static struct hlist_head *mm_slots_hash __read_mostly;
static struct kmem_cache *mm_slot_cache __read_mostly;
+#ifdef CONFIG_FB
+extern const struct file_operations fb_fops;
+
+#define is_fb_vma(vma) \
+ (vma->vm_file && vma->vm_file->f_op == &fb_fops)
+#else
+#define is_fb_vma(vma) 0
+#endif
+
+static void split_fb_pmd(struct vm_area_struct *vma, pmd_t *pmd);
+
/**
* struct mm_slot - hash lookup from mm to mm_slot
* @hash: hash collision list
spin_lock(&tlb->mm->page_table_lock);
if (likely(pmd_trans_huge(*pmd))) {
+ if (is_fb_vma(vma)) {
+ split_fb_pmd(vma, pmd);
+ return 0;
+ }
+
if (unlikely(pmd_trans_splitting(*pmd))) {
spin_unlock(&tlb->mm->page_table_lock);
wait_split_huge_page(vma->anon_vma,
return ret;
}
+/* callers must hold mmap_sem (madvise() does) */
+static int collapse_fb_pmd(struct mm_struct *mm, pmd_t *pmd,
+ unsigned long addr, struct vm_area_struct *vma)
+{
+ unsigned long _addr;
+ struct page *page;
+ pgtable_t pgtable;
+ pte_t *pte, *_pte;
+ pmd_t _pmd;
+ u32 pa;
+
+ pte = pte_offset_map(pmd, addr);
+ page = pte_page(*pte);
+ pa = __pfn_to_phys(page_to_pfn(page));
+ _pmd = pmdp_clear_flush_notify(vma, addr, pmd);
+
+ if ((addr | pa) & ~HPAGE_PMD_MASK) {
+ printk(KERN_ERR "collapse_fb: bad alignment: %08lx->%08x\n",
+ addr, pa);
+ pte_unmap(pte);
+ return -EINVAL;
+ }
+
+ for (_pte = pte, _addr = addr; _pte < pte + HPAGE_PMD_NR; _pte++) {
+ pte_t pteval = *_pte;
+ struct page *src_page;
+
+ if (!pte_none(pteval)) {
+ src_page = pte_page(pteval);
+
+ pte_clear(vma->vm_mm, _addr, _pte);
+ if (pte_present(pteval))
+ page_remove_rmap(src_page);
+ }
+
+ _addr += PAGE_SIZE;
+ }
+
+ pte_unmap(pte);
+ pgtable = pmd_pgtable(_pmd);
+ VM_BUG_ON(page_count(pgtable) != 1);
+ VM_BUG_ON(page_mapcount(pgtable) != 0);
+
+ _pmd = mk_pmd(page, vma->vm_page_prot);
+ _pmd = maybe_pmd_mkwrite(pmd_mkdirty(_pmd), vma);
+ _pmd = pmd_mkhuge(_pmd);
+
+ smp_wmb();
+
+ spin_lock(&mm->page_table_lock);
+ BUG_ON(!pmd_none(*pmd));
+ set_pmd_at(mm, addr, pmd, _pmd);
+ update_mmu_cache(vma, addr, pmd);
+ prepare_pmd_huge_pte(pgtable, mm);
+ spin_unlock(&mm->page_table_lock);
+
+ return 0;
+}
+
+static int try_collapse_fb(struct vm_area_struct *vma)
+{
+ struct mm_struct *mm = vma->vm_mm;
+ unsigned long hstart, hend, addr;
+ int ret = 0;
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd;
+
+ hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
+ hend = vma->vm_end & HPAGE_PMD_MASK;
+ if (hstart >= hend)
+ return -EINVAL;
+
+ for (addr = hstart; addr < hend; addr += HPAGE_PMD_SIZE) {
+ pgd = pgd_offset(mm, addr);
+ if (!pgd_present(*pgd))
+ return -EINVAL;
+
+ pud = pud_offset(pgd, addr);
+ if (!pud_present(*pud))
+ return -EINVAL;
+
+ pmd = pmd_offset(pud, addr);
+ if (!pmd_present(*pmd))
+ return -EINVAL;
+ if (pmd_trans_huge(*pmd))
+ continue;
+
+ ret = collapse_fb_pmd(mm, pmd, addr, vma);
+ if (ret)
+ break;
+ }
+
+ return ret;
+}
+
+/* undo collapse_fb_pmd(), restore pages so that mm subsys can release them
+ * page_table_lock() should be held */
+static void split_fb_pmd(struct vm_area_struct *vma, pmd_t *pmd)
+{
+ struct mm_struct *mm = vma->vm_mm;
+ unsigned long addr, haddr, pfn;
+ struct page *page;
+ pgtable_t pgtable;
+ pmd_t _pmd;
+ int i;
+
+ page = pmd_page(*pmd);
+ pgtable = get_pmd_huge_pte(mm);
+ pfn = page_to_pfn(page);
+ addr = pfn << PAGE_SHIFT;
+
+ pmd_populate(mm, &_pmd, pgtable);
+
+ for (i = 0, haddr = addr; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) {
+ pte_t *pte, entry;
+ BUG_ON(PageCompound(page + i));
+ entry = mk_pte(page + i, vma->vm_page_prot);
+ entry = maybe_mkwrite(pte_mkdirty(entry), vma);
+ if (!pmd_young(*pmd))
+ entry = pte_mkold(entry);
+ atomic_set(&page[i]._mapcount, 0); // hack?
+ pte = pte_offset_map(&_pmd, haddr);
+ BUG_ON(!pte_none(*pte));
+ set_pte_at(mm, haddr, pte, entry);
+ pte_unmap(pte);
+ }
+
+ set_pmd_at(mm, addr, pmd, pmd_mknotpresent(*pmd));
+ flush_tlb_range(vma, addr, addr + HPAGE_PMD_SIZE);
+ pmd_populate(mm, pmd, pgtable);
+}
+
+#ifndef __arm__
+#error arm only..
+#endif
+static u32 pmd_to_va(struct mm_struct *mm, pmd_t *pmd)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd0;
+ u32 ret;
+
+ pgd = pgd_offset(mm, 0);
+ pud = pud_offset(pgd, 0);
+ pmd0 = pmd_offset(pud, 0);
+
+ ret = (pmd - pmd0) << SECTION_SHIFT;
+ return ret;
+}
+
#define VM_NO_THP (VM_SPECIAL|VM_INSERTPAGE|VM_MIXEDMAP|VM_SAO| \
VM_HUGETLB|VM_SHARED|VM_MAYSHARE)
{
switch (advice) {
case MADV_HUGEPAGE:
+ if (is_fb_vma(vma))
+ return try_collapse_fb(vma);
+
/*
* Be somewhat over-protective like KSM for now!
*/
void __split_huge_page_pmd(struct mm_struct *mm, pmd_t *pmd)
{
+ struct vm_area_struct *vma;
struct page *page;
spin_lock(&mm->page_table_lock);
spin_unlock(&mm->page_table_lock);
return;
}
+ vma = find_vma(mm, pmd_to_va(mm, pmd));
+ if (vma && is_fb_vma(vma)) {
+ split_fb_pmd(vma, pmd);
+ spin_unlock(&mm->page_table_lock);
+ return;
+ }
page = pmd_page(*pmd);
VM_BUG_ON(!page_count(page));
get_page(page);
git.openpandora.org / pandora-kernel.git / blobdiff