Differential D17419 Diff 49760 share/man/man9/contigmalloc.9

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share/man/man9/contigmalloc.9

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	.Fa "vm_paddr_t boundary"			.Fa "vm_paddr_t boundary"
	.Fc			.Fc
	.Ft void			.Ft void
	.Fo contigfree			.Fo contigfree
	.Fa "void *addr"			.Fa "void *addr"
	.Fa "unsigned long size"			.Fa "unsigned long size"
	.Fa "struct malloc_type *type"			.Fa "struct malloc_type *type"
	.Fc			.Fc
				.In sys/param.h
				.In sys/domainset.h
				.Ft "void *"
				.Fo contigmalloc_domainset
				.Fa "unsigned long size"
				.Fa "struct malloc_type *type"
				.Fa "struct domainset *ds"
				.Fa "int flags"
				.Fa "vm_paddr_t low"
				.Fa "vm_paddr_t high"
				.Fa "unsigned long alignment"
				.Fa "vm_paddr_t boundary"
				.Fc
	.Sh DESCRIPTION			.Sh DESCRIPTION
	The			The
	.Fn contigmalloc			.Fn contigmalloc
	function allocates			function allocates
	.Fa size			.Fa size
	bytes of contiguous physical memory that is aligned to			bytes of contiguous physical memory that is aligned to
	.Fa alignment			.Fa alignment
	bytes, and which does not cross a boundary of			bytes, and which does not cross a boundary of
	.Fa boundary			.Fa boundary
	bytes.			bytes.
	If successful, the allocation will reside between physical addresses			If successful, the allocation will reside between physical addresses
	.Fa low			.Fa low
	and			and
	.Fa high .			.Fa high .
	The returned pointer points to a wired kernel virtual			The returned pointer points to a wired kernel virtual
	address range of			address range of
	.Fa size			.Fa size
	bytes allocated from the kernel virtual address (KVA) map.			bytes allocated from the kernel virtual address (KVA) map.
	.Pp			.Pp
	The			The
				.Fn contigmalloc_domainset
				variant allows the caller to additionally specify a
				.Xr numa 4
				domain selection policy.
				See
				.Xr domainset 9
				for some example policies.
				.Pp
				The
	.Fa flags			.Fa flags
	parameter modifies			parameter modifies
	.Fn contigmalloc Ns 's			.Fn contigmalloc Ns 's
	behaviour as follows:			behaviour as follows:
	.Bl -tag -width indent			.Bl -tag -width indent
	.It Dv M_ZERO			.It Dv M_ZERO
	Causes the allocated physical memory to be zero filled.			Causes the allocated physical memory to be zero filled.
	.It Dv M_NOWAIT			.It Dv M_NOWAIT
	Causes			Causes
	.Fn contigmalloc			.Fn contigmalloc
	to return			to return
	.Dv NULL			.Dv NULL
	if the request cannot be immediately fulfilled due to resource shortage.			if the request cannot be immediately fulfilled due to resource shortage.
	.El			.El
	.Pp			.Pp
	Other flags (if present) are ignored.			Other flags (if present) are ignored.
	.Pp			.Pp
	The			The
	.Fn contigfree			.Fn contigfree
	function deallocates memory allocated by a previous call to			function deallocates memory allocated by a previous call to
	.Fn contigmalloc .			.Fn contigmalloc
				or
				.Fn contigmalloc_domainset .
	.Sh IMPLEMENTATION NOTES			.Sh IMPLEMENTATION NOTES
	The			The
	.Fn contigmalloc			.Fn contigmalloc
	function does not sleep waiting for memory resources to be freed up,			function does not sleep waiting for memory resources to be freed up,
	but instead actively reclaims pages before giving up.			but instead actively reclaims pages before giving up.
	However, unless			However, unless
	.Dv M_NOWAIT			.Dv M_NOWAIT
	is specified, it may select a page for reclamation that must first be			is specified, it may select a page for reclamation that must first be
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