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memblock: Introduce default allocation limit and use it to replace explicit ones

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This introduce memblock.current_limit which is used to limit allocations
from memblock_alloc() or memblock_alloc_base(..., MEMBLOCK_ALLOC_ACCESSIBLE).

The old MEMBLOCK_ALLOC_ANYWHERE changes value from 0 to ~(u64)0 and can still
be used with memblock_alloc_base() to allocate really anywhere.

It is -no-longer- cropped to MEMBLOCK_REAL_LIMIT which disappears.

Note to archs: I'm leaving the default limit to MEMBLOCK_ALLOC_ANYWHERE. I
strongly recommend that you ensure that you set an appropriate limit
during boot in order to guarantee that an memblock_alloc() at any time
results in something that is accessible with a simple __va().

The reason is that a subsequent patch will introduce the ability for
the array to resize itself by reallocating itself. The MEMBLOCK core will
honor the current limit when performing those allocations.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Benjamin Herrenschmidt
2010-07-06 15:39:01 -07:00
parent 27f574c223
commit e63075a3c9
14 changed files with 63 additions and 53 deletions
Download Patch File Download Diff File Expand all files Collapse all files

19
mm/memblock.c
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@@ -115,6 +115,8 @@ void __init memblock_init(void)
memblock.reserved.regions[0].base = 0;
memblock.reserved.regions[0].size = 0;
memblock.reserved.cnt = 1;
memblock.current_limit = MEMBLOCK_ALLOC_ANYWHERE;
}
void __init memblock_analyze(void)
@@ -373,7 +375,7 @@ u64 __init memblock_alloc_nid(u64 size, u64 align, int nid)
u64 __init memblock_alloc(u64 size, u64 align)
{
return memblock_alloc_base(size, align, MEMBLOCK_ALLOC_ANYWHERE);
return memblock_alloc_base(size, align, MEMBLOCK_ALLOC_ACCESSIBLE);
}
u64 __init memblock_alloc_base(u64 size, u64 align, u64 max_addr)
@@ -399,14 +401,9 @@ u64 __init __memblock_alloc_base(u64 size, u64 align, u64 max_addr)
size = memblock_align_up(size, align);
/* On some platforms, make sure we allocate lowmem */
/* Note that MEMBLOCK_REAL_LIMIT may be MEMBLOCK_ALLOC_ANYWHERE */
if (max_addr == MEMBLOCK_ALLOC_ANYWHERE)
max_addr = MEMBLOCK_REAL_LIMIT;
/* Pump up max_addr */
if (max_addr == MEMBLOCK_ALLOC_ANYWHERE)
max_addr = ~(u64)0;
if (max_addr == MEMBLOCK_ALLOC_ACCESSIBLE)
max_addr = memblock.current_limit;
/* We do a top-down search, this tends to limit memory
* fragmentation by keeping early boot allocs near the
@@ -527,3 +524,9 @@ int memblock_is_region_reserved(u64 base, u64 size)
return memblock_overlaps_region(&memblock.reserved, base, size) >= 0;
}
void __init memblock_set_current_limit(u64 limit)
{
memblock.current_limit = limit;
}