Re: [PATCH 1/6 v2] allow arch specific function for allocating gigantic pages

[Nick Piggin <npiggin@suse.de>]

On Tue, May 13, 2008 at 12:19:36PM -0500, Jon Tollefson wrote:
> Allow alloc_bm_huge_page() to be overridden by architectures that can't
> always use bootmem. This requires huge_boot_pages to be available for
> use by this function. The 16G pages on ppc64 have to be reserved prior
> to boot-time. The location of these pages are indicated in the device
> tree.

That looks fine. I wonder if we should call it something else now?
Anyway, nevermind naming for the moment.


> A BUG_ON in huge_add_hstate is commented out in order to allow 64K huge
> pages to continue to work on power.

Fine. I'll remove the BUG_ON completely from where it was
introduced.


> Signed-off-by: Jon Tollefson <kniht@linux.vnet.ibm.com>
> ---
> 
> include/linux/hugetlb.h |   10 ++++++++++
> mm/hugetlb.c            |   15 ++++++---------
> 2 files changed, 16 insertions(+), 9 deletions(-)
> 
> 
> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
> index 8c47ca7..b550ec7 100644
> --- a/include/linux/hugetlb.h
> +++ b/include/linux/hugetlb.h
> @@ -35,6 +35,7 @@ void hugetlb_unreserve_pages(struct inode *inode, long 
> offset, long freed);
> extern unsigned long hugepages_treat_as_movable;
> extern const unsigned long hugetlb_zero, hugetlb_infinity;
> extern int sysctl_hugetlb_shm_group;
> +extern struct list_head huge_boot_pages;
> 
> /* arch callbacks */
> 
> @@ -205,6 +206,14 @@ struct hstate {
> 	unsigned int surplus_huge_pages_node[MAX_NUMNODES];
> };
> 
> +struct huge_bm_page {
> +	struct list_head list;
> +	struct hstate *hstate;
> +};
> +
> +/* arch callback */
> +int alloc_bm_huge_page(struct hstate *h);
> +
> void __init huge_add_hstate(unsigned order);
> struct hstate *size_to_hstate(unsigned long size);
> 
> @@ -256,6 +265,7 @@ extern unsigned long 
> sysctl_overcommit_huge_pages[HUGE_MAX_HSTATE];
> 
> #else
> struct hstate {};
> +#define alloc_bm_huge_page(h) NULL
> #define hstate_file(f) NULL
> #define hstate_vma(v) NULL
> #define hstate_inode(i) NULL
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 5273f6c..efb5805 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -27,6 +27,7 @@ unsigned long max_huge_pages[HUGE_MAX_HSTATE];
> unsigned long sysctl_overcommit_huge_pages[HUGE_MAX_HSTATE];
> static gfp_t htlb_alloc_mask = GFP_HIGHUSER;
> unsigned long hugepages_treat_as_movable;
> +struct list_head huge_boot_pages;
> 
> static int max_hstate = 0;
> 
> @@ -533,14 +534,8 @@ static struct page *alloc_huge_page(struct 
> vm_area_struct *vma,
> 	return page;
> }
> 
> -static __initdata LIST_HEAD(huge_boot_pages);
> -
> -struct huge_bm_page {
> -	struct list_head list;
> -	struct hstate *hstate;
> -};
> -
> -static int __init alloc_bm_huge_page(struct hstate *h)
> +/* Can be overriden by architectures */
> +__attribute__((weak)) int alloc_bm_huge_page(struct hstate *h)
> {
> 	struct huge_bm_page *m;
> 	int nr_nodes = nodes_weight(node_online_map);
> @@ -583,6 +578,8 @@ static void __init hugetlb_init_hstate(struct hstate *h)
> 	unsigned long i;
> 
> 	/* Don't reinitialize lists if they have been already init'ed */
> +	if (!huge_boot_pages.next)
> +		INIT_LIST_HEAD(&huge_boot_pages);
> 	if (!h->hugepage_freelists[0].next) {
> 		for (i = 0; i < MAX_NUMNODES; ++i)
> 			INIT_LIST_HEAD(&h->hugepage_freelists[i]);
> @@ -664,7 +661,7 @@ void __init huge_add_hstate(unsigned order)
> 		return;
> 	}
> 	BUG_ON(max_hstate >= HUGE_MAX_HSTATE);
> -	BUG_ON(order < HPAGE_SHIFT - PAGE_SHIFT);
> +/*	BUG_ON(order < HPAGE_SHIFT - PAGE_SHIFT);*/
> 	h = &hstates[max_hstate++];
> 	h->order = order;
> 	h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
> 
> 
>