xalloc, xallocz, xspanalloc, xfree, xsummary – basic memory management
void* xalloc(ulong size)
void* xallocz(ulong size, int clr)
void* xspanalloc(ulong size, int align, ulong span)
void xfree(void *p)
These are primitives used by higher-level memory allocators in the kernel,
They are not intended for use directly by most kernel routines.
The main exceptions are routines that permanently allocate large structures,
or need the special alignment properties guaranteed by
returns a pointer to a range of size bytes of memory. The memory will be zero filled and aligned on a 8 byte
address. If the memory is not available,
returns a null pointer.
will clear the memory after allocation if
is set to a value other than zero. Since it is used by
the same diagnostics apply.
allocates memory given alignment and spanning constraints.
The block returned will contain
bytes, aligned on a boundary that is
0 mod align,
in such a way that the memory in the block does not
span an address that is
0 mod span.
is intended for use
allocating hardware data structures (eg, page tables) or I/O buffers
that must satisfy specific alignment restrictions.
cannot allocate memory to satisfy the given constraints, it will
The technique it uses can sometimes cause memory to be wasted.
should be used sparingly.
frees the block of memory at
which must be an address previously returned by
dumps memory allocation statistics to the console.
The output includes the total free space, the number of free holes,
and a summary of active holes.
Each line shows ‘address top size’.