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[S390] memory hotplug: prevent memory zone interleave

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This fixes a kernel oops with CONFIG_DEBUG_VM triggered by a
VM_BUG_ON(bad_range()): kernel BUG at mm/page_alloc.c:748.

With memory hotplug on System z, it is possible that the memory
online/offline state is preserved over a system restart, e.g. there
may be offline memory blocks in ZONE_DMA or ZONE_NORMAL. So far,
the offline memory range has always been added to ZONE_MOVABLE during
system start, so that it was possible to have ZONE_MOVABLE interleave
with ZONE_DMA or ZONE_NORMAL. This patch fixes that by checking for
zone overlap before adding memory.

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Gerald Schaefer 2012-02-24 18:01:29 +01:00 committed by Martin Schwidefsky
parent d60331ac0d
commit 892365ab4d
1 changed files with 26 additions and 4 deletions
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30
arch/s390/mm/init.c
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@ -223,16 +223,38 @@ void free_initrd_mem(unsigned long start, unsigned long end)
#ifdef CONFIG_MEMORY_HOTPLUG
int arch_add_memory(int nid, u64 start, u64 size)
{
struct pglist_data *pgdat;
unsigned long zone_start_pfn, zone_end_pfn, nr_pages;
unsigned long start_pfn = PFN_DOWN(start);
unsigned long size_pages = PFN_DOWN(size);
struct zone *zone;
int rc;
pgdat = NODE_DATA(nid);
zone = pgdat->node_zones + ZONE_MOVABLE;
rc = vmem_add_mapping(start, size);
if (rc)
return rc;
rc = __add_pages(nid, zone, PFN_DOWN(start), PFN_DOWN(size));
for_each_zone(zone) {
if (zone_idx(zone) != ZONE_MOVABLE) {
/* Add range within existing zone limits */
zone_start_pfn = zone->zone_start_pfn;
zone_end_pfn = zone->zone_start_pfn +
zone->spanned_pages;
} else {
/* Add remaining range to ZONE_MOVABLE */
zone_start_pfn = start_pfn;
zone_end_pfn = start_pfn + size_pages;
}
if (start_pfn < zone_start_pfn || start_pfn >= zone_end_pfn)
continue;
nr_pages = (start_pfn + size_pages > zone_end_pfn) ?
zone_end_pfn - start_pfn : size_pages;
rc = __add_pages(nid, zone, start_pfn, nr_pages);
if (rc)
break;
start_pfn += nr_pages;
size_pages -= nr_pages;
if (!size_pages)
break;
}
if (rc)
vmem_remove_mapping(start, size);
return rc;