/* 在pf表示的虚拟内存池中申请pg_cnt个虚拟页,
* 成功则返回虚拟页的起始地址, 失败则返回NULL */
static void* vaddr_get(enum pool_flags pf, uint32_t pg_cnt) {
int vaddr_start = 0, bit_idx_start = -1;
uint32_t cnt = 0;
if (pf == PF_KERNEL) { // 内核内存池
bit_idx_start = bitmap_scan(&kernel_vaddr.vaddr_bitmap, pg_cnt);
if (bit_idx_start == -1) {
return NULL;
}
while(cnt < pg_cnt) {
bitmap_set(&kernel_vaddr.vaddr_bitmap, bit_idx_start + cnt++, 1);
}
vaddr_start = kernel_vaddr.vaddr_start + bit_idx_start * PG_SIZE;
} else { // 用户内存池
struct task_struct* cur = running_thread();
bit_idx_start = bitmap_scan(&cur->userprog_vaddr.vaddr_bitmap, pg_cnt);
if (bit_idx_start == -1) {
return NULL;
}
while(cnt < pg_cnt) {
bitmap_set(&cur->userprog_vaddr.vaddr_bitmap, bit_idx_start + cnt++, 1);
}
vaddr_start = cur->userprog_vaddr.vaddr_start + bit_idx_start * PG_SIZE;
/* (0xc0000000 - PG_SIZE)做为用户3级栈已经在start_process被分配 */
ASSERT((uint32_t)vaddr_start < (0xc0000000 - PG_SIZE));
}
return (void*)vaddr_start;
}
//adds a page to swap space, gets called with the physical memory position
size_t add_swap (void * addr) {
//init swap if necessary
if (swap == NULL) //init the swap table
init_swap ();
//lock the swap table
lock_acquire(&swap_lock);
//find a free entry in the bitmap table
size_t free = bitmap_scan (swap_table, 0, 1, false);
//if the swap table is full panic the kernel
if (free == BITMAP_ERROR) PANIC ("Swaptable is full\n");
int i;
//get frame and the memory position and write it to swap
for (i = 0; i< SECPP; i++)
//write block to swap, free * SECPP is the correct block position and + i because a page has a different size, same for addr
block_write (swap, free * SECPP + i, addr + BLOCK_SECTOR_SIZE * i);
//set the corresponding entry in the swap_table to true
bitmap_set (swap_table, free, true);
//release the lock for the swap table
lock_release(&swap_lock);
return free;
}
/* 分配一个i结点,返回i结点号 */
int32_t inode_bitmap_alloc(struct partition* part) {
int32_t bit_idx = bitmap_scan(&part->inode_bitmap, 1);
if (bit_idx == -1) {
return -1;
}
bitmap_set(&part->inode_bitmap, bit_idx, 1);
return bit_idx;
}
/* 分配1个扇区,返回其扇区地址 */
int32_t block_bitmap_alloc(struct partition* part) {
int32_t bit_idx = bitmap_scan(&part->block_bitmap, 1);
if (bit_idx == -1) {
return -1;
}
bitmap_set(&part->block_bitmap, bit_idx, 1);
/* 和inode_bitmap_malloc不同,此处返回的不是位图索引,而是具体可用的扇区地址 */
return (part->sb->data_start_lba + bit_idx);
}
/* adds a block to cache */
static size_t
cache_add (block_sector_t bid)
{
/* lock the cache */
lock_acquire(&cache_globallock);
//bool hellYeah = bid == (unsigned) 163;
/* lock for a free_cache_block cache block */
size_t free_cache_block = bitmap_scan (cache_table, 0, 1, false);
//if(DEBUG || hellYeah) printf("bitscan complete bla\n");
/* if no free cache block is found, evict one and
* search again */
if (free_cache_block == BITMAP_ERROR) {
//if(DEBUG || hellYeah) printf("evict some\n");
cache_evict();
free_cache_block = bitmap_scan (cache_table, 0, 1, false);
}
ASSERT(free_cache_block != BITMAP_ERROR);
//if(DEBUG || hellYeah) printf("add cache block %d\n",bid);
/* copy block to cache */
block_read (fs_device, bid, cache[free_cache_block]->kpage);
/* setup cache entry */
cache[free_cache_block]->dirty = false;
cache[free_cache_block]->accessed = false;
cache[free_cache_block]->bid = bid;
/* set used bit of the cache table for this entry */
bitmap_set (cache_table, free_cache_block, true);
/* release the lock for the cache table */
lock_release(&cache_globallock);
if(CACHE_DEBUG) printf("added cache block %u for sector %u\n", (unsigned int) free_cache_block, (unsigned int) bid);
return free_cache_block;
}
size_t swap_out(void *kaddr)
{
lock_acquire(&swap_lock);
//size_t free_index = bitmap_scan_and_flip(swap_map,0,1,SWAP_FREE);
size_t free_index = bitmap_scan(swap_map,0,1,SWAP_FREE);
bitmap_flip(swap_map,free_index);
size_t i;
for(i = 0;i <SECTORS_PER_PAGE;i++)
{
block_write(swap_block,free_index*SECTORS_PER_PAGE +i,
(uint8_t*)kaddr + i*BLOCK_SECTOR_SIZE);
}
lock_release(&swap_lock);
return free_index;
}
/* 在pf表示的虚拟内存池中申请pg_cnt个虚拟页,
* 成功则返回虚拟页的起始地址, 失败则返回NULL */
static void* vaddr_get(enum pool_flags pf, uint32_t pg_cnt) {
int vaddr_start = 0, bit_idx_start = -1;
uint32_t cnt = 0;
if (pf == PF_KERNEL) {
bit_idx_start = bitmap_scan(&kernel_vaddr.vaddr_bitmap, pg_cnt);
if (bit_idx_start == -1) {
return NULL;
}
while(cnt < pg_cnt) {
bitmap_set(&kernel_vaddr.vaddr_bitmap, bit_idx_start + cnt++, 1);
}
vaddr_start = kernel_vaddr.vaddr_start + bit_idx_start * PG_SIZE;
} else {
// 用户内存池,将来实现用户进程再补充
}
return (void*)vaddr_start;
}
static void
update_ct_zones(struct sset *lports, struct simap *ct_zones,
unsigned long *ct_zone_bitmap)
{
struct simap_node *ct_zone, *ct_zone_next;
const char *iface_id;
int scan_start = 1;
/* xxx This is wasteful to assign a zone to each port--even if no
* xxx security policy is applied. */
/* Delete any zones that are associated with removed ports. */
SIMAP_FOR_EACH_SAFE(ct_zone, ct_zone_next, ct_zones) {
if (!sset_contains(lports, ct_zone->name)) {
bitmap_set0(ct_zone_bitmap, ct_zone->data);
simap_delete(ct_zones, ct_zone);
}
}
/* Assign a unique zone id for each logical port. */
SSET_FOR_EACH(iface_id, lports) {
size_t zone;
if (simap_contains(ct_zones, iface_id)) {
continue;
}
/* We assume that there are 64K zones and that we own them all. */
zone = bitmap_scan(ct_zone_bitmap, 0, scan_start, MAX_CT_ZONES + 1);
if (zone == MAX_CT_ZONES + 1) {
static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 1);
VLOG_WARN_RL(&rl, "exhausted all ct zones");
return;
}
scan_start = zone + 1;
bitmap_set1(ct_zone_bitmap, zone);
simap_put(ct_zones, iface_id, zone);
/* xxx We should erase any old entries for this
* xxx zone, but we need a generic interface to the conntrack
* xxx table. */
}
uint32
bitmap_scan_and_set (struct bitmap* bmap, uint32 num)
{
if (bmap == NULL || num == 0)
return BITMAP_ERROR;
uint32 idx = bitmap_scan (bmap, num);
if (idx == BITMAP_ERROR) return idx;
uint32 i;
uint32 end = idx + num;
for (i = idx; i < end; i++)
bitmap_set (bmap, i);
return idx;
//
// uint32 i;
// for (i = 0; i < bmap->length; i++)
// {
// if (bmap->bits[i] != 0xFFFFFFFF)
// {
// sint32 j;
// bool one = false;
// uint32 count = 0;
// sint32 idx = 0;
// for (j = 31; j >= 0; j--)
// {
// if (!(bmap->bits[i] & (uint32) (0x1 << j)))
// {
// if (!one)
// {
// idx = j;
// count = 0;
// }
// count++;
// one = true;
// }
// else
// one = false;
//
// if (count == num)
// break;
// }
//
// ASSERT (count <= num);
// ASSERT (idx < 32);
// if (count == num)
// {
// /* We must flip NUM contiguous bits. */
// sint32 k;
// for (k = idx; k > (sint32) (idx - num); k--)
// {
// bmap->bits[i] |= (uint32) (0x1 << k);
// }
//
// return i * 32 + (31 - idx);
// }
// }
// }
//
// return BITMAP_ERROR;
};
