Re: boot panic with memcg enabled (Was [PATCH 3/4] memcg: don't use bootmem allocator in setup code)

[KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>]

On Fri, 12 Jun 2009 10:50:00 +0800
Li Zefan <lizf@cn.fujitsu.com> wrote:

> (This patch should have CCed memcg maitainers)
> 
> My box failed to boot due to initialization failure of page_cgroup, and
> it's caused by this patch:
> 
> +	page = alloc_pages_node(nid, GFP_NOWAIT | __GFP_ZERO, order);
> 

Oh, I don't know this patch ;(

> I added a printk, and found that order == 11 == MAX_ORDER.
> 
maybe possible because this allocates countinous pages of 60%? length of
memmap. 
If __alloc_bootmem_node_nopanic() is not available any more, memcg should be
only used under CONFIG_SPARSEMEM. 

Is that a request from bootmem maintainer ?

Thanks,
-Kame


> Pekka J Enberg wrote:
> > From: Yinghai Lu <yinghai@kernel.org>
> > 
> > The bootmem allocator is no longer available for page_cgroup_init() because we
> > set up the kernel slab allocator much earlier now.
> > 
> > Cc: Ingo Molnar <mingo@elte.hu>
> > Cc: Johannes Weiner <hannes@cmpxchg.org>
> > Cc: Linus Torvalds <torvalds@linux-foundation.org>
> > Signed-off-by: Yinghai Lu <yinghai@kernel.org>
> > Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
> > ---
> >  mm/page_cgroup.c |   12 ++++++++----
> >  1 files changed, 8 insertions(+), 4 deletions(-)
> > 
> > diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c
> > index 791905c..3dd4a90 100644
> > --- a/mm/page_cgroup.c
> > +++ b/mm/page_cgroup.c
> > @@ -47,6 +47,8 @@ static int __init alloc_node_page_cgroup(int nid)
> >  	struct page_cgroup *base, *pc;
> >  	unsigned long table_size;
> >  	unsigned long start_pfn, nr_pages, index;
> > +	struct page *page;
> > +	unsigned int order;
> >  
> >  	start_pfn = NODE_DATA(nid)->node_start_pfn;
> >  	nr_pages = NODE_DATA(nid)->node_spanned_pages;
> > @@ -55,11 +57,13 @@ static int __init alloc_node_page_cgroup(int nid)
> >  		return 0;
> >  
> >  	table_size = sizeof(struct page_cgroup) * nr_pages;
> > -
> > -	base = __alloc_bootmem_node_nopanic(NODE_DATA(nid),
> > -			table_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
> > -	if (!base)
> > +	order = get_order(table_size);
> > +	page = alloc_pages_node(nid, GFP_NOWAIT | __GFP_ZERO, order);
> > +	if (!page)
> > +		page = alloc_pages_node(-1, GFP_NOWAIT | __GFP_ZERO, order);
> > +	if (!page)
> >  		return -ENOMEM;
> > +	base = page_address(page);
> >  	for (index = 0; index < nr_pages; index++) {
> >  		pc = base + index;
> >  		__init_page_cgroup(pc, start_pfn + index);
> 
> 

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