ksize(9) [centos man page]

KSIZE(9)						    Memory Management in Linux							  KSIZE(9)

NAME

       ksize - get the actual amount of memory allocated for a given object

SYNOPSIS

       size_t ksize(const void * objp);

ARGUMENTS

       objp
	   Pointer to the object

DESCRIPTION

       kmalloc may internally round up allocations and return more memory than requested.  ksize can be used to determine the actual amount of
       memory allocated. The caller may use this additional memory, even though a smaller amount of memory was initially specified with the
       kmalloc call. The caller must guarantee that objp points to a valid object previously allocated with either kmalloc or kmem_cache_alloc.
       The object must not be freed during the duration of the call.

COPYRIGHT

Kernel Hackers Manual 3.10					     June 2014								  KSIZE(9)

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)