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

[Jon Tollefson]

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.


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



Signed-off-by: Jon Tollefson <[EMAIL PROTECTED]>
---

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);




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