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mm, thp: drop do_huge_pmd_wp_zero_page_fallback()

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I've realized that there's no need for do_huge_pmd_wp_zero_page_fallback().
We can just split zero page with split_huge_page_pmd() and return
VM_FAULT_FALLBACK.  handle_pte_fault() will handle write-protection
fault for us.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Kirill A. Shutemov 2014-04-03 14:48:17 -07:00 • committed by Linus Torvalds
parent 3bb9779469
commit e9b71ca91a
1 changed files with 2 additions and 77 deletions
Download patch file Download diff file Expand all files Collapse all files

79
mm/huge_memory.c
View file

@ -941,81 +941,6 @@ unlock:
spin_unlock(ptl); spin_unlock(ptl);
} }
static int do_huge_pmd_wp_zero_page_fallback(struct mm_struct *mm,
struct vm_area_struct *vma, unsigned long address,
pmd_t *pmd, pmd_t orig_pmd, unsigned long haddr)
{
spinlock_t *ptl;
pgtable_t pgtable;
pmd_t _pmd;
struct page *page;
int i, ret = 0;
unsigned long mmun_start; /* For mmu_notifiers */
unsigned long mmun_end; /* For mmu_notifiers */
page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
if (!page) {
ret |= VM_FAULT_OOM;
goto out;
}
if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL)) {
put_page(page);
ret |= VM_FAULT_OOM;
goto out;
}
clear_user_highpage(page, address);
__SetPageUptodate(page);
mmun_start = haddr;
mmun_end = haddr + HPAGE_PMD_SIZE;
mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
ptl = pmd_lock(mm, pmd);
if (unlikely(!pmd_same(*pmd, orig_pmd)))
goto out_free_page;
pmdp_clear_flush(vma, haddr, pmd);
/* leave pmd empty until pte is filled */
pgtable = pgtable_trans_huge_withdraw(mm, pmd);
pmd_populate(mm, &_pmd, pgtable);
for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) {
pte_t *pte, entry;
if (haddr == (address & PAGE_MASK)) {
entry = mk_pte(page, vma->vm_page_prot);
entry = maybe_mkwrite(pte_mkdirty(entry), vma);
page_add_new_anon_rmap(page, vma, haddr);
} else {
entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot);
entry = pte_mkspecial(entry);
}
pte = pte_offset_map(&_pmd, haddr);
VM_BUG_ON(!pte_none(*pte));
set_pte_at(mm, haddr, pte, entry);
pte_unmap(pte);
}
smp_wmb(); /* make pte visible before pmd */
pmd_populate(mm, pmd, pgtable);
spin_unlock(ptl);
put_huge_zero_page();
inc_mm_counter(mm, MM_ANONPAGES);
mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
ret |= VM_FAULT_WRITE;
out:
return ret;
out_free_page:
spin_unlock(ptl);
mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
mem_cgroup_uncharge_page(page);
put_page(page);
goto out;
}
static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm, static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm,
struct vm_area_struct *vma, struct vm_area_struct *vma,
unsigned long address, unsigned long address,
@ -1161,8 +1086,8 @@ alloc:
if (unlikely(!new_page)) { if (unlikely(!new_page)) {
if (!page) { if (!page) {
ret = do_huge_pmd_wp_zero_page_fallback(mm, vma, split_huge_page_pmd(vma, address, pmd);
address, pmd, orig_pmd, haddr); ret |= VM_FAULT_FALLBACK;
} else { } else {
ret = do_huge_pmd_wp_page_fallback(mm, vma, address, ret = do_huge_pmd_wp_page_fallback(mm, vma, address,
pmd, orig_pmd, page, haddr); pmd, orig_pmd, page, haddr);