minix/servers/vm/phys_region.h

#ifndef PHYS_REGION_H
#define PHYS_REGION_H 1

#include <stddef.h>

#include "memtype.h"

typedef struct phys_region {
	struct phys_block	*ph;
	struct vir_region	*parent; /* vir_region or NULL if yielded */
	vir_bytes		offset;	/* offset from start of vir region */
#if SANITYCHECKS
	int			written;	/* written to pagetable */
#endif

	mem_type_t		*memtype;

	/* list of phys_regions that reference the same phys_block */
	struct phys_region	*next_ph_list;	

	/* AVL fields */
	struct phys_region	*less, *greater;
	int			factor;
} phys_region_t;

#endif
secondary cache feature in vm. A new call to vm lets processes yield a part of their memory to vm, together with an id, getting newly allocated memory in return. vm is allowed to forget about it if it runs out of memory. processes can ask for it back using the same id. (These two operations are normally combined in a single call.) It can be used as a as-big-as-memory-will-allow block cache for filesystems, which is how mfs now uses it. 2010-05-05 13:35:04 +02:00			`#ifndef PHYS_REGION_H`
			`#define PHYS_REGION_H 1`

			`#include <stddef.h>`

VM: make mapping types explicit Introduce explicit abstractions for different mapping types, handling the instantiation, forking, pagefaults and freeing of anonymous memory, direct physical mappings, shared memory and physically contiguous anonymous memory as separate types, making region.c more generic. Also some other genericification like merging the 3 munmap cases into one. COW and SMAP safemap code is still implicit in region.c. 2012-10-11 15:15:49 +02:00			`#include "memtype.h"`

secondary cache feature in vm. A new call to vm lets processes yield a part of their memory to vm, together with an id, getting newly allocated memory in return. vm is allowed to forget about it if it runs out of memory. processes can ask for it back using the same id. (These two operations are normally combined in a single call.) It can be used as a as-big-as-memory-will-allow block cache for filesystems, which is how mfs now uses it. 2010-05-05 13:35:04 +02:00			`typedef struct phys_region {`
			`struct phys_block *ph;`
			`struct vir_region parent; / vir_region or NULL if yielded */`
			`vir_bytes offset; /* offset from start of vir region */`
			`#if SANITYCHECKS`
			`int written; /* written to pagetable */`
			`#endif`

VM: make mapping types explicit Introduce explicit abstractions for different mapping types, handling the instantiation, forking, pagefaults and freeing of anonymous memory, direct physical mappings, shared memory and physically contiguous anonymous memory as separate types, making region.c more generic. Also some other genericification like merging the 3 munmap cases into one. COW and SMAP safemap code is still implicit in region.c. 2012-10-11 15:15:49 +02:00			`mem_type_t *memtype;`

secondary cache feature in vm. A new call to vm lets processes yield a part of their memory to vm, together with an id, getting newly allocated memory in return. vm is allowed to forget about it if it runs out of memory. processes can ask for it back using the same id. (These two operations are normally combined in a single call.) It can be used as a as-big-as-memory-will-allow block cache for filesystems, which is how mfs now uses it. 2010-05-05 13:35:04 +02:00			`/* list of phys_regions that reference the same phys_block */`
			`struct phys_region *next_ph_list;`

			`/* AVL fields */`
			`struct phys_region less, greater;`
			`int factor;`
			`} phys_region_t;`

			`#endif`