On Wed, 24 Dec 2008 23:35:36 -0800 Andrew Morton <a...@linux-foundation.org>
wrote:
> - Please put [patch] in the Subject: line of patches
>
> - Please choose a suitable title, as per
> Documentation/SubmittingPatches, section 15.
>
> - Please cc suitable mailing lists and maintainers on bug reports and
> on patches.
Also the patch was wordwrapped and the changelog was filled with weird
UTF8 characters.
I think I have it all cleaned up now.
From: Chandru <chan...@in.ibm.com>
When booted with crashkernel=2...@32m or any memory size less than this,
the system boots properly. The following was the observation.. The
system comes up with two nodes (0-256M and 256M-4GB). The crashkernel
memory reservation spans across these two nodes. The
mark_reserved_regions_for_nid() in arch/powerpc/mm/numa.c resizes the
reserved part of the memory within it as:
if (end_pfn > node_ar.end_pfn)
reserve_size = (node_ar.end_pfn << PAGE_SHIFT)
- (start_pfn << PAGE_SHIFT);
but the reserve_bootmem_node() in mm/bootmem.c raises the pfn value of end
end = PFN_UP(physaddr + size);
This causes end to get a value past the last page in the 0-256M node.
Again when reserve_bootmem_node() returns, mark_reserved_regions_for_nid()
loops around to set the rest of the crashkernel memory in the next node as
reserved. It references NODE_DATA(node_ar.nid) and this causes another
'Oops: kernel access of bad area' problem. The following changes made the
system to boot with any amount of crashkernel memory size.
Signed-off-by: Chandru S <chan...@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Cc: Paul Mackerras <pau...@samba.org>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
---
arch/powerpc/mm/numa.c | 7 ++++---
mm/bootmem.c | 4 ++++
2 files changed, 8 insertions(+), 3 deletions(-)
diff -puN
arch/powerpc/mm/numa.c~powerpc-fix-code-for-reserved-memory-spanning-across-nodes
arch/powerpc/mm/numa.c
---
a/arch/powerpc/mm/numa.c~powerpc-fix-code-for-reserved-memory-spanning-across-nodes
+++ a/arch/powerpc/mm/numa.c
@@ -995,10 +995,11 @@ void __init do_init_bootmem(void)
start_pfn, end_pfn);
free_bootmem_with_active_regions(nid, end_pfn);
+ }
+
+ for_each_online_node(nid) {
/*
- * Be very careful about moving this around. Future
- * calls to careful_allocation() depend on this getting
- * done correctly.
+ * Be very careful about moving this around.
*/
mark_reserved_regions_for_nid(nid);
sparse_memory_present_with_active_regions(nid);
diff -puN
mm/bootmem.c~powerpc-fix-code-for-reserved-memory-spanning-across-nodes
mm/bootmem.c
--- a/mm/bootmem.c~powerpc-fix-code-for-reserved-memory-spanning-across-nodes
+++ a/mm/bootmem.c
@@ -375,10 +375,14 @@ int __init reserve_bootmem_node(pg_data_
unsigned long size, int flags)
{
unsigned long start, end;
+ bootmem_data_t *bdata = pgdat->bdata;
start = PFN_DOWN(physaddr);
end = PFN_UP(physaddr + size);
+ if (end > bdata->node_low_pfn)
+ end = bdata->node_low_pfn;
+
return mark_bootmem_node(pgdat->bdata, start, end, 1, flags);
}
_
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