KMALLOC(9) Memory Management in Linux KMALLOC(9)NAMEkmalloc - allocate memory
SYNOPSIS
void * kmalloc(size_t size, gfp_t flags);
ARGUMENTS
size
how many bytes of memory are required.
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.
kmalloc is the normal method of allocating memory in the kernel.
COPYRIGHTKernel Hackers Manual 3.11 November 2013 KMALLOC(9)
