Memory manager. More...

Functions
void	mm_debug_print (struct mmnode *mmnode, int space)
	Debug printout of the status of all nodes. More...

errval_t	mm_init (struct mm mm, enum objtype objtype, genpaddr_t base, uint8_t sizebits, uint8_t maxchildbits, slab_refill_func_t slab_refill_func, slot_alloc_t slot_alloc_func, slot_refill_t slot_refill_func, void slot_alloc_inst, bool delete_chunked)
	Initialise a memory manager instance. More...

void	mm_destroy (struct mm *mm)
	Destroy a memory manager instance. More...

errval_t	mm_add (struct mm *mm, struct capref cap, uint8_t sizebits, genpaddr_t base)
	Add a new region to the memory manager. More...

errval_t	mm_add_multi (struct mm *mm, struct capref cap, gensize_t size, genpaddr_t base)
	Add a new region to the memory manager. The region does not need to be power-of-two sized or aligned. More...

errval_t	mm_alloc (struct mm mm, uint8_t sizebits, struct capref retcap, genpaddr_t *retbase)
	Allocate an arbitrary memory region of a given size. More...

errval_t	mm_alloc_range (struct mm mm, uint8_t sizebits, genpaddr_t minbase, genpaddr_t maxlimit, struct capref retcap, genpaddr_t *retbase)
	Allocate memory region of a given size within a given address range. More...

errval_t	mm_realloc_range (struct mm mm, uint8_t sizebits, genpaddr_t base, struct capref retcap)
	Return cap to a specific region, that may be partially allocated. More...

errval_t	mm_free (struct mm *mm, struct capref cap, genpaddr_t base, uint8_t sizebits)
	Free an allocated region. More...

size_t	mm_relinquish_all (struct mm mm, struct mem_cap ret, size_t retlen)
	Fills an array with metadata for all free regions. More...

size_t	mm_relinquish_range (struct mm mm, genpaddr_t base, genpaddr_t limit, struct mem_cap ret, size_t retlen)
	Fills an array with metadata for all free regions within a given range. More...

Detailed Description

Memory manager.

This code manages memory regions (which may refer to actual RAM, or physical address space, or other spaces) and the capabilities to those regions.

The meta-data is structured as a B-tree. Every node has a variable power-of-two-sized number of children (up to a limit fixed at initialisation time), which is stored in the node itself (as "childbits"). Nodes without any children have childbits = -1 (FLAGBITS).

The position of a node in the tree exactly determines its size and address relative to the size and address of the region being managed by the allocator (all sizes must be powers of two).

A node may be one of four types (see nodetype): 0. A "dummy" node, which exists structurally in the tree, but for which we do not have a capability (ie. the region is incomplete).

A "chunked" node, for which we have a capability, but which has been split up into child nodes for smaller allocations.
A free node, which is a regular free child node in the tree.
An allocated node.

Function Documentation

errval_t mm_add	(	struct mm *	mm,
		struct capref	cap,
		uint8_t	sizebits,
		genpaddr_t	base
	)

Add a new region to the memory manager.

It is an error if any part of the region has already been added, or the region doesn't fit within the base and size specified for the allocator.

Parameters

mm	Memory manager instance
cap	Capability to newly-added region
sizebits	Size of region
base	Physical base address of region

errval_t mm_add_multi	(	struct mm *	mm,
		struct capref	cap,
		gensize_t	size,
		genpaddr_t	base
	)

Add a new region to the memory manager. The region does not need to be power-of-two sized or aligned.

It is an error if any part of the region has already been added, or the region doesn't fit within the base and size specified for the allocator.

Parameters

mm	Memory manager instance
cap	Capability to newly-added region
size	Size of region
base	Physical base address of region

errval_t mm_alloc	(	struct mm *	mm,
		uint8_t	sizebits,
		struct capref *	retcap,
		genpaddr_t *	retbase
	)

Allocate an arbitrary memory region of a given size.

Parameters

mm	Memory manager instance
sizebits	Size of requested region
retcap	Pointer to capref struct, to be filled-in
retbase	If non-NULL, the base address of the allocated region is returned here

errval_t mm_alloc_range	(	struct mm *	mm,
		uint8_t	sizebits,
		genpaddr_t	minbase,
		genpaddr_t	maxlimit,
		struct capref *	retcap,
		genpaddr_t *	retbase
	)

Allocate memory region of a given size within a given address range.

If this call succeeds, it must be the case that: *retbase >= minbase && *retbase + (1UL << sizebits) <= maxlimit

Parameters

mm	Memory manager instance
sizebits	Size of requested region
minbase	Minimum base address of region to allocate
maxlimit	Maximum limit address of region to allocate
retcap	Pointer to capref struct, to be filled-in
retbase	If non-NULL, the base address of the allocated region is returned here

void mm_debug_print	(	struct mmnode *	mmnode,
		int	space
	)

Debug printout of the status of all nodes.

Parameters

mmnode	Struct mmnode to print from
space	Call with 0, used to track depth for pretty printing

void mm_destroy ( struct mm * mm )

Destroy a memory manager instance.

Parameters

mm	Memory manager instance

errval_t mm_free	(	struct mm *	mm,
		struct capref	cap,
		genpaddr_t	base,
		uint8_t	sizebits
	)

Free an allocated region.

Marks the region (which must previously have been allocated) as free.

Parameters

mm	Memory manager instance
cap	Cap to re-insert (specify NULL_CAP if delete_chunked == false)
base	Physical base address of region
sizebits	Size of region

errval_t mm_init	(	struct mm *	mm,
		enum objtype objtype	,
		genpaddr_t	base,
		uint8_t	sizebits,
		uint8_t	maxchildbits,
		slab_refill_func_t	slab_refill_func,
		slot_alloc_t	slot_alloc_func,
		slot_refill_t	slot_refill_func,
		void *	slot_alloc_inst,
		bool	delete_chunked
	)

Initialise a memory manager instance.

Parameters

mm	Pointer to memory manager instance, to be filled-in
objtype	Kernel object type to be managed
base	Base address of region to be managed
sizebits	Size (in bits) of region to be managed
maxchildbits	Maximum number of children (in bits) at each node
slab_refill_func	Function to be used to refill slab allocator If this is NULL, the caller must provide static storage with slab_grow.
slot_alloc_func	Slot allocator function
slot_refill_func	Slot allocator refill function
slot_alloc_inst	Slot allocator opaque instance pointer
delete_chunked	Whether to delete chunked caps

Note: Setting maxchildbits > 1 saves substantial space, but may lead to the situation where an allocation request cannot be satisfied despite memory being available, because the memory has been chunked up into smaller caps that, while free, cannot be recombined without revoking existing allocations.

errval_t mm_realloc_range	(	struct mm *	mm,
		uint8_t	sizebits,
		genpaddr_t	base,
		struct capref *	retcap
	)

Return cap to a specific region, that may be partially allocated.

The parameters to this function specify a fixed memory region (base and size) that may overlap one or more already-allocated memory regions. It marks the entire region as allocated, returning a cap to it.

Warning: It is assumed that the caller knows what they are doing.

Parameters

mm	Memory manager instance
sizebits	Size of region
base	Base address of region
retcap	Pointer to capref struct, to be filled-in

size_t mm_relinquish_all	(	struct mm *	mm,
		struct mem_cap *	ret,
		size_t	retlen
	)

Fills an array with metadata for all free regions.

The regions returned are marked as allocated.

Parameters

mm	Memory manager instance
ret	Pointer to return array to be filled-in
retlen	Length of the array, in slots

Returns: Number of caps that could have been stored in the return array. If this is less than or equal to #retlen, all caps have been returned.

size_t mm_relinquish_range	(	struct mm *	mm,
		genpaddr_t	base,
		genpaddr_t	limit,
		struct mem_cap *	ret,
		size_t	retlen
	)

Fills an array with metadata for all free regions within a given range.

The regions returned are marked as allocated.

It must be the case for every returned cap (i) that: ret[i]->base >= base && ret[i]->base + (1UL << ret[i]->sizebits) <= limit

Parameters

mm	Memory manager instance
base	Base address of range from which to relinquish memory
limit	Limit address of range from which to relinquish memory
ret	Pointer to return array to be filled-in
retlen	Length of the array, in slots

Returns: Number of caps that could have been stored in the return array. If this is less than or equal to #retlen, all caps have been returned.

Functions

Detailed Description

Function Documentation