefn == NULL) { + /* + * The new segment will never be released, so see if it is + * contiguous with respect to an existing segment. In this case + * a span tag is not needed, and it may be possible now or in + * the future to coalesce the new segment with an existing free + * segment. + */ + btprev = TAILQ_LAST(&vm->vm_seglist, vmem_seglist); + if ((!bt_isbusy(btprev) && !bt_isfree(btprev)) || + btprev->bt_start + btprev->bt_size != addr) + btprev = NULL; + } else { + btprev = NULL; + } - btfree = bt_alloc(vm); - btfree->bt_type = BT_TYPE_FREE; - btfree->bt_start = addr; - btfree->bt_size = size; - bt_insseg(vm, btfree, btspan); - bt_insfree(vm, btfree); + if (btprev == NULL || bt_isbusy(btprev)) { + if (btprev == NULL) { + btspan = bt_alloc(vm); + btspan->bt_type = type; + btspan->bt_start = addr; + btspan->bt_size = size; + bt_insseg_tail(vm, btspan); + } + + btfree = bt_alloc(vm); + btfree->bt_type = BT_TYPE_FREE; + btfree->bt_start = addr; + btfree->bt_size = size; + bt_insseg_tail(vm, btfree); + bt_insfree(vm, btfree); + } else { + bt_remfree(vm, btprev); + btprev->bt_size += size; + bt_insfree(vm, btprev); + } vm->vm_size += size; } @@ -1147,6 +1183,7 @@ vmem_set_import(vmem_t *vm, vmem_import_t *importfn, { VMEM_LOCK(vm); + KASSERT(vm->vm_size == 0, ("%s: arena is non-empty", __func__)); vm->vm_importfn = importfn; vm->vm_releasefn = releasefn; vm->vm_arg = arg; |