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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

29
arch/powerpc/mm/init_32.c
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@@ -91,12 +91,6 @@ int __allow_ioremap_reserved;
/* max amount of low RAM to map in */
unsigned long __max_low_memory = MAX_LOW_MEM;
/*
* address of the limit of what is accessible with initial MMU setup -
* 256MB usually, but only 16MB on 601.
*/
phys_addr_t __initial_memory_limit_addr = (phys_addr_t)0x10000000;
/*
* Check for command-line options that affect what MMU_init will do.
*/
@@ -126,13 +120,6 @@ void __init MMU_init(void)
if (ppc_md.progress)
ppc_md.progress("MMU:enter", 0x111);
/* 601 can only access 16MB at the moment */
if (PVR_VER(mfspr(SPRN_PVR)) == 1)
__initial_memory_limit_addr = 0x01000000;
/* 8xx can only access 8MB at the moment */
if (PVR_VER(mfspr(SPRN_PVR)) == 0x50)
__initial_memory_limit_addr = 0x00800000;
/* parse args from command line */
MMU_setup();
@@ -190,20 +177,18 @@ void __init MMU_init(void)
#ifdef CONFIG_BOOTX_TEXT
btext_unmap();
#endif
/* Shortly after that, the entire linear mapping will be available */
memblock_set_current_limit(lowmem_end_addr);
}
/* This is only called until mem_init is done. */
void __init *early_get_page(void)
{
void *p;
if (init_bootmem_done) {
p = alloc_bootmem_pages(PAGE_SIZE);
} else {
p = __va(memblock_alloc_base(PAGE_SIZE, PAGE_SIZE,
__initial_memory_limit_addr));
}
return p;
if (init_bootmem_done)
return alloc_bootmem_pages(PAGE_SIZE);
else
return __va(memblock_alloc(PAGE_SIZE, PAGE_SIZE));
}
/* Free up now-unused memory */