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提交 f8d394aa 创建 作者: Nickolai Zeldovich's avatar Nickolai Zeldovich
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hybrid rcu vm

上级 d9d15998
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正在显示 包含 61 行增加 和 59 行删除
defs.h
浏览文件 @ f8d394aa
......@@ -234,10 +234,9 @@ void vmn_free(struct vmnode *);
int vmn_load(struct vmnode *, struct inode*, uint, uint);
struct vmap * vmap_alloc(void);
void vmap_decref(struct vmap *);
int vmap_overlap(struct vmap *m, uint start, uint end);
struct vma * vmap_overlap(struct vmap *m, uint start, uint end);
int vmap_insert(struct vmap *, struct vmnode *n, uint);
int vmap_remove(struct vmap *, uint va_start, uint len);
struct vma * vmap_lookup(struct vmap *, uint);
struct vmap * vmap_copy(struct vmap *, int);
void switchuvm(struct proc*);
void switchkvm(void);
......
proc.c
浏览文件 @ f8d394aa
......@@ -188,18 +188,20 @@ growproc(int n)
// find first unallocated address in brk..brk+n
uint newstart = proc->brk;
uint newn = n;
rcu_begin_read();
while(newn > 0){
int ind = vmap_overlap(m, newstart, 1);
if(ind == -1)
struct vma *e = vmap_overlap(m, newstart, 1);
if(e == 0)
break;
if(m->e[ind]->va_end >= newstart + newn){
if(e->va_end >= newstart + newn){
newstart += newn;
newn = 0;
break;
}
newn -= m->e[ind]->va_end - newstart;
newstart = m->e[ind]->va_end;
newn -= e->va_end - newstart;
newstart = e->va_end;
}
rcu_end_read();
if(newn <= 0){
// no need to allocate
......@@ -210,8 +212,7 @@ growproc(int n)
}
// is there space for newstart..newstart+newn?
if(vmap_overlap(m, newstart, newn) != -1){
release(&m->lock);
if(vmap_overlap(m, newstart, newn) != 0){
cprintf("growproc: not enough room in address space; brk %d n %d\n",
proc->brk, n);
return -1;
......@@ -220,8 +221,7 @@ growproc(int n)
// would the newly allocated region abut the next-higher
// vma? we can't allow that, since then a future sbrk()
// would start to use the next region (e.g. the stack).
if(vmap_overlap(m, PGROUNDUP(newstart+newn), 1) != -1){
release(&m->lock);
if(vmap_overlap(m, PGROUNDUP(newstart+newn), 1) != 0){
cprintf("growproc: would abut next vma; brk %d n %d\n",
proc->brk, n);
return -1;
......
vm.c
浏览文件 @ f8d394aa
......@@ -494,29 +494,26 @@ vmap_decref(struct vmap *m)
}
// Does any vma overlap start..start+len?
// If yes, return the m->e[] index.
// If no, return -1.
// If yes, return the vma pointer.
// If no, return 0.
// This code can't handle regions at the very end
// of the address space, e.g. 0xffffffff..0x0
int
struct vma *
vmap_overlap(struct vmap *m, uint start, uint len)
{
#if SPINLOCK_DEBUG
if(holding(&m->lock) == 0)
panic("vmap_overlap no lock");
#endif
if(start + len < start)
panic("vmap_overlap bad len");
for(uint i = 0; i < NELEM(m->e); i++){
if(m->e[i]){
if(m->e[i]->va_end <= m->e[i]->va_start)
struct vma *e = m->e[i];
if(e) {
if(e->va_end <= e->va_start)
panic("vmap_overlap bad vma");
if(m->e[i]->va_start < start+len && m->e[i]->va_end > start)
return i;
if(e->va_start < start+len && e->va_end > start)
return e;
}
}
return -1;
return 0;
}
int
......@@ -525,8 +522,7 @@ vmap_insert(struct vmap *m, struct vmnode *n, uint va_start)
acquire(&m->lock);
uint len = n->npages * PGSIZE;
if(vmap_overlap(m, va_start, len) != -1){
release(&m->lock);
if(vmap_overlap(m, va_start, len)){
cprintf("vmap_insert: overlap\n");
return -1;
}
......@@ -570,33 +566,6 @@ vmap_remove(struct vmap *m, uint va_start, uint len)
return 0;
}
struct vma *
vmap_lookup(struct vmap *m, uint va)
{
acquire(&m->lock); // rcu read
int ind = vmap_overlap(m, va, 1);
if(ind >= 0){
struct vma *e = m->e[ind];
acquire(&e->lock);
release(&m->lock);
return e;
}
release(&m->lock);
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)
{
......@@ -619,8 +588,11 @@ vmap_copy(struct vmap *m, int share)
if (share) {
c->e[i]->n = m->e[i]->n;
c->e[i]->va_type = COW;
acquire(&m->e[i]->lock);
m->e[i]->va_type = COW;
updatepages(m->pgdir, (void *) (m->e[i]->va_start), (void *) (m->e[i]->va_end), PTE_COW);
release(&m->e[i]->lock);
} else {
c->e[i]->n = vmn_copy(m->e[i]->n);
c->e[i]->va_type = m->e[i]->va_type;
......@@ -677,10 +649,17 @@ copyout(struct vmap *vmap, uint va, void *p, uint len)
char *buf = (char*)p;
while(len > 0){
uint va0 = (uint)PGROUNDDOWN(va);
struct vma *vma = vmap_lookup(vmap, va);
if(vma == 0)
rcu_begin_read();
acquire(&vmap->lock);
struct vma *vma = vmap_overlap(vmap, va, 1);
if(vma == 0) {
release(&vmap->lock);
rcu_end_read();
return -1;
}
acquire(&vma->lock);
release(&vmap->lock);
uint pn = (va0 - vma->va_start) / PGSIZE;
char *p0 = vma->n->page[pn];
if(p0 == 0)
......@@ -693,6 +672,7 @@ copyout(struct vmap *vmap, uint va, void *p, uint len)
buf += n;
va = va0 + PGSIZE;
release(&vma->lock);
rcu_end_read();
}
return 0;
}
......@@ -703,10 +683,17 @@ copyin(struct vmap *vmap, uint va, void *p, uint len)
char *buf = (char*)p;
while(len > 0){
uint va0 = (uint)PGROUNDDOWN(va);
struct vma *vma = vmap_lookup(vmap, va);
if(vma == 0)
rcu_begin_read();
acquire(&vmap->lock);
struct vma *vma = vmap_overlap(vmap, va, 1);
if(vma == 0) {
release(&vmap->lock);
rcu_end_read();
return -1;
}
acquire(&vma->lock);
release(&vmap->lock);
uint pn = (va0 - vma->va_start) / PGSIZE;
char *p0 = vma->n->page[pn];
if(p0 == 0)
......@@ -719,6 +706,7 @@ copyin(struct vmap *vmap, uint va, void *p, uint len)
buf += n;
va = va0 + PGSIZE;
release(&vma->lock);
rcu_end_read();
}
return 0;
}
......@@ -733,7 +721,12 @@ pagefault_ondemand(struct vmap *vmap, uint va, uint err, struct vma *m)
if (vmn_doload(m->n, m->n->ip, m->n->offset, m->n->sz) < 0) {
panic("pagefault: couldn't load");
}
m = vmap_lookup(vmap, va); // re-acquire lock on m
acquire(&vmap->lock);
m = vmap_overlap(vmap, va, 1);
if (!m)
panic("pagefault_ondemand");
acquire(&m->lock); // re-acquire lock on m
release(&vmap->lock);
return m;
}
......@@ -766,10 +759,18 @@ pagefault(struct vmap *vmap, uint va, uint err)
pte_t *pte = walkpgdir(vmap->pgdir, (const void *)va, 1);
if((*pte & (PTE_P|PTE_U|PTE_W)) == (PTE_P|PTE_U|PTE_W))
return 0;
struct vma *m = vmap_lookup(vmap, va);
if(m == 0)
rcu_begin_read();
acquire(&vmap->lock);
struct vma *m = vmap_overlap(vmap, va, 1);
if(m == 0) {
release(&vmap->lock);
rcu_end_read();
return -1;
}
acquire(&m->lock);
release(&vmap->lock);
uint npg = (PGROUNDDOWN(va) - m->va_start) / PGSIZE;
if (m->n && m->n->type == ONDEMAND && m->n->page[npg] == 0) {
m = pagefault_ondemand(vmap, va, err, m);
......@@ -777,6 +778,7 @@ pagefault(struct vmap *vmap, uint va, uint err)
if (m->va_type == COW && (err & FEC_WR)) {
if (pagefault_wcow(vmap, va, pte, m, npg) < 0) {
release(&m->lock);
rcu_end_read();
return -1;
}
} else if (m->va_type == COW) {
......@@ -789,5 +791,6 @@ pagefault(struct vmap *vmap, uint va, uint err)
}
lcr3(v2p(vmap->pgdir)); // Reload hardware page tables
release(&m->lock);
rcu_end_read();
return 1;
}
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