memory management during boot process

 

/*  * node_bootmem_map is a map pointer - the bits represent all physical  * memory pages (including holes) on the node.  */ typedef struct bootmem_data {     unsigned long node_min_pfn;     unsigned long node_low_pfn;     void *node_bootmem_map;     unsigned long last_end_off;     unsigned long hint_idx;     struct list_head list; } bootmem_data_t;

node_low_pfn is the number of the last page of the physical address space that can be managed directly; in other words, it is the end of ZONE_NORMAL.

node_bootmem_map is a pointer to the memory area in which the allocation bitmap is stored. On IA-32 systems, the memory area immediately following the kernel image is used for this purpose. The corresponding address is held in the _end variable, which is automatically patched into the kernel image during linking.