kalloc/kfree now only a page at a time
do not keep sorted contiguous free list
This commit is contained in:
Robert Morris
parent
81b30b14d6
commit
7d7dc9331b
5
defs.h
5
defs.h
|
|
@ -60,9 +60,8 @@ extern uchar ioapicid;
|
|||
void ioapicinit(void);
|
||||
|
||||
// kalloc.c
|
||||
extern int nfreemem;
|
||||
char* kalloc(int);
|
||||
void kfree(char*, int);
|
||||
char* kalloc(void);
|
||||
void kfree(char*);
|
||||
void kinit(char*,uint);
|
||||
|
||||
// kbd.c
|
||||
|
|
|
|||
89
kalloc.c
89
kalloc.c
|
|
@ -1,8 +1,6 @@
|
|||
// Physical memory allocator, intended to allocate
|
||||
// memory for user processes. Allocates in 4096-byte pages.
|
||||
// Free list is kept sorted and combines adjacent pages into
|
||||
// long runs, to make it easier to allocate big segments.
|
||||
// This combining is not useful now that xv6 uses paging.
|
||||
// memory for user processes, kernel stacks, page table pages,
|
||||
// and pipe buffers. Allocates 4096-byte pages.
|
||||
|
||||
#include "types.h"
|
||||
#include "defs.h"
|
||||
|
|
@ -12,7 +10,6 @@
|
|||
|
||||
struct run {
|
||||
struct run *next;
|
||||
int len; // bytes
|
||||
};
|
||||
|
||||
struct {
|
||||
|
|
@ -20,92 +17,52 @@ struct {
|
|||
struct run *freelist;
|
||||
} kmem;
|
||||
|
||||
int nfreemem;
|
||||
|
||||
// Initialize free list of physical pages.
|
||||
void
|
||||
kinit(char *p, uint len)
|
||||
{
|
||||
initlock(&kmem.lock, "kmem");
|
||||
nfreemem = 0;
|
||||
kfree(p, len);
|
||||
char *p1 = (char*)PGROUNDUP((uint)p);
|
||||
char *p2 = PGROUNDDOWN(p + len);
|
||||
for( ; p1 < p2; p1 += 4096)
|
||||
kfree(p1);
|
||||
}
|
||||
|
||||
// Free the len bytes of memory pointed at by v,
|
||||
// Free the page of physical memory pointed at by v,
|
||||
// which normally should have been returned by a
|
||||
// call to kalloc(len). (The exception is when
|
||||
// call to kalloc(). (The exception is when
|
||||
// initializing the allocator; see kinit above.)
|
||||
void
|
||||
kfree(char *v, int len)
|
||||
kfree(char *v)
|
||||
{
|
||||
struct run *r, *rend, **rp, *p, *pend;
|
||||
struct run *r;
|
||||
|
||||
if(len <= 0 || len % PGSIZE)
|
||||
if(((uint) v) % PGSIZE || (uint)v < 1024*1024 || (uint)v >= PHYSTOP)
|
||||
panic("kfree");
|
||||
|
||||
// Fill with junk to catch dangling refs.
|
||||
memset(v, 1, len);
|
||||
memset(v, 1, PGSIZE);
|
||||
|
||||
acquire(&kmem.lock);
|
||||
nfreemem += len;
|
||||
p = (struct run*)v;
|
||||
pend = (struct run*)(v + len);
|
||||
for(rp=&kmem.freelist; (r=*rp) != 0 && r <= pend; rp=&r->next){
|
||||
rend = (struct run*)((char*)r + r->len);
|
||||
if(r <= p && p < rend) {
|
||||
cprintf("freeing a free page: r = 0x%x p = 0x%x rend = 0x%x\n",
|
||||
r, p, rend);
|
||||
panic("freeing free page");
|
||||
}
|
||||
if(rend == p){ // r before p: expand r to include p
|
||||
r->len += len;
|
||||
if(r->next && r->next == pend){ // r now next to r->next?
|
||||
r->len += r->next->len;
|
||||
r->next = r->next->next;
|
||||
}
|
||||
goto out;
|
||||
}
|
||||
if(pend == r){ // p before r: expand p to include, replace r
|
||||
p->len = len + r->len;
|
||||
p->next = r->next;
|
||||
*rp = p;
|
||||
goto out;
|
||||
}
|
||||
}
|
||||
// Insert p before r in list.
|
||||
p->len = len;
|
||||
p->next = r;
|
||||
*rp = p;
|
||||
|
||||
out:
|
||||
r = (struct run *) v;
|
||||
r->next = kmem.freelist;
|
||||
kmem.freelist = r;
|
||||
release(&kmem.lock);
|
||||
}
|
||||
|
||||
// Allocate n bytes of physical memory.
|
||||
// Returns a kernel-segment pointer.
|
||||
// Allocate one 4096-byte page of physical memory.
|
||||
// Returns a pointer that the kernel can use.
|
||||
// Returns 0 if the memory cannot be allocated.
|
||||
char*
|
||||
kalloc(int n)
|
||||
kalloc()
|
||||
{
|
||||
char *p;
|
||||
struct run *r, **rp;
|
||||
|
||||
if(n % PGSIZE || n <= 0)
|
||||
panic("kalloc");
|
||||
struct run *r;
|
||||
|
||||
acquire(&kmem.lock);
|
||||
for(rp=&kmem.freelist; (r=*rp) != 0; rp=&r->next){
|
||||
if(r->len >= n){
|
||||
r->len -= n;
|
||||
p = (char*)r + r->len;
|
||||
if(r->len == 0)
|
||||
*rp = r->next;
|
||||
nfreemem -= n;
|
||||
r = kmem.freelist;
|
||||
if(r)
|
||||
kmem.freelist = r->next;
|
||||
release(&kmem.lock);
|
||||
return p;
|
||||
}
|
||||
}
|
||||
release(&kmem.lock);
|
||||
return 0;
|
||||
return (char*) r;
|
||||
}
|
||||
|
||||
|
|
|
|||
4
main.c
4
main.c
|
|
@ -28,7 +28,7 @@ main(void)
|
|||
void
|
||||
jkstack(void)
|
||||
{
|
||||
char *kstack = kalloc(PGSIZE);
|
||||
char *kstack = kalloc();
|
||||
if (!kstack)
|
||||
panic("jkstack\n");
|
||||
char *top = kstack + PGSIZE;
|
||||
|
|
@ -92,7 +92,7 @@ bootothers(void)
|
|||
continue;
|
||||
|
||||
// Fill in %esp, %eip and start code on cpu.
|
||||
stack = kalloc(KSTACKSIZE);
|
||||
stack = kalloc();
|
||||
*(void**)(code-4) = stack + KSTACKSIZE;
|
||||
*(void**)(code-8) = mpmain;
|
||||
lapicstartap(c->id, (uint)code);
|
||||
|
|
|
|||
2
mmu.h
2
mmu.h
|
|
@ -112,7 +112,7 @@ struct segdesc {
|
|||
#define PDXSHIFT 22 // offset of PDX in a linear address
|
||||
|
||||
#define PGROUNDUP(sz) (((sz)+PGSIZE-1) & ~(PGSIZE-1))
|
||||
#define PGROUNDDOWN(a) ((char*)((((unsigned int)a) & ~(PGSIZE-1))))
|
||||
#define PGROUNDDOWN(a) ((char*)((((unsigned int)(a)) & ~(PGSIZE-1))))
|
||||
|
||||
// Page table/directory entry flags.
|
||||
#define PTE_P 0x001 // Present
|
||||
|
|
|
|||
4
param.h
4
param.h
|
|
@ -1,6 +1,5 @@
|
|||
#define NPROC 64 // maximum number of processes
|
||||
#define PAGE 4096 // conveniently chosen to be equal to PGSIZE
|
||||
#define KSTACKSIZE PAGE // size of per-process kernel stack
|
||||
#define KSTACKSIZE 4096 // size of per-process kernel stack
|
||||
#define NCPU 8 // maximum number of CPUs
|
||||
#define NOFILE 16 // open files per process
|
||||
#define NFILE 100 // open files per system
|
||||
|
|
@ -8,3 +7,4 @@
|
|||
#define NINODE 50 // maximum number of active i-nodes
|
||||
#define NDEV 10 // maximum major device number
|
||||
#define ROOTDEV 1 // device number of file system root disk
|
||||
#define PHYSTOP 0x1000000 // use phys mem up to here as free pool
|
||||
|
|
|
|||
6
pipe.c
6
pipe.c
|
|
@ -27,7 +27,7 @@ pipealloc(struct file **f0, struct file **f1)
|
|||
*f0 = *f1 = 0;
|
||||
if((*f0 = filealloc()) == 0 || (*f1 = filealloc()) == 0)
|
||||
goto bad;
|
||||
if((p = (struct pipe*)kalloc(PAGE)) == 0)
|
||||
if((p = (struct pipe*)kalloc()) == 0)
|
||||
goto bad;
|
||||
p->readopen = 1;
|
||||
p->writeopen = 1;
|
||||
|
|
@ -47,7 +47,7 @@ pipealloc(struct file **f0, struct file **f1)
|
|||
//PAGEBREAK: 20
|
||||
bad:
|
||||
if(p)
|
||||
kfree((char*)p, PAGE);
|
||||
kfree((char*)p);
|
||||
if(*f0)
|
||||
fileclose(*f0);
|
||||
if(*f1)
|
||||
|
|
@ -68,7 +68,7 @@ pipeclose(struct pipe *p, int writable)
|
|||
}
|
||||
if(p->readopen == 0 && p->writeopen == 0) {
|
||||
release(&p->lock);
|
||||
kfree((char*)p, PAGE);
|
||||
kfree((char*)p);
|
||||
} else
|
||||
release(&p->lock);
|
||||
}
|
||||
|
|
|
|||
6
proc.c
6
proc.c
|
|
@ -84,7 +84,7 @@ found:
|
|||
release(&ptable.lock);
|
||||
|
||||
// Allocate kernel stack if possible.
|
||||
if((p->kstack = kalloc(KSTACKSIZE)) == 0){
|
||||
if((p->kstack = kalloc()) == 0){
|
||||
p->state = UNUSED;
|
||||
return 0;
|
||||
}
|
||||
|
|
@ -169,7 +169,7 @@ fork(void)
|
|||
|
||||
// Copy process state from p.
|
||||
if (!(np->pgdir = copyuvm(proc->pgdir, proc->sz))) {
|
||||
kfree(np->kstack, KSTACKSIZE);
|
||||
kfree(np->kstack);
|
||||
np->kstack = 0;
|
||||
np->state = UNUSED;
|
||||
return -1;
|
||||
|
|
@ -418,7 +418,7 @@ wait(void)
|
|||
if(p->state == ZOMBIE){
|
||||
// Found one.
|
||||
pid = p->pid;
|
||||
kfree(p->kstack, KSTACKSIZE);
|
||||
kfree(p->kstack);
|
||||
p->kstack = 0;
|
||||
freevm(p->pgdir);
|
||||
p->state = UNUSED;
|
||||
|
|
|
|||
|
|
@ -49,8 +49,8 @@ morecore(uint nu)
|
|||
char *p;
|
||||
Header *hp;
|
||||
|
||||
if(nu < PAGE)
|
||||
nu = PAGE;
|
||||
if(nu < 4096)
|
||||
nu = 4096;
|
||||
p = sbrk(nu * sizeof(Header));
|
||||
if(p == (char*) -1)
|
||||
return 0;
|
||||
|
|
|
|||
17
vm.c
17
vm.c
|
|
@ -29,7 +29,6 @@
|
|||
// (both in physical memory and in the kernel's virtual address
|
||||
// space).
|
||||
|
||||
#define PHYSTOP 0x1000000
|
||||
#define USERTOP 0xA0000
|
||||
|
||||
static uint kerntext; // Linker starts kernel at 1MB
|
||||
|
|
@ -53,7 +52,7 @@ walkpgdir(pde_t *pgdir, const void *va, int create)
|
|||
pde = &pgdir[PDX(va)];
|
||||
if (*pde & PTE_P) {
|
||||
pgtab = (pte_t*) PTE_ADDR(*pde);
|
||||
} else if (!create || !(r = (uint) kalloc(PGSIZE)))
|
||||
} else if (!create || !(r = (uint) kalloc()))
|
||||
return 0;
|
||||
else {
|
||||
pgtab = (pte_t*) r;
|
||||
|
|
@ -156,7 +155,7 @@ setupkvm(void)
|
|||
pde_t *pgdir;
|
||||
|
||||
// Allocate page directory
|
||||
if (!(pgdir = (pde_t *) kalloc(PGSIZE)))
|
||||
if (!(pgdir = (pde_t *) kalloc()))
|
||||
return 0;
|
||||
memset(pgdir, 0, PGSIZE);
|
||||
// Map IO space from 640K to 1Mbyte
|
||||
|
|
@ -206,7 +205,7 @@ allocuvm(pde_t *pgdir, char *addr, uint sz)
|
|||
for(a = first; a <= last; a += PGSIZE){
|
||||
pte_t *pte = walkpgdir(pgdir, a, 0);
|
||||
if(pte == 0 || (*pte & PTE_P) == 0){
|
||||
char *mem = kalloc(PGSIZE);
|
||||
char *mem = kalloc();
|
||||
if(mem == 0){
|
||||
// XXX clean up?
|
||||
return 0;
|
||||
|
|
@ -235,7 +234,7 @@ deallocuvm(pde_t *pgdir, char *addr, uint sz)
|
|||
uint pa = PTE_ADDR(*pte);
|
||||
if(pa == 0)
|
||||
panic("deallocuvm");
|
||||
kfree((void *) pa, PGSIZE);
|
||||
kfree((void *) pa);
|
||||
*pte = 0;
|
||||
}
|
||||
}
|
||||
|
|
@ -260,15 +259,15 @@ freevm(pde_t *pgdir)
|
|||
uint pa = PTE_ADDR(pgtab[j]);
|
||||
uint va = PGADDR(i, j, 0);
|
||||
if (va < USERTOP) // user memory
|
||||
kfree((void *) pa, PGSIZE);
|
||||
kfree((void *) pa);
|
||||
pgtab[j] = 0;
|
||||
}
|
||||
}
|
||||
kfree((void *) da, PGSIZE);
|
||||
kfree((void *) da);
|
||||
pgdir[i] = 0;
|
||||
}
|
||||
}
|
||||
kfree((void *) pgdir, PGSIZE);
|
||||
kfree((void *) pgdir);
|
||||
}
|
||||
|
||||
int
|
||||
|
|
@ -324,7 +323,7 @@ copyuvm(pde_t *pgdir, uint sz)
|
|||
panic("copyuvm: pte should exist\n");
|
||||
if(*pte & PTE_P){
|
||||
pa = PTE_ADDR(*pte);
|
||||
if (!(mem = kalloc(PGSIZE)))
|
||||
if (!(mem = kalloc()))
|
||||
return 0;
|
||||
memmove(mem, (char *)pa, PGSIZE);
|
||||
if (!mappages(d, (void *)i, PGSIZE, PADDR(mem), PTE_W|PTE_U))
|
||||
|
|
|
|||
Loading…
Reference in a new issue