Messages in this thread | | | Date | Fri, 9 May 2008 11:31:46 +0100 | From | Andy Whitcroft <> | Subject | Re: [PATCH] sparsemem vmemmap: initialize memmap. |
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On Fri, May 09, 2008 at 08:38:56AM +0200, Heiko Carstens wrote: > From: Heiko Carstens <heiko.carstens@de.ibm.com> > > Trying to online a new memory section that was added via memory hotplug > results in lots of messages of pages in bad page state. > Reason is that the alloacted virtual memmap isn't initialized. > This is only an issue for memory sections that get added after boot > time since for all other memmaps the bootmem allocator was used which > returns only initialized memory. > > I noticed this on s390 which has its private vmemmap_populate function > without using callbacks to the common code. But as far as I can see the > generic code has the same bug, so fix it just once. > > Cc: Andy Whitcroft <apw@shadowen.org> > Cc: Christoph Lameter <clameter@sgi.com> > Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com> > Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> > --- > mm/sparse-vmemmap.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > Index: linux-2.6/mm/sparse-vmemmap.c > =================================================================== > --- linux-2.6.orig/mm/sparse-vmemmap.c > +++ linux-2.6/mm/sparse-vmemmap.c > @@ -154,6 +154,6 @@ struct page * __meminit sparse_mem_map_p > int error = vmemmap_populate(map, PAGES_PER_SECTION, nid); > if (error) > return NULL; > - > + memset(map, 0, PAGES_PER_SECTION * sizeof(struct page)); > return map; > }
The normal expectation is that all allocations are made using vmemmap_alloc_block() which allocates from the appropriate place. Once the buddy is up and available it uses:
struct page *page = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, get_order(size));
to get the memory so it should all be zero'd. So I would expect all existing users to be covered by that? Can you not simply use __GFP_ZERO for your allocations or use vmemmap_alloc_block() ?
-apw
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