25'ten fazla konu seçemezsiniz
Konular bir harf veya rakamla başlamalı, kısa çizgiler ('-') içerebilir ve en fazla 35 karakter uzunluğunda olabilir.
305 satır
6.8 KiB
305 satır
6.8 KiB
#include <defs.h>
|
|
#include <list.h>
|
|
#include <memlayout.h>
|
|
#include <assert.h>
|
|
#include <kmalloc.h>
|
|
#include <sync.h>
|
|
#include <pmm.h>
|
|
#include <stdio.h>
|
|
|
|
/*
|
|
* SLOB Allocator: Simple List Of Blocks
|
|
*
|
|
* Matt Mackall <mpm@selenic.com> 12/30/03
|
|
*
|
|
* How SLOB works:
|
|
*
|
|
* The core of SLOB is a traditional K&R style heap allocator, with
|
|
* support for returning aligned objects. The granularity of this
|
|
* allocator is 8 bytes on x86, though it's perhaps possible to reduce
|
|
* this to 4 if it's deemed worth the effort. The slob heap is a
|
|
* singly-linked list of pages from __get_free_page, grown on demand
|
|
* and allocation from the heap is currently first-fit.
|
|
*
|
|
* Above this is an implementation of kmalloc/kfree. Blocks returned
|
|
* from kmalloc are 8-byte aligned and prepended with a 8-byte header.
|
|
* If kmalloc is asked for objects of PAGE_SIZE or larger, it calls
|
|
* __get_free_pages directly so that it can return page-aligned blocks
|
|
* and keeps a linked list of such pages and their orders. These
|
|
* objects are detected in kfree() by their page alignment.
|
|
*
|
|
* SLAB is emulated on top of SLOB by simply calling constructors and
|
|
* destructors for every SLAB allocation. Objects are returned with
|
|
* the 8-byte alignment unless the SLAB_MUST_HWCACHE_ALIGN flag is
|
|
* set, in which case the low-level allocator will fragment blocks to
|
|
* create the proper alignment. Again, objects of page-size or greater
|
|
* are allocated by calling __get_free_pages. As SLAB objects know
|
|
* their size, no separate size bookkeeping is necessary and there is
|
|
* essentially no allocation space overhead.
|
|
*/
|
|
|
|
|
|
//some helper
|
|
#define spin_lock_irqsave(l, f) local_intr_save(f)
|
|
#define spin_unlock_irqrestore(l, f) local_intr_restore(f)
|
|
typedef unsigned int gfp_t;
|
|
#ifndef PAGE_SIZE
|
|
#define PAGE_SIZE PGSIZE
|
|
#endif
|
|
|
|
#ifndef L1_CACHE_BYTES
|
|
#define L1_CACHE_BYTES 64
|
|
#endif
|
|
|
|
#ifndef ALIGN
|
|
#define ALIGN(addr,size) (((addr)+(size)-1)&(~((size)-1)))
|
|
#endif
|
|
|
|
|
|
struct slob_block {
|
|
int units;
|
|
struct slob_block *next;
|
|
};
|
|
typedef struct slob_block slob_t;
|
|
|
|
#define SLOB_UNIT sizeof(slob_t)
|
|
#define SLOB_UNITS(size) (((size) + SLOB_UNIT - 1)/SLOB_UNIT)
|
|
#define SLOB_ALIGN L1_CACHE_BYTES
|
|
|
|
struct bigblock {
|
|
int order;
|
|
void *pages;
|
|
struct bigblock *next;
|
|
};
|
|
typedef struct bigblock bigblock_t;
|
|
|
|
static slob_t arena = { .next = &arena, .units = 1 };
|
|
static slob_t *slobfree = &arena;
|
|
static bigblock_t *bigblocks;
|
|
|
|
|
|
static void* __slob_get_free_pages(gfp_t gfp, int order)
|
|
{
|
|
struct Page * page = alloc_pages(1 << order);
|
|
if(!page)
|
|
return NULL;
|
|
return page2kva(page);
|
|
}
|
|
|
|
#define __slob_get_free_page(gfp) __slob_get_free_pages(gfp, 0)
|
|
|
|
static inline void __slob_free_pages(unsigned long kva, int order)
|
|
{
|
|
free_pages(kva2page(kva), 1 << order);
|
|
}
|
|
|
|
static void slob_free(void *b, int size);
|
|
|
|
static void *slob_alloc(size_t size, gfp_t gfp, int align)
|
|
{
|
|
assert( (size + SLOB_UNIT) < PAGE_SIZE );
|
|
|
|
slob_t *prev, *cur, *aligned = 0;
|
|
int delta = 0, units = SLOB_UNITS(size);
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&slob_lock, flags);
|
|
prev = slobfree;
|
|
for (cur = prev->next; ; prev = cur, cur = cur->next) {
|
|
if (align) {
|
|
aligned = (slob_t *)ALIGN((unsigned long)cur, align);
|
|
delta = aligned - cur;
|
|
}
|
|
if (cur->units >= units + delta) { /* room enough? */
|
|
if (delta) { /* need to fragment head to align? */
|
|
aligned->units = cur->units - delta;
|
|
aligned->next = cur->next;
|
|
cur->next = aligned;
|
|
cur->units = delta;
|
|
prev = cur;
|
|
cur = aligned;
|
|
}
|
|
|
|
if (cur->units == units) /* exact fit? */
|
|
prev->next = cur->next; /* unlink */
|
|
else { /* fragment */
|
|
prev->next = cur + units;
|
|
prev->next->units = cur->units - units;
|
|
prev->next->next = cur->next;
|
|
cur->units = units;
|
|
}
|
|
|
|
slobfree = prev;
|
|
spin_unlock_irqrestore(&slob_lock, flags);
|
|
return cur;
|
|
}
|
|
if (cur == slobfree) {
|
|
spin_unlock_irqrestore(&slob_lock, flags);
|
|
|
|
if (size == PAGE_SIZE) /* trying to shrink arena? */
|
|
return 0;
|
|
|
|
cur = (slob_t *)__slob_get_free_page(gfp);
|
|
if (!cur)
|
|
return 0;
|
|
|
|
slob_free(cur, PAGE_SIZE);
|
|
spin_lock_irqsave(&slob_lock, flags);
|
|
cur = slobfree;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void slob_free(void *block, int size)
|
|
{
|
|
slob_t *cur, *b = (slob_t *)block;
|
|
unsigned long flags;
|
|
|
|
if (!block)
|
|
return;
|
|
|
|
if (size)
|
|
b->units = SLOB_UNITS(size);
|
|
|
|
/* Find reinsertion point */
|
|
spin_lock_irqsave(&slob_lock, flags);
|
|
for (cur = slobfree; !(b > cur && b < cur->next); cur = cur->next)
|
|
if (cur >= cur->next && (b > cur || b < cur->next))
|
|
break;
|
|
|
|
if (b + b->units == cur->next) {
|
|
b->units += cur->next->units;
|
|
b->next = cur->next->next;
|
|
} else
|
|
b->next = cur->next;
|
|
|
|
if (cur + cur->units == b) {
|
|
cur->units += b->units;
|
|
cur->next = b->next;
|
|
} else
|
|
cur->next = b;
|
|
|
|
slobfree = cur;
|
|
|
|
spin_unlock_irqrestore(&slob_lock, flags);
|
|
}
|
|
|
|
|
|
|
|
void
|
|
slob_init(void) {
|
|
cprintf("use SLOB allocator\n");
|
|
}
|
|
|
|
inline void
|
|
kmalloc_init(void) {
|
|
slob_init();
|
|
cprintf("kmalloc_init() succeeded!\n");
|
|
}
|
|
|
|
size_t
|
|
slob_allocated(void) {
|
|
return 0;
|
|
}
|
|
|
|
size_t
|
|
kallocated(void) {
|
|
return slob_allocated();
|
|
}
|
|
|
|
static int find_order(int size)
|
|
{
|
|
int order = 0;
|
|
for ( ; size > 4096 ; size >>=1)
|
|
order++;
|
|
return order;
|
|
}
|
|
|
|
static void *__kmalloc(size_t size, gfp_t gfp)
|
|
{
|
|
slob_t *m;
|
|
bigblock_t *bb;
|
|
unsigned long flags;
|
|
|
|
if (size < PAGE_SIZE - SLOB_UNIT) {
|
|
m = slob_alloc(size + SLOB_UNIT, gfp, 0);
|
|
return m ? (void *)(m + 1) : 0;
|
|
}
|
|
|
|
bb = slob_alloc(sizeof(bigblock_t), gfp, 0);
|
|
if (!bb)
|
|
return 0;
|
|
|
|
bb->order = find_order(size);
|
|
bb->pages = (void *)__slob_get_free_pages(gfp, bb->order);
|
|
|
|
if (bb->pages) {
|
|
spin_lock_irqsave(&block_lock, flags);
|
|
bb->next = bigblocks;
|
|
bigblocks = bb;
|
|
spin_unlock_irqrestore(&block_lock, flags);
|
|
return bb->pages;
|
|
}
|
|
|
|
slob_free(bb, sizeof(bigblock_t));
|
|
return 0;
|
|
}
|
|
|
|
void *
|
|
kmalloc(size_t size)
|
|
{
|
|
return __kmalloc(size, 0);
|
|
}
|
|
|
|
|
|
void kfree(void *block)
|
|
{
|
|
bigblock_t *bb, **last = &bigblocks;
|
|
unsigned long flags;
|
|
|
|
if (!block)
|
|
return;
|
|
|
|
if (!((unsigned long)block & (PAGE_SIZE-1))) {
|
|
/* might be on the big block list */
|
|
spin_lock_irqsave(&block_lock, flags);
|
|
for (bb = bigblocks; bb; last = &bb->next, bb = bb->next) {
|
|
if (bb->pages == block) {
|
|
*last = bb->next;
|
|
spin_unlock_irqrestore(&block_lock, flags);
|
|
__slob_free_pages((unsigned long)block, bb->order);
|
|
slob_free(bb, sizeof(bigblock_t));
|
|
return;
|
|
}
|
|
}
|
|
spin_unlock_irqrestore(&block_lock, flags);
|
|
}
|
|
|
|
slob_free((slob_t *)block - 1, 0);
|
|
return;
|
|
}
|
|
|
|
|
|
unsigned int ksize(const void *block)
|
|
{
|
|
bigblock_t *bb;
|
|
unsigned long flags;
|
|
|
|
if (!block)
|
|
return 0;
|
|
|
|
if (!((unsigned long)block & (PAGE_SIZE-1))) {
|
|
spin_lock_irqsave(&block_lock, flags);
|
|
for (bb = bigblocks; bb; bb = bb->next)
|
|
if (bb->pages == block) {
|
|
spin_unlock_irqrestore(&slob_lock, flags);
|
|
return PAGE_SIZE << bb->order;
|
|
}
|
|
spin_unlock_irqrestore(&block_lock, flags);
|
|
}
|
|
|
|
return ((slob_t *)block - 1)->units * SLOB_UNIT;
|
|
}
|
|
|
|
|
|
|