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From: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
To: "'Adam Litke'" <agl@us.ibm.com>, <linux-kernel@vger.kernel.org>
Cc: <ak@suse.de>, <christoph@lameter.com>, <dwg@au1.ibm.com>
Subject: RE: [RFC] Demand faulting for large pages
Date: Fri, 5 Aug 2005 14:33:41 -0700
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Adam Litke wrote on Friday, August 05, 2005 8:22 AM
> +int hugetlb_pte_fault(struct mm_struct *mm, struct vm_area_struct *vma,
> +			unsigned long address, int write_access)
> +{
> +	int ret = VM_FAULT_MINOR;
> +	unsigned long idx;
> +	pte_t *pte;
> +	struct page *page;
> +	struct address_space *mapping;
> +
> +	WARN_ON(!is_vm_hugetlb_page(vma));

Spurious WARN_ON.  Calls to hugetlb_pte_fault() is conditioned upon 
if (is_vm_hugetlb_page(vma))



> +int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
> +			unsigned long address, int write_access)
> +{
> +   ....
> +	if (pte_none(*ptep))
> +		rc = hugetlb_pte_fault(mm, vma, address, write_access);
> +}

Broken here.  Return VM_FAULT_SIGBUS when *pte is present??  Why
can't you move all the logic into hugetlb_pte_fault and simply call
it directly from handle_mm_fault?