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memblock: Implement for_each_free_mem_range() 

Implement for_each_free_mem_range() which iterates over free memory
areas according to memblock (memory && !reserved).  This will be used
to simplify memblock users.

Signed-off-by: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/1310462166-31469-7-git-send-email-tj@kernel.org
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
Tejun Heo 2011-07-12 11:15:59 +02:00 committed by H. Peter Anvin
parent ab5d140b9e
commit 35fd0808d7
2 changed files with 96 additions and 0 deletions
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20
include/linux/memblock.h
View File

@ -61,6 +61,26 @@ extern long memblock_remove(phys_addr_t base, phys_addr_t size);
extern long memblock_free(phys_addr_t base, phys_addr_t size);
extern long memblock_reserve(phys_addr_t base, phys_addr_t size);
extern void __next_free_mem_range(u64 *idx, int nid, phys_addr_t *out_start,
phys_addr_t *out_end, int *out_nid);
/**
* for_each_free_mem_range - iterate through free memblock areas
* @i: u64 used as loop variable
* @nid: node selector, %MAX_NUMNODES for all nodes
* @p_start: ptr to phys_addr_t for start address of the range, can be %NULL
* @p_end: ptr to phys_addr_t for end address of the range, can be %NULL
* @p_nid: ptr to int for nid of the range, can be %NULL
*
* Walks over free (memory && !reserved) areas of memblock. Available as
* soon as memblock is initialized.
*/
#define for_each_free_mem_range(i, nid, p_start, p_end, p_nid) \
for (i = 0, \
__next_free_mem_range(&i, nid, p_start, p_end, p_nid); \
i != (u64)ULLONG_MAX; \
__next_free_mem_range(&i, nid, p_start, p_end, p_nid))
#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
extern int memblock_set_node(phys_addr_t base, phys_addr_t size, int nid);

76
mm/memblock.c
View File

@ -461,6 +461,82 @@ long __init_memblock memblock_reserve(phys_addr_t base, phys_addr_t size)
return memblock_add_region(_rgn, base, size);
}
/**
* __next_free_mem_range - next function for for_each_free_mem_range()
* @idx: pointer to u64 loop variable
* @nid: nid: node selector, %MAX_NUMNODES for all nodes
* @p_start: ptr to phys_addr_t for start address of the range, can be %NULL
* @p_end: ptr to phys_addr_t for end address of the range, can be %NULL
* @p_nid: ptr to int for nid of the range, can be %NULL
*
* Find the first free area from *@idx which matches @nid, fill the out
* parameters, and update *@idx for the next iteration. The lower 32bit of
* *@idx contains index into memory region and the upper 32bit indexes the
* areas before each reserved region. For example, if reserved regions
* look like the following,
*
* 0:[0-16), 1:[32-48), 2:[128-130)
*
* The upper 32bit indexes the following regions.
*
* 0:[0-0), 1:[16-32), 2:[48-128), 3:[130-MAX)
*
* As both region arrays are sorted, the function advances the two indices
* in lockstep and returns each intersection.
*/
void __init_memblock __next_free_mem_range(u64 *idx, int nid,
phys_addr_t *out_start,
phys_addr_t *out_end, int *out_nid)
{
struct memblock_type *mem = &memblock.memory;
struct memblock_type *rsv = &memblock.reserved;
int mi = *idx & 0xffffffff;
int ri = *idx >> 32;
for ( ; mi < mem->cnt; mi++) {
struct memblock_region *m = &mem->regions[mi];
phys_addr_t m_start = m->base;
phys_addr_t m_end = m->base + m->size;
/* only memory regions are associated with nodes, check it */
if (nid != MAX_NUMNODES && nid != memblock_get_region_node(m))
continue;
/* scan areas before each reservation for intersection */
for ( ; ri < rsv->cnt + 1; ri++) {
struct memblock_region *r = &rsv->regions[ri];
phys_addr_t r_start = ri ? r[-1].base + r[-1].size : 0;
phys_addr_t r_end = ri < rsv->cnt ? r->base : ULLONG_MAX;
/* if ri advanced past mi, break out to advance mi */
if (r_start >= m_end)
break;
/* if the two regions intersect, we're done */
if (m_start < r_end) {
if (out_start)
*out_start = max(m_start, r_start);
if (out_end)
*out_end = min(m_end, r_end);
if (out_nid)
*out_nid = memblock_get_region_node(m);
/*
* The region which ends first is advanced
* for the next iteration.
*/
if (m_end <= r_end)
mi++;
else
ri++;
*idx = (u32)mi | (u64)ri << 32;
return;
}
}
}
/* signal end of iteration */
*idx = ULLONG_MAX;
}
#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
/*
* Common iterator interface used to define for_each_mem_range().