[ 09/54] x86, mm: Trim memory in memblock to be page aligned

From: Greg Kroah-Hartman
Date: Mon Oct 29 2012 - 17:56:34 EST


3.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Yinghai Lu <yinghai@xxxxxxxxxx>

commit 6ede1fd3cb404c0016de6ac529df46d561bd558b upstream.

We will not map partial pages, so need to make sure memblock
allocation will not allocate those bytes out.

Also we will use for_each_mem_pfn_range() to loop to map memory
range to keep them consistent.

Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/CAE9FiQVZirvaBMFYRfXMmWEcHbKSicQEHz4VAwUv0xFCk51ZNw@xxxxxxxxxxxxxx
Acked-by: Jacob Shin <jacob.shin@xxxxxxx>
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/x86/kernel/e820.c | 3 +++
include/linux/memblock.h | 1 +
mm/memblock.c | 24 ++++++++++++++++++++++++
3 files changed, 28 insertions(+)

--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -1076,6 +1076,9 @@ void __init memblock_x86_fill(void)
memblock_add(ei->addr, ei->size);
}

+ /* throw away partial pages */
+ memblock_trim_memory(PAGE_SIZE);
+
memblock_dump_all();
}

--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -57,6 +57,7 @@ int memblock_add(phys_addr_t base, phys_
int memblock_remove(phys_addr_t base, phys_addr_t size);
int memblock_free(phys_addr_t base, phys_addr_t size);
int memblock_reserve(phys_addr_t base, phys_addr_t size);
+void memblock_trim_memory(phys_addr_t align);

#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
void __next_mem_pfn_range(int *idx, int nid, unsigned long *out_start_pfn,
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -908,6 +908,30 @@ int __init_memblock memblock_is_region_r
return memblock_overlaps_region(&memblock.reserved, base, size) >= 0;
}

+void __init_memblock memblock_trim_memory(phys_addr_t align)
+{
+ int i;
+ phys_addr_t start, end, orig_start, orig_end;
+ struct memblock_type *mem = &memblock.memory;
+
+ for (i = 0; i < mem->cnt; i++) {
+ orig_start = mem->regions[i].base;
+ orig_end = mem->regions[i].base + mem->regions[i].size;
+ start = round_up(orig_start, align);
+ end = round_down(orig_end, align);
+
+ if (start == orig_start && end == orig_end)
+ continue;
+
+ if (start < end) {
+ mem->regions[i].base = start;
+ mem->regions[i].size = end - start;
+ } else {
+ memblock_remove_region(mem, i);
+ i--;
+ }
+ }
+}

void __init_memblock memblock_set_current_limit(phys_addr_t limit)
{


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