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Commit 993ba158 authored by Tejun Heo's avatar Tejun Heo Committed by H. Peter Anvin
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x86-32, numa: Update remap allocator comments 



Now that remap allocator is cleaned up, update comments such that they
are in docbook function description format and reflect the actual
implementation.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/1301955840-7246-15-git-send-email-tj@kernel.org


Acked-by: default avatarYinghai Lu <yinghai@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent 198bd06b

arch/x86/mm/numa_32.c

+42 −14
Original line number Diff line number Diff line
@@ -176,17 +176,31 @@ static void __init allocate_pgdat(int nid) 
}



/*

 * In the DISCONTIGMEM and SPARSEMEM memory model, a portion of the kernel

 * virtual address space (KVA) is reserved and portions of nodes are mapped

 * using it. This is to allow node-local memory to be allocated for

 * structures that would normally require ZONE_NORMAL. The memory is

 * allocated with alloc_remap() and callers should be prepared to allocate

 * from the bootmem allocator instead.

 * Remap memory allocator

 */

static unsigned long node_remap_start_pfn[MAX_NUMNODES];

static void *node_remap_end_vaddr[MAX_NUMNODES];

static void *node_remap_alloc_vaddr[MAX_NUMNODES];



/**

 * alloc_remap - Allocate remapped memory

 * @nid: NUMA node to allocate memory from

 * @size: The size of allocation

 *

 * Allocate @size bytes from the remap area of NUMA node @nid.  The

 * size of the remap area is predetermined by init_alloc_remap() and

 * only the callers considered there should call this function.  For

 * more info, please read the comment on top of init_alloc_remap().

 *

 * The caller must be ready to handle allocation failure from this

 * function and fall back to regular memory allocator in such cases.

 *

 * CONTEXT:

 * Single CPU early boot context.

 *

 * RETURNS:

 * Pointer to the allocated memory on success, %NULL on failure.

 */

void *alloc_remap(int nid, unsigned long size)

{

	void *allocation = node_remap_alloc_vaddr[nid];
@@ -238,6 +252,28 @@ void resume_map_numa_kva(pgd_t *pgd_base) 
}

#endif



/**

 * init_alloc_remap - Initialize remap allocator for a NUMA node

 * @nid: NUMA node to initizlie remap allocator for

 *

 * NUMA nodes may end up without any lowmem.  As allocating pgdat and

 * memmap on a different node with lowmem is inefficient, a special

 * remap allocator is implemented which can be used by alloc_remap().

 *

 * For each node, the amount of memory which will be necessary for

 * pgdat and memmap is calculated and two memory areas of the size are

 * allocated - one in the node and the other in lowmem; then, the area

 * in the node is remapped to the lowmem area.

 *

 * As pgdat and memmap must be allocated in lowmem anyway, this

 * doesn't waste lowmem address space; however, the actual lowmem

 * which gets remapped over is wasted.  The amount shouldn't be

 * problematic on machines this feature will be used.

 *

 * Initialization failure isn't fatal.  alloc_remap() is used

 * opportunistically and the callers will fall back to other memory

 * allocation mechanisms on failure.

 */

static __init void init_alloc_remap(int nid)

{

	unsigned long size, pfn;
@@ -306,14 +342,6 @@ void __init initmem_init(void) 
{

	int nid;



	/*

	 * When mapping a NUMA machine we allocate the node_mem_map arrays

	 * from node local memory.  They are then mapped directly into KVA

	 * between zone normal and vmalloc space.  Calculate the size of

	 * this space and use it to adjust the boundary between ZONE_NORMAL

	 * and ZONE_HIGHMEM.

	 */



	get_memcfg_numa();

	numa_init_array();