thp: consolidate code between handle_mm_fault() and do_huge_pmd_anonymous_page()
do_huge_pmd_anonymous_page() has copy-pasted piece of handle_mm_fault()
to handle fallback path.
Let's consolidate code back by introducing VM_FAULT_FALLBACK return
code.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Hillf Danton <dhillf@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Hugh Dickins <hughd@google.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 6551dd0..243f4cc 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -783,10 +783,9 @@
{
struct page *page;
unsigned long haddr = address & HPAGE_PMD_MASK;
- pte_t *pte;
if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end)
- goto out;
+ return VM_FAULT_FALLBACK;
if (unlikely(anon_vma_prepare(vma)))
return VM_FAULT_OOM;
if (unlikely(khugepaged_enter(vma)))
@@ -803,7 +802,7 @@
if (unlikely(!zero_page)) {
pte_free(mm, pgtable);
count_vm_event(THP_FAULT_FALLBACK);
- goto out;
+ return VM_FAULT_FALLBACK;
}
spin_lock(&mm->page_table_lock);
set = set_huge_zero_page(pgtable, mm, vma, haddr, pmd,
@@ -819,40 +818,20 @@
vma, haddr, numa_node_id(), 0);
if (unlikely(!page)) {
count_vm_event(THP_FAULT_FALLBACK);
- goto out;
+ return VM_FAULT_FALLBACK;
}
count_vm_event(THP_FAULT_ALLOC);
if (unlikely(mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))) {
put_page(page);
- goto out;
+ return VM_FAULT_FALLBACK;
}
if (unlikely(__do_huge_pmd_anonymous_page(mm, vma, haddr, pmd, page))) {
mem_cgroup_uncharge_page(page);
put_page(page);
- goto out;
+ return VM_FAULT_FALLBACK;
}
return 0;
-out:
- /*
- * Use __pte_alloc instead of pte_alloc_map, because we can't
- * run pte_offset_map on the pmd, if an huge pmd could
- * materialize from under us from a different thread.
- */
- if (unlikely(pmd_none(*pmd)) &&
- unlikely(__pte_alloc(mm, vma, pmd, address)))
- return VM_FAULT_OOM;
- /* if an huge pmd materialized from under us just retry later */
- if (unlikely(pmd_trans_huge(*pmd)))
- return 0;
- /*
- * A regular pmd is established and it can't morph into a huge pmd
- * from under us anymore at this point because we hold the mmap_sem
- * read mode and khugepaged takes it in write mode. So now it's
- * safe to run pte_offset_map().
- */
- pte = pte_offset_map(pmd, address);
- return handle_pte_fault(mm, vma, address, pte, pmd, flags);
}
int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
diff --git a/mm/memory.c b/mm/memory.c
index 5ec6f19..ca00039 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3695,7 +3695,7 @@
* but allow concurrent faults), and pte mapped but not yet locked.
* We return with mmap_sem still held, but pte unmapped and unlocked.
*/
-int handle_pte_fault(struct mm_struct *mm,
+static int handle_pte_fault(struct mm_struct *mm,
struct vm_area_struct *vma, unsigned long address,
pte_t *pte, pmd_t *pmd, unsigned int flags)
{
@@ -3774,9 +3774,12 @@
if (!pmd)
return VM_FAULT_OOM;
if (pmd_none(*pmd) && transparent_hugepage_enabled(vma)) {
+ int ret = VM_FAULT_FALLBACK;
if (!vma->vm_ops)
- return do_huge_pmd_anonymous_page(mm, vma, address,
- pmd, flags);
+ ret = do_huge_pmd_anonymous_page(mm, vma, address,
+ pmd, flags);
+ if (!(ret & VM_FAULT_FALLBACK))
+ return ret;
} else {
pmd_t orig_pmd = *pmd;
int ret;