> > As you say, it's not clear why the normal discontig kernel boots because
> > the regions should have been skipped by add_active_range().
> >
> I think that depends on the init value of memmap, if they are all zero,
> free_pages_check will be happy and not report any thing. So I guess we may
> see this bug in normal kernel with a warm reboot, or with a machine which
> PROM does not clear memory to all zero.
It could have been just luck. See more below
>
> > Try your patch and see does it work for kdump. It should work fine in the
> > normal case because at very worst, slightly more memmap is allocated than
> > is strictly required.
> >
> It works for kdump.
>
Can you try out the patch below please as a possibly simplier alternative? It's
a patch from Bob Picco that addresses a similar problem with initmem on a
kernel booting as normal. The only difference between Bob's original patch
and this one is the addition of the CONFIG_KEXEC stuff from your patch. It
survived a simply boot test.
Thanks
>>> Begin Bob's patch
While pursuing and unrelated issue with 64Mb granules I noticed a problem
related to inconsistent use of add_active_range. There doesn't appear any
reason to me why FLATMEM versus DISCONTIG_MEM should register memory
to add_active_range with different code. So I've changed the code into
a common implementation.
The other subtle issue fixed by this patch was calling add_active_range
in count_node_pages before granule aligning is performed. We were lucky with
16MB granules but not so with 64MB granules. count_node_pages has reserved
regions filtered out and as a consequence linked kernel text and data
aren't covered by calls to count_node_pages. So linked kernel regions
wasn't reported to add_active_regions. This resulted in free_initmem causing
numerous bad_page reports. This won't occur with this patch because now
all known memory regions are reported by register_active_ranges.
Acked-by: Mel Gorman <mel@xxxxxxxxx>
Signed-off-by: Bob Picco <bob.picco@xxxxxx>
arch/ia64/mm/contig.c | 3 +--
arch/ia64/mm/discontig.c | 4 +++-
arch/ia64/mm/init.c | 24 +++++++++++++++++-------
include/asm-ia64/meminit.h | 3 ++-
4 files changed, 23 insertions(+), 11 deletions(-)
diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.19-rc5-clean/arch/ia64/mm/contig.c linux-2.6.19-rc5-register_all_memory/arch/ia64/mm/contig.c
--- linux-2.6.19-rc5-clean/arch/ia64/mm/contig.c 2006-11-08 02:24:20.000000000 +0000
+++ linux-2.6.19-rc5-register_all_memory/arch/ia64/mm/contig.c 2006-11-16 15:29:31.000000000 +0000
@@ -226,7 +226,6 @@ void __init
paging_init (void)
{
unsigned long max_dma;
- unsigned long nid = 0;
unsigned long max_zone_pfns[MAX_NR_ZONES];
num_physpages = 0;
@@ -238,7 +237,7 @@ paging_init (void)
max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
#ifdef CONFIG_VIRTUAL_MEM_MAP
- efi_memmap_walk(register_active_ranges, &nid);
+ efi_memmap_walk(register_active_ranges, NULL);
efi_memmap_walk(find_largest_hole, (u64 *)&max_gap);
if (max_gap < LARGE_GAP) {
vmem_map = (struct page *) 0;
diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.19-rc5-clean/arch/ia64/mm/discontig.c linux-2.6.19-rc5-register_all_memory/arch/ia64/mm/discontig.c
--- linux-2.6.19-rc5-clean/arch/ia64/mm/discontig.c 2006-11-08 02:24:20.000000000 +0000
+++ linux-2.6.19-rc5-register_all_memory/arch/ia64/mm/discontig.c 2006-11-16 15:29:31.000000000 +0000
@@ -473,6 +473,9 @@ void __init find_memory(void)
node_clear(node, memory_less_mask);
mem_data[node].min_pfn = ~0UL;
}
+
+ efi_memmap_walk(register_active_ranges, NULL);
+
/*
* Initialize the boot memory maps in reverse order since that's
* what the bootmem allocator expects
@@ -654,7 +657,6 @@ static __init int count_node_pages(unsig
{
unsigned long end = start + len;
- add_active_range(node, start >> PAGE_SHIFT, end >> PAGE_SHIFT);
mem_data[node].num_physpages += len >> PAGE_SHIFT;
if (start <= __pa(MAX_DMA_ADDRESS))
mem_data[node].num_dma_physpages +=
diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.19-rc5-clean/arch/ia64/mm/init.c linux-2.6.19-rc5-register_all_memory/arch/ia64/mm/init.c
--- linux-2.6.19-rc5-clean/arch/ia64/mm/init.c 2006-11-08 02:24:20.000000000 +0000
+++ linux-2.6.19-rc5-register_all_memory/arch/ia64/mm/init.c 2006-11-16 15:33:25.000000000 +0000
@@ -594,18 +594,28 @@ find_largest_hole (u64 start, u64 end, v
return 0;
}
+#endif /* CONFIG_VIRTUAL_MEM_MAP */
+
int __init
-register_active_ranges(u64 start, u64 end, void *nid)
+register_active_ranges(u64 start, u64 end, void *arg)
{
- BUG_ON(nid == NULL);
- BUG_ON(*(unsigned long *)nid >= MAX_NUMNODES);
+ int nid = paddr_to_nid(__pa(start));
+
+ if (nid < 0)
+ nid = 0;
- add_active_range(*(unsigned long *)nid,
- __pa(start) >> PAGE_SHIFT,
- __pa(end) >> PAGE_SHIFT);
+#ifdef CONFIG_KEXEC
+ if (start > crashk_res.start && start < crashk_res.end)
+ start = max(start, crashk_res.end);
+ if (end > crashk_res.start && end < crashk_res.end)
+ end = min(end, crashk_res.start);
+#endif
+
+ if (start < end)
+ add_active_range(nid, __pa(start) >> PAGE_SHIFT,
+ __pa(end) >> PAGE_SHIFT);
return 0;
}
-#endif /* CONFIG_VIRTUAL_MEM_MAP */
static int __init
count_reserved_pages (u64 start, u64 end, void *arg)
diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.19-rc5-clean/include/asm-ia64/meminit.h linux-2.6.19-rc5-register_all_memory/include/asm-ia64/meminit.h
--- linux-2.6.19-rc5-clean/include/asm-ia64/meminit.h 2006-11-08 02:24:20.000000000 +0000
+++ linux-2.6.19-rc5-register_all_memory/include/asm-ia64/meminit.h 2006-11-16 15:29:31.000000000 +0000
@@ -50,12 +50,13 @@ extern void efi_memmap_init(unsigned lon
#define IGNORE_PFN0 1 /* XXX fix me: ignore pfn 0 until TLB miss handler is updated... */
+extern int register_active_ranges (u64 start, u64 end, void *arg);
+
#ifdef CONFIG_VIRTUAL_MEM_MAP
# define LARGE_GAP 0x40000000 /* Use virtual mem map if hole is > than this */
extern unsigned long vmalloc_end;
extern struct page *vmem_map;
extern int find_largest_hole (u64 start, u64 end, void *arg);
- extern int register_active_ranges (u64 start, u64 end, void *arg);
extern int create_mem_map_page_table (u64 start, u64 end, void *arg);
extern int vmemmap_find_next_valid_pfn(int, int);
#else
--
Mel Gorman
Part-time Phd Student Linux Technology Center
University of Limerick IBM Dublin Software Lab
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