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.