KCALLOC(9) Memory Management in Linux KCALLOC(9)
NAME
kcalloc - allocate memory for an array. The memory is set to zero.
SYNOPSIS
void * kcalloc(size_t n, size_t size, gfp_t flags);
ARGUMENTS
n
number of elements.
size
element size.
flags
the type of memory to allocate.
DESCRIPTION
The flags argument may be one of:
GFP_USER - Allocate memory on behalf of user. May sleep.
GFP_KERNEL - Allocate normal kernel ram. May sleep.
GFP_ATOMIC - Allocation will not sleep. May use emergency pools. For example, use this inside interrupt handlers.
GFP_HIGHUSER - Allocate pages from high memory.
GFP_NOIO - Do not do any I/O at all while trying to get memory.
GFP_NOFS - Do not make any fs calls while trying to get memory.
GFP_NOWAIT - Allocation will not sleep.
GFP_THISNODE - Allocate node-local memory only.
GFP_DMA - Allocation suitable for DMA. Should only be used for kmalloc caches. Otherwise, use a slab created with SLAB_DMA.
Also it is possible to set different flags by OR'ing in one or more of the following additional flags:
__GFP_COLD - Request cache-cold pages instead of trying to return cache-warm pages.
__GFP_HIGH - This allocation has high priority and may use emergency pools.
__GFP_NOFAIL - Indicate that this allocation is in no way allowed to fail (think twice before using).
__GFP_NORETRY - If memory is not immediately available, then give up at once.
__GFP_NOWARN - If allocation fails, don't issue any warnings.
__GFP_REPEAT - If allocation fails initially, try once more before failing.
There are other flags available as well, but these are not intended for general use, and so are not documented here. For a full list of
potential flags, always refer to linux/gfp.h.
COPYRIGHT
Kernel Hackers Manual 2.6. July 2010 KCALLOC(9)