/* during fragmentation poll the hugepage allocator once every minute */
static unsigned int khugepaged_alloc_sleep_millisecs __read_mostly = 60000;
static struct task_struct *khugepaged_thread __read_mostly;
+static unsigned long huge_zero_pfn __read_mostly;
static DEFINE_MUTEX(khugepaged_mutex);
static DEFINE_SPINLOCK(khugepaged_mm_lock);
static DECLARE_WAIT_QUEUE_HEAD(khugepaged_wait);
return err;
}
+static int __init init_huge_zero_page(void)
+{
+ struct page *hpage;
+
+ hpage = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE,
+ HPAGE_PMD_ORDER);
+ if (!hpage)
+ return -ENOMEM;
+
+ huge_zero_pfn = page_to_pfn(hpage);
+ return 0;
+}
+
+static inline bool is_huge_zero_pfn(unsigned long pfn)
+{
+ return pfn == huge_zero_pfn;
+}
+
+static inline bool is_huge_zero_pmd(pmd_t pmd)
+{
+ return is_huge_zero_pfn(pmd_pfn(pmd));
+}
+
#ifdef CONFIG_SYSFS
static ssize_t double_flag_show(struct kobject *kobj,
if (err)
return err;
+ err = init_huge_zero_page();
+ if (err)
+ goto out;
+
err = khugepaged_slab_init();
if (err)
goto out;
return 0;
out:
+ if (huge_zero_pfn)
+ __free_page(pfn_to_page(huge_zero_pfn));
hugepage_exit_sysfs(hugepage_kobj);
return err;
}
}
#endif
+static void set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm,
+ struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd)
+{
+ pmd_t entry;
+ entry = pfn_pmd(huge_zero_pfn, vma->vm_page_prot);
+ entry = pmd_wrprotect(entry);
+ entry = pmd_mkhuge(entry);
+ set_pmd_at(mm, haddr, pmd, entry);
+ pgtable_trans_huge_deposit(mm, pgtable);
+ mm->nr_ptes++;
+}
+
int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, pmd_t *pmd,
unsigned int flags)
pte_free(dst_mm, pgtable);
goto out_unlock;
}
+ /*
+ * mm->page_table_lock is enough to be sure that huge zero pmd is not
+ * under splitting since we don't split the page itself, only pmd to
+ * a page table.
+ */
+ if (is_huge_zero_pmd(pmd)) {
+ set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd);
+ ret = 0;
+ goto out_unlock;
+ }
if (unlikely(pmd_trans_splitting(pmd))) {
/* split huge page running from under us */
spin_unlock(&src_mm->page_table_lock);
return ret;
}
+void huge_pmd_set_accessed(struct mm_struct *mm,
+ struct vm_area_struct *vma,
+ unsigned long address,
+ pmd_t *pmd, pmd_t orig_pmd,
+ int dirty)
+{
+ pmd_t entry;
+ unsigned long haddr;
+
+ spin_lock(&mm->page_table_lock);
+ if (unlikely(!pmd_same(*pmd, orig_pmd)))
+ goto unlock;
+
+ entry = pmd_mkyoung(orig_pmd);
+ haddr = address & HPAGE_PMD_MASK;
+ if (pmdp_set_access_flags(vma, haddr, pmd, entry, dirty))
+ update_mmu_cache_pmd(vma, address, pmd);
+
+unlock:
+ spin_unlock(&mm->page_table_lock);
+}
+
+static int do_huge_pmd_wp_zero_page_fallback(struct mm_struct *mm,
+ struct vm_area_struct *vma, unsigned long address,
+ pmd_t *pmd, unsigned long haddr)
+{
+ 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);
+
+ spin_lock(&mm->page_table_lock);
+ pmdp_clear_flush(vma, haddr, pmd);
+ /* leave pmd empty until pte is filled */
+
+ pgtable = pgtable_trans_huge_withdraw(mm);
+ 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(&mm->page_table_lock);
+ inc_mm_counter(mm, MM_ANONPAGES);
+
+ mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
+
+ ret |= VM_FAULT_WRITE;
+out:
+ return ret;
+}
+
static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm,
struct vm_area_struct *vma,
unsigned long address,
unsigned long address, pmd_t *pmd, pmd_t orig_pmd)
{
int ret = 0;
- struct page *page, *new_page;
+ struct page *page = NULL, *new_page;
unsigned long haddr;
unsigned long mmun_start; /* For mmu_notifiers */
unsigned long mmun_end; /* For mmu_notifiers */
VM_BUG_ON(!vma->anon_vma);
+ haddr = address & HPAGE_PMD_MASK;
+ if (is_huge_zero_pmd(orig_pmd))
+ goto alloc;
spin_lock(&mm->page_table_lock);
if (unlikely(!pmd_same(*pmd, orig_pmd)))
goto out_unlock;
page = pmd_page(orig_pmd);
VM_BUG_ON(!PageCompound(page) || !PageHead(page));
- haddr = address & HPAGE_PMD_MASK;
if (page_mapcount(page) == 1) {
pmd_t entry;
entry = pmd_mkyoung(orig_pmd);
}
get_page(page);
spin_unlock(&mm->page_table_lock);
-
+alloc:
if (transparent_hugepage_enabled(vma) &&
!transparent_hugepage_debug_cow())
new_page = alloc_hugepage_vma(transparent_hugepage_defrag(vma),
if (unlikely(!new_page)) {
count_vm_event(THP_FAULT_FALLBACK);
- ret = do_huge_pmd_wp_page_fallback(mm, vma, address,
- pmd, orig_pmd, page, haddr);
- if (ret & VM_FAULT_OOM)
- split_huge_page(page);
- put_page(page);
+ if (is_huge_zero_pmd(orig_pmd)) {
+ ret = do_huge_pmd_wp_zero_page_fallback(mm, vma,
+ address, pmd, haddr);
+ } else {
+ ret = do_huge_pmd_wp_page_fallback(mm, vma, address,
+ pmd, orig_pmd, page, haddr);
+ if (ret & VM_FAULT_OOM)
+ split_huge_page(page);
+ put_page(page);
+ }
goto out;
}
count_vm_event(THP_FAULT_ALLOC);
if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) {
put_page(new_page);
- split_huge_page(page);
- put_page(page);
+ if (page) {
+ split_huge_page(page);
+ put_page(page);
+ }
ret |= VM_FAULT_OOM;
goto out;
}
- copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR);
+ if (is_huge_zero_pmd(orig_pmd))
+ clear_huge_page(new_page, haddr, HPAGE_PMD_NR);
+ else
+ copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR);
__SetPageUptodate(new_page);
mmun_start = haddr;
mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
spin_lock(&mm->page_table_lock);
- put_page(page);
+ if (page)
+ put_page(page);
if (unlikely(!pmd_same(*pmd, orig_pmd))) {
spin_unlock(&mm->page_table_lock);
mem_cgroup_uncharge_page(new_page);
goto out_mn;
} else {
pmd_t entry;
- VM_BUG_ON(!PageHead(page));
entry = mk_huge_pmd(new_page, vma);
pmdp_clear_flush(vma, haddr, pmd);
page_add_new_anon_rmap(new_page, vma, haddr);
set_pmd_at(mm, haddr, pmd, entry);
update_mmu_cache_pmd(vma, address, pmd);
- page_remove_rmap(page);
- put_page(page);
+ if (is_huge_zero_pmd(orig_pmd))
+ add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR);
+ else {
+ VM_BUG_ON(!PageHead(page));
+ page_remove_rmap(page);
+ put_page(page);
+ }
ret |= VM_FAULT_WRITE;
}
spin_unlock(&mm->page_table_lock);
pmd_t orig_pmd;
pgtable = pgtable_trans_huge_withdraw(tlb->mm);
orig_pmd = pmdp_get_and_clear(tlb->mm, addr, pmd);
- page = pmd_page(orig_pmd);
tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
- page_remove_rmap(page);
- VM_BUG_ON(page_mapcount(page) < 0);
- add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);
- VM_BUG_ON(!PageHead(page));
- tlb->mm->nr_ptes--;
- spin_unlock(&tlb->mm->page_table_lock);
- tlb_remove_page(tlb, page);
+ if (is_huge_zero_pmd(orig_pmd)) {
+ tlb->mm->nr_ptes--;
+ spin_unlock(&tlb->mm->page_table_lock);
+ } else {
+ page = pmd_page(orig_pmd);
+ page_remove_rmap(page);
+ VM_BUG_ON(page_mapcount(page) < 0);
+ add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);
+ VM_BUG_ON(!PageHead(page));
+ tlb->mm->nr_ptes--;
+ spin_unlock(&tlb->mm->page_table_lock);
+ tlb_remove_page(tlb, page);
+ }
pte_free(tlb->mm, pgtable);
ret = 1;
}
projects / can-eth-gw-linux.git / blobdiff