Re: [PATCH 2/2] Allocate memory cgroup structures in local nodes v3

[Michal Hocko <mhocko@suse.cz>]

On Thu 05-05-11 12:46:02, Andi Kleen wrote:
> From: Andi Kleen <ak@linux.intel.com>
> 
> dde79e005a769 added a regression that the memory cgroup data structures
> all end up in node 0 because the first attempt at allocating them
> would not pass in a node hint. Since the initialization runs on CPU #0
> it would all end up node 0. This is a problem on large memory systems,
> where node 0 would lose a lot of memory.
> 
> Change the alloc_pages_exact to alloc_pages_exact_node. This will
> still fall back to other nodes if not enough memory is available.
> 
> [RED-PEN: right now it would fall back first before trying
> vmalloc_node. Probably not the best strategy ... But I left it like
> that for now.]
> 
> v3: Really call the correct function now. Thanks for everyone who commented.
> Reported-by: Doug Nelson
> Cc: rientjes@google.com
> CC: Michal Hocko <mhocko@suse.cz>
> Cc: Dave Hansen <dave@linux.vnet.ibm.com>
> Cc: Balbir Singh <balbir@in.ibm.com>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Signed-off-by: Andi Kleen <ak@linux.intel.com>
> ---
>  mm/page_alloc.c  |    4 ++--
>  mm/page_cgroup.c |    6 ++++--
>  2 files changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 5219dac..44e175d 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -2317,7 +2317,7 @@ void free_pages(unsigned long addr, unsigned int order)
>  
>  EXPORT_SYMBOL(free_pages);
>  
> -static void *make_alloc_exact(void *addr, unsigned order, size_t size)
> +static void *make_alloc_exact(unsigned long addr, unsigned order, size_t size)
>  {
>  	if (addr) {
>  		unsigned long alloc_end = addr + (PAGE_SIZE << order);
> @@ -2371,7 +2371,7 @@ void *alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask)
>  	struct page *p = alloc_pages_node(nid, gfp_mask, order);
>  	if (!p)
>  		return NULL;
> -	return make_alloc_exact(page_address(p), order, size);
> +	return make_alloc_exact((unsigned long)page_address(p), order, size);

I am not sure whether this doesn't clash with what Dave was working on. Some
pieces are already in the -mm tree but I do not see node versions to be
renamed.

>  }
>  EXPORT_SYMBOL(alloc_pages_exact_nid);
>  
> diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c
> index 9905501..347ab60 100644
> --- a/mm/page_cgroup.c
> +++ b/mm/page_cgroup.c
> @@ -134,9 +134,11 @@ static void *__init_refok alloc_page_cgroup(size_t size, int nid)
>  {
>  	void *addr = NULL;
>  
> -	addr = alloc_pages_exact(size, GFP_KERNEL | __GFP_NOWARN);
> -	if (addr)
> +	addr = alloc_pages_exact_nid(nid, size, GFP_KERNEL | __GFP_NOWARN);
> +	if (addr) {
> +		printk("%s: allocated exact\n", __FUNCTION__);

What is this printk for? Other than that the change looks good to me.
Reviewed-by: Michal Hocko <mhocko@suse.cz>

Thanks
-- 
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9    
Czech Republic

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