Re: [PATCH] [13/18] Add support to allocate hugepages of different size with hugepages=...

[Mel Gorman <mel@csn.ul.ie>]

On (17/03/08 02:58), Andi Kleen didst pronounce:
> Signed-off-by: Andi Kleen <ak@suse.de>
> 
> ---
>  include/linux/hugetlb.h |    1 +
>  mm/hugetlb.c            |   23 ++++++++++++++++++-----
>  2 files changed, 19 insertions(+), 5 deletions(-)
> 
> Index: linux/mm/hugetlb.c
> ===================================================================
> --- linux.orig/mm/hugetlb.c
> +++ linux/mm/hugetlb.c
> @@ -552,19 +552,23 @@ static int __init hugetlb_init_hstate(st
>  {
>  	unsigned long i;
>  
> -	for (i = 0; i < MAX_NUMNODES; ++i)
> -		INIT_LIST_HEAD(&h->hugepage_freelists[i]);
> +	/* Don't reinitialize lists if they have been already init'ed */
> +	if (!h->hugepage_freelists[0].next) {
> +		for (i = 0; i < MAX_NUMNODES; ++i)
> +			INIT_LIST_HEAD(&h->hugepage_freelists[i]);
>  
> -	h->hugetlb_next_nid = first_node(node_online_map);
> +		h->hugetlb_next_nid = first_node(node_online_map);
> +	}


hmm, it's not very clear to me how hugetlb_init_hstate() would get
called twice for the same hstate. Should it be VM_BUG_ON() if a hstate
gets initialised twice instead?

>  
> -	for (i = 0; i < max_huge_pages[h - hstates]; ++i) {
> +	while (h->parsed_hugepages < max_huge_pages[h - hstates]) {
>  		if (h->order > MAX_ORDER) {
>  			if (!alloc_bm_huge_page(h))
>  				break;
>  		} else if (!alloc_fresh_huge_page(h))
>  			break;
> +		h->parsed_hugepages++;
>  	}
> -	max_huge_pages[h - hstates] = h->free_huge_pages = h->nr_huge_pages = i;
> +	max_huge_pages[h - hstates] = h->parsed_hugepages;
>  
>  	printk(KERN_INFO "Total HugeTLB memory allocated, %ld %dMB pages\n",
>  			h->free_huge_pages,
> @@ -602,6 +606,15 @@ static int __init hugetlb_setup(char *s)
>  	unsigned long *mhp = &max_huge_pages[parsed_hstate - hstates];
>  	if (sscanf(s, "%lu", mhp) <= 0)
>  		*mhp = 0;
> +	/*
> +	 * Global state is always initialized later in hugetlb_init.
> +	 * But we need to allocate > MAX_ORDER hstates here early to still
> +	 * use the bootmem allocator.
> +	 * If you add additional hstates <= MAX_ORDER you'll need
> +	 * to fix that.
> +	 */
> +	if (parsed_hstate != &global_hstate)
> +		hugetlb_init_hstate(parsed_hstate);
>  	return 1;
>  }
>  __setup("hugepages=", hugetlb_setup);
> Index: linux/include/linux/hugetlb.h
> ===================================================================
> --- linux.orig/include/linux/hugetlb.h
> +++ linux/include/linux/hugetlb.h
> @@ -212,6 +212,7 @@ struct hstate {
>  	unsigned int nr_huge_pages_node[MAX_NUMNODES];
>  	unsigned int free_huge_pages_node[MAX_NUMNODES];
>  	unsigned int surplus_huge_pages_node[MAX_NUMNODES];
> +	unsigned long parsed_hugepages;
>  };
>  
>  void __init huge_add_hstate(unsigned order);
> 
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> 

-- 
Mel Gorman
Part-time Phd Student                          Linux Technology Center
University of Limerick                         IBM Dublin Software Lab

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