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提交 2623b3bd 创建 作者: Frans Kaashoek's avatar Frans Kaashoek
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dynamically allocate vma

delay free vmap and vma
上级 7663c33b
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内嵌 并排
正在显示 包含 78 行增加 和 39 行删除
proc.c
浏览文件 @ 2623b3bd
......@@ -192,13 +192,13 @@ growproc(int n)
int ind = vmap_overlap(m, newstart, 1);
if(ind == -1)
break;
if(m->e[ind].va_end >= newstart + newn){
if(m->e[ind]->va_end >= newstart + newn){
newstart += newn;
newn = 0;
break;
}
newn -= m->e[ind].va_end - newstart;
newstart = m->e[ind].va_end;
newn -= m->e[ind]->va_end - newstart;
newstart = m->e[ind]->va_end;
}
if(newn <= 0){
......
proc.h
浏览文件 @ 2623b3bd
......@@ -58,7 +58,7 @@ struct vma {
// An address space: a set of vmas plus h/w page table.
// The elements of e[] are not ordered by address.
struct vmap {
struct vma e[16];
struct vma* e[16];
struct spinlock lock; // serialize map/lookup/unmap
uint ref;
uint alloc;
......
vm.c
浏览文件 @ 2623b3bd
......@@ -433,6 +433,19 @@ vmn_copy(struct vmnode *n)
return c;
}
static struct vma *
vma_alloc(void)
{
struct vma *e = kmalloc(sizeof(struct vma));
if (e == 0)
return 0;
memset(e, 0, sizeof(struct vma));
e->va_type = PRIVATE;
snprintf(e->lockname, sizeof(e->lockname), "vma:%p", e);
initlock(&e->lock, e->lockname);
return e;
}
struct vmap *
vmap_alloc(void)
{
......@@ -441,11 +454,6 @@ vmap_alloc(void)
return 0;
memset(m, 0, sizeof(struct vmap));
for(uint j = 0; j < NELEM(m->e); j++){
m->e[j].va_type = PRIVATE;
snprintf(m->e[j].lockname, sizeof(m->e[j].lockname), "vma:%p", &m->e[j]);
initlock(&m->e[j].lock, m->e[j].lockname);
}
snprintf(m->lockname, sizeof(m->lockname), "vmap:%p", m);
initlock(&m->lock, m->lockname);
m->ref = 1;
......@@ -459,11 +467,21 @@ vmap_alloc(void)
}
static void
vmap_free(struct vmap *m)
vma_free(void *p)
{
struct vma *e = (struct vma *) p;
if(e->n)
vmn_decref(e->n);
kmfree(e);
}
static void
vmap_free(void *p)
{
struct vmap *m = (struct vmap *) p;
for(uint i = 0; i < NELEM(m->e); i++) {
if(m->e[i].n)
vmn_decref(m->e[i].n);
if (m->e[i])
vma_free(m->e[i]);
}
freevm(m->pgdir);
m->pgdir = 0;
......@@ -474,7 +492,7 @@ void
vmap_decref(struct vmap *m)
{
if(__sync_sub_and_fetch(&m->ref, 1) == 0)
vmap_free(m);
rcu_delayed(m, vmap_free);
}
// Does any vma overlap start..start+len?
......@@ -493,10 +511,10 @@ vmap_overlap(struct vmap *m, uint start, uint len)
panic("vmap_overlap bad len");
for(uint i = 0; i < NELEM(m->e); i++){
if(m->e[i].n){
if(m->e[i].va_end <= m->e[i].va_start)
if(m->e[i]){
if(m->e[i]->va_end <= m->e[i]->va_start)
panic("vmap_overlap bad vma");
if(m->e[i].va_start < start+len && m->e[i].va_end > start)
if(m->e[i]->va_start < start+len && m->e[i]->va_end > start)
return i;
}
}
......@@ -516,12 +534,15 @@ vmap_insert(struct vmap *m, struct vmnode *n, uint va_start)
}
for(uint i = 0; i < NELEM(m->e); i++) {
if(m->e[i].n)
if(m->e[i])
continue;
m->e[i] = vma_alloc();
if (m->e[i] == 0)
return -1;
m->e[i]->va_start = va_start;
m->e[i]->va_end = va_start + len;
m->e[i]->n = n;
__sync_fetch_and_add(&n->ref, 1);
m->e[i].va_start = va_start;
m->e[i].va_end = va_start + len;
m->e[i].n = n;
release(&m->lock);
return 0;
}
......@@ -537,14 +558,14 @@ vmap_remove(struct vmap *m, uint va_start, uint len)
acquire(&m->lock);
uint va_end = va_start + len;
for(uint i = 0; i < NELEM(m->e); i++) {
if(m->e[i].n && (m->e[i].va_start < va_end && m->e[i].va_end > va_start)) {
if(m->e[i].va_start != va_start || m->e[i].va_end != va_end) {
if(m->e[i] && (m->e[i]->va_start < va_end && m->e[i]->va_end > va_start)) {
if(m->e[i]->va_start != va_start || m->e[i]->va_end != va_end) {
release(&m->lock);
cprintf("vmap_remove: partial unmap unsupported\n");
return -1;
}
vmn_decref(m->e[i].n);
m->e[i].n = 0;
rcu_delayed(m->e[i], vma_free);
m->e[i] = 0;
}
}
release(&m->lock);
......@@ -554,10 +575,10 @@ vmap_remove(struct vmap *m, uint va_start, uint len)
struct vma *
vmap_lookup(struct vmap *m, uint va)
{
acquire(&m->lock);
acquire(&m->lock); // rcu read
int ind = vmap_overlap(m, va, 1);
if(ind >= 0){
struct vma *e = &m->e[ind];
struct vma *e = m->e[ind];
acquire(&e->lock);
release(&m->lock);
return e;
......@@ -566,6 +587,18 @@ vmap_lookup(struct vmap *m, uint va)
return 0;
}
struct vma *
vmap_lookup_rcu(struct vmap *m, uint va)
{
rcu_begin_read();
int ind = vmap_overlap(m, va, 1);
if(ind >= 0){
struct vma *e = m->e[ind];
return e;
}
return 0;
}
struct vmap *
vmap_copy(struct vmap *m, int share)
{
......@@ -575,25 +608,31 @@ vmap_copy(struct vmap *m, int share)
acquire(&m->lock);
for(uint i = 0; i < NELEM(m->e); i++) {
if(m->e[i].n == 0)
if(m->e[i] == 0)
continue;
c->e[i].va_start = m->e[i].va_start;
c->e[i].va_end = m->e[i].va_end;
c->e[i] = vma_alloc();
if (c->e[i] == 0) {
release(&m->lock);
vmap_free(c);
return 0;
}
c->e[i]->va_start = m->e[i]->va_start;
c->e[i]->va_end = m->e[i]->va_end;
if (share) {
c->e[i].n = m->e[i].n;
c->e[i].va_type = COW;
m->e[i].va_type = COW;
updatepages(m->pgdir, (void *) (m->e[i].va_start), (void *) (m->e[i].va_end), PTE_COW);
c->e[i]->n = m->e[i]->n;
c->e[i]->va_type = COW;
m->e[i]->va_type = COW;
updatepages(m->pgdir, (void *) (m->e[i]->va_start), (void *) (m->e[i]->va_end), PTE_COW);
} else {
c->e[i].n = vmn_copy(m->e[i].n);
c->e[i].va_type = m->e[i].va_type;
c->e[i]->n = vmn_copy(m->e[i]->n);
c->e[i]->va_type = m->e[i]->va_type;
}
if(c->e[i].n == 0) {
if(c->e[i]->n == 0) {
release(&m->lock);
vmap_free(c);
return 0;
}
__sync_fetch_and_add(&c->e[i].n->ref, 1);
__sync_fetch_and_add(&c->e[i]->n->ref, 1);
}
if (share)
lcr3(v2p(m->pgdir)); // Reload hardware page table
......@@ -705,7 +744,7 @@ pagefault_wcow(struct vmap *vmap, uint va, pte_t *pte, struct vma *m, uint npg)
{
// Always make a copy of n, even if this process has the only ref, because other processes
// may change ref count while this process is handling wcow
struct vmnode *o = m->n;
struct vmnode *n = m->n;
struct vmnode *c = vmn_copy(m->n);
if (c == 0) {
cprintf("pagefault_wcow: out of mem\n");
......@@ -719,7 +758,7 @@ pagefault_wcow(struct vmap *vmap, uint va, pte_t *pte, struct vma *m, uint npg)
pte = walkpgdir(vmap->pgdir, (const void *)va, 0);
*pte = v2p(m->n->page[npg]) | PTE_P | PTE_U | PTE_W;
// drop my ref to vmnode
vmn_decref(o);
vmn_decref(n);
return 0;
}
......
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