linux启动内存分配器2。。。。。。。。。。。。
linux启动内存分配器2。。。。。。。。。。。。view plaincopy to clipboardprint?void __init setup_bootmem_allocator(void)
{
int nodeid;
unsigned long bootmap_size, bootmap;
/*
* Initialize the boot-time allocator (with low memory only):
*/
/*计算所需要的映射页面大小一个字节一位，
所以需要对总的页面大小除以8*/
bootmap_size = bootmem_bootmap_pages(max_low_pfn)<<PAGE_SHIFT;
/*直接中e820中找到一个大小合适的内存块，返回基址*/
bootmap = find_e820_area(0, max_pfn_mapped<<PAGE_SHIFT, bootmap_size,
PAGE_SIZE);
if (bootmap == -1L)
panic("Cannot find bootmem map of size %ld\n", bootmap_size);
/*将用于位图映射的页面保留*/
reserve_early(bootmap, bootmap + bootmap_size, "BOOTMAP");
printk(KERN_INFO "mapped low ram: 0 - %08lx\n",
max_pfn_mapped<<PAGE_SHIFT);
printk(KERN_INFO "low ram: 0 - %08lx\n", max_low_pfn<<PAGE_SHIFT);
/*对每一个在线的node*/
for_each_online_node(nodeid) {
unsigned long start_pfn, end_pfn;
#ifdef CONFIG_NEED_MULTIPLE_NODES/*not set*/
start_pfn = node_start_pfn;
end_pfn = node_end_pfn;
if (start_pfn > max_low_pfn)
continue;
if (end_pfn > max_low_pfn)
end_pfn = max_low_pfn;
#else
start_pfn = 0;
end_pfn = max_low_pfn;
#endif
/*对指定节点安装启动分配器*/
bootmap = setup_node_bootmem(nodeid, start_pfn, end_pfn,
bootmap);
}
/*bootmem的分配制度到这里就已经建立完成，把after_bootmem
变量置成1，标识*/
after_bootmem = 1;
}
void __init setup_bootmem_allocator(void)
{
int nodeid;
unsigned long bootmap_size, bootmap;
/*
* Initialize the boot-time allocator (with low memory only):
*/
/*计算所需要的映射页面大小一个字节一位，
所以需要对总的页面大小除以8*/
bootmap_size = bootmem_bootmap_pages(max_low_pfn)<<PAGE_SHIFT;
/*直接中e820中找到一个大小合适的内存块，返回基址*/
bootmap = find_e820_area(0, max_pfn_mapped<<PAGE_SHIFT, bootmap_size,
PAGE_SIZE);
if (bootmap == -1L)
panic("Cannot find bootmem map of size %ld\n", bootmap_size);
/*将用于位图映射的页面保留*/
reserve_early(bootmap, bootmap + bootmap_size, "BOOTMAP");
printk(KERN_INFO "mapped low ram: 0 - %08lx\n",
max_pfn_mapped<<PAGE_SHIFT);
printk(KERN_INFO "low ram: 0 - %08lx\n", max_low_pfn<<PAGE_SHIFT);
/*对每一个在线的node*/
for_each_online_node(nodeid) {
unsigned long start_pfn, end_pfn;
#ifdef CONFIG_NEED_MULTIPLE_NODES/*not set*/
start_pfn = node_start_pfn;
end_pfn = node_end_pfn;
if (start_pfn > max_low_pfn)
continue;
if (end_pfn > max_low_pfn)
end_pfn = max_low_pfn;
#else
start_pfn = 0;
end_pfn = max_low_pfn;
#endif
/*对指定节点安装启动分配器*/
bootmap = setup_node_bootmem(nodeid, start_pfn, end_pfn,
bootmap);
}
/*bootmem的分配制度到这里就已经建立完成，把after_bootmem
变量置成1，标识*/
after_bootmem = 1;
}view plaincopy to clipboardprint?static unsigned long __init setup_node_bootmem(int nodeid,
unsigned long start_pfn,
unsigned long end_pfn,
unsigned long bootmap)
{
unsigned long bootmap_size;
/* don't touch min_low_pfn */
/*初始化映射位图，将位图中的所有位置1*/
bootmap_size = init_bootmem_node(NODE_DATA(nodeid),
bootmap >> PAGE_SHIFT,
start_pfn, end_pfn);
printk(KERN_INFO "node %d low ram: %08lx - %08lx\n",
nodeid, start_pfn<<PAGE_SHIFT, end_pfn<<PAGE_SHIFT);
printk(KERN_INFO "node %d bootmap %08lx - %08lx\n",
nodeid, bootmap, bootmap + bootmap_size);
/*将活动内存区对应位图相关位置0，表示可被分配的*/
free_bootmem_with_active_regions(nodeid, end_pfn);
/*对置保留位的相关页面对应的位图设置为1，表示已经分配
或者不可用(不能被分配)*/
early_res_to_bootmem(start_pfn<<PAGE_SHIFT, end_pfn<<PAGE_SHIFT);
/*返回映射页面的最后地址，下次映射即可以从这里开始*/
return bootmap + bootmap_size;
}
static unsigned long __init setup_node_bootmem(int nodeid,
unsigned long start_pfn,
unsigned long end_pfn,
unsigned long bootmap)
{
unsigned long bootmap_size;
/* don't touch min_low_pfn */
/*初始化映射位图，将位图中的所有位置1*/
bootmap_size = init_bootmem_node(NODE_DATA(nodeid),
bootmap >> PAGE_SHIFT,
start_pfn, end_pfn);
printk(KERN_INFO "node %d low ram: %08lx - %08lx\n",
nodeid, start_pfn<<PAGE_SHIFT, end_pfn<<PAGE_SHIFT);
printk(KERN_INFO "node %d bootmap %08lx - %08lx\n",
nodeid, bootmap, bootmap + bootmap_size);
/*将活动内存区对应位图相关位置0，表示可被分配的*/
free_bootmem_with_active_regions(nodeid, end_pfn);
/*对置保留位的相关页面对应的位图设置为1，表示已经分配
或者不可用(不能被分配)*/
early_res_to_bootmem(start_pfn<<PAGE_SHIFT, end_pfn<<PAGE_SHIFT);
/*返回映射页面的最后地址，下次映射即可以从这里开始*/
return bootmap + bootmap_size;
}
对于初始化映射位图，最终调用init_bootmem_core()
view plaincopy to clipboardprint?/*
* Called once to set up the allocator itself.
*/
static unsigned long __init init_bootmem_core(bootmem_data_t *bdata,
unsigned long mapstart, unsigned long start, unsigned long end)
{
unsigned long mapsize;
mminit_validate_memmodel_limits(&start, &end);
bdata->node_bootmem_map = phys_to_virt(PFN_PHYS(mapstart));
bdata->node_min_pfn = start;
bdata->node_low_pfn = end;
/*添加bdata变量到链表中*/
link_bootmem(bdata);
/*
* Initially all pages are reserved - setup_arch() has to
* register free RAM areas explicitly.
*/
/*计算本bdata的mapsize，也就是内存页面大小的1/8*/
mapsize = bootmap_bytes(end - start);
/*将所有map置1*/
memset(bdata->node_bootmem_map, 0xff, mapsize);
bdebug("nid=%td start=%lx map=%lx end=%lx mapsize=%lx\n",
bdata - bootmem_node_data, start, mapstart, end, mapsize);
return mapsize;
}
/*
* Called once to set up the allocator itself.
*/
static unsigned long __init init_bootmem_core(bootmem_data_t *bdata,
unsigned long mapstart, unsigned long start, unsigned long end)
{
unsigned long mapsize;
mminit_validate_memmodel_limits(&start, &end);
bdata->node_bootmem_map = phys_to_virt(PFN_PHYS(mapstart));
bdata->node_min_pfn = start;
bdata->node_low_pfn = end;
/*添加bdata变量到链表中*/
link_bootmem(bdata);
/*
* Initially all pages are reserved - setup_arch() has to
* register free RAM areas explicitly.
*/
/*计算本bdata的mapsize，也就是内存页面大小的1/8*/
mapsize = bootmap_bytes(end - start);
/*将所有map置1*/
memset(bdata->node_bootmem_map, 0xff, mapsize);
bdebug("nid=%td start=%lx map=%lx end=%lx mapsize=%lx\n",
bdata - bootmem_node_data, start, mapstart, end, mapsize);
return mapsize;
}
view plaincopy to clipboardprint?/*
* link bdata in order
*/
/*添加到链表，由添加的代码可知
链表中的数据开始位置为递增的*/
static void __init link_bootmem(bootmem_data_t *bdata)
{
struct list_head *iter;
/*添加到全局链表bdata_list中*/
list_for_each(iter, &bdata_list) {
bootmem_data_t *ent;
ent = list_entry(iter, bootmem_data_t, list);
if (bdata->node_min_pfn < ent->node_min_pfn)
break;
}
list_add_tail(&bdata->list, iter);
}
/*
* link bdata in order
*/
/*添加到链表，由添加的代码可知
链表中的数据开始位置为递增的*/
static void __init link_bootmem(bootmem_data_t *bdata)
{
struct list_head *iter;
/*添加到全局链表bdata_list中*/
list_for_each(iter, &bdata_list) {
bootmem_data_t *ent;
ent = list_entry(iter, bootmem_data_t, list);
if (bdata->node_min_pfn < ent->node_min_pfn)
break;
}
list_add_tail(&bdata->list, iter);
}view plaincopy to clipboardprint?/**
* free_bootmem_with_active_regions - Call free_bootmem_node for each active range
* @nid: The node to free memory on. If MAX_NUMNODES, all nodes are freed.
* @max_low_pfn: The highest PFN that will be passed to free_bootmem_node
*
* If an architecture guarantees that all ranges registered with
* add_active_ranges() contain no holes and may be freed, this
* this function may be used instead of calling free_bootmem() manually.
*/
/*用active_region来初始化bootmem分配器，基于低端内存区*/
void __init free_bootmem_with_active_regions(int nid,
unsigned long max_low_pfn)
{
int i;
/*对每个节点上得活动内存区*/
for_each_active_range_index_in_nid(i, nid) {
unsigned long size_pages = 0;
unsigned long end_pfn = early_node_map.end_pfn;
if (early_node_map.start_pfn >= max_low_pfn)
continue;
if (end_pfn > max_low_pfn)
end_pfn = max_low_pfn;
/*计算活动区的页面数*/
size_pages = end_pfn - early_node_map.start_pfn;
/*释放这部分内存，起始就是对应位图值0*/
free_bootmem_node(NODE_DATA(early_node_map.nid),
PFN_PHYS(early_node_map.start_pfn),
size_pages << PAGE_SHIFT);
}
}
/**
* free_bootmem_with_active_regions - Call free_bootmem_node for each active range
* @nid: The node to free memory on. If MAX_NUMNODES, all nodes are freed.
* @max_low_pfn: The highest PFN that will be passed to free_bootmem_node
*
* If an architecture guarantees that all ranges registered with
* add_active_ranges() contain no holes and may be freed, this
* this function may be used instead of calling free_bootmem() manually.
*/
/*用active_region来初始化bootmem分配器，基于低端内存区*/
void __init free_bootmem_with_active_regions(int nid,
unsigned long max_low_pfn)
{
int i;
/*对每个节点上得活动内存区*/
for_each_active_range_index_in_nid(i, nid) {
unsigned long size_pages = 0;
unsigned long end_pfn = early_node_map.end_pfn;
if (early_node_map.start_pfn >= max_low_pfn)
continue;
if (end_pfn > max_low_pfn)
end_pfn = max_low_pfn;
/*计算活动区的页面数*/
size_pages = end_pfn - early_node_map.start_pfn;
/*释放这部分内存，起始就是对应位图值0*/
free_bootmem_node(NODE_DATA(early_node_map.nid),
PFN_PHYS(early_node_map.start_pfn),
size_pages << PAGE_SHIFT);
}
}view plaincopy to clipboardprint?/**
* free_bootmem_node - mark a page range as usable
* @pgdat: node the range resides on
* @physaddr: starting address of the range
* @size: size of the range in bytes
*
* Partial pages will be considered reserved and left as they are.
*
* The range must reside completely on the specified node.
*/
void __init free_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
unsigned long size)
{
unsigned long start, end;
/*相关宏进行控制,调试用*/
kmemleak_free_part(__va(physaddr), size);
start = PFN_UP(physaddr);/*取上界*/
end = PFN_DOWN(physaddr + size);/*取下界*/
/*调用此函数对相关bit位清0，表示没有分配，这里保留位为0*/
mark_bootmem_node(pgdat->bdata, start, end, 0, 0);
}
/**
* free_bootmem_node - mark a page range as usable
* @pgdat: node the range resides on
* @physaddr: starting address of the range
* @size: size of the range in bytes
*
* Partial pages will be considered reserved and left as they are.
*
* The range must reside completely on the specified node.
*/
void __init free_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
unsigned long size)
{
unsigned long start, end;
/*相关宏进行控制,调试用*/
kmemleak_free_part(__va(physaddr), size);
start = PFN_UP(physaddr);/*取上界*/
end = PFN_DOWN(physaddr + size);/*取下界*/
/*调用此函数对相关bit位清0，表示没有分配，这里保留位为0*/
mark_bootmem_node(pgdat->bdata, start, end, 0, 0);
}view plaincopy to clipboardprint?static int __init mark_bootmem_node(bootmem_data_t *bdata,
unsigned long start, unsigned long end,
int reserve, int flags)
{
unsigned long sidx, eidx;
bdebug("nid=%td start=%lx end=%lx reserve=%d flags=%x\n",
bdata - bootmem_node_data, start, end, reserve, flags);
BUG_ON(start < bdata->node_min_pfn);
BUG_ON(end > bdata->node_low_pfn);
/*此两个变量为到节点最小内存页面的偏移量*/
sidx = start - bdata->node_min_pfn;
eidx = end - bdata->node_min_pfn;
if (reserve)/*如果设置了保留位*/
return __reserve(bdata, sidx, eidx, flags);
else/*相关的map位清0*/
__free(bdata, sidx, eidx);
return 0;
}
static int __init mark_bootmem_node(bootmem_data_t *bdata,
unsigned long start, unsigned long end,
int reserve, int flags)
{
unsigned long sidx, eidx;
bdebug("nid=%td start=%lx end=%lx reserve=%d flags=%x\n",
bdata - bootmem_node_data, start, end, reserve, flags);
BUG_ON(start < bdata->node_min_pfn);
BUG_ON(end > bdata->node_low_pfn);
/*此两个变量为到节点最小内存页面的偏移量*/
sidx = start - bdata->node_min_pfn;
eidx = end - bdata->node_min_pfn;
if (reserve)/*如果设置了保留位*/
return __reserve(bdata, sidx, eidx, flags);
else/*相关的map位清0*/
__free(bdata, sidx, eidx);
return 0;
}view plaincopy to clipboardprint?/*bootmem分配器的保留操作*/
static int __init __reserve(bootmem_data_t *bdata, unsigned long sidx,
unsigned long eidx, int flags)
{
unsigned long idx;
int exclusive = flags & BOOTMEM_EXCLUSIVE;
bdebug("nid=%td start=%lx end=%lx flags=%x\n",
bdata - bootmem_node_data,
sidx + bdata->node_min_pfn,
eidx + bdata->node_min_pfn,
flags);
/*对连续的几个页面设置为保留*/
for (idx = sidx; idx < eidx; idx++)
if (test_and_set_bit(idx, bdata->node_bootmem_map)) {
if (exclusive) {
__free(bdata, sidx, idx);
return -EBUSY;
}
bdebug("silent double reserve of PFN %lx\n",
idx + bdata->node_min_pfn);
}
return 0;
}
/*bootmem分配器的保留操作*/
static int __init __reserve(bootmem_data_t *bdata, unsigned long sidx,
unsigned long eidx, int flags)
{
unsigned long idx;
int exclusive = flags & BOOTMEM_EXCLUSIVE;
bdebug("nid=%td start=%lx end=%lx flags=%x\n",
bdata - bootmem_node_data,
sidx + bdata->node_min_pfn,
eidx + bdata->node_min_pfn,
flags);
/*对连续的几个页面设置为保留*/
for (idx = sidx; idx < eidx; idx++)
if (test_and_set_bit(idx, bdata->node_bootmem_map)) {
if (exclusive) {
__free(bdata, sidx, idx);
return -EBUSY;
}
bdebug("silent double reserve of PFN %lx\n",
idx + bdata->node_min_pfn);
}
return 0;
}view plaincopy to clipboardprint?/*bootmem分配器中释放内存*/
static void __init __free(bootmem_data_t *bdata,
unsigned long sidx, unsigned long eidx)
{
unsigned long idx;
bdebug("nid=%td start=%lx end=%lx\n", bdata - bootmem_node_data,
sidx + bdata->node_min_pfn,
eidx + bdata->node_min_pfn);
if (bdata->hint_idx > sidx)
bdata->hint_idx = sidx;/*更新变量hint_idx，用于分配*/
for (idx = sidx; idx < eidx; idx++)/*对应位清0*/
if (!test_and_clear_bit(idx, bdata->node_bootmem_map))
BUG();
}
/*bootmem分配器中释放内存*/
static void __init __free(bootmem_data_t *bdata,
unsigned long sidx, unsigned long eidx)
{
unsigned long idx;
bdebug("nid=%td start=%lx end=%lx\n", bdata - bootmem_node_data,
sidx + bdata->node_min_pfn,
eidx + bdata->node_min_pfn);
if (bdata->hint_idx > sidx)
bdata->hint_idx = sidx;/*更新变量hint_idx，用于分配*/
for (idx = sidx; idx < eidx; idx++)/*对应位清0*/
if (!test_and_clear_bit(idx, bdata->node_bootmem_map))
BUG();
}view plaincopy to clipboardprint?void __init early_res_to_bootmem(u64 start, u64 end)
{
int i, count;
u64 final_start, final_end;
count= 0;
for (i = 0; i < MAX_EARLY_RES && early_res.end; i++)
count++;/*计算保留块的个数*/
printk(KERN_INFO "(%d early reservations) ==> bootmem [%010llx - %010llx]\n",
count, start, end);
for (i = 0; i < count; i++) {
struct early_res *r = &early_res;
printk(KERN_INFO "#%d [%010llx - %010llx] %16s", i,
r->start, r->end, r->name);
final_start = max(start, r->start);
final_end = min(end, r->end);
if (final_start >= final_end) {
printk(KERN_CONT "\n");
continue;
}
printk(KERN_CONT " ==> [%010llx - %010llx]\n",
final_start, final_end);
/*将指定区间置为保留*/
reserve_bootmem_generic(final_start, final_end - final_start,
BOOTMEM_DEFAULT);
}
}
void __init early_res_to_bootmem(u64 start, u64 end)
{
int i, count;
u64 final_start, final_end;
count= 0;
for (i = 0; i < MAX_EARLY_RES && early_res.end; i++)
count++;/*计算保留块的个数*/
printk(KERN_INFO "(%d early reservations) ==> bootmem [%010llx - %010llx]\n",
count, start, end);
for (i = 0; i < count; i++) {
struct early_res *r = &early_res;
printk(KERN_INFO "#%d [%010llx - %010llx] %16s", i,
r->start, r->end, r->name);
final_start = max(start, r->start);
final_end = min(end, r->end);
if (final_start >= final_end) {
printk(KERN_CONT "\n");
continue;
}
printk(KERN_CONT " ==> [%010llx - %010llx]\n",
final_start, final_end);
/*将指定区间置为保留*/
reserve_bootmem_generic(final_start, final_end - final_start,
BOOTMEM_DEFAULT);
}
}上面的保留指定区间reserve_bootmem_generic()函数最终调用如下函数
] 谢谢分享
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