VMALLOC(9) Memory Management in Linux VMALLOC(9)NAME
vmalloc - allocate virtually contiguous memory
SYNOPSIS
void * vmalloc(unsigned long size);
ARGUMENTS
size
allocation size Allocate enough pages to cover size from the page level allocator and map them into contiguous kernel virtual space.
DESCRIPTION
For tight control over page level allocator and protection flags use __vmalloc instead.
COPYRIGHT Kernel Hackers Manual 2.6. July 2010 VMALLOC(9)
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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)
mail:/var/lib/named/proc # ls -l |grep kcore
-r-------- 1 root root 140737486266368 Jun 3 19:47 kcore
mail:/var/lib/named/proc # du -a |grep kcore
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