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authorMel Gorman <mel@csn.ul.ie>2007-10-16 01:25:56 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-16 09:43:00 -0700
commit5c0e3066474b57c56ff0d88ca31d95bd14232fee (patch)
tree90c963c62891db4a9039e84e615c01408b09c845 /mm/sparse.c
parent46dafbca2bba811665b01d8cedf911204820623c (diff)
downloadlinux-5c0e3066474b57c56ff0d88ca31d95bd14232fee.tar.gz
Fix corruption of memmap on IA64 SPARSEMEM when mem_section is not a power of 2
There are problems in the use of SPARSEMEM and pageblock flags that causes problems on ia64. The first part of the problem is that units are incorrect in SECTION_BLOCKFLAGS_BITS computation. This results in a map_section's section_mem_map being treated as part of a bitmap which isn't good. This was evident with an invalid virtual address when mem_init attempted to free bootmem pages while relinquishing control from the bootmem allocator. The second part of the problem occurs because the pageblock flags bitmap is be located with the mem_section. The SECTIONS_PER_ROOT computation using sizeof (mem_section) may not be a power of 2 depending on the size of the bitmap. This renders masks and other such things not power of 2 base. This issue was seen with SPARSEMEM_EXTREME on ia64. This patch moves the bitmap outside of mem_section and uses a pointer instead in the mem_section. The bitmaps are allocated when the section is being initialised. Note that sparse_early_usemap_alloc() does not use alloc_remap() like sparse_early_mem_map_alloc(). The allocation required for the bitmap on x86, the only architecture that uses alloc_remap is typically smaller than a cache line. alloc_remap() pads out allocations to the cache size which would be a needless waste. Credit to Bob Picco for identifying the original problem and effecting a fix for the SECTION_BLOCKFLAGS_BITS calculation. Credit to Andy Whitcroft for devising the best way of allocating the bitmaps only when required for the section. [wli@holomorphy.com: warning fix] Signed-off-by: Bob Picco <bob.picco@hp.com> Signed-off-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Mel Gorman <mel@csn.ul.ie> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: William Irwin <bill.irwin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/sparse.c')
-rw-r--r--mm/sparse.c54
1 files changed, 51 insertions, 3 deletions
diff --git a/mm/sparse.c b/mm/sparse.c
index 52843a76fee..1f4dbb867b8 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -206,7 +206,8 @@ struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pn
}
static int __meminit sparse_init_one_section(struct mem_section *ms,
- unsigned long pnum, struct page *mem_map)
+ unsigned long pnum, struct page *mem_map,
+ unsigned long *pageblock_bitmap)
{
if (!present_section(ms))
return -EINVAL;
@@ -214,6 +215,7 @@ static int __meminit sparse_init_one_section(struct mem_section *ms,
ms->section_mem_map &= ~SECTION_MAP_MASK;
ms->section_mem_map |= sparse_encode_mem_map(mem_map, pnum) |
SECTION_HAS_MEM_MAP;
+ ms->pageblock_flags = pageblock_bitmap;
return 1;
}
@@ -224,6 +226,38 @@ void *alloc_bootmem_high_node(pg_data_t *pgdat, unsigned long size)
return NULL;
}
+static unsigned long usemap_size(void)
+{
+ unsigned long size_bytes;
+ size_bytes = roundup(SECTION_BLOCKFLAGS_BITS, 8) / 8;
+ size_bytes = roundup(size_bytes, sizeof(unsigned long));
+ return size_bytes;
+}
+
+#ifdef CONFIG_MEMORY_HOTPLUG
+static unsigned long *__kmalloc_section_usemap(void)
+{
+ return kmalloc(usemap_size(), GFP_KERNEL);
+}
+#endif /* CONFIG_MEMORY_HOTPLUG */
+
+static unsigned long *sparse_early_usemap_alloc(unsigned long pnum)
+{
+ unsigned long *usemap;
+ struct mem_section *ms = __nr_to_section(pnum);
+ int nid = sparse_early_nid(ms);
+
+ usemap = alloc_bootmem_node(NODE_DATA(nid), usemap_size());
+ if (usemap)
+ return usemap;
+
+ /* Stupid: suppress gcc warning for SPARSEMEM && !NUMA */
+ nid = 0;
+
+ printk(KERN_WARNING "%s: allocation failed\n", __FUNCTION__);
+ return NULL;
+}
+
#ifndef CONFIG_SPARSEMEM_VMEMMAP
struct page __init *sparse_early_mem_map_populate(unsigned long pnum, int nid)
{
@@ -268,6 +302,7 @@ void __init sparse_init(void)
{
unsigned long pnum;
struct page *map;
+ unsigned long *usemap;
for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
if (!present_section_nr(pnum))
@@ -276,7 +311,13 @@ void __init sparse_init(void)
map = sparse_early_mem_map_alloc(pnum);
if (!map)
continue;
- sparse_init_one_section(__nr_to_section(pnum), pnum, map);
+
+ usemap = sparse_early_usemap_alloc(pnum);
+ if (!usemap)
+ continue;
+
+ sparse_init_one_section(__nr_to_section(pnum), pnum, map,
+ usemap);
}
}
@@ -332,6 +373,7 @@ int sparse_add_one_section(struct zone *zone, unsigned long start_pfn,
struct pglist_data *pgdat = zone->zone_pgdat;
struct mem_section *ms;
struct page *memmap;
+ unsigned long *usemap;
unsigned long flags;
int ret;
@@ -341,6 +383,7 @@ int sparse_add_one_section(struct zone *zone, unsigned long start_pfn,
*/
sparse_index_init(section_nr, pgdat->node_id);
memmap = __kmalloc_section_memmap(nr_pages);
+ usemap = __kmalloc_section_usemap();
pgdat_resize_lock(pgdat, &flags);
@@ -349,9 +392,14 @@ int sparse_add_one_section(struct zone *zone, unsigned long start_pfn,
ret = -EEXIST;
goto out;
}
+
+ if (!usemap) {
+ ret = -ENOMEM;
+ goto out;
+ }
ms->section_mem_map |= SECTION_MARKED_PRESENT;
- ret = sparse_init_one_section(ms, section_nr, memmap);
+ ret = sparse_init_one_section(ms, section_nr, memmap, usemap);
out:
pgdat_resize_unlock(pgdat, &flags);