[PATCH] ppc64: add useful warning message in hugepage code

From: David Gibson <david@gibson.dropbear.id.au>

This patch adds a debugging message to the ppc64 hugepage code when we
attempt to open the "low" (32-bit) hugepage window on PPC64, but can't
because a (non-hugepage) mapping already exists in the region.

diff --git a/arch/ppc64/mm/hugetlbpage.c b/arch/ppc64/mm/hugetlbpage.c
index 3a50af4962dd27c3cf1cbe3e3ede72b7700ac448..ed3d4ce2e5905ff794c42d4987ad07e33b31a5e1 100644 (file)
--- a/arch/ppc64/mm/hugetlbpage.c
+++ b/arch/ppc64/mm/hugetlbpage.c
@@ -253,8 +253,11 @@ static int open_32bit_htlbpage_range(struct mm_struct *mm)
        /* Check no VMAs are in the region */
        vma = find_vma(mm, TASK_HPAGE_BASE_32);
 
-       if (vma && (vma->vm_start < TASK_HPAGE_END_32))
+       if (vma && (vma->vm_start < TASK_HPAGE_END_32)) {
+               printk(KERN_DEBUG "Low HTLB region busy: PID=%d  vma @ %lx-%lx\n",
+                      current->pid, vma->vm_start, vma->vm_end);
                return -EBUSY;
+       }
 
        /* Clean up any leftover PTE pages in the region */
        spin_lock(&mm->page_table_lock);