hugetlb: fix overcommit locking

[karo-tx-linux.git] / mm / hugetlb.c

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index e0fda156f0212a1a44c0d27f13dc8ffd1cda1064..cb1b3a7ecdfcc5030ef0547f3544d697f3b6a30e 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -24,14 +24,15 @@
 const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
 static unsigned long nr_huge_pages, free_huge_pages, resv_huge_pages;
 static unsigned long surplus_huge_pages;
+static unsigned long nr_overcommit_huge_pages;
 unsigned long max_huge_pages;
+unsigned long sysctl_overcommit_huge_pages;
 static struct list_head hugepage_freelists[MAX_NUMNODES];
 static unsigned int nr_huge_pages_node[MAX_NUMNODES];
 static unsigned int free_huge_pages_node[MAX_NUMNODES];
 static unsigned int surplus_huge_pages_node[MAX_NUMNODES];
 static gfp_t htlb_alloc_mask = GFP_HIGHUSER;
 unsigned long hugepages_treat_as_movable;
-unsigned long nr_overcommit_huge_pages;
 static int hugetlb_next_nid;
 
 /*
@@ -605,6 +606,17 @@ int hugetlb_treat_movable_handler(struct ctl_table *table, int write,
        return 0;
 }
 
+int hugetlb_overcommit_handler(struct ctl_table *table, int write,
+                       struct file *file, void __user *buffer,
+                       size_t *length, loff_t *ppos)
+{
+       proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
+       spin_lock(&hugetlb_lock);
+       nr_overcommit_huge_pages = sysctl_overcommit_huge_pages;
+       spin_unlock(&hugetlb_lock);
+       return 0;
+}
+
 #endif /* CONFIG_SYSCTL */
 
 int hugetlb_report_meminfo(char *buf)
@@ -699,6 +711,11 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
                dst_pte = huge_pte_alloc(dst, addr);
                if (!dst_pte)
                        goto nomem;
+
+               /* If the pagetables are shared don't copy or take references */
+               if (dst_pte == src_pte)
+                       continue;
+
                spin_lock(&dst->page_table_lock);
                spin_lock(&src->page_table_lock);
                if (!pte_none(*src_pte)) {
@@ -808,6 +825,7 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
 
        spin_unlock(&mm->page_table_lock);
        copy_huge_page(new_page, old_page, address, vma);
+       __SetPageUptodate(new_page);
        spin_lock(&mm->page_table_lock);
 
        ptep = huge_pte_offset(mm, address & HPAGE_MASK);
@@ -853,6 +871,7 @@ retry:
                        goto out;
                }
                clear_huge_page(page, address);
+               __SetPageUptodate(page);
 
                if (vma->vm_flags & VM_SHARED) {
                        int err;