124 lines
3.5 KiB
Groff
124 lines
3.5 KiB
Groff
.\"
|
|
.\" Copyright (c) 2004 Joseph Koshy
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS''
|
|
.\" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
|
|
.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
|
.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE
|
|
.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
|
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
|
.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
|
.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
|
.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
|
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
.\" POSSIBILITY OF SUCH DAMAGE.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd August 10, 2004
|
|
.Dt CONTIGMALLOC 9
|
|
.Os
|
|
.Sh NAME
|
|
.Nm contigmalloc , contigfree
|
|
.Nd manage contiguous kernel physical memory
|
|
.Sh SYNOPSIS
|
|
.In sys/types.h
|
|
.In sys/malloc.h
|
|
.Ft "void *"
|
|
.Fo contigmalloc
|
|
.Fa "unsigned long size"
|
|
.Fa "struct malloc_type *type"
|
|
.Fa "int flags"
|
|
.Fa "vm_paddr_t low"
|
|
.Fa "vm_paddr_t high"
|
|
.Fa "unsigned long alignment"
|
|
.Fa "unsigned long boundary"
|
|
.Fc
|
|
.Ft void
|
|
.Fo contigfree
|
|
.Fa "void *addr"
|
|
.Fa "unsigned long size"
|
|
.Fa "struct malloc_type *type"
|
|
.Fc
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn contigmalloc
|
|
function allocates
|
|
.Fa size
|
|
bytes of contiguous physical memory that is aligned to
|
|
.Fa alignment
|
|
bytes, and which does not cross a boundary of
|
|
.Fa boundary
|
|
bytes.
|
|
If successful, the allocation will reside between physical addresses
|
|
.Fa low
|
|
and
|
|
.Fa high .
|
|
The returned pointer points to a wired kernel virtual
|
|
address range of
|
|
.Fa size
|
|
bytes allocated from the kernel virtual address (KVA) map.
|
|
.Pp
|
|
The
|
|
.Fa flags
|
|
parameter modifies
|
|
.Fn contigmalloc Ns 's
|
|
behaviour as follows:
|
|
.Bl -tag -width indent
|
|
.It Dv M_ZERO
|
|
Causes the allocated physical memory to be zero filled.
|
|
.El
|
|
Other flags (if present) are ignored.
|
|
.Pp
|
|
The
|
|
.Fn contigfree
|
|
function deallocates memory allocated by a previous call to
|
|
.Fn contigmalloc .
|
|
.Sh IMPLEMENTATION NOTES
|
|
The
|
|
.Fn contigmalloc
|
|
function does not sleep waiting for memory resources to be freed up,
|
|
but instead scans available physical memory a small number of times
|
|
for a suitably sized free address range before giving up.
|
|
Memory allocation is done on a first-fit basis, starting from the
|
|
top of the provided address range.
|
|
.Sh RETURN VALUES
|
|
The
|
|
.Fn contigmalloc
|
|
function returns a kernel virtual address if allocation succeeds,
|
|
or
|
|
.Dv NULL
|
|
otherwise.
|
|
.Sh EXAMPLES
|
|
.Bd -literal
|
|
void *p;
|
|
p = contigmalloc(8192, M_DEVBUF, M_ZERO, 0, (1L << 22),
|
|
32 * 1024, 1024 * 1024);
|
|
.Ed
|
|
.Pp
|
|
Ask for 8192 bytes of zero-filled memory residing between physical
|
|
address 0 and 4194303 inclusive, aligned to a 32K boundary and not
|
|
crossing a 1M address boundary.
|
|
.Sh DIAGNOSTICS
|
|
The
|
|
.Fn contigmalloc
|
|
function will panic if
|
|
.Fa size
|
|
is zero, or if
|
|
.Fa alignment
|
|
or
|
|
.Fa boundary
|
|
is not a power of two.
|
|
.Sh SEE ALSO
|
|
.Xr malloc 9
|